A clinical reasoning companion for the USMLE Step 2 CK

Don't memorize.
Reason.

Step 2 CK is not a trivia test. Every vignette is a diagnostic exercise: take the chief complaint, build the differential, narrow with the next right question, pick the next right action. This reference teaches you to think like the exam thinks, organized by organ system and driven by chief complaints rather than disease lists.

Organ systems
10
Chief complaints
35+
Diagnoses covered
140+
Classic vignettes
80+
01

Systems

START HERE

Every organ system opens with its high-yield chief complaints. Each complaint gives you the full differential, the can't-miss diagnoses, the workup sequence, and a classic vignette. Deep dives on individual diseases sit one click away.

♥
01 · 16%
Cardiovascular
Chest pain, dyspnea, palpitations, syncope, edema. The most heavily tested system.
5 complaints18 diagnoses
◯
02 · 11%
Pulmonary
Obstructive vs restrictive vs vascular vs infectious. Dyspnea and cough lead.
3 complaints12 diagnoses
∫
03 · 9%
Gastrointestinal
Abdominal pain by location. GI bleeding, jaundice, diarrhea patterns.
4 complaints16 diagnoses
∂
04 · 8%
Renal & GU
AKI, CKD, electrolytes, acid-base, hematuria. Nephritic vs nephrotic.
4 complaints14 diagnoses
§
05 · 8%
Neurology
Headache, focal deficit, altered mental status, seizures, weakness.
5 complaints14 diagnoses
◈
06 · 7%
Endocrine
Diabetes, thyroid, adrenal, pituitary, calcium. Classic labs patterns.
3 complaints14 diagnoses
∞
07 · 8%
Infectious Disease
Fever workup, sepsis, meningitis, endocarditis, HIV, travel infections.
3 complaints14 diagnoses
ΩΩ
08 · 10%
OB / Gyn
Pregnancy, bleeding, contraception, prenatal screening, complications.
4 complaints16 diagnoses
↟
09 · 8%
Pediatrics
Fever, rash, failure to thrive, respiratory distress, developmental red flags.
4 complaints14 diagnoses
ψ
10 · 9%
Psychiatry
Mood, anxiety, psychosis, substance use, personality. Suicide risk assessment.
4 complaints14 diagnoses
02

The method

HOW TO THINK

Every Step 2 CK question can be attacked the same way. The question writer gives you a story designed to land you on a diagnosis (or a branch point), then asks about it. Your job is to resist the urge to read passively. Read like a clinician taking a history.

i.
Anchor on the chief complaint
The first line is not filler. When you see 65M with crushing substernal chest pain, a short mental list of five to seven diagnoses should fire immediately. If it doesn't, you're reading passively. Build the list before reading the rest.
ii.
Read demographics as risk factors
Age, sex, race, occupation, travel, smoking, alcohol are never decorative. A 23-year-old African-American woman with fatigue is sarcoidosis or SLE until proven otherwise. A 58-year-old man with 40 pack-years and hemoptysis has lung cancer.
iii.
Let the exam narrow the tree
Each sign is a fork in the differential. Pulsatile abdominal mass in a smoker is AAA. Unilateral lower extremity edema is DVT. JVD with clear lungs is tamponade or RV failure. Let findings eliminate branches.
iv.
Pick the next best step
The question is almost always what do you do next, not what do you do total. Next step is the cheapest, fastest, safest test that narrows the differential, or the intervention that prevents imminent harm. ABCs beat CTs.
v.
Rule out the killers first
Every chief complaint has a shortlist of diagnoses that kill. Chest pain: MI, PE, dissection, tamponade, tension pneumo, esophageal rupture. Headache: SAH, meningitis, stroke, GCA. Name them before chasing outpatient differentials.
vi.
Match the question, not the topic
A stem about pneumonia may end with a question about smoking cessation counseling. The topic is pulmonary; the answer is preventive medicine. Read the actual question twice before scanning answer choices.
03

Reason with the agents

AI, GROUNDED IN THE REFERENCE

Two AI tools that read from the same Clinica reference you do. The Study assistant walks you through differentials and cites the section it pulled from. The Practice generator drafts single-best-answer vignettes on demand. Both are best treated as warm-up — keep UWorld for your primary practice.

AGENT · 01
Study chat
Ask any clinical reasoning question. Streaming answers grounded in the Clinica content with inline citations. Great for "what's the next best step" walkthroughs.
Sonnet 4.6Citations
?
AGENT · 02
Practice vignettes
Generate Step 2-style single-best-answer questions on demand. Pick a system, difficulty, and optional focus. Five choices, full explanation, distractor analysis, pearls.
Opus 4.750 / day
04

Get started

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