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Encephalitis, Herpes Simplex - An acute (or rarely chronic) inflammatory process of the brain caused by SIMPLEXVIRUS infections which may be fatal. The majority of infections are caused by human herpesvirus 1 (HERPESVIRUS 1, HUMAN) and less often by human herpesvirus 2 (HERPESVIRUS 2, HUMAN). Clinical manifestations include FEVER; HEADACHE; SEIZURES; HALLUCINATIONS; behavioral alterations; APHASIA; hemiparesis; and COMA. Pathologically, the condition is marked by a hemorrhagic necrosis involving the medial and inferior TEMPORAL LOBE and orbital regions of the FRONTAL LOBE. (From Adams et al., Principles of Neurology, 6th ed, pp751-4) |
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Encephalitis, Varicella Zoster - Inflammation of brain tissue caused by infection with the varicella-zoster virus (HERPESVIRUS 3, HUMAN). This condition is associated with immunocompromised states, including the ACQUIRED IMMUNODEFICIENCY SYNDROME. Pathologically, the virus tends to induce a vasculopathy and infect oligodendrocytes and ependymal cells, leading to CEREBRAL INFARCTION, multifocal regions of demyelination, and periventricular necrosis. Manifestations of varicella encephalitis usually occur 5-7 days after onset of HERPES ZOSTER and include HEADACHE; VOMITING; lethargy; focal neurologic deficits; FEVER; and COMA. (From Joynt, Clinical Neurology, 1996, Ch 26, pp29-32; Hum Pathol 1996 Sep;27(9):927-38) |
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Leukoencephalopathy, Progressive Multifocal - An opportunistic viral infection of the central nervous system associated with conditions that impair cell-mediated immunity (e.g., ACQUIRED IMMUNODEFICIENCY SYNDROME and other IMMUNOLOGIC DEFICIENCY SYNDROMES; HEMATOLOGIC NEOPLASMS; IMMUNOSUPPRESSION; and COLLAGEN DISEASES). The causative organism is JC Polyomavirus (JC VIRUS) which primarily affects oligodendrocytes, resulting in multiple areas of demyelination. Clinical manifestations include DEMENTIA; ATAXIA; visual disturbances; and other focal neurologic deficits, generally progressing to a vegetative state within 6 months. (From Joynt, Clinical Neurology, 1996, Ch26, pp36-7) |
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Subacute Sclerosing Panencephalitis - A rare, slowly progressive encephalitis caused by chronic infection with the MEASLES VIRUS. The condition occurs primarily in children and young adults, approximately 2-8 years after the initial infection. A gradual decline in intellectual abilities and behavioral alterations are followed by progressive MYOCLONUS; MUSCLE SPASTICITY; SEIZURES; DEMENTIA; autonomic dysfunction; and ATAXIA. DEATH usually occurs 1-3 years after disease onset. Pathologic features include perivascular cuffing, eosinophilic cytoplasmic inclusions, neurophagia, and fibrous gliosis. It is caused by the SSPE virus, which is a defective variant of MEASLES VIRUS. (From Adams et al., Principles of Neurology, 6th ed, pp767-8) |