Abstract 58: Favourable outcomes with therapeutic glucocorticoid regimen compared to replacement glucocorticoid regimen in primary hypophysitis

Background: Primary hypophysitis (PH) is most commonly treated with glucocorticoids. But there is considerable variation in the treatment regimens. Aims and Objectives: We aimed to compare the outcomes of therapeutic versus replacement glucocorticoid regimens in PH. Therapeutic regimen (TR) comprised oral prednisolone (1mg/kg/d) for 6-12 weeks followed by tapering. Replacement regimen (RR) comprised standard hydrocortisone. Response was defined as complete recovery of all pituitary axes, without any requirement of hormonal replacement. Results: Mean age of the cohort (n=30) was 37.8 ± 10.4 years with a female preponderance (79.3%). Response to glucocorticoids was present in 23.3% of the cohort, all on TR. There was no difference between responders and non-responders in terms of age, gender, duration of symptoms or follow-up (p>0.05). Headache was more frequent in responders than non-responders (100% vs 57.1%, p<0.05). Secondary hypocortisolism (100% vs 71.4%), hypothyroidism (71.4% vs 52.4%), hypogonadism (71.4% vs 42.8%), hyposomatotropism (57.1% vs 25%) and hyperprolactinemia (85.7 vs 57.1%) were more common among responders (p<0.05). Diabetes insipidus was not different (42.3% vs 38%, p=0.56). Pituitary enlargement (100% vs 76.2%) and absent posterior pituitary bright spot (PPBS) (71.4% vs 57.1%) were more frequent among responders (p<0.05). Asymmetric enlargement was more common in non-responders (23.8% vs 0, p<0.05). Stalk thickening (80.9% vs 85.7%) and T2 parasellar dark intensity (28.5% each) were not different (p>0.05). The mass regressed in 85.7% in responders and 57.1% of non-responders at a mean follow-up duration of 4.6 ± 2.7 years. Conclusion: Response in PH is optimal with TR. Multiple hormone deficiencies, hyperprolactinemia, symmetric pituitary enlargement and absent PPBS portend favourable response, whereas asymmetric pituitary enlargement is more common among non-responders.