Internal Medicine (General and Specialty Content)
Domain overview
The OMSB Internal Medicine (OEIM) domain tests whether you can move from an undifferentiated presentation to a safe, guideline-consistent next step across general internal medicine and its specialties: cardiology, pulmonology, gastroenterology, nephrology, endocrinology, hematology, infectious diseases, rheumatology and geriatrics. Questions reward structured problem representation, not isolated recall. State the syndrome, severity, likely mechanism and the single most useful next action.
Core rules
- Stabilize before diagnosing: airway, breathing, circulation and glucose take precedence over a clever differential.
- Use pretest probability to order tests; a high-probability pulmonary embolism warrants definitive imaging, not a D-dimer.
- Interpret labs in context: correct sodium for hyperglycemia, calculate anion and osmolal gaps, and confirm AKI with a change from baseline creatinine and urine output.
- Treat the dangerous reversible cause first: hyperkalemia with ECG changes gets calcium, insulin/dextrose and potassium removal; sepsis gets cultures and antibiotics within the first hour.
- Apply guideline thresholds: ADA glucose targets, KDIGO AKI staging, ACC/AHA acute coronary syndrome pathways, and Surviving Sepsis bundles.
- Reassess after each intervention; a response or nonresponse changes the differential.
Worked example
A 62-year-old man has sudden dyspnea, pleuritic chest pain and right calf swelling. HR 112/min, BP 128/76, SpO2 93% on room air. ECG shows sinus tachycardia. He is hemodynamically stable. The question asks the best next step. The presentation is high pretest probability for pulmonary embolism (Wells score positive). In a stable patient without contraindication, CT pulmonary angiography is the next step. D-dimer is appropriate only in low/intermediate probability; empiric thrombolysis is reserved for hemodynamic instability.
Traps
Don't choose the most likely diagnosis when the stem asks for the next step. Don't ignore severity labels (septic shock, STEMI, severe hypercalcemia). Don't order contrast imaging before checking renal function and allergy history when time permits. Don't attribute anemia to chronic disease without excluding iron deficiency.