Subacute Sclerosing Panencephalitis (SSPE)
Subacute sclerosing panencephalitis is a progressive, usually fatal brain disorder occurring months to usually years after an attack of measles. It causes mental deterioration, myoclonic jerks, and seizures. Diagnosis involves EEG, CT or MRI, CSF examination, and measles serologic testing. Treatment is supportive.
Most viruses that infect humans can affect both adults and children and are discussed elsewhere in The Manual. Viruses with specific effects on neonates are discussed in see Infections in Neonates. This chapter covers viral infections that are typically acquired during childhood (although many may also affect adults).
Subacute sclerosing panencephalitis (SSPE) is probably a persistent measles virus infection. The measles virus is present in brain tissue.
Historically, SSPE occurred in about 7 to 300 cases per million people who had wild measles and in about 1 case per million people who received measles vaccine; all post-vaccination cases are probably due to unrecognized measles before vaccination. Males are more often affected. Onset is usually before age 20. SSPE is exceedingly rare in the US and Western Europe because there are few measles cases. However, analyses of more recent measles outbreaks suggest that the incidence of SSPE may be higher than previously thought, perhaps as high as 1 per 600 to 25,000 measles cases (40 to 1,700 per million), with an even higher risk in infants who develop measles before 1 yr of age (1).
1. Wendorf KA, Winter K, Zipprich J, et al: Subacute sclerosing panencephalitis: The devastating measles complication that might be more common than previously estimated. Clin Infect Dis 65(2):226–232, 2017. doi: 10.1093/cid/cix302.
Often, the first signs are subtle—diminished performance in schoolwork, forgetfulness, temper tantrums, distractibility, and sleeplessness. However, hallucinations and myoclonic jerks may then occur, followed by generalized seizures. There is further intellectual decline and speech deterioration. Dystonic movements and transient opisthotonos occur. Later, muscular rigidity, dysphagia, cortical blindness, and optic atrophy may occur. Focal chorioretinitis and other funduscopic abnormalities are common. In the final phases, hypothalamic involvement may cause intermittent hyperthermia, diaphoresis, and pulse and BP disturbances.
SSPE is suspected in young patients with dementia and neuromuscular irritability. EEG, CT or MRI, CSF examination, and measles serologic testing are done. EEG shows periodic complexes with high-voltage diphasic waves occurring synchronously throughout the recording. CT or MRI may show cortical atrophy or white matter lesions. CSF examination usually reveals normal pressure, cell count, and total protein content; however, CSF globulin is almost always elevated, constituting up to 20 to 60% of CSF protein. Serum and CSF contain elevated levels of measles virus antibodies. Anti-measles IgG appears to increase as the disease progresses.
If test results are inconclusive, brain biopsy may be needed.
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