Primary autoimmune hypothalamitis: management strategies and long-term outcomes in a tertiary care setting with a focused review of literature.

Background: Primary autoimmune hypothalamitis is an exceptionally rare inflammatory condition of the hypothalamus. Its etiology, clinical presentation, and management are not well established, with significant overlap and distinctions from hypophysitis.

Material and methods: This study presents management and outcomes of patients with autoimmune hypothalamitis managed at a tertiary care centre. A literature review was also performed analyzing clinico-demographic, biochemical, radiological, and therapeutic characteristics.

Results: There were 4 cases of autoimmune hypothalamitis out of 2200 sellar-suprasellar lesions managed over the past decade at our centre. Case 1 presented with arginine vasopressin (AVP) deficiency and adipsia, showing partial radiological response to glucocorticoids. Case 2 presented with neuropsychiatric features, with limited improvement on therapy. Case 3 had panhypopituitarism with stable disease on imaging, while Case 4 had AVP deficiency and hypogonadism with no significant radiological or hormonal recovery post therapy. Literature review (n = 34) of all cases showed female predominance (88%), but minimal association with pregnancy (6%). Polyuria-polydipsia was the most common presentation (81%), followed by memory disturbances and/or confusion (35%). Secondary hypogonadism was most common (88%) hormone deficiency followed by hypocortisolism (85%) and AVP deficiency (82%). T2 hyperintensity was the most common feature (95%) on MRI. Glucocorticoids enabled partial radiological response in most cases (82%), with hormonal recovery being less common (18%). Adjunctive medical therapy was required in 54.1% cases (most commonly azathioprine). Surgery was primarily used for biopsy and adjunctive radiotherapy in 3 cases. FDG-PET demonstrated utility in diagnosis, systemic involvement and follow-up.

Conclusion: Autoimmune hypothalamitis remains a challenging diagnosis due to its rarity and overlapping features with other sellar pathologies. Histopathological evaluation or circulating antibodies can point towards the diagnosis. FDG-PET can be valuable in diagnosis and follow-up. Glucocorticoids are the mainstay of treatment, with partial radiological response commonly observed.