Relapsing subarachnoid hemorrhage as a clinical manifestation in microscopic polyangiitis: a case report and literature review.

Microscopic polyangiitis (MPA) is a systemic small-vessel vasculitis associated with anti-neutrophil cytoplasmic antibody (ANCA) and predominantly causes kidney and pulmonary injuries. Subarachnoid hemorrhage, a life-threatening manifestation of the central nervous system (CNS), rarely occurs in patients with ANCA-associated vasculitis (AAV). We report the case of a young man with spontaneous SAH recurrence and active nephritis. The patient was treated with a glucocorticoid pulse and intravenous cyclophosphamide (CTX) in combination with decreasing cerebral perfusion pressure and analgesic therapy. All the patients' symptoms except the proteinuria resolved. We reviewed the clinical characteristics of 34 previously reported cases of SAH with AAV, comprising six cases of MPA, eight cases of granulomatosis with polyangiitis (GPA), and 19 cases of eosinophilic granulomatosis with polyangiitis (EGPA), and one case of unclassified AAV. All the cases showed features of active vasculitis. Concomitant nephritis and peripheral neuropathy were found in the MPA and EGPA cases with SAH, respectively. Renal and pulmonary manifestations were predominant in the patients with GPA and SAH. Ten patients had aneurysmal abnormalities, and six patients had cardiac abnormalities. Thirty-one patients were treated with glucocorticoids, and 18 patients received concurrent immunosuppressants. Patients with SAH had a mortality rate of 38.2%. The presence of cerebrovascular events or cardiac involvement in patients with AAV and SAH is associated with increased mortality of 64.3%. Our study indicates that SAH should be cautioned as a disease occurring in patients with AAV. Early diagnosis with aggressive immunosuppressive therapy can help improve the prognosis of patients with SAH.