Pituitary dysfunction in patients with ANCA associated vasculitis: prevalence, presentation, and outcomes

Hypophysitis Secondary to Small Vessel ANCA Vasculitis Treated With Rituximab

Background/Objective

Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis is a rare small vessel vasculitis that can cause pituitary hypophysitis. Hypophysitis is difficult to treat, often requiring high doses of glucocorticoids with frequent flaring as glucocorticoids are tapered. We present a case of ANCA vasculitis involving the pituitary gland successfully treated with rituximab.

Case Report

Fifty-one-year-old woman developed progressive frontal headaches, congestion, and epistaxis. Sinus computed tomography scan showed pituitary enlargement and chronic mucosal disease. Pituitary magnetic resonance imaging (MRI) confirmed a diffusely enlarged pituitary with a thickened pituitary stalk. Serologic evaluation revealed elevated inflammatory markers, positive perinuclear ANCA (p-ANCA), and an elevated serum anti-proteinase 3 (anti-PR3) antibody. The patient underwent pituitary biopsy, which showed adenohypophysitis with dense lymphoplasmacytic infiltration, some arranged perivascularly, compatible with involvement of the pituitary gland by ANCA vasculitis. The patient began rituximab and reported resolution of daily headaches, congestion, and epistaxis. Pituitary MRI scan 6 months after rituximab showed reduction in pituitary gland size and stalk thickening.

Discussion

ANCA vasculitis is a rare etiology of pituitary hypophysitis, which can present a diagnostic and therapeutic challenge. Pituitary involvement of ANCA vasculitis can be identified through p-ANCA or cytoplasmic ANCA (c-ANCA) and biopsy of the involved tissue. Rituximab, a monoclonal antibody against CD20, has been successfully used to treat ANCA vasculitis and in this case, led to clinical improvements and reduction in the size of the pituitary gland.

Conclusion

Pituitary biopsy enabled confirmation of ANCA hypophysitis and facilitated treatment with a steroid-sparing agent.

Clinical characteristics and primary outcomes of patients with ANCA-associated vasculitis and central diabetes insipidus

Introduction

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is characterized by systemic small-vessel vasculitis and may rarely present as central diabetes insipidus (CDI). In this study, we aimed to determine the clinical characteristics and prognosis of patients with AAV-associated CDI.

Methods

This was a nested case-control study where AAV patients with CDI at the Peking Union Medical College Hospital were followed from January 2012 to April 2022. Case-control matching with AAV patients without CDI was performed (1:5), and participants were matched by age, sex, and AAV classification. We collected clinical data every 3-6 months and conducted a literature review using PubMed to identify relevant articles published from 1983-2022.

Results

Among 1203 hospitalized AAV patients, 16 patients with CDI were included (1.3%). The average age was 49 years, and men accounted for 56.3%. Granulomatosis with polyangiitis (GPA) accounted for 87.5% of patients. AAV patients with CDI had more ear, nose, and throat (ENT) (81.3%) involvement and less renal impairment than those in the control group (P<0.05). After a mean follow-up of four years, 50% of patients were in remission from AAV, 37.5% relapsed, and 12.5% died. Our literature review suggested that patients in Asian countries tend to be older men and have higher myeloperoxidase (MPO-ANCA) positivity than those in Western countries. Furthermore, proteinase 3 (PR3-ANCA) positivity may predict disease recurrence.

Discussion

AAV patients with CDI had more ENT involvement and a higher eGFR. MPO-ANCA positivity is more commonly observed in Asian countries than Western countries, and PR3-ANCA positivity may predict recurrence.