Neurologic manifestations of Henoch-Schönlein purpura.

Henoch-Shönlein purpura (HSP) is a systemic small vessel vasculitis. Most patients present during childhood. The characteristic association of purpura, arthralgia, abdominal pain, and nephritis reflects the predominant distribution of vasculitis. Headaches and mild behavioral changes suggest CNS involvement in one-third of HSP patients. Salient central nervous system (CNS) manifestations are rarer and mostly reported in adults and patients with a severe disease course. Diagnosis of CNS vasculitis is rarely confirmed by histopathology and generally relies on "suggestive" imaging showing brain hemorrhages, infarcts and edema, predominantly located in the parieto-occipital regions. Vessel wall friability and thrombogenicity of active vasculitis, antiphospholipid antibody synthesis, and other hemostatic disturbances may contribute to hemorrhagic and thrombotic complications of HSP. Posterior reversible encephalopathy syndrome and hypertensive encephalopathy occur in HSP and can be difficult to differentiate from CNS vasculitis. Some 53% of patients with neurologic complications experience seizures. Cerebral venous thrombosis, subdural hematoma, subarachnoidal hemorrhage, neuro-ophthalmologic complications, myelopathy, and diverse neuromuscular manifestations are also reported. In contrast with other systemic small vessel vasculitides, peripheral nervous system involvement is infrequent in HSP. Systemic involvement of HSP and homeostatic disorders such as hypertension, uremia, and electrolyte disturbances, as well as superimposed infections can affect the nervous system secondarily. Identification of nervous system complications of HSP is often challenging due to prominent systemic manifestations. HSP is usually a self-limiting disease that requires only supportive care. Patients with CNS vasculitis are commonly treated with corticosteroids. One-fifth of patients with CNS involvement remain with sequelae.