Endocrinology and Nephrology
Endocrinology and nephrology tests diabetic emergencies, thyroid and adrenal disorders, electrolyte correction, and acute and chronic kidney disease. The exam focuses on safe sequencing: fluids before insulin, potassium before bicarbonate, and cause before creatinine.
Core rules
- DKA: hyperglycemia, ketosis, acidosis; fluids first, insulin infusion 0.1 U/kg/h, potassium replacement if <5.2 mmol/L and urine output is adequate; add dextrose when glucose <14 mmol/L; bicarbonate only if pH <6.9.
- HHS: glucose >33.3 mmol/L, osmolality >320 mOsm/kg, minimal ketosis; fluids and insulin; correct osmolality slowly.
- Thyroid: TSH first; primary hypothyroidism shows high TSH and low FT4; Graves disease shows TSI/TRAb; thyroid storm: beta-blocker, PTU, iodine after PTU, steroids.
- Adrenal crisis: hypotension, hyponatremia, hyperkalemia; draw cortisol/ACTH then give hydrocortisone immediately with fluids.
- CKD/AKI: KDIGO AKI is creatinine rise ≥0.3 mg/dL in 48 hours or ≥1.5× baseline in 7 days; assess albuminuria; ACE inhibitor/ARB and SGLT2 inhibitor for CKD with albuminuria.
Worked example
A 22-year-old with type 1 diabetes has vomiting, glucose 28 mmol/L, pH 7.10, HCO3 10 mmol/L, ketones 5 mmol/L, and K 5.6 mmol/L. This is DKA: start 0.9% saline, give insulin infusion, and hold potassium until K <5.2 mmol/L; monitor ECG and renal function. Treat the precipitant and add dextrose when glucose falls below 14 mmol/L.
Traps
- Giving an insulin bolus before fluids.
- Routine bicarbonate in DKA.
- Missing potassium depletion despite a normal or high serum potassium.
- Treating HHS as DKA.
- Starting ACE inhibitor/ARB during AKI or without checking renal function.