A Toluene-induced Infundibulo-neurohypophysitis: A New Cause of Hypophysitis Secondary to Toxic Exposure.

Background: Hypophysitis is a rare inflammatory disorder of the pituitary gland. Symptoms and signs of hypophysitis can be various, and its recognition may be challenging. Arginine vasopressin deficiency (AVP-D) due to exposure to a variety of drugs and toxic substances is rare, but some cases have been reported. Only 2 cases of AVP-D following toxic exposure to toluene, an aromatic hydrocarbon, have been reported in the literature. To our knowledge, our case represents the first description of an infundibulo neurohypophysitis (INH), manifested with AVP-D, secondary to inhalation of toluene.

Case report: A 59-year-old man with an unremarkable medical history was referred to our department for headache, polyuria, and polydipsia after the inhalation of spray film containing toluene. The blood tests revealed a hyperosmolar plasma hypernatremia with normal kidney function. A desmopressin test was performed, with an improvement in water balances, blood electrolytes, and diuresis contraction. A pituitary MRI detected the absence of a normal hyperintense signal of the neuro-pituitary in the T1-weighted images. In consideration of the clinical signs and radiological imaging suggestive of INH, a therapy with desmopressin and corticosteroids was instituted, with gradual improvement of polyuria and resolution of the radiological features of INH.

Conclusion: The exceptional finding of INH, manifested with AVP-D, following toluene inhalation could represent a new secondary cause of hypophysitis. The possibility that drugs or toxic substances never reported before could induce INH should not be excluded since the study on hypophysitis is relatively recent but emerging, predictably destined to increase exponentially in the coming years.