Endocrine, Metabolic and Electrolyte Emergencies
This domain tests diabetic ketoacidosis, hyperosmolar hyperglycaemic state, hypoglycaemia, thyroid storm, adrenal crisis, and dangerous electrolyte abnormalities. The exam expects correct sequencing of fluids, insulin, potassium, and definitive treatment.
Core rules
- DKA: start isotonic fluids, check potassium, and give insulin only after potassium is known and adequate. Add dextrose when glucose falls while continuing insulin to clear ketones.
- HHS: profound dehydration and hyperosmolality; fluid resuscitation is central, with cautious insulin and monitoring for cerebral oedema.
- Hypoglycaemia: give IV glucose or glucagon; recheck and provide longer-acting carbohydrate.
- Hyperkalaemia with ECG changes: give IV calcium, shift potassium intracellularly, and remove potassium from the body.
- Thyroid storm and adrenal crisis are clinical diagnoses; treat before confirmatory results return.
Worked example
A DKA patient has glucose 28 mmol/L and potassium 3.1 mmol/L. Give fluids and replace potassium before starting insulin; insulin will worsen hypokalaemia and can precipitate arrhythmia.
Traps
- Do not start insulin before checking potassium in DKA.
- Do not stop insulin when glucose normalises if ketones remain elevated; add dextrose instead.
- Do not correct sodium rapidly in chronic hyponatraemia.
- Do not miss adrenal crisis in unexplained shock unresponsive to fluids.