The MOST common electrolyte abnormality in acute intermittent porphyria is

(B). Hyponatremia is common during acute attacks. Inappropriate antidiuretic hormone secretion is often the most likely mechanism, but salt depletion from excess renal sodium loss, gastrointestinal loss, and poor intake have been suggested as causes of hyponatremia in some patients. Other electrolyte abnormalities may include hypomagnesemia and hypercalcemia