Internal Medicine: Safe First Steps and Common Emergencies
What this domain tests
Internal Medicine questions move from a short vignette to the safest next step. Expect chest pain, breathlessness, fever, altered consciousness, edema, jaundice, ECG interpretation, acid–base disorders, endocrine emergencies, and rational antibiotic choice. The exam rewards the first 30 minutes of management more than rare syndromes.
Core rules
- Resuscitate before diagnosing: airway, breathing, circulation, capillary glucose, and a focused bedside set.
- Read acid–base status in order: pH, PaCO2, HCO3, anion gap, then compensation.
- In diabetic ketoacidosis, begin isotonic saline, check potassium, and start insulin only when K+ is known and adequate (>3.3 mmol/L).
- For suspected acute coronary syndrome, obtain an ECG within 10 minutes and give aspirin unless contraindicated.
- Treat hyponatremia according to symptoms and chronicity, not the number alone.
Worked example
A 22-year-old with type 1 diabetes has vomiting, Kussmaul breathing, glucose 28 mmol/L, pH 7.10, HCO3 8 mmol/L, and K+ 3.0 mmol/L. This is DKA with hypokalemia. Give isotonic saline and replace potassium; withhold insulin infusion until K+ is corrected, because insulin shifts potassium intracellularly and can trigger arrhythmia. Bicarbonate is not routine at pH 7.10. Look for infection and continue fluid reassessment.
Traps
Giving insulin before fluids and potassium; missing euglycemic DKA with SGLT2 inhibitors; calling a high anion gap “normal” because chloride is normal; treating every wheeze as asthma without considering pulmonary edema; ignoring a normal ECG in ongoing chest pain.
Exam strategy
Anchor each answer to stability: unstable patients get resuscitation and bedside treatment, not lengthy investigation. For stable patients, choose the test that changes management.