Endocrine and Metabolic Disorders
Diabetic emergencies
DKA and HHS share treatment principles but differ in detail. DKA: ketotic, acidemic, variable glucose. HHS: profound hyperosmolality, larger free water deficit, minimal ketosis. For both, start isotonic fluid, check potassium before insulin (hold insulin if K under 3.3 mEq/L), run an insulin infusion around 0.1 unit/kg/h, add dextrose when glucose falls to about 200–250 mg/dL, and continue insulin until the anion gap closes and ketones clear. Transition to subcutaneous insulin with overlap to avoid rebound ketosis.
Other high-yield items
- ICU glucose target roughly 140–180 mg/dL with scheduled insulin rather than sliding scale alone.
- Adrenal crisis: hydrocortisone 100 mg then 50 mg every 6 hours plus isotonic fluid; do not delay steroids for a cosyntropin result.
- Thyroid storm: thionamide first, then iodine at least an hour later, plus beta-blockade and steroids; myxedema coma needs stress steroids before levothyroxine.
- Diabetes insipidus: desmopressin with free water replacement; distinguish from SIADH by urine osmolality and volume status.
Traps
Giving bicarbonate unless pH is profoundly low; dropping osmolality too fast in HHS; starting insulin before checking potassium; giving iodine before a thionamide; using sliding-scale-only insulin in a patient eating; forgetting that steroids raise glucose.
Worked example
A patient in DKA with K 3.0 mEq/L: replace potassium first, then start the insulin infusion once K is above 3.3 - insulin drives potassium intracellularly and can precipitate an arrhythmia.
Rule of thumb
Fluids, potassium, insulin - in that order - and keep insulin running until the gap closes, not until glucose normalizes.