Pleural effusions, seen in 12% of SLE patients, are usually exudative in nature. Like rheumatoid arthritis, the inflammation of the hands, specifically the proximal interphalangeal and the metacarpophalangeal joints, is symmetric. Clinical nephritis, defined as persistent proteinuria, is seen in approximately 50% of patients. Nervous system manifestations are varied and include seizures, stroke, psychosis, migraines, and peripheral neuropathies, but are rarely the initial sign. Pericarditis is the most common cardiac manifestation of SLE, reported in 30% of patients.