Systemic lupus erythematosus is an autoimmune disease associated with mild valvular regurgitation. However, there have been no detailed reports of infective endocarditis in patients with systemic lupus erythematosus. Here, we describe a case of a 55-year-old woman without any cardiac abnormalities who was diagnosed with lupus nephritis by renal biopsy; she contracted infective endocarditis while receiving immunosuppressive therapy. Our case emphasizes that special consideration of the occurrence of infective endocarditis, and its early diagnosis and treatment are mandatory for patient survival. We propose that echocardiography should be performed before treating patients with systemic lupus erythematosus who have an uncertain cardiac status.

Microscopic polyangiitis (MPA), an anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, is a systemic disease that damages all organs through predominantly affecting small vessels. However, few cases of MPA are related to aneurysms on medium-sized muscular vessels, and whether subarachnoid hemorrhage (SAH) is associated with MPA is still unclear. An 85-year-old woman with rapid progressive glomerular nephritis caused by MPA complained of sudden severe headache due to SAH 2 days after admission and subsequently underwent surgery. Cerebrovascular disease occurring simultaneously with MPA might result in poor prognosis, and the complications exacerbate the condition and lead to high mortality; thus, physicians should pay more attention to cerebral aneurysms concurrent with MPA. Among patients with MPA, it is important to identify priority cases and investigate the intracranial vessel environment. To the best of our knowledge, this is a rare report about SAH associated with MPA. We recommend that the presence of cerebrovascular disease should be considered in patients with MPA to improve their prognosis.