Four cases of cerebrovascular disease following varicella infection are reported from the Giannina Gaslini Children’s Hospital and Research Institute, Genoa, Italy. All were male, and ages ranged from 6 months to 6 years. Primary varicella zoster viral (VZV) infection was confirmed by detection of specific IgM antibodies. None was immunocompromised. Three children presented with hemiparesis and one with facial paresis, hypotonia and gait impairment. Neuroimaging with MRI, MRA, and/or CT showed occlusion or stenosis of the middle cerebral artery in 3 cases or nucleo capsular signal alteration without vessel occlusion in one. The incubation time from rash to onset of stroke was 2 to 30 days. Congenital prothrombotic abnormalities present in 2 cases, and a concurrent streptococcal bacteremia in one other may have contributed to the cerebrovascular disease. Treatment included acyclovir and acetylsalicylic acid (ASA). One patient developed cerebral hemorrhage and ASA was discontinued. The 3 patients with hemiparesis had persistent deficits on follow-up. The facial palsy resolved. 
COMMENT. Pathogenic mechanisms for varicella-associated stroke include vasculitis, acquired protein S deficiency, antiphospholipid and anticardiolipin antibodies, and lupus anticoagulant activity. No common mechanism is described. Antiphospholipid antibody was positive in 2 of the above 4 cases; it became negative after 1 month follow-up. VZV infection is a rare but significant cause of stroke in children.
Varicella and delayed stroke. Acute hemiplegia developed 7 weeks to 4 months after varicella infection in 4 children in Japan . Carotid angiography showed segmental narrowing and occlusion of the middle cerebral artery, and cerebral angiitis was cited as the cause. The frequency of delayed stroke was estimated at 1 in 6500 cases of varicella in Japan.