Diabetes insipidus as the first manifestation of granulomatosis with polyangiitis: A case report

Background: Granulomatosis with Polyangiitis (GPA) is a necrotizing granulomatosis vasculitis that may influence most organs, but posterior pituitary involvement as the first manifestation is unusual. However, there are some case reports in this regard. Case presentation: A 49-year-old menopausal woman presented with polyuria, polydipsia and weight loss over time headache, purulent nasal discharge, malaise, ear pain developed. After right myringotomy due to secretory otitis media and nasal cavity biopsy, the symptoms exacerbated. Diabetes insipidus was documented by Deprivation test. Thus, 20 microgram nasal spray DDAVP was prescribed. Pituitary MRI +/- Gad demonstrated pituitary involvement. Pituitary axis hormone evaluation was consistent with menopausal state. Chest spiral CT scan showed speculated border soft tissue mass lesion. GPA confirmed with ACR criteria and C-ANCA positive. Therefore, corticosteroid and rituximab were started. Symptoms of DI responded well to the treatment and the spray dosage was decreased. Conclusion: DI can be the first manifestation of GPA; although it is rare, it is worth to be diagnosed early and serious treatment of vasculitis should be started to prevent irreversible damage to the hypophysis cell and unnecessary procedure.