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.