Endocrine Abstracts

Introduction: Infundibuloneurohypophysitis (INH) is an autoimmune disease that typically presents as central diabetes insipidus (CDI). It is often more common in women with an autoimmune background. Here, we have the opportunity to describe an unusual case of a female patient who developed Sjögren’ syndrome (SJS) following CDI.

Case presentation: A 55-year-old female was admitted to our department for exploration of polyuoropolydipsic syndrome evolving for 8 years, of abrupt onset, estimated at 12L per day and associated with nyctiuria. The urine density was low at 1005. The urinary osmolarity was 60 mosml/l. The patient underwent the two-stage water deprivation test that strongly indicated the presence of CDI. After hydric restriction, the antidiuretic hormone vasopressin level was low (0.5 pmol/l). The pituitary MRI displayed the absence of classical posterior pituitary lobe hyperintensity in T1 and a decrease in anterior pituitary gland height with partial intrasellar arachnoidocele. Further endocrinological assessment did not reveal any pituitary axes impairement. The patient started oral desmopressin, experiencing a marked relief of polyuria, as well as polydipsia. After 2 years, the patient developed dry eye and mouth syndrome that were explored. She presented pulmonary and central neurological involvement characterized by demyelinating encephalic lesions. Immunological tests revealed positive antinuclear, antiSSA52 and antiSSA60 antibodies. The diagnosis of primary SGS was established based on 4 out of the 6 American-European criteria. She was treated with corticosteroids.

Conclusion: The diagnosis of the underlying condition of CDI is challenging and raises several concerns for patients as it requires long-term follow-up. This report outlines the notably rare association between INH, an inflammatory disorder of the pituitary gland revealed herein by CDI and primary SJS. The pathogenesis is poorly understood. However, the autoimmune origin is strongly suggested by its association with connective tissue disorders, particularly SJS.