Medical Licensing (MD/DO) · Independent exam preparation
ABIM Internal Medicine Certification: Clinical Decisions Guide Study Guide
Practise diagnostic testing, treatment selection, and urgent recognition across adult internal medicine with 60 focused concepts, clinical questions, and recall cards.
By CertMedbry · Updated 19 October 2026
Choose informative diagnostic tests, distinguish similar presentations, and recognise findings that change treatment urgently. This selective guide develops 60 clinical decisions across all 18 categories of ABIM’s January 2026 Internal Medicine Certification Examination blueprint. The official outline defines the full examination scope, including many conditions beyond these selected lessons. Use the questions for independent practice and the cards for active recall.
Try 20 free practice questionsWhat is the exam format?
Check the question types, timing and outline before planning your revision.
Which examination and certification level does this guide address?
The ABIM Internal Medicine Certification Examination evaluates the knowledge, diagnostic reasoning, and clinical judgment expected of a certified internist. Passing the examination is one certification requirement alongside education, postgraduate training, clinical competence, and licensure. It does not itself grant medical licensure in any jurisdiction.
Internal Medicine & Subspecialty Policies · Internal Medicine Blueprint: Certification Examination (CERT), January 2026
How many questions are administered, and which questions count?
The January 2026 CERT blueprint specifies up to 240 questions, with approximately 35 new questions that do not count toward the score. The remaining questions contribute to scoring; the wording does not establish a universal fixed scored-question count. ABIM’s certification preparation page describes four sessions containing up to 60 questions each.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026 · Register, Prepare For and Take Your Internal Medicine Certification Exam
What question styles and clinical media should candidates expect?
The examination uses single-best-answer multiple-choice questions. Most describe patient scenarios involving diagnosis, test selection or interpretation, treatment, risk or prognosis, epidemiology, or applicable pathophysiology. Clinical information may include photographs, radiographs, electrocardiograms, heart or lung sound recordings, and other media. This guide’s four-option text questions are independent learning drills.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
How long is the examination, and how are breaks allocated?
ABIM publishes an overall examination appointment of approximately 10 hours. There are four examination sessions of up to two hours each, with up to 60 questions per session. The eight hours of maximum session time are distinct from the overall appointment, which also accommodates instructions, the optional tutorial, breaks, and other scheduled activities. Candidates have 100 total break minutes shared between three breaks; this is not 100 minutes per break. Confirm the current schedule, delivery arrangements, and any approved accommodations in ABIM’s examination-day instructions because arrangements can change.
Register, Prepare For and Take Your Internal Medicine Certification Exam
Which blueprint applies, and how should its percentages guide study?
This guide follows the CERT blueprint printed January 2026 and linked from ABIM’s certification preparation page. January 2026 is its revision date; a separate effective date is not stated. Category percentages describe a typical examination and are approximate. Cardiovascular Disease accounts for 14%; Endocrinology, Gastroenterology, Infectious Disease, Pulmonary Disease, and Rheumatology and Orthopedics each account for 9%. Hypertension contributes 5% across its listed specialties, while obstructive airway disease and evaluation of common pulmonary symptoms each contribute 2.5%. The official outline provides all category and subsection details.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026 · Register, Prepare For and Take Your Internal Medicine Certification Exam
How do initial certification, MOC, and the LKA differ for preparation?
The initial Internal Medicine Certification Examination uses the CERT blueprint addressed here. Maintenance of Certification and the Longitudinal Knowledge Assessment concern continuing certification and should be prepared for using their own current instructions and assessment specifications. A shared specialty name does not make their logistics interchangeable.
Register, Prepare For and Take Your Internal Medicine Certification Exam · Internal Medicine & Subspecialty Policies
Does completing this guide demonstrate examination readiness?
The 60 concepts cover every official category selectively. The 20 questions and 20 cards emphasise major specialties while extending breadth across the combined sets; these small sets cannot reproduce every blueprint percentage. Performance identifies learning needs and does not predict passing. Reconcile your study plan with the complete official outline, including cross-cutting prevention, ethics, patient safety, critical care, and health equity.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
This guide addresses physicians pursuing initial ABIM Internal Medicine Certification. Specialty board certification is separate from medical licensure. Maintenance of Certification examinations and the Longitudinal Knowledge Assessment follow different assessment pathways. These independently authored learning materials are not ABIM examination items.
Outline used: January 2026 Internal Medicine Blueprint, Certification Examination (CERT), linked from ABIM's current certification page and opened on 2026-10-10. January 2026 is the printed revision date; a separate effective date is not stated. The workbook label names the awarding body and is mapped to its initial Internal Medicine Certification Examination while preserving the assigned slug.
60 key concepts: understand, apply and avoid the traps
Work through the questions by exam domain. Explain the answer in your own words, try the example, then check the common pitfall.
Allergy and Immunology2%
1.When does anaphylaxis require immediate intramuscular epinephrine?
Anaphylaxis is an acute systemic hypersensitivity reaction that can compromise the airway, breathing, or circulation. Skin findings help recognition but may be absent, especially when hypotension or bronchospasm follows a known or highly probable allergen. Intramuscular epinephrine in the anterolateral thigh is first-line treatment because it counters vasodilation, tissue swelling, and bronchoconstriction. Airway support, oxygen, and intravenous fluids complement treatment; antihistamines do not reverse the life-threatening physiology.
Apply it
Minutes after an antibiotic infusion, a patient develops wheezing, hoarseness, and hypotension without a rash. Stop the exposure, give intramuscular epinephrine immediately, and mobilise airway and circulatory support while reassessing the response.
Common pitfall: Waiting for urticaria or substituting an antihistamine delays effective treatment. Intravenous epinephrine boluses carry greater risk and are not the routine initial route.
Cardiovascular Disease14%
2.How does ejection fraction classify heart failure?
Heart failure with reduced ejection fraction has an LVEF of 40% or less; mildly reduced EF is 41%–49%, and preserved EF is at least 50%. For the latter two groups, evidence of increased filling pressures supports the diagnosis because EF alone cannot establish heart failure. Symptoms, congestion, natriuretic peptides, and imaging must fit together. A normal EF describes a proportion of ventricular emptying, not normal diastolic function or normal filling pressure.
Apply it
A patient has exertional dyspnoea, oedema, LVEF 58%, elevated natriuretic peptides, and echocardiographic evidence of increased filling pressures. The preserved EF does not exclude heart failure; the additional findings support a preserved-EF syndrome.
Common pitfall: Calling every breathless patient with a normal EF HFpEF ignores competing pulmonary, haematologic, and other causes. Preserved EF requires supporting clinical and haemodynamic evidence.
New ACC, AHA, HFSA Guideline Updates Recommendations For Managing HF
3.Which medication classes form foundational HFrEF therapy?
Foundational HFrEF treatment combines renin–angiotensin system inhibition, preferably an angiotensin receptor–neprilysin inhibitor when appropriate, a beta blocker with demonstrated HFrEF outcome benefit, a mineralocorticoid receptor antagonist, and an SGLT2 inhibitor. The qualifying beta blockers are carvedilol, bisoprolol, and sustained-release metoprolol succinate. Their evidence should not be generalised to every beta blocker or to immediate-release metoprolol tartrate. Loop diuretics relieve congestion but do not replace these foundational therapies. Selection and titration depend on stability, kidney function, potassium, contraindications, and tolerance. See the [official heart-failure guideline slide set](https://www.heart.org/-/media/PHD-Files-2/Science-News/2/2022/2022-Heart-Failure-Guideline-Slide-Set.pdf), including the beta-blocker recommendations.
Apply it
A stable patient with LVEF 30% takes sacubitril–valsartan, carvedilol, spironolactone, and furosemide. With acceptable kidney function and no contraindication, adding an SGLT2 inhibitor addresses a missing foundational class despite the absence of diabetes.
Common pitfall: A comfortable, euvolaemic patient may still lack outcome-improving therapy. Neither increasing a loop diuretic nor substituting an unproven beta-blocker formulation completes the foundational regimen.
New ACC, AHA, HFSA Guideline Updates Recommendations For Managing HF
4.Why must ACE inhibition be separated from sacubitril–valsartan?
Sacubitril inhibits neprilysin, which degrades vasoactive peptides including bradykinin; ACE inhibition also reduces bradykinin breakdown. Combining the two increases angioedema risk. Stop the ACE inhibitor and allow at least 36 hours after its last dose before starting sacubitril–valsartan. The combination already contains an ARB, so another ARB is unnecessary. A history of angioedema contraindicates ARNI treatment. Monitor blood pressure, potassium, and renal function. These safety rules are specified in the [official heart-failure guideline slide set](https://www.heart.org/-/media/PHD-Files-2/Science-News/2/2022/2022-Heart-Failure-Guideline-Slide-Set.pdf), in the renin–angiotensin system inhibition recommendations.
Apply it
A patient with symptomatic HFrEF took lisinopril this morning and is being considered for sacubitril–valsartan. Plan the change after a washout of at least 36 hours, rather than administering both agents during the transition.
Common pitfall: Treating sacubitril–valsartan as an add-on to an ACE inhibitor creates a dangerous interaction. The required washout is a safety interval, not a titration preference.
New ACC, AHA, HFSA Guideline Updates Recommendations For Managing HF
5.When is a mineralocorticoid receptor antagonist appropriate in HFrEF?
Spironolactone or eplerenone reduces morbidity and mortality in appropriately selected symptomatic HFrEF by opposing aldosterone effects. Initiation requires eGFR above 30 mL/min/1.73 m² and potassium below 5.0 mEq/L, with close renal-function and potassium monitoring. Discontinue the MRA if potassium cannot be maintained below 5.5 mEq/L. These thresholds are specified in the [official heart-failure guideline slide set](https://www.heart.org/-/media/PHD-Files-2/Science-News/2/2022/2022-Heart-Failure-Guideline-Slide-Set.pdf), in the MRA recommendations.
Apply it
A patient with symptomatic HFrEF has eGFR 42 mL/min/1.73 m² and potassium 4.4 mEq/L. Spironolactone may be appropriate with planned monitoring; a different patient with potassium 5.3 mEq/L is not an equivalent initiation candidate.
Common pitfall: Using the same prescribing decision for all patients with low EF ignores potassium and renal clearance. A normal baseline potassium also does not remove monitoring requirements.
New ACC, AHA, HFSA Guideline Updates Recommendations For Managing HF
6.Why continue therapy after a reduced ejection fraction improves?
Heart failure with improved EF describes a patient whose previous LVEF was 40% or less and subsequently rises above 40%. Improvement may represent effective suppression of disease mechanisms rather than permanent cure. Guideline-directed HFrEF therapy should continue, including in asymptomatic patients, to reduce relapse of ventricular dysfunction and heart failure. The historical EF therefore remains clinically important even when the current echocardiogram would otherwise suggest a different EF category.
Apply it
After two years of treatment, a patient’s LVEF rises from 28% to 52% and exercise tolerance normalises. Explain that recovery supports treatment effectiveness and continue appropriate HFrEF therapy rather than stopping medications solely because EF improved.
Common pitfall: Reclassifying the patient using only the latest EF can erase the prior cardiomyopathy. Symptom resolution does not establish that withdrawing protective therapy is safe.
New ACC, AHA, HFSA Guideline Updates Recommendations For Managing HF
7.Which anticoagulation principles apply to mechanical heart valves?
Mechanical prosthetic valves require vitamin K antagonist anticoagulation; direct oral anticoagulants are contraindicated for this indication. The target INR depends on valve position, prosthesis characteristics, and thromboembolic risk. A mechanical mitral valve generally requires a target INR of 3.0, whereas a current-generation mechanical aortic valve without additional risk factors generally uses 2.5. A narrowly defined lower-INR option for selected On-X aortic valves should not be generalised to other mechanical prostheses.
Apply it
A patient with a mechanical mitral valve asks to replace warfarin with apixaban to avoid INR checks. Explain that the prosthesis requires vitamin K antagonist therapy and review the valve-specific INR target and monitoring plan.
Common pitfall: Anticoagulant choices appropriate for atrial fibrillation do not automatically apply to mechanical valves. A lower-INR aortic-valve exception does not apply to mechanical mitral replacement.
2020 ACC/AHA Heart Valve Disease Guideline: Key Perspectives, Part 3
8.How do concordant measurements identify moderate aortic stenosis?
Concordant moderate aortic stenosis generally shows peak aortic velocity at least 3.0 but below 4.0 m/s, mean gradient at least 20 but below 40 mm Hg, and valve area approximately 1.0–1.5 cm². Peak velocity at least 4.0 m/s or mean gradient at least 40 mm Hg meets severe high-gradient criteria. Interpret these measurements together with valve anatomy, flow, ventricular function, and measurement quality. Low flow can produce a low gradient despite severe obstruction, while an inaccurate left ventricular outflow tract measurement can distort the calculated valve area.
Apply it
Velocity 3.3 m/s, mean gradient 27 mm Hg, and valve area 1.2 cm² support moderate stenosis. Velocity 4.0 m/s and mean gradient 40 mm Hg reach severe high-gradient thresholds. A valve area of 0.8 cm² with a lower gradient and reduced ejection fraction requires assessment for discordant low-flow disease; low-dose dobutamine stress echocardiography can help distinguish true severe from pseudo-severe stenosis.
Common pitfall: Including 4.0 m/s or 40 mm Hg within the moderate ranges misclassifies the severe boundary. Conversely, a gradient below 40 mm Hg does not exclude severe stenosis. Check Doppler alignment, outflow tract measurements, and flow before assigning severity from discordant findings.
9.When should suspected endocarditis prompt transoesophageal echocardiography?
Transthoracic echocardiography is an initial imaging test in suspected infective endocarditis, but a negative or limited study does not exclude infection when clinical suspicion remains high. Transoesophageal echocardiography provides better assessment of vegetations and complications, especially around prosthetic valves or intracardiac devices. It is indicated when transthoracic images are nondiagnostic or complications are suspected. Imaging interpretation must remain linked to blood cultures, embolic findings, prosthetic material, and the overall clinical presentation.
Apply it
A patient with a prosthetic valve has persistent bloodstream infection and a nondiagnostic transthoracic echocardiogram. Obtain transoesophageal imaging to assess the prosthesis and surrounding structures rather than dismissing endocarditis because the first study showed no vegetation.
Common pitfall: A negative transthoracic study is less reassuring when prosthetic material or persistent bacteraemia raises pretest probability. Imaging sensitivity and clinical probability must be considered together.
2020 ACC/AHA Heart Valve Disease Guideline: Key Perspectives, Part 3
11.What distinguishes hypertensive emergency from severe hypertension without acute organ injury?
Hypertensive emergency combines severe blood-pressure elevation with new or worsening target-organ injury, such as encephalopathy, acute pulmonary oedema, myocardial ischaemia, aortic dissection, or acute kidney injury. The pressure value alone does not establish an emergency. A nonpregnant patient with pressure above 180/120 mm Hg but no acute injury generally needs timely oral treatment adjustment and follow-up rather than rapid intravenous reduction. Confirm measurement accuracy and assess symptoms and organ injury before choosing the setting and route of treatment. See the [AHA/ACC hypertension guideline summary](https://professional.heart.org/en/science-news/2025-high-blood-pressure-guideline/top-things-to-know).
Apply it
A patient with pressure 212/124 mm Hg, acute hypoxaemia, and pulmonary oedema requires monitored emergency treatment. Another patient with the same pressure but no acute organ injury needs confirmation, assessment of medication use, and prompt adjustment of oral therapy with follow-up.
Common pitfall: Treating a number alone can cause harmful overtreatment. Conversely, labelling acute pulmonary oedema as asymptomatic hypertension overlooks target-organ injury.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
Dermatology3%
10.Which ABCDE findings make a pigmented lesion suspicious?
The ABCDE warning features are asymmetry, irregular border, varied colour, diameter often greater than 6 mm, and evolution. They organise recognition rather than define a diagnostic rule that every melanoma must satisfy. Evolution includes changes in size, shape, colour, or symptoms. A suspicious lesion warrants dermatologic assessment even when it is small. Comparing a lesion with the patient’s other moles can also identify an outlier that deserves closer evaluation.
Apply it
A patient reports that a 4-mm mole has developed an irregular edge and two new colours over several months. Its small diameter does not offset the concerning evolution, so arrange assessment rather than offering reassurance based on size.
Common pitfall: Treating 6 mm as a minimum melanoma diameter misses smaller cancers. Several concerning changes can outweigh an otherwise reassuring size measurement in an evolving lesion.
Endocrinology, Diabetes, and Metabolism9%
12.How does Graves disease produce hyperthyroidism, and when is radioiodine unsuitable?
Graves disease results from antibodies that stimulate the TSH receptor, increasing thyroid hormone production despite pituitary TSH suppression. Typical findings are low TSH with elevated free T4 and/or T3. Diffuse goitre, thyroid eye disease, and TSH-receptor antibodies support the diagnosis. When uncertain, appropriately selected uptake testing can distinguish increased synthesis from destructive thyroiditis. Radioiodine damages iodine-concentrating thyroid tissue and often causes hypothyroidism. It is contraindicated during pregnancy and breastfeeding and can worsen Graves eye disease; these factors influence selection of antithyroid drugs or surgery.
Apply it
A pregnant patient has weight loss, tremor, diffuse goitre, proptosis, suppressed TSH, and elevated free T4. TSH-receptor antibodies support Graves disease. Pregnancy excludes radioiodine, so arrange pregnancy-appropriate antithyroid management.
Common pitfall: Suppressed TSH identifies possible thyrotoxicosis without establishing its cause. A treatment that works for Graves disease may still be unsuitable because of pregnancy or eye involvement.
13.Which test results establish diabetes, and when is confirmation required?
For nonpregnant adults, diabetes thresholds include laboratory A1C at least 6.5%, fasting plasma glucose at least 126 mg/dL after at least eight hours without caloric intake, or two-hour plasma glucose at least 200 mg/dL during a 75-g oral glucose tolerance test. Random plasma glucose at least 200 mg/dL with typical hyperglycaemic symptoms can also establish diabetes. Without unequivocal symptomatic hyperglycaemia, confirm an abnormal result with repeat diagnostic testing. A1C reflects glycation over red-cell exposure time, so altered red-cell survival or some haemoglobin variants can distort it. See [NIDDK’s diagnostic criteria](https://www.niddk.nih.gov/health-information/diabetes/overview/tests-diagnosis).
Apply it
An asymptomatic adult has a laboratory A1C of 6.7%. Arrange confirmatory testing rather than diagnosing from an isolated screening result. If recent blood loss makes A1C unreliable, use plasma-glucose criteria.
Common pitfall: A home glucose-meter reading is not equivalent to a diagnostic laboratory plasma-glucose measurement. Pregnancy uses a separate diagnostic pathway.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
14.Which findings distinguish primary from central adrenal insufficiency?
Primary adrenal insufficiency reflects adrenal cortical failure, so cortisol is low and ACTH rises; aldosterone deficiency may produce volume depletion and hyperkalaemia. Elevated ACTH can cause hyperpigmentation. Secondary or tertiary insufficiency reflects inadequate upstream stimulation, with low or inappropriately normal ACTH and usually preserved aldosterone because its principal control is the renin–angiotensin system. Hyponatraemia can occur in either form, so potassium, pigmentation, medication history, and pituitary context provide useful discriminating clues.
Apply it
A patient with weight loss, postural symptoms, darkening skin, hyperkalaemia, and low cortisol has a pattern suggesting primary adrenal failure. A patient after pituitary surgery with low cortisol but normal potassium requires evaluation for central insufficiency.
Common pitfall: Normal potassium does not exclude cortisol deficiency. Conversely, hyponatraemia alone cannot distinguish primary from central disease because impaired water handling can occur in both forms.
Symptoms & Causes of Adrenal Insufficiency & Addison's Disease · Diagnosis of Adrenal Insufficiency & Addison's Disease
15.Why can ACTH stimulation miss recent central adrenal insufficiency?
An ACTH stimulation test assesses the adrenal glands’ capacity to produce cortisol after synthetic ACTH. In longstanding ACTH deficiency, adrenal atrophy reduces that response. Soon after pituitary injury or surgery, however, the adrenals may retain responsiveness despite inadequate endogenous ACTH secretion. An apparently normal stimulation response can therefore be misleading in recent central insufficiency. Interpretation requires the timing of pituitary disease, baseline hormonal findings, clinical suspicion, and selection of further evaluation when necessary.
Apply it
Ten days after pituitary surgery, a patient develops fatigue and hypotension with low morning cortisol but retains a cortisol response to synthetic ACTH. Do not dismiss recent central insufficiency solely because the adrenal glands still respond.
Common pitfall: A stimulation test measures adrenal responsiveness, not every aspect of hypothalamic–pituitary function. Its apparent reassurance is limited soon after a new loss of ACTH stimulation.
16.How can stopping glucocorticoids cause adrenal insufficiency?
Exogenous glucocorticoids suppress hypothalamic CRH and pituitary ACTH through negative feedback. With prolonged exposure, reduced ACTH stimulation can diminish endogenous cortisol production and adrenal responsiveness. Abrupt withdrawal may then leave the patient unable to meet ordinary or stress-related cortisol needs. The history must include prescribed steroids and other substantial glucocorticoid exposure. Withdrawal planning depends on exposure and clinical context; a person with suppressed cortisol production may also require a specific illness or procedure plan.
Apply it
A patient abruptly stops months of prednisone and develops marked fatigue, nausea, and postural dizziness. Recognise glucocorticoid-related adrenal insufficiency as a plausible mechanism and assess urgently rather than attributing every symptom to recurrence of the original inflammatory disease.
Common pitfall: Calling this primary adrenal destruction misidentifies the mechanism. Preserved aldosterone and absence of hyperpigmentation can fit central suppression and do not make cortisol deficiency harmless.
Symptoms & Causes of Adrenal Insufficiency & Addison's Disease
Gastroenterology9%
17.Which initial blood tests best assess suspected celiac disease?
Tissue transglutaminase IgA is the preferred initial serologic test for most patients with suspected celiac disease. Total IgA helps identify deficiency that could make an IgA-based result falsely reassuring. Testing should occur while the patient consumes gluten because avoidance can reduce antibody levels and intestinal injury. Symptoms may include diarrhoea, weight loss, or otherwise unexplained iron deficiency. A compatible presentation determines pretest probability; serology must be interpreted with exposure and immune status.
Apply it
A patient with chronic loose stools and iron deficiency still eats wheat daily. Order tissue transglutaminase IgA with assessment of total IgA rather than starting a gluten-free diet before obtaining diagnostically useful testing.
Common pitfall: A negative antibody test after gluten avoidance may reflect reduced exposure. It should not be interpreted as equivalent to a negative test during regular gluten consumption.
18.How does IgA deficiency change celiac testing?
Selective IgA deficiency can cause falsely negative IgA-based celiac serology because the relevant antibody class is not produced adequately. When total IgA is deficient, IgG-based testing, such as tissue transglutaminase IgG or deamidated gliadin peptide IgG, becomes useful. This is a targeted adjustment to the testing pathway rather than a reason to order every antibody panel routinely. In patients with normal IgA, isolated tissue transglutaminase IgG is less diagnostically useful.
Apply it
A patient with persistent diarrhoea and iron deficiency has negative tissue transglutaminase IgA but profoundly low total IgA. Continue the evaluation with appropriate IgG-based serology instead of treating the initial result as a reliable exclusion.
Common pitfall: Repeating the same IgA assay does not correct an antibody-class deficiency. Conversely, a positive isolated IgG result in an IgA-sufficient patient needs cautious interpretation.
19.When does celiac evaluation require duodenal biopsy?
In adults, positive celiac serology commonly leads to upper endoscopy with multiple duodenal biopsies to confirm characteristic intestinal injury. Sampling matters because involvement may be patchy, including the duodenal bulb. Strong clinical suspicion can also justify biopsy despite negative serology, particularly when test limitations are present. The patient should remain on gluten during diagnostic evaluation when feasible. Symptomatic improvement after gluten avoidance alone cannot distinguish celiac disease from several other dietary or gastrointestinal conditions.
Apply it
An adult with iron deficiency and positive tissue transglutaminase IgA asks to begin lifelong dietary restriction immediately. Arrange confirmatory evaluation while gluten exposure continues, explaining that a secure diagnosis affects long-term treatment and family counselling.
Common pitfall: Dietary response alone is not specific enough to establish celiac disease. Starting restriction before confirmation may make later serology and biopsy harder to interpret.
20.When should cirrhotic ascites be tested for spontaneous bacterial peritonitis?
Hospitalised patients with cirrhosis and ascites should undergo prompt diagnostic paracentesis because spontaneous bacterial peritonitis may lack fever or focal abdominal pain. An ascitic polymorphonuclear neutrophil count of at least 250 cells/mm³ supports treatment, including when culture is negative. Encephalopathy, kidney injury, hypotension, or clinical deterioration strengthen urgency. Obtain appropriate fluid studies and cultures promptly, but do not delay indicated antibiotics while awaiting culture growth once the neutrophil threshold is met.
Apply it
A hospitalised patient with cirrhosis develops worsening confusion without abdominal tenderness. Paracentesis shows 310 neutrophils/mm³. Begin treatment for spontaneous bacterial peritonitis despite the absence of fever and before final culture results return.
Common pitfall: Waiting for a positive culture misses culture-negative neutrocytic ascites. A benign abdominal examination also cannot reliably exclude infection in a patient with decompensated cirrhosis.
Why Timing Matters: Paracentesis on Admission for Cirrhosis with Ascites
21.How does the serum–ascites albumin gradient identify portal hypertension?
The serum–ascites albumin gradient is serum albumin minus ascitic fluid albumin, using appropriately paired measurements. A gradient of at least 1.1 g/dL supports portal hypertension as the mechanism of ascites. It does not establish cirrhosis as the only possible cause, because other portal hypertensive conditions can produce a high gradient. Ascitic total protein and the wider clinical picture refine the differential. The gradient assesses mechanism, while the neutrophil count separately assesses infection.
Apply it
Serum albumin is 2.8 g/dL and ascitic albumin is 1.2 g/dL, giving a gradient of 1.6 g/dL. This supports portal hypertension, while a separate ascitic neutrophil count is still needed to assess bacterial infection.
Common pitfall: A high gradient does not rule out infected ascites or prove cirrhosis by itself. Albumin gradient and neutrophil count answer different clinical questions.
Why Timing Matters: Paracentesis on Admission for Cirrhosis with Ascites
Hematology6%
23.How should ferritin be interpreted when inflammation is present?
Iron deficiency limits haemoglobin synthesis and often produces microcytic, hypochromic anaemia, although early deficiency can have a normal MCV. Ferritin reflects stored iron: a clearly low value supports depleted stores. Ferritin is also an acute-phase protein, so inflammation may conceal deficiency behind an apparently normal value. Interpret it with transferrin saturation, inflammatory markers, the clinical context, and sometimes the response to iron. Low serum iron alone is insufficient because inflammation can lower circulating iron without exhausting stores.
Apply it
A patient with active inflammatory disease has anaemia, low transferrin saturation, and ferritin within the laboratory reference range. Consider coexisting iron deficiency rather than using the normal-range ferritin as an unconditional exclusion.
Common pitfall: Neither normal cell size nor a normal-range ferritin during inflammation reliably excludes iron deficiency. Microcytosis itself is also not specific for depleted iron.
Iron-Deficiency-Aneamia-in-Adults.pdf · Anemia: Iron-Deficiency Anemia
24.Which investigation is generally indicated for unexplained iron-deficiency anaemia in an adult man?
Newly diagnosed unexplained iron-deficiency anaemia in an appropriate adult man generally warrants examination of both the upper and lower gastrointestinal tract, usually gastroscopy and colonoscopy. Gastrointestinal malignancy can present without visible bleeding or local symptoms. Initial assessment should also include a detailed bleeding and medication history, urinalysis, and celiac screening. CT colonography is an alternative when colonoscopy is unsuitable. In major comorbidity, frailty, or limited performance status, weigh procedural risks, likely benefit, and patient preferences. Treat iron deficiency alongside investigation rather than assuming replacement resolves the cause.
Apply it
An older man has confirmed iron-deficiency anaemia without visible bleeding or an adequate alternative explanation. If clinically suitable, arrange gastroscopy and colonoscopy with assessment for urinary loss, celiac disease, and medication-related bleeding; adapt the pathway if comorbidity makes invasive testing disproportionate.
Common pitfall: A haemoglobin rise after iron does not exclude a bleeding lesion. Restricting evaluation to one gastrointestinal segment can miss a relevant upper or lower tract cause.
25.How do iron restriction and thalassaemia change the differential diagnosis of microcytic anaemia?
Absolute iron deficiency means depleted body stores. Functional iron deficiency means iron delivery to erythropoiesis is inadequate despite retained stores; hepcidin-mediated restriction of intestinal absorption and iron availability contributes in chronic inflammatory disease and CKD. Both can produce low transferrin saturation, and they can coexist. Microcytosis also occurs in thalassaemia, sometimes disproportionately to the degree of anaemia. Persistent microcytosis with normal iron studies should prompt consideration of haemoglobin analysis rather than automatic iron treatment or gastrointestinal investigation.
Apply it
A patient with inflammatory arthritis has anaemia, raised inflammatory markers, low transferrin saturation, and preserved ferritin. Consider functional restriction and possible concurrent absolute deficiency. In a different patient with longstanding marked microcytosis and normal iron studies, assess for a haemoglobinopathy.
Common pitfall: Low serum iron does not distinguish depleted stores from inflammatory sequestration. Normal iron studies with microcytosis require a broader differential rather than repeated empiric iron prescriptions.
Infectious Disease9%
26.Why is asymptomatic bacteriuria usually left untreated in older adults?
Asymptomatic bacteriuria is bacterial growth in urine without symptoms attributable to urinary infection, whether or not pyuria is present. In older adults, a positive culture is common and does not independently explain a fall or delirium. Without local urinary symptoms or systemic signs such as fever or haemodynamic instability, guidelines favour assessment for other causes and observation rather than antibiotics. Unnecessary treatment exposes patients to adverse effects, resistance, and Clostridioides difficile infection.
Apply it
An older resident has a positive urine culture after a fall but no dysuria, frequency, fever, flank pain, or instability. Assess the fall and other possible causes rather than prescribing antibiotics solely for bacteriuria.
Common pitfall: Pyuria does not convert asymptomatic bacteriuria into symptomatic infection. Sepsis physiology requires a different urgent assessment and should not be dismissed using a non-treatment rule.
IDSA 2019 Clinical Practice Guideline Update for the Management of Asymptomatic Bacteriuria
27.Which patients should receive treatment for asymptomatic bacteriuria?
Pregnancy and planned endoscopic urologic procedures associated with mucosal trauma are key situations in which screening and treating asymptomatic bacteriuria can prevent important complications. These exceptions depend on the patient’s circumstances and procedure, not simply the culture result. For a traumatic urologic procedure, culture-guided peri-procedural treatment is appropriate. Diabetes, advanced age, or an indwelling catheter alone does not create the same general indication to treat bacteriuria without attributable symptoms.
Apply it
Two patients have positive cultures without urinary symptoms: one is pregnant, and the other is a stable older adult awaiting cataract surgery. The pregnant patient has a treatment indication; the nonurologic procedure does not create the same exception.
Common pitfall: Calling every procedure an indication for antibiotics overextends the exception. The relevant procedural risk is urologic mucosal trauma, not the mere presence of planned surgery.
IDSA 2019 Clinical Practice Guideline Update for the Management of Asymptomatic Bacteriuria
28.When is primary Pneumocystis prophylaxis indicated in HIV?
Pneumocystis prophylaxis decisions combine CD4 count with antiretroviral treatment and virologic context. For patients on ART, indications include CD4 below 100 cells/mm³ regardless of viral load, or CD4 100–200 cells/mm³ with HIV RNA remaining detectable. Patients not on ART or starting ART require prophylaxis when CD4 is below 200. Trimethoprim–sulfamethoxazole is preferred when suitable. A suppressed viral load does not erase the prophylaxis indication at a CD4 count below 100.
Apply it
A patient on effective ART has undetectable HIV RNA but a CD4 count of 76 cells/mm³. Start indicated primary prophylaxis rather than treating virologic suppression as sufficient protection at this degree of immune depletion.
Common pitfall: Using a CD4 threshold without ART and viral-load context oversimplifies current guidance. Equally, viral suppression alone does not override the recommendation below 100 cells/mm³.
Pneumocystis Pneumonia: Adult and Adolescent Opportunistic Infections
29.How are alternatives to trimethoprim–sulfamethoxazole selected?
When trimethoprim–sulfamethoxazole cannot be used for Pneumocystis prophylaxis, alternatives include atovaquone, selected dapsone regimens, and aerosolised pentamidine. Choice depends on the adverse reaction, G6PD status, Toxoplasma serostatus, and practical feasibility. G6PD testing is required before dapsone because deficiency increases haemolysis risk. Dapsone alone and aerosolised pentamidine do not provide adequate toxoplasmosis prophylaxis, so they are unsuitable as the sole strategy when protection against both infections is needed.
Apply it
A Toxoplasma-seropositive patient needs Pneumocystis prophylaxis but cannot tolerate trimethoprim–sulfamethoxazole. Check G6PD status and select a regimen that also addresses toxoplasmosis rather than assuming aerosolised pentamidine protects against both opportunistic infections.
Common pitfall: Alternative regimens are not interchangeable. Choosing solely by convenience can overlook G6PD-associated haemolysis or leave a patient without needed protection against toxoplasmosis as well.
Pneumocystis Pneumonia: Adult and Adolescent Opportunistic Infections
30.When does HIV-associated Pneumocystis pneumonia need adjunctive corticosteroids?
Adjunctive corticosteroids are indicated for HIV-associated Pneumocystis pneumonia with substantial hypoxaemia: room-air PaO2 below 70 mm Hg or an alveolar–arterial oxygen gradient of at least 35 mm Hg. They reduce harmful inflammatory deterioration during treatment and should begin as soon as possible, ideally within 72 hours of antimicrobial initiation. The oxygenation criteria distinguish patients likely to benefit; imaging appearance or cough severity alone does not define this indication.
Apply it
A patient with HIV and confirmed Pneumocystis pneumonia has room-air PaO2 62 mm Hg. Begin appropriate antimicrobial therapy and adjunctive corticosteroids promptly because the oxygenation result meets the severity criterion, even if the patient reports only modest breathlessness.
Common pitfall: Waiting for respiratory failure misses the intended treatment window. Conversely, every patient with suspected Pneumocystis does not automatically require corticosteroids without assessing disease severity and oxygenation.
Pneumocystis Pneumonia: Adult and Adolescent Opportunistic Infections
Miscellaneous2%
22.How should informed refusal be distinguished from inability to decide?
Assess four decision-specific abilities: understanding the relevant information, appreciating how the condition and possible consequences apply personally, reasoning between alternatives, and communicating a choice. Explain the proposed intervention, benefits, material harms, alternatives, and consequences of declining; also establish voluntariness. Ask the patient to explain the information, its personal implications, and the reasoning behind the decision. Capacity can fluctuate. Disagreement or a psychiatric diagnosis alone does not establish incapacity. Address communication barriers before assessing these abilities. See the [AMA discussion of capacity](https://edhub.ama-assn.org/ama-journal-of-ethics/module/2765634) and [AHRQ informed-consent training](https://www.ahrq.gov/health-literacy/professional-training/informed-choice/audio-script.html).
Apply it
A patient declining endoscopy explains its purpose and risks, then says, “Cancer could be causing my anemia. Declining could delay diagnosis and reduce my chance of successful treatment.” After comparing alternatives, the patient explains that a previous procedural complication makes avoiding another procedure a higher priority despite that personal risk. Confirm the choice is voluntary, address concerns, and document the four abilities and informed refusal.
Common pitfall: Repeating disclosed risks demonstrates neither personal appreciation nor reasoning by itself. An unwelcome decision does not establish incapacity, and a signature does not replace assessment. A capable adult's refusal does not authorize transferring the decision to family.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
31.How should an observational association change clinical probability?
An observed association can support a diagnostic hypothesis without proving causation or making a finding specific to one disease. The reported association between small-cell lung cancer and SIADH is useful when interpreting compatible clinical findings, but hyponatraemia has many causes. Evaluate the population, comparison group, denominators, and study design before applying a result. Relative differences should also be translated into absolute differences so their clinical magnitude remains clear to the reader.
Apply it
In a hypothetical cohort, an outcome occurs in 20 of 100 exposed patients and 10 of 100 unexposed patients. The risk ratio is 2, and the absolute risk difference is 10 percentage points; neither alone proves causation.
Common pitfall: An association does not establish that every affected patient has the linked disease. Relative risk also cannot convey absolute outcome frequency without a baseline risk.
The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in small-cell lung cancer
57.How can a PDSA cycle test a proposed improvement in clinical care?
A Plan–Do–Study–Act cycle tests a defined change on a manageable scale. Plan the intervention, prediction, responsibilities, and measurement; do the test and record problems; study results against the prediction; then act by adapting, adopting, or abandoning the change. Define a denominator so apparent improvement does not simply reflect different patient volume. Track whether the desired care process occurred and whether it caused unintended burdens. Repeated small cycles allow learning before wider implementation. See [AHRQ’s PDSA worksheet and examples](https://www.ahrq.gov/health-literacy/improve/precautions/tool2b.html).
Apply it
A clinic tests a teach-back reminder for one clinician for one week. Record completed teach-back discussions divided by eligible visits, assess patient understanding, and note added visit time. Study the results and revise the reminder before expanding it.
Common pitfall: Introducing a change without a prediction or measurement does not show that care improved. Raw counts can rise simply because more patients attended.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
58.How can clinicians address language and comprehension barriers without mistaking them for poor engagement?
Language barriers can prevent a patient from understanding choices and carrying out a treatment plan. Use a qualified medical interpreter when needed, communicate directly with the patient in plain language, and check understanding through teach-back. Ask the patient to explain the plan in their own words, then clarify and reassess if needed. This checks the effectiveness of the explanation rather than testing the patient. Identifying and correcting communication barriers is a concrete health-equity intervention because identical instructions do not provide equal access to understanding. See [AHRQ’s teach-back guidance](https://www.ahrq.gov/teamstepps-program/curriculum/communication/tools/teachback.html).
Apply it
A patient repeatedly uses an inhaler incorrectly after English-only instructions. Arrange a qualified interpreter, demonstrate the technique, and ask the patient to demonstrate it back before attributing the problem to unwillingness or increasing treatment.
Common pitfall: Conversational fluency does not guarantee comprehension of complex medical decisions. Asking only whether the patient understands can miss substantial misunderstanding.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
Nephrology and Urology6%
32.When do abnormal kidney markers establish chronic kidney disease?
Chronic kidney disease requires kidney structure or function abnormalities present for at least three months, with implications for health. These include persistent eGFR below 60 mL/min/1.73 m² or evidence of damage such as albuminuria. One low eGFR during dehydration does not distinguish CKD from acute kidney injury. Prior measurements, repeat testing, urine findings, and clinical context help establish duration and identify the likely underlying process.
Apply it
A dehydrated patient has eGFR 48 mL/min/1.73 m² with no previous results. Correct the acute problem and reassess kidney function and urine markers rather than assigning CKD solely from this single measurement during illness.
Common pitfall: An abnormal value is not automatically a chronic diagnosis. The opposite error is overlooking CKD when persistent albuminuria documents damage despite a preserved filtration estimate.
Identify & Evaluate Patients with Chronic Kidney Disease · KDIGO-2024-CKD-Guideline.pdf
33.How is the urine albumin-to-creatinine ratio calculated?
The urine albumin-to-creatinine ratio divides urine albumin by urine creatinine to account for urine concentration. When albumin is expressed in mg/dL and creatinine in g/dL, the result is mg/g. If creatinine is reported in mg/dL, convert it to g/dL first. A spot sample generally avoids the burden of timed collection. The ratio assesses albumin leakage and complements eGFR, which estimates filtration rather than urinary protein loss.
Apply it
Urine albumin is 12 mg/dL and urine creatinine is 80 mg/dL. Convert creatinine to 0.080 g/dL, then divide 12 by 0.080 to obtain a UACR of 150 mg/g rather than 0.15 mg/g.
Common pitfall: Dividing two numbers without checking units produces a thousand-fold error. Albumin concentration alone also varies with hydration and cannot replace the concentration-corrected ratio in routine assessment.
34.Why assess albuminuria when estimated GFR is preserved?
Albuminuria and eGFR describe different dimensions of kidney health. Albumin leakage can reveal kidney damage before filtration falls, so a preserved eGFR does not exclude CKD when abnormal albumin excretion persists. A UACR of at least 30 mg/g is an albuminuria marker of kidney damage and should be interpreted with repeat measurements and clinical context. Using both measures identifies patients who would be missed by creatinine testing alone and helps characterise their kidney disease more meaningfully.
Apply it
A patient with diabetes has eGFR 88 mL/min/1.73 m² but repeatedly elevated UACR over several months. Recognise persistent kidney damage despite preserved filtration and investigate and manage the kidney risk rather than declaring the kidneys normal.
Common pitfall: A creatinine value within the reference interval is not a complete kidney assessment. Albuminuria can be clinically important before a substantial decline in estimated GFR occurs.
Identify & Evaluate Patients with Chronic Kidney Disease · Assess Urine Albumin · KDIGO-2024-CKD-Guideline.pdf
35.Why should newly detected albuminuria be confirmed?
Urine albumin excretion varies, and an isolated abnormal result may not represent persistent kidney damage. Repeat testing, preferably using a suitable spot specimen and consistent methods, helps distinguish sustained albuminuria from a transient finding. Interpret results alongside recent illness, exercise, urinary findings, and the broader clinical picture. Confirmation is particularly important when a result would establish a chronic diagnosis or materially change risk assessment. A timed urine collection is usually unnecessary for routine UACR assessment.
Apply it
A patient’s first screening UACR is elevated during an acute illness, while prior kidney tests were normal. Arrange repeat assessment after recovery and review the clinical context before concluding that the patient has persistent albuminuric CKD.
Common pitfall: Repeating a test should resolve persistence, not postpone evaluation of an important abnormality indefinitely. Marked abnormalities or associated concerning findings still require timely clinical assessment.
Assess Urine Albumin · Identify & Evaluate Patients with Chronic Kidney Disease
Neurology4%
36.Which weakness pattern suggests myasthenia gravis?
Myasthenia gravis impairs neuromuscular transmission and produces fluctuating weakness that worsens with repeated activity and improves with rest. Ptosis and diplopia are common, while bulbar involvement can cause chewing fatigue, dysarthria, or dysphagia. Sensory loss is not the defining pattern. Respiratory muscle weakness or major swallowing difficulty signals a potentially life-threatening deterioration requiring urgent assessment. The distribution and fatigability distinguish this syndrome from fixed weakness or disorders dominated by sensory symptoms.
Apply it
A patient develops diplopia late in the day and must pause while chewing dinner, with improvement after rest. Suspect myasthenia gravis; new breathlessness or inability to swallow would change the situation from outpatient investigation to urgent assessment.
Common pitfall: Labeling fluctuating ocular symptoms as ordinary fatigue can miss neuromuscular disease. A normal examination after rest also does not erase a convincing history of fatigability.
37.How is suspected myasthenia investigated when antibodies are negative?
Antibody testing supports myasthenia gravis, but a negative result does not exclude it, particularly in disease limited to the eyes. When the clinical pattern remains suggestive, specialist electrophysiologic testing can assess impaired neuromuscular transmission. Repetitive nerve stimulation or single-fibre electromyography may provide additional evidence. Chest imaging can evaluate the thymus once the diagnosis is being assessed. Test interpretation should therefore follow the syndrome rather than treating one negative antibody result as definitive.
Apply it
A patient has reproducible fatigable ptosis and diplopia but negative initial antibody testing. Arrange specialist evaluation and appropriate electrophysiology rather than abandoning the diagnosis solely because the first blood test failed to detect antibodies.
Common pitfall: Seronegativity does not exclude every form of myasthenia. Conversely, nonspecific tiredness without objective fatigable weakness should not automatically trigger a neuromuscular junction diagnosis on its own.
Obstetrics and Gynecology3%
38.Which symptoms raise concern for a rupturing ectopic pregnancy?
Ectopic pregnancy occurs when implantation develops outside the uterine cavity, most often in a fallopian tube. Unilateral lower abdominal pain, vaginal bleeding, and a missed period should prompt consideration, even before pregnancy has been confirmed. Sudden severe pain, shoulder-tip pain, dizziness, or collapse can indicate internal bleeding and rupture. Haemodynamic instability changes the priority to emergency assessment and treatment rather than a routine outpatient diagnostic sequence. Absence of obvious external bleeding is not reassuring.
Apply it
A patient with a missed period develops unilateral pelvic pain, spotting, shoulder-tip pain, and near-syncope. Arrange emergency evaluation for possible ruptured ectopic pregnancy rather than waiting for a scheduled routine ultrasound several days later.
Common pitfall: Light vaginal bleeding can coexist with major internal haemorrhage. Lack of a previously positive pregnancy test does not safely exclude an ectopic pregnancy in this presentation.
39.How do ultrasound and serial hCG clarify an uncertain pregnancy location?
Transvaginal ultrasound assesses pregnancy location, while blood hCG measurements and their change over time help interpret an early or uncertain presentation. A positive pregnancy test without a visible intrauterine pregnancy does not by itself establish ectopic implantation; the pregnancy may be too early to locate. A stable patient may require structured follow-up with repeat testing. Symptoms and haemodynamic status remain decisive because new pain, faintness, or instability can make waiting unsafe.
Apply it
A stable patient has a positive pregnancy test and an initial scan that does not identify the pregnancy location. Arrange a defined serial hCG and ultrasound plan with clear emergency return instructions rather than declaring either a normal pregnancy or an ectopic.
Common pitfall: One hCG value cannot independently locate a pregnancy. A follow-up pathway appropriate for a stable patient must be abandoned if symptoms suggest rupture or clinical instability.
Medical Oncology6%
40.When does back pain in a patient with cancer suggest metastatic spinal cord compression?
Progressive back pain accompanied by new limb weakness, gait disturbance, sensory change, or bladder or bowel dysfunction in a patient with cancer raises concern for metastatic spinal cord compression. Neurologic deficits make this an oncologic emergency. Arrange immediate specialist coordination and urgent spinal MRI, within 24 hours when cord compression is suspected with neurologic signs. For neurologic symptoms or signs of compression, NICE recommends prompt dexamethasone 16 mg orally or an equivalent parenteral dose while definitive management is arranged. Assess stability and avoid movements that could worsen an unstable spine. See [NICE’s spinal cord compression recommendations](https://www.nice.org.uk/guidance/ng234/chapter/recommendations).
Apply it
A patient with known metastatic breast cancer develops worsening thoracic pain, new leg weakness, and urinary retention. Initiate the emergency cord-compression pathway, arrange urgent MRI, and start indicated corticosteroid treatment rather than treating the pain alone.
Common pitfall: A normal plain radiograph does not exclude epidural compression. Waiting for paralysis or permanent sphincter dysfunction can sacrifice recoverable neurologic function.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
41.Why is smoking cessation still clinically useful after a cancer diagnosis?
Smoking cessation remains beneficial after cancer develops. Continued smoking exposes tissues to carcinogens and carbon monoxide and can impair treatment tolerance, healing, and recovery. Quitting can improve prognosis and reduce risks of additional smoking-related disease and second cancers. Explain that nicotine dependence makes quitting difficult and offer practical cessation support rather than treating continued smoking as a moral failing. A cancer diagnosis does not eliminate the value of prevention and supportive care. See the [NCI review of smoking harms and cessation benefits](https://www.cancer.gov/about-cancer/causes-prevention/risk/tobacco/cessation-fact-sheet).
Apply it
A patient beginning treatment for a smoking-associated cancer says it is too late to quit. Explain the remaining treatment and long-term benefits, assess readiness and barriers, and connect the patient with behavioural and appropriate medication support.
Common pitfall: Assuming prevention no longer matters after diagnosis misses an actionable component of cancer care. Reducing cigarette consumption does not make continued smoking safe.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
42.Which findings support SIADH in a patient with small-cell lung cancer?
Small-cell lung cancer can produce inappropriate antidiuretic activity, retaining water and causing dilutional hyponatraemia. Typical SIADH criteria include effective serum osmolality below 275 mOsm/kg, urine osmolality above 100 mOsm/kg despite hypotonicity, clinical euvolaemia, and urine sodium above 30 mmol/L with normal salt and water intake. Interpret urine sodium with intake, medications, and renal function; a low value can indicate reduced effective arterial volume but is not diagnostic alone. Exclude adrenal, thyroid, pituitary, and renal insufficiency and recent diuretic effects. The cancer association alone cannot establish SIADH. See the [joint hyponatraemia guideline](https://academic.oup.com/ejendo/article/170/3/G1/6668028?searchresult=1).
Apply it
A patient with small-cell lung cancer has sodium 124 mmol/L, effective serum osmolality 262 mOsm/kg, urine osmolality 420 mOsm/kg, urine sodium 52 mmol/L, and no clinical volume depletion or oedema. This supports SIADH only after relevant endocrine, renal, medication, and intake-related alternatives are excluded.
Common pitfall: Hyponatraemia alone is insufficient. Diuretics and adrenal insufficiency can imitate parts of the pattern, and these diagnostic criteria do not specify a safe sodium-correction regimen.
The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in small-cell lung cancer
43.How do stage and treatment sequence guide small-cell lung cancer management?
Limited-stage SCLC is generally confined to a tolerable thoracic radiation field; distant metastasis establishes extensive-stage disease. Staging includes brain imaging, preferably MRI when appropriate, because metastases can be silent. Suitable limited-stage patients generally receive platinum–etoposide with concurrent thoracic radiation. Eligible adults without progression after concurrent platinum-based chemoradiation can receive subsequent consolidation durvalumab, approved by the FDA on December 4, 2024. Consolidation follows chemoradiation; it is not synonymous with concurrent treatment. Extensive-stage treatment can combine platinum–etoposide with a PD-L1 inhibitor such as atezolizumab or durvalumab. Surgery remains an option for a small, carefully staged early-disease subset.
Apply it
A suitable adult completes concurrent platinum–etoposide and thoracic radiation for limited-stage SCLC without progression. Assess eligibility for consolidation durvalumab. A confirmed liver metastasis instead establishes extensive-stage disease even if the thoracic tumour fits within a radiation field.
Common pitfall: A small primary does not imply limited stage, and a normal neurologic examination does not replace brain staging. Do not omit the post-chemoradiation consolidation decision in eligible limited-stage disease.
Small Cell Lung Cancer Treatment (PDQ): Health Professional Version · FDA approves durvalumab for limited-stage small cell lung cancer | FDA
Ophthalmology1%
44.When do flashes and floaters suggest retinal detachment?
Retinal detachment separates the light-sensitive retina from its supporting tissue and threatens permanent vision loss. Sudden new floaters, flashes of light, or a dark curtain or shadow across the visual field require urgent eye assessment. Pain is not necessary, so a comfortable eye does not make the presentation benign. Prompt dilated examination can identify a retinal tear or detachment and guide treatment before further separation damages vision. Waiting for major acuity loss is unsafe.
Apply it
A patient develops a sudden shower of floaters and a dark curtain at the edge of one eye’s vision without pain. Arrange urgent ophthalmic assessment rather than scheduling a routine refraction or waiting to see whether the symptoms settle.
Common pitfall: Painless visual symptoms can still represent an emergency. Preserved central acuity does not exclude a peripheral retinal detachment that may progress toward central vision soon.
Otolaryngology and Dental Medicine1%
45.How should sudden hearing loss be assessed promptly?
The initial assessment should distinguish conductive loss from sensorineural loss rather than assuming sudden muffling is wax or congestion. For sudden sensorineural hearing loss, audiometry should be obtained as soon as possible and within 14 days of symptom onset. Timely specialist assessment matters because initial corticosteroid treatment may be offered within two weeks. History and examination should also identify bilateral or recurrent episodes and focal neurologic findings that require broader evaluation.
Apply it
A patient reports abrupt unilateral hearing loss beginning yesterday, with a normal-looking ear canal and tympanic membrane. Arrange prompt audiometry and specialist assessment rather than an extended trial of decongestants that delays evaluation of possible sensorineural loss.
Common pitfall: A normal otoscopic examination does not exclude important inner-ear disease. The 14-day audiometry interval is an outer recommendation, not a reason to delay an available assessment.
Sudden Hearing Loss: Update to Guideline to Improve Implementation and Awareness
Psychiatry4%
46.Which clinical pattern distinguishes mania from ordinary increased energy?
Mania involves a distinct period of elevated, expansive, or irritable mood together with increased energy or activity and associated features such as decreased need for sleep, pressured speech, racing thoughts, grandiosity, distractibility, and risky behaviour. Marked functional impairment, psychosis, or need for hospital care distinguishes it from a merely productive or cheerful period. A manic episode usually lasts at least seven days, or less when hospitalisation is necessary. Substance and medical causes require assessment.
Apply it
For nine days, a patient has persistently expansive mood, sleeps two hours without fatigue, speaks rapidly, claims exceptional business powers, and spends rent money on implausible ventures. Recognise a manic syndrome and assess safety and possible contributing substances or medical illness.
Common pitfall: Reduced need for sleep differs from insomnia with exhaustion. Increased energy alone does not establish mania without the characteristic mood change and associated syndrome.
47.Which episode history distinguishes bipolar I from bipolar II disorder?
Bipolar I disorder requires a manic episode; a major depressive episode is common but is not required. Bipolar II requires at least one hypomanic episode and at least one major depressive episode, with no manic episode. Hypomania lasts at least four consecutive days, includes abnormal elevated, expansive, or irritable mood with increased activity or energy, and produces an unequivocal change from baseline observable by others. It does not cause marked functional impairment, require hospitalisation, or include psychosis. Psychosis during an activated mood episode establishes manic severity. Obtain a longitudinal history rather than classifying from the current depressive presentation alone. See the [VA/DoD bipolar disorder guideline](https://www.healthquality.va.gov/guidelines/MH/bd/VA-DoD-CPG-BD-Full-CPGFinal508.pdf).
Apply it
A patient with a major depressive episode reports a previous five-day period of clearly increased energy and elevated mood that others noticed, without marked impairment or psychosis. Assess the full hypomanic criteria and exclude past mania before considering bipolar II. A past manic hospitalisation instead supports bipolar I.
Common pitfall: Unspecified low mood does not establish a major depressive episode, and a brief energetic afternoon does not establish hypomania. Good functioning between episodes does not determine the bipolar subtype.
Pulmonary Disease9%
48.How do Light’s criteria classify a pleural effusion?
A pleural effusion is exudative if any Light criterion is met: pleural-to-serum protein ratio above 0.5, pleural-to-serum LDH ratio above 0.6, or pleural LDH above two-thirds the upper limit of normal serum LDH. These criteria identify a biochemical pattern rather than its cause. Infection, malignancy, and inflammatory disease require further differentiation. Diuretic-treated cardiac effusions may be misclassified as exudates, so results should be reconciled with the patient’s clinical context.
Apply it
Pleural protein is 3.6 g/dL and serum protein is 6.0 g/dL, giving a ratio of 0.60. The effusion meets an exudative criterion even if the LDH ratios fall below their thresholds on the same sample.
Common pitfall: All three criteria do not need to be positive. An exudative classification also does not independently prove malignancy or infection without additional clinical and fluid evidence.
49.When does a parapneumonic effusion require drainage?
Frank pus establishes empyema and requires drainage. For nonpurulent parapneumonic fluid, pH at or below 7.2 supports intercostal drainage when an accessible collection is present. At pH above 7.2 but below 7.4, LDH above 900 IU/L plus findings such as persistent fever, low glucose, a large collection, pleural enhancement, or ultrasound septations strengthens the case for drainage. Antibiotics may not adequately control an infected pleural space without source control. Collect pH accurately because local anaesthetic contamination can lower it.
Apply it
An accessible collection with correctly measured pH 7.10 needs antibiotics and drainage. A collection with pH 7.30, LDH 1,200 IU/L, persistent fever, and septations also merits consideration of drainage rather than reassurance from pH alone.
Common pitfall: Culture negativity or absence of frank pus does not establish an uncomplicated effusion. A single threshold should not override intermediate-risk features or poor specimen quality.
50.What objective evidence supports asthma, and what follows normal initial spirometry?
Asthma diagnosis combines typical respiratory symptoms that vary over time and intensity with documented variable expiratory airflow. In adults, GINA 2026 defines a positive bronchodilator response as an increase in FEV1 or FVC of at least 12% AND at least 200 mL from that measurement's pre-bronchodilator value. Calculate percentage change using the pre-bronchodilator value as the denominator. This finding supports asthma in a compatible clinical context; it does not establish the diagnosis independently of the history and alternative explanations. When feasible, document objective evidence before starting inhaled corticosteroids, because treatment can reduce measurable airflow variability.
Apply it
An adult with episodic nocturnal wheeze has an FEV1 increase from 2.00 L to 2.30 L after bronchodilator: the increase is 300 mL and 15%, satisfying both adult criteria. If initial spirometry is normal between episodes, repeat spirometry with bronchodilator testing during symptoms, withholding bronchodilators beforehand when safe and according to testing instructions. Another pathway is morning and evening peak expiratory flow monitoring with the same meter for two weeks; average daily variability greater than 10% supports asthma in adults. Daily variability is the difference between the two readings divided by their mean, expressed as a percentage, then averaged across days. If uncertainty persists, specialist bronchial challenge testing, such as methacholine challenge, can assess airway hyperresponsiveness.
Common pitfall: Normal spirometry or an absent bronchodilator response on one occasion does not exclude asthma. Conversely, wheeze, symptomatic improvement with a bronchodilator, or elevated inflammatory biomarkers alone does not prove it. Interpret objective variability alongside the symptom pattern and assess competing diagnoses when findings remain discordant.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026 · GINA-Summary-Guide-2026-WEB-WMS.pdf
51.Which spirometric finding is required to confirm COPD?
Consider COPD in a patient with chronic dyspnoea, cough or sputum and relevant exposures, but confirm persistent obstruction with post-bronchodilator spirometry. GOLD uses FEV1/FVC below 0.70 as the required spirometric criterion in the appropriate clinical setting. Symptoms, smoking history, or emphysema on imaging alone do not replace this assessment. A reduced FEV1 by itself does not establish obstruction because it can occur with other ventilatory patterns. Interpret borderline results with test quality and the clinical context. See [GOLD’s spirometry guide](https://goldcopd.org/spirometry-quick-guide/).
Apply it
A patient with chronic exertional dyspnoea and substantial tobacco exposure has post-bronchodilator FEV1/FVC 0.61 on technically satisfactory testing. This supports COPD in context. Another symptomatic smoker with preserved post-bronchodilator ratio requires evaluation beyond an assumed COPD label.
Common pitfall: Pre-bronchodilator obstruction alone does not fulfil the stated diagnostic criterion. Persistent obstruction also requires clinical interpretation because it is not unique to COPD.
Internal Medicine Blueprint: Certification Examination (CERT), January 2026
52.When can primary spontaneous pneumothorax be managed conservatively?
Conservative management can be considered for selected adults with primary spontaneous pneumothorax who are minimally symptomatic and have no physiological compromise, regardless of radiographic size. Selection requires reliable follow-up, appropriate support, and clear advice about deterioration. Symptoms and physiology therefore matter more than size alone in this pathway. This recommendation must not be extended to tension physiology or automatically applied to secondary pneumothorax, where underlying lung disease changes risk and management considerations.
Apply it
A previously healthy adult has a primary spontaneous pneumothorax, minimal pain, no breathlessness, stable observations, and reliable follow-up. Discuss an appropriate conservative pathway instead of assuming that radiographic size alone mandates an invasive procedure.
Common pitfall: A stable primary pneumothorax pathway does not apply to hypotension or respiratory compromise. Primary and secondary pneumothorax also should not be treated as interchangeable populations.
Rheumatology and Orthopedics9%
53.Which joint pattern suggests rheumatoid arthritis?
Rheumatoid arthritis is an immune-mediated inflammatory disease that commonly produces persistent swelling and pain in symmetric small joints, particularly the hands and wrists. Prolonged morning stiffness and improvement with movement support inflammation, while structural damage can develop over time. The pattern is more informative than pain intensity alone. Early recognition matters because symptoms may fluctuate, yet ongoing synovial inflammation can injure cartilage and bone before a patient has dramatic deformity or severe disability.
Apply it
A patient has several months of bilateral wrist and knuckle swelling with morning stiffness lasting over an hour. Recognise an inflammatory polyarthritis pattern and arrange prompt assessment rather than attributing the symptoms solely to repetitive hand use.
Common pitfall: Mechanical pain and inflammatory synovitis can coexist. Reassurance based on preserved function or absent deformity may delay recognition of early rheumatoid arthritis and allow damage.
54.How should rheumatoid arthritis-associated interstitial lung disease be recognized and investigated?
Rheumatoid arthritis can cause inflammation and scarring of lung tissue, producing interstitial lung disease (ILD). Progressive exertional breathlessness, persistent dry cough, and fine inspiratory crackles raise suspicion even when joint symptoms are modest. Investigate symptomatic patients with high-resolution chest CT (HRCT) to characterize interstitial abnormalities and pulmonary function tests (PFTs), including spirometry, lung volumes, and diffusing capacity for carbon monoxide (DLCO), to assess physiological impairment. Imaging and physiology provide complementary information; neither symptoms nor auscultation alone reliably exclude ILD.
Apply it
A patient with rheumatoid arthritis develops months of dry cough, worsening exertional dyspnea, and bibasal inspiratory crackles. Assess oxygenation, obtain HRCT and complete PFTs, and arrange coordinated pulmonary and rheumatology assessment. Review the symptom time course, medication exposures, and evidence of infection rather than assigning the cause from the arthritis diagnosis alone. Interstitial abnormalities accompanied by reduced lung volumes and DLCO support clinically significant pulmonary involvement.
Common pitfall: Diagnostic evaluation of new respiratory symptoms differs from screening an asymptomatic patient. The [ACR screening guideline](https://rheumatology.org/api/asset/blt7e2cadfc7bc986fb) conditionally recommends HRCT plus PFTs for patients at increased ILD risk, rather than universal CT screening of everyone with rheumatoid arthritis. Risk factors include smoking and older age at arthritis onset. Chest radiography alone is an inadequate screening strategy. Infection and medication toxicity can mimic disease-associated lung injury.
Rheumatoid Arthritis Symptoms, Causes, & Risk Factors · Rheumatoid Arthritis: Diagnosis, Treatment, and Steps to Take
55.How do rheumatoid antibodies support rather than replace clinical diagnosis?
Rheumatoid factor and anti-cyclic citrullinated peptide antibodies can support rheumatoid arthritis when a compatible inflammatory joint pattern is present. No single blood test establishes the diagnosis independently, and some patients do not have detectable antibodies. Clinical examination, duration and distribution of synovitis, inflammatory markers, and imaging contribute to assessment. A positive antibody result in a patient without inflammatory arthritis should therefore be interpreted differently from the same result in someone with persistent symmetric swollen joints.
Apply it
A patient has persistent symmetric wrist and metacarpophalangeal synovitis but negative rheumatoid factor. Continue a structured inflammatory arthritis assessment rather than excluding rheumatoid arthritis solely because one commonly associated antibody was not detected on initial testing.
Common pitfall: Antibody positivity without the right syndrome can mislead, while seronegativity can falsely reassure. Clinical synovitis and its pattern remain central to interpretation of laboratory findings.
Rheumatoid Arthritis: Diagnosis, Treatment, and Steps to Take
56.How should urgent treatment and diagnostic confirmation be coordinated in giant cell arteritis?
New headache, scalp tenderness, jaw claudication, or visual symptoms in an older adult should raise concern for giant cell arteritis. Strong suspicion warrants treatment without waiting for biopsy. Threatened vision favours pulse intravenous glucocorticoids; without cranial ischaemia, high-dose oral treatment is generally preferred. Arrange temporal artery biopsy promptly, preferably within two weeks of starting oral glucocorticoids, because treatment does not immediately eliminate diagnostic yield. Baseline large-vessel imaging can assess aortic and branch involvement; it is also useful when biopsy is negative but suspicion persists.
Apply it
An older patient has temporal headache, jaw claudication, and transient monocular visual loss. Begin emergency treatment for threatened vision and arrange confirmation. If biopsy is negative but limb claudication or other findings sustain suspicion, pursue large-vessel assessment.
Common pitfall: Waiting for biopsy or permanent visual loss can forfeit vision. A negative temporal artery specimen does not exclude disease in other arterial territories.
Geriatric Syndromes3%
59.How does delirium differ from a chronic cognitive decline?
Delirium is an acute change in mental state that commonly includes impaired attention, disorientation, altered perception, or fluctuating alertness. Its development over hours or days contrasts with the usual longer course of a chronic cognitive disorder, although delirium can occur on top of dementia. Sudden confusion requires urgent assessment for an underlying cause. Information from family or carers about baseline cognition and timing is often essential because the affected patient may provide an unreliable history.
Apply it
A patient with mild stable memory impairment becomes inattentive and disoriented overnight, alternating between drowsiness and agitation. Treat the abrupt change as possible delirium requiring urgent assessment rather than assuming it is inevitable progression of the pre-existing memory disorder.
Common pitfall: Quiet, drowsy delirium can be missed if only agitation is recognised. Existing dementia increases diagnostic difficulty but does not make a sudden cognitive change routine or harmless.
60.Why should acute confusion trigger a broad search for causes?
Sudden confusion can arise from infection, hypoglycaemia, stroke, medicines, intoxication or withdrawal, and other acute physiological disturbances. Initial assessment should establish urgency, check readily reversible threats, review recent changes, and seek collateral history. A positive urine culture should not end the investigation when urinary symptoms and systemic infection signs are absent. The aim is to identify the precipitating illness or exposure while providing a calm, supported environment and appropriate medical assessment.
Apply it
An older patient becomes suddenly confused after a medication change and poor oral intake. A urine culture is positive, but there is no fever or urinary complaint. Review glucose, hydration, medicines, and other causes rather than anchoring on bacteriuria.
Common pitfall: A common incidental abnormality can distract from a time-sensitive cause. The rule against treating asymptomatic bacteriuria does not justify overlooking fever, instability, or another serious infection.
Sudden confusion (delirium) · IDSA 2019 Clinical Practice Guideline Update for the Management of Asymptomatic Bacteriuria
What to focus on during revision
The following are CertMedbry study suggestions. Use the official outline to check the full scope of your examination.
- Give Cardiovascular Disease the largest share of study time and account for hypertension’s 5% contribution across specialties. Revisit the five 9% categories regularly.
- Within Pulmonary Disease, prioritise obstructive airway disease and evaluation of common symptoms, each assigned 2.5%, alongside the selected pleural decisions.
- Practise thresholds with their conditions: HFrEF medication eligibility, diabetes confirmation, ascitic neutrophils, pleural pH, CKD chronicity, UACR units, SIADH exclusions, and HIV prophylaxis criteria.
- Link each test to its limitations: early central adrenal insufficiency, IgA-deficient celiac testing, negative myasthenia antibodies, ferritin during inflammation, and nondiagnostic transthoracic echocardiography.
- Recognise findings that change urgency: anaphylaxis, acute hypertensive organ injury, cord compression, threatened vision in giant cell arteritis, ectopic rupture, retinal warning symptoms, and delirium.
- Practise informed refusal, small PDSA tests, interpreter use, and teach-back as clinical decisions. Use the complete official outline to extend this selective coverage.
A practical preparation plan
1. Map the complete outline
Read the January 2026 CERT outline and mark each subsection as secure, uncertain, or unfamiliar. Use its approximate category and subsection weights to allocate study time while preserving scheduled coverage of smaller categories.
2. Explain each decision aloud
For each concept, state the mechanism, decisive cue, action, and boundary without looking. Then change one feature of the mini-case, such as pregnancy, low flow, IgA deficiency, or haemodynamic instability, and explain how the decision changes.
3. Complete the questions independently
Answer all 20 questions before reading explanations. For every option, identify the finding that supports or weakens it. Record errors as a missing fact, misinterpreted test, overlooked qualifier, or incorrect priority.
4. Revisit calculations and thresholds
Recalculate UACR, serum–ascites albumin gradient, and Light’s criteria with new numbers. Pair every threshold with its clinical context so a memorised number does not override specimen quality, chronicity, flow, or physiological stability.
5. Space recall and broaden coverage
Review cards after increasing intervals and return difficult items to earlier review. Use a larger independent question resource and ABIM’s official tutorial to broaden clinical and media interpretation practice beyond this selective set.
Use your sample score as a starting point
The free set contains 20 original practice questions. It is a small learning sample, not an official examination or a validated pass prediction. Review each explanation and its source before moving to another topic.
Start the free sampleOfficial sources and updates
- Register, Prepare For and Take Your Internal Medicine Certification Exam
- Internal Medicine Blueprint: Certification Examination (CERT), January 2026
- Internal Medicine & Subspecialty Policies
- New ACC, AHA, HFSA Guideline Updates Recommendations For Managing HF
- 2020 ACC/AHA Heart Valve Disease Guideline: Key Perspectives, Part 3
- Managing Patients With Moderate Aortic Stenosis: Key Points
- Graves’ Disease
- Symptoms & Causes of Adrenal Insufficiency & Addison's Disease
- Diagnosis of Adrenal Insufficiency & Addison's Disease
- Celiac Disease Tests
- Why Timing Matters: Paracentesis on Admission for Cirrhosis with Ascites
- Anemia: Iron-Deficiency Anemia
- IDSA 2019 Clinical Practice Guideline Update for the Management of Asymptomatic Bacteriuria
- Pneumocystis Pneumonia: Adult and Adolescent Opportunistic Infections
- Identify & Evaluate Patients with Chronic Kidney Disease
- Assess Urine Albumin
- Myasthenia gravis: Diagnosis
- Myasthenia gravis: Symptoms
- The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in small-cell lung cancer
- Small Cell Lung Cancer Treatment (PDQ): Health Professional Version
- British Thoracic Society Guideline for Pleural Disease and Clinical Statement on Pleural Procedures, July 2023
- Rheumatoid Arthritis Symptoms, Causes, & Risk Factors
- 2021 American College of Rheumatology/Vasculitis Foundation Guideline for Giant Cell Arteritis and Takayasu Arteritis
- Sudden confusion (delirium)
- World Allergy Organization Anaphylaxis Guidance 2020
- What to look for: ABCDEs of melanoma
- Ectopic pregnancy
- Retinal Detachment
- Sudden Hearing Loss: Update to Guideline to Improve Implementation and Awareness
- Bipolar Disorder
- Iron-Deficiency-Aneamia-in-Adults.pdf
- KDIGO-2024-CKD-Guideline.pdf
- FDA approves durvalumab for limited-stage small cell lung cancer | FDA
- Rheumatoid Arthritis: Diagnosis, Treatment, and Steps to Take
- Anaphylaxis_Guidelines_Poster.pdf
- Ectopic pregnancy - Diagnosis - NHS
- Diabetes Tests & Diagnosis - NIDDK
- Diagnosis - Lambert-Eaton Myasthenic Syndrome (LEMS) - Diseases | Muscular Dystrophy Association
- Recommendations | Spinal metastases and metastatic spinal cord compression | Guidance | NICE
- Harms of Cigarette Smoking and Health Benefits of Quitting - NCI
- Bipolar and Related Disorders | Veterans Affairs Canada
- Spirometry Quick Guide - Global Initiative for Chronic Obstructive Lung Disease - GOLD
- Nephrol.%20Dial.%20Transplant.-2014-Spasovski-i1-i39.pdf
- blt7e2cadfc7bc986fb
- Low-Flow/Low-Gradient AS: Intervention vs. No Intervention - American College of Cardiology
- VA-DOD-CPG-BD-Full-CPGFinal508.pdf
- GINA-Summary-Guide-2026-WEB-WMS.pdf
- Resource-Document-2019-Decisional-Capacity-Determinations-in-Consultation-Liaison-Psychiatry.pdf
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