Rubella. Rubella is a generalized maculopapular exanthem associated with fever. Arthralgias, lymphadenopathy, and conjunctivitis may also be associated with the acute illness.
Acute Encephalitis. Acute encephalitis is a rare complication of rubella infection. Symptoms usually appear within 1 to 6 days after the typical maculopapular rash develops and are characterized by headache, dizziness, lethargy, behavioral abnormalities, coma, and generalized or focal seizures in as many as 50 percent of cases. Ihe case fatality rate of acute rubella encephalitis is low, and most nonfatal cases recover rapidly with minimal or no sequelae. '331
Postrubella Polyradiculoneuritis. Postrubella polyradiculoneuritis develops abruptly as the exanthem of rubella fades and has the clinical features of the Guillain-Barre syndrome. Ihe duration of the illness is usually brief. y
Congenital Rubella Syndrome. Features of the congenital rubella syndrome include intrauterine growth retardation, sensorineural deafness, cataracts, congenital glaucoma, patent ductus arteriosus, pulmonic stenosis, microcephaly, mental retardation, meningoencephalitis, purpuric rash, hepatosplenomegaly, and radiolucent bone densities. y In addition to these clinical signs, which are present at birth, children with congenital rubella syndrome may develop delayed-onset progressive rubella panencephalitis, a slow virus disease of the CNS that has many clinical similarities to subacute sclerosing panencephalitis caused by measles virus. y This syndrome may also follow childhood rubella in rare instances. y Symptoms typically begin between the ages of 8 and 19 years with deterioration in school performance and behavior sometimes associated with seizures. The neurological deterioration progresses to a global dementia with ataxia, spasticity of gait, dysarthria, and dysphagia. Progressive pallor of the optic disks and a maculopathy occur. y
Differential Diagnosis. Examination of the CSF in patients with rubella encephalitis may be normal or may demonstrate a mild to moderate mononuclear cell pleocytosis and an elevated protein concentration. Virus is rarely isolated from the CSF in patients with rubella encephalitis. Electroencephalography may demonstrate diffuse or focal abnormalities. Diagnosis is made by detection of rubella-specific IgM antibodies in serum or by demonstration of a fourfold rise in rubella-specific IgG in the convalescent sera compared to the acute sera. '331 Similarly, the diagnosis of postrubella polyradiculoneuritis is based on the findings of a demyelinating peripheral neuropathy following an exanthematous illness. One of the characteristics of the rash of rubella is that the maculopapular rash almost invariably begins on the face before it becomes generalized, and it is often associated with posterior cervical adenopathy. y A description of this type of rash preceding the clinical syndrome of polyradiculoneuritis is suggestive of rubella. By the time the polyradiculoneuritis develops, serum for IgM antibodies to rubella virus may
be negative. A single elevated rubella IgG titer is suggestive but not diagnostic of a recent rubella infection, but when associated with a history of the rubella rash as described above it is quite compatible with the diagnosis.
In infants who have clinical evidence of the congenital rubella syndrome at birth, serum IgM antibody to rubella virus and viral cultures should be obtained. Other laboratory abnormalities supporting the diagnosis of congenital rubella syndrome include hyperbilirubinemia, thrombocytopenia, elevated serum transaminase levels, and long bone radiographs demonstrating metaphyseal lucencies. Neuro- imaging studies reveal intracranial calcifications, delayed myelination, or ventriculitis. y Several different methods have been used to make an intrauterine diagnosis of rubella infection including isolation of the rubella virus in the amniotic fluid obtained by amniocentesis, cordocentesis, use of the polymerase chain reaction method on extracts from chorionic villi and placenta, and ultrastructural examination of amniotic fluid cells using transmission and scanning electron microscopy. y Examination of the CSF in progressive rubella panencephalitis demonstrates a mild lymphocytic pleocytosis (0 to 37 cells/mm3 ), a moderate increase in the protein concentration (60 to 142 mg/ml), and intrathecal immunoglobulin synthesis. y
Management and Prognosis. Ihe key to management of the neurological complications of rubella is prevention. Ihe rubella vaccine licensed for use in the United States is a live attenuated RA 27/3 rubella virus. y Ihe immunogenicity of the vaccine is reduced by whole blood transfusion; therefore, it is recommended that rubella vaccine not be given for 3 months after immunoglobulin or whole blood transfusion. y Ihe incidence of arthritis after vaccination is low when the RA 27/3 strain of rubella vaccine is used. Breast feeding is not a contraindication to postpartum immunization. Infants infected with the rubella virus through breast milk may experience a mild rash, but the majority remain asymptomatic, and no serious adverse effects have been reported. y Currently, the first dose of rubella vaccine is given to children as part of the measles- mumps-rubella (MMR) vaccine at 12 to 15 months of age. A second dose of the MMR vaccine is recommended when the child first enters school or later when he or she enters middle school. y
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