Bowel and Small Joint Involvement in Granulomatosis With Polyangiitis: A Case Report

We discuss the case of a 45-year-old male with complaints of abdominal pain, loose stools with on and off melena, and multiple joint pains bilaterally. The patient reported having similar episodes in the past, with slight variations in the symptoms and relief with short courses of steroids. Initially, a workup was done to identify an infectious etiology of the diarrhea. However, no such cause was identified. Similarly, an autoimmune profile was ordered to investigate the patient's joint complaints, albeit with no conclusive findings. His renal function tests and urinalysis showed findings indicative of an acute kidney injury. This prompted an antineutrophil cytoplasmic antibody (ANCA) profile, which was positive for c-ANCA. A diagnosis of granulomatosis with polyangiitis (GPA) was made, and the patient was started on pulse steroid and immunomodulator therapy with improvement in the patient's condition. This case is atypical due to its involvement of the gastrointestinal system, which is relatively rare, as well as polyarthritis of the small joints.