Varicella is an acute, febrile, exanthematous, and highly infectious disease that mostly occurs in childhood. Although varicella has usually an uncomplicated course in early childhood, severalcomplications may occur. The range of complications was thought to depend on the immune status and underlying diseases, such as chronic cutaneous or pulmonary disorders and immunosuppressive therapies. Immunocompromised individuals, especially those with T-cell defects, are at increased risk of dissemination of the virus to the internal organs, including lungs, liver, brain, heart, and kidneys. However, healthy individuals may experiencecomplications as well.

The neurological complications of varicella-zoster virus (VZV) may be categorized into those caused by the primary infection and those associated with virus reactivation. The latter is more frequent among elderly individuals and immunodeficient paticnts.Significant neurological involvement in immunocompetent children following VZV reactivation is exceptionally rare.

The main neurologic syndromes related to primary acute varicella (primary) infections are encephalitis, acute cerebellar ataxia, myelitis, and meningitis. Other syndromes, such as acute inflammatory demyelinatingradiculoneuropathy, arc sccn less frequently. Early reports of acute central nervous system (CNS) disease associated

with varicella often combined encephalitis and Reye's syndrome. Encephalitis is often severe, and may be fatal. Most cases of encephalitis occur in the week following the cxanthcm, but onset may vary, and encephalitis may occur in the absence of rash. The onset may be abrupt or more gradual over several days, and fever,headache, vomiting, lethargy, seizures, mcningismus, and coma may occur. Dccp tendon reflexes and muscle tone may be increased or decreased. Other manifestations may include visual impairment, hemiplegia, sensory deficits, and urinary dysfunction.