Subacute sclerosing panencephalitis

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Subacute sclerosing panencephalitis
SpecialtyNeuropathology
SymptomsBehavior changes, Seizures, spasticity, poor coordination, coma
Usual onset6-10 years after infection by measles
CausesMeasles virus
Risk factorsMeasles infection
Diagnostic methodEEG, Serologic testing, brain biopsy
PreventionMeasles vaccine
TreatmentMedications (only works at Stage 1), supportive treatment
MedicationIntrathecal interferon alpha, intravenous ribavirin
PrognosisUsually fatal
FrequencyAbout 1 in 10,000 people infected by measles [1]


Subacute sclerosing panencephalitis (SSPE) is a rare form of chronic progressive brain inflammation caused by measles virus. The condition primarily affects children and young adults. It has been estimated that about 1 in 10,000 people who get measles will eventually develop SSPE.[1] However, a 2016 study estimated that the rate for babies who contracted measles was as high as 1 in 609.[2] No cure for SSPE exists and the condition is often fatal. However, SSPE may be manageable by medication if treatment is started at an early stage. SSPE should not be confused with acute disseminated encephalomyelitis which has a similar cause but very different timing and course.[3]

Signs and symptoms[edit]

SSPE is characterized by a history of primary measles infection, followed by an asymptomatic period that lasts 7 years on average but can range from 1 month to 27 years. After the asymptomatic period, progressive neurological deterioration occurs, characterized by behavior change, intellectual problems, myoclonic seizures, blindness, ataxia, and eventually death.[4][5]

Progression[edit]

Symptoms progress though the following 5 stages:[6]

  • Stage 1: There may be personality changes, mood swings, or depression. Fever and headache may also be present. This stage may last up to 6 months.
  • Stage 2: This stage may involve jerking, muscle spasms, seizures, loss of vision, and dementia.
  • Stage 3: Jerking movements are replaced by writhing (twisting) movements and rigidity. At this stage complications may result in death.
  • Stage 4: The final stage, in which breathing, heart rate, and blood pressure are affected, leading to coma and death.

Pathogenesis[edit]

A large number of nucleocapsids are produced in the neurons and the glial cells. In these cells the viral genes that encode envelope proteins have restricted expression.[7] As a result, infectious particles like the M protein are not produced, and the virus is able to survive persistently without evoking an immune response. Eventually the infection will lead to SSPE.[citation needed]

Diagnosis[edit]

Subacute sclerosing panencephalitis. Figure 1. MRI scans of the brain at the time of presentation in the neurology clinic (A and B) and 3 months later (C and D). Panels A and C are T1-weighted images; B and D are T2-weighted images. The initial MRI scan (A and B) reveals a focal abnormality in the subcortical white matter of the left frontal lobe, consisting of a hypointense signal on the T1-weighted image (arrow in A) and a hyperintense signal on the T2-weighted image (arrow in B). In the follow-up scan, the focal abnormality in the left frontal lobe is less obvious than previously (arrow in D), but advanced and diffuse cortical atrophy is present, signified by the ventriculomegaly and markedly enlarged sulci (arrowheads in C).

According to the merk manual:[5]

"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."

Treatment[edit]

If the diagnosis is made during stage 1 it may be possible to treat the disease with oral isoprinosine (Inosiplex) and intraventricular interferon alfa, but the response to these drugs varies from patient to patient,[8] and the only accepted treatments are supportive measures such as anticonvulsants.[5]

Prognosis[edit]

In the classic presentation of the disease death occurs in 1 to 3 years,[9] but faster and slower progressions can occur. Faster deterioration in cases of acute fulminant SSPE leads to death within 3 months of diagnosis.[10][11]

Although the prognosis is bleak for SSPE past stage 1, there is a 5% spontaneous remission rate—this may be either a full remission that may last many years or an improvement in condition giving a longer progression period or at least a longer period with the less severe symptoms.[12][11]

Epidemiology[edit]

SSPE is a rare condition, although there is still relatively high incidence in Asia and the Middle East. However, the number of reported cases is declining since the introduction of the measles vaccine—eradication of the measles virus prevents the SSPE mutation and therefore the progression of the disease or even the initial infection itself.

References[edit]

  1. ^ a b Bellini WJ, Rota JS, Lowe LE, Katz RS, Dyken PR, Zaki SR, Shieh WJ, Rota PA (2005). "Subacute sclerosing panencephalitis: more cases of this fatal disease are prevented by measles immunization than was previously recognized". The Journal of Infectious Diseases. 192 (10): 1686–1693. doi:10.1086/497169. PMID 16235165.
  2. ^ Sun, Lena (October 28, 2016). "New data shows a deadly measles complication is more common than thought". The Washington Post. Retrieved October 28, 2016.
  3. ^ Fisher DL, Defres S, Solomon T (2015). "Measles-induced encephalitis". QJM. 108. doi:10.1093/qjmed/hcu113. PMID 24865261.
  4. ^ "CDC pinkbook".
  5. ^ a b c "merckmanuals.com".
  6. ^ "medline.gov".
  7. ^ Jawetz. Melnick & Adelberg's Medical Microbiology. Lange. 2010. p. 586. ISBN 978-0-07-174271-9.
  8. ^
    • Gascon G, Yamanis S, Crowell J, et al. Combined oralisoprinosine-intraventricular alpha-interferon therapy for subacute sclerosing panencephalitis. Brain Dev. 1993; 15:346–55.
    • Anlar B, Yalaz K, Oktem F, et al. Long-term follow-up of patients with subacute sclerosing panencephalitis treated with intraventricular alpha-interferon. Neurology 1997; 48:526–8
    • Cianchetti C, Marrosu MG, Muntoni F, et al. Intraventricularalpha-inteferon in subacute sclerosing panencephalitis. Neurology 1998; 50:315–16.
  9. ^ [>https://www.ninds.nih.gov/Disorders/All-Disorders/Subacute-Sclerosing-Panencephalitis-Information-Page#disorders-r1 "SSPE information page www.ninds.nih.gov"] Check |url= value (help).
  10. ^ Risk WS, Haddad FS. The variable natural history of subacute sclerosing panencephalitis: a study of 118 cases from the Middle East.Arch Neurol 1979; 56:610–14.
  11. ^ a b Garg, R K (1 February 2002). "Subacute sclerosing panencephalitis". Postgraduate Medical Journal. 78 (916): 63–70. doi:10.1136/pmj.78.916.63.
  12. ^
    • Grunewald T, Lampe J, Weissbrich B, et al. A 35-year old bricklayer with hemimyoclonic jerks. Lancet 1998; 351:1926.
    • Santoshkumar B, Radhakrishnan K. Substantial spontaneous long-term remission in subacute sclerosing panencephalitis (SSPE).J Neurol Sci 1998; 154:83–8.

Further reading[edit]

External links[edit]

Classification
External resources