Seizure in a normal marrow donor: Addison's disease unmasked.

Adrenal insufficiency may be clinically occult yet cause life-threatening complications following even minor surgery. We report the case of a patient who became acutely hyponatremic after undergoing a marrow harvesting procedure using spinal anesthesia. The initial presentation mimicked the syndrome of inappropriate ADH (SIADH) secretion; however, further investigation revealed Addison's disease as the underlying cause.