Internal Medicine and Related Specialties for the Intensivist
Core concepts
Intensive care questions frequently test internal medicine reasoning. Understand the diagnosis and management of acute coronary syndromes, heart failure and arrhythmias, including the indications for rate versus rhythm control and anticoagulation. Know the causes of acute kidney injury, the prerenal versus intrinsic distinction, urinary indices and the indications for dialysis.
Respiratory medicine requires competence in asthma and COPD exacerbations, pulmonary embolism risk stratification, pleural effusion and pneumothorax management, and the interpretation of spirometry and chest imaging. Endocrinology topics include diabetic ketoacidosis and hyperosmolar states, thyroid storm and myxoedema coma, and adrenal insufficiency in the critically ill. Gastroenterology questions cover upper gastrointestinal bleeding, pancreatitis severity scoring and hepatic encephalopathy.
Neurology requires recognition of stroke mimics, the time window for thrombolysis and thrombectomy, status epilepticus algorithms, and the assessment of delirium versus dementia. Haematology questions test transfusion thresholds, heparin-induced thrombocytopenia and the approach to thrombocytopenia and coagulopathy.
Traps in questions
- Attributing AKI to prerenal causes without checking for nephrotoxins or obstruction.
- Using the same fluid strategy in heart failure as in sepsis.
- Missing thyroid or adrenal disease as a cause of refractory shock.
- Forgetting that heparin-induced thrombocytopenia paradoxically causes thrombosis.
- Treating delirium with sedation alone before addressing precipitants.
Worked example
A patient with a urinary sodium of 15 mmol/L, fractional excretion of sodium below 1% and bland urine sediment most likely has prerenal AKI. However, if diuretics have been given, the indices become unreliable and volume status must be judged clinically. Rule of thumb: treat the patient, not the number, and always exclude obstruction with imaging.