Infundibulo-neurohypophysitis

Infundibulo-neurohypophysitis is a rare inflammatory condition affecting the posterior pituitary gland (neurohypophysis) and the pituitary stalk (infundibulum). It is considered a subtype of primary hypophysitis, a group of autoimmune or inflammatory disorders targeting the pituitary gland. In this condition, inflammation is specifically localized to the posterior pituitary and infundibulum, distinguishing it from lymphocytic adenohypophysitis (which affects the anterior pituitary) and infundibulohypophysitis (which affects both regions). The condition is also sometimes referred to as lymphocytic infundibulo-neurohypophysitis when lymphocytic infiltration is the predominant histological finding. The hallmark clinical feature is central diabetes insipidus, resulting from impaired secretion of antidiuretic hormone (vasopressin) by the damaged posterior pituitary. Patients typically present with excessive thirst (polydipsia) and excessive urination (polyuria). MRI imaging characteristically shows thickening of the pituitary stalk and loss of the normal posterior pituitary bright spot on T1-weighted images. Some patients may also experience headaches and, less commonly, visual disturbances if the inflammatory mass exerts pressure on nearby structures such as the optic chiasm. Anterior pituitary function is generally preserved, though partial hypopituitarism can occasionally occur. Treatment primarily involves hormone replacement therapy with desmopressin (a synthetic vasopressin analogue) to manage central diabetes insipidus. In some cases, immunosuppressive therapy with high-dose glucocorticoids may be used to reduce inflammation, particularly when there is significant stalk thickening or mass effect. The condition may follow a relapsing-remitting course, and long-term follow-up is recommended to monitor for disease progression or the development of additional pituitary hormone deficiencies. The prognosis is generally favorable with appropriate management, though some patients may require lifelong desmopressin therapy.

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