Diabetes insipidus is an unfavorable prognostic factor for response to glucocorticoids in patients with autoimmune hypophysitis.

Introduction: Autoimmune hypophysitis (AH) has a variable clinical presentation and natural history; likewise, its response to glucocorticoid therapy is often unpredictable.
Objective: To identify clinical and radiological findings associated with response to glucocorticoids.
Design and Methods: 12 consecutive patients with AH, evaluated from 2008 to 2016. AH was the exclusion diagnosis after ruling out other pituitary masses and secondary causes of hypophysitis. Mean follow-up time was 30 ± 27 months (range 12-96 months).
Results: MRI identified two main patterns of presentation: global enlargement of the pituitary gland or panhypophysitis ( n  = 4, PH), and pituitary stalk abnormality only, or infundibulo-neuro-hypophysitis ( n  = 8, INH). Multiple tropin defects were more common in PH (100%) than those in INH (28% P  = 0.014), whereas diabetes insipidus was more common in INH (100%) than that in PH (50%; P  = 0.028). All 4 PH and 4 out of 8 INH were treated with glucocorticoids. Pituitary volume significantly reduced in all PH patients ( P  = 0.012), defective anterior pituitary function recovered only in the two patients without diabetes insipidus (50%) and panhypopituitarism persisted, along with diabetes insipidus, in the remaining 2 (50%). In all INH patients, either treated or untreated, pituitary stalk diameter reduced ( P  = 0.008) but diabetes insipidus persisted in all.
Conclusions: Glucocorticoid therapy may improve anterior pituitary function in a subset of patients but has no effect on restoring posterior pituitary function. Diabetes insipidus appears as a negative prognostic factor for response to glucocorticoids.
(© 2017 European Society of Endocrinology.)