A 10-year-old child is admitted with diabetic ketoacidosis (DKA). Blood glucose 450 mg/dL, pH 7.10, HCO3 8 mEq/L, Na 128 mEq/L, effective osmolality 310 mOsm/kg. IV fluids and insulin infusion are commenced. Six hours later, the child develops sudden headache, vomiting, altered consciousness, and anisocoria. The MOST likely complication and its primary pathophysiology are:
- A Hypoglycaemia from excess insulin; direct glucose deprivation of brain cells
- B Cerebral venous sinus thrombosis from dehydration-induced hypercoagulability
- C Cerebral oedema; rapid osmolar shift due to aggressive fluid or insulin therapy causing water influx into brain cells ✓
- D Intracerebral haemorrhage from severe thrombocytopenia in DKA
Explanation
Cerebral oedema is the most feared complication of DKA in children, occurring in 0.5–0.9% of paediatric DKA episodes but accounting for 60–90% of DKA mortality. The mechanism involves idiogenic osmoles (taurine, inositol, glutamine) that accumulate in brain cells during hyperosmolality; when serum osmolality falls rapidly (due to aggressive fluid resuscitation and insulin therapy), water follows the osmotic gradient into brain cells, causing cerebral oedema. Warning signs include headache, behavioural change, bradycardia, and Cushing's triad. Treatment is mannitol or hypertonic saline.
Reference: Ghai Essential Pediatrics, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.