Master Internal Medicine
for USMLE Step 2 CK
Access 50+ high-yield questions tailored for the 2026 syllabus. Includes AI-powered explanations and performance tracking.
Core Concepts
Internal Medicine on USMLE Step 2 CK emphasizes a structured approach to common adult diseases, focusing on differential diagnosis, initial workup, and first-line management. Key principles include recognizing life-threatening conditions, understanding pathophysiology, and applying evidence-based medicine. Many questions test the ability to interpret lab results, imaging, and patient history to arrive at the most likely diagnosis and appropriate intervention. Always consider patient comorbidities and drug interactions.
Clinical Presentation
- Cardiology: Chest pain (anginal vs. pleuritic vs. positional), dyspnea (exertional, orthopnea, PND), palpitations, syncope, peripheral edema.
- Pulmonology: Cough (acute vs. chronic, productive vs. dry), dyspnea (acute vs. chronic, inspiratory vs. expiratory), hemoptysis, wheezing, pleuritic chest pain.
- Gastroenterology: Abdominal pain (location, character, radiation), nausea/vomiting, diarrhea/constipation, GI bleeding (hematemesis, melena, hematochezia), jaundice, dysphagia.
- Nephrology: Edema, changes in urine output, flank pain, hematuria, polyuria/polydipsia, symptoms of uremia (fatigue, pruritus, altered mental status).
- Endocrinology: Weight changes (gain/loss), polyuria/polydipsia, heat/cold intolerance, fatigue, changes in skin/hair, mood disturbances.
- Rheumatology: Joint pain/swelling (monoarticular vs. polyarticular, inflammatory vs. mechanical), morning stiffness, rash, oral ulcers, photosensitivity, Raynaud's phenomenon.
- Hematology/Oncology: Fatigue, pallor, easy bruising/bleeding, recurrent infections, unexplained weight loss, night sweats, lymphadenopathy.
- Infectious Disease: Fever, chills, myalgias, localized pain, rash, lymphadenopathy.
Diagnosis (Gold Standard)
Often involves a combination of clinical picture, labs, and imaging.
- MI: ECG changes (ST elevation/depression, T-wave inversion) + cardiac troponins.
- Heart Failure: Echocardiogram (EF, ventricular function).
- Pulmonary Embolism (PE): CT Pulmonary Angiography (CT-PA).
- COPD/Asthma: Spirometry (FEV1/FVC ratio).
- Peptic Ulcer Disease (PUD): Upper Endoscopy.
- Acute Pancreatitis: Lipase >3x ULN + characteristic abdominal pain.
- IBD (Crohn's/UC): Colonoscopy with biopsy.
- Chronic Kidney Disease (CKD): eGFR <60 for >3 months + albuminuria.
- Diabetes Mellitus: HbA1c ≥6.5% OR FBG ≥126 mg/dL OR 2hr OGTT ≥200 mg/dL OR random BG ≥200 mg/dL with symptoms.
- Hypothyroidism: Elevated TSH, low Free T4.
- Gout: Synovial fluid analysis showing negatively birefringent needle-shaped crystals.
- Lupus (SLE): Clinical criteria + positive ANA (highly sensitive).
- Sepsis: Suspected infection + new organ dysfunction (SOFA score).
Management (First Line)
- MI (STEMI): Aspirin, P2Y12 inhibitor, nitrates, statin, O2, morphine + prompt reperfusion (PCI within 90-120 min or fibrinolytics).
- Heart Failure (HFrEF): ACEi/ARB, beta-blocker, aldosterone antagonist, SGLT2 inhibitor. Loop diuretics for symptom relief.
- Hypertension: Lifestyle modifications. First-line agents: Thiazide diuretics, ACEi/ARB, CCB.
- PE: Anticoagulation (heparin products, then oral DOACs). Thrombolysis for massive PE with hemodynamic instability.
- COPD Exacerbation: SABA, systemic corticosteroids, antibiotics if signs of bacterial infection.
- Asthma Exacerbation: SABA, systemic corticosteroids.
- PUD: PPI. H. pylori eradication (PPI + 2-3 antibiotics) if present.
- Acute Pancreatitis: Aggressive IV fluids, pain control, NPO.
- Diabetic Ketoacidosis (DKA): IV fluids, insulin drip, potassium replacement.
- Hypothyroidism: Levothyroxine.
- Gout Flare: NSAIDs (e.g., indomethacin), colchicine, or oral corticosteroids.
- Septic Shock: IV fluid resuscitation (30ml/kg crystalloids), broad-spectrum antibiotics (within 1 hour), vasopressors (norepinephrine) if hypotension persists.
- Community-Acquired Pneumonia (CAP): Macrolide or doxycycline (outpatient); ceftriaxone + azithromycin/doxycycline or fluoroquinolone (inpatient).
Exam Red Flags
- Acute Chest Pain + ST Elevation/New LBBB: STEMI - activate cath lab!
- Acute Dyspnea + Hypotension + Tachycardia: Consider PE, cardiac tamponade, tension pneumothorax.
- Sudden, Severe Headache + Stiff Neck: Meningitis or subarachnoid hemorrhage.
- Abdominal Pain + Peritoneal Signs + Hypotension: Surgical emergency (e.g., perforation, ruptured AAA, mesenteric ischemia).
- GI Bleed + Hemodynamic Instability: Requires immediate fluid resuscitation, blood products, and emergent endoscopy/intervention.
- Altered Mental Status + Fever + Hypotension: Sepsis/Septic Shock - STAT fluids and broad-spectrum antibiotics.
- Acute Unilateral Vision Loss + Pain on Eye Movement: Optic neuritis (often MS).
- Unilateral Weakness/Numbness + Facial Droop + Aphasia: Stroke - activate stroke protocol!
- Diabetic + Altered Mental Status + Kussmaul Respirations: DKA.
Sample Practice Questions
A 30-year-old woman presents with a 1-week history of low-grade fever, persistent non-productive cough, malaise, and mild dyspnea. She has no significant past medical history and does not smoke. Physical examination reveals scattered crackles on lung auscultation, but no signs of consolidation. A chest X-ray shows diffuse interstitial infiltrates. Sputum Gram stain reveals few neutrophils and no predominant organisms.
A 62-year-old female, 3 days status post-abdominal hysterectomy, develops sudden onset dyspnea, pleuritic chest pain, and a cough. Her vital signs are: HR 105 bpm, RR 24 breaths/min, BP 120/80 mmHg, and O2 saturation 90% on room air. Physical examination reveals clear lungs. An ECG shows sinus tachycardia. Laboratory tests reveal an elevated D-dimer. Which of the following is the most appropriate next diagnostic step given the suspicion?
A 28-year-old male with type 1 diabetes mellitus presents to the emergency department with 2 days of polyuria, polydipsia, generalized weakness, and confusion. His blood pressure is 90/60 mmHg, heart rate 110 bpm, respiratory rate 28 bpm with Kussmaul breathing. Laboratory results show blood glucose 680 mg/dL, pH 7.15, bicarbonate 8 mEq/L, anion gap 24, and serum potassium 5.8 mEq/L. What is the most critical initial intervention in the management of this patient?
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