Which electrolyte disturbance is a potential complication of subarachnoid hemorrhage?

• A. Hyponatremia
• B. Hyperkalemia
• C. Hypercalcemia
• D. Hypophosphatemia

Answer: (A)

Subarachnoid hemorrhage often disrupts brain regulation of fluids and electrolytes, making hyponatremia a common and important complication. The brain injury can trigger excess antidiuretic hormone release (SIADH) or cause renal loss of sodium (cerebral salt wasting), both reducing serum sodium. Low sodium worsens cerebral edema and can lead to confusion, seizures, or other neurologic deterioration, so it’s a critical issue to monitor and treat promptly. Management hinges on the underlying cause and the degree of symptoms: fluid restriction for SIADH, cautious use of hypertonic saline for symptomatic hyponatremia, and careful correction pace to avoid osmotic demyelination. Hyperkalemia, hypercalcemia, and hypophosphatemia aren’t typical, specific complications of SAH in this context.