Can Measles Cause SSPE in Adults?
Yes, measles can cause subacute sclerosing panencephalitis (SSPE) in adults, though it occurs less frequently than in children who contracted measles at younger ages. 1, 2
Understanding SSPE Across Age Groups
SSPE is a rare but fatal late complication of measles infection that can appear years after the initial infection in immunologically normal individuals. 1, 2 While the disease predominantly affects those who contracted measles during childhood (particularly under age 5), adult-onset SSPE is well-documented. 3, 4
Key Epidemiological Facts
The true risk of SSPE is approximately 4-11 per 100,000 measles cases, though this underestimates actual risk due to dramatic underreporting of measles infections (only 11% of actual cases are officially reported). 5
The highest risk occurs in children who contracted measles before age 5, with risk of 6.5-11 per 100,000 measles cases. 3
Adult-onset SSPE exists as a distinct entity: In one clinical series, 38% of SSPE patients (13 of 34) had disease onset after age 15, with ages ranging from 3 to 31 years at presentation. 4
Critical Timing Distinction
The mean incubation period between measles infection and SSPE onset is approximately 9.6 years, but this can extend much longer in adult-onset cases. 4 The adult-onset group demonstrated a longer interval between measles infection and SSPE presentation compared to childhood-onset cases. 4
Clinical Presentation in Adults
The clinical profile of adult-onset SSPE does not substantially differ from childhood-onset disease, with one notable exception: ophthalmic symptoms are more common as presenting features in adult-onset SSPE. 4
Progressive Stages
SSPE manifests through characteristic stages:
- Initial stage: Insidious onset with subtle personality changes and declining intellectual performance 6
- Progressive deterioration: Mental deterioration, seizures, myoclonic jerks, motor signs 6
- Advanced stage: Progression to coma and death 6
Diagnostic Features
- EEG shows well-defined periodic complexes with 1:1 relationship to myoclonic jerks, which is pathognomonic. 6
- Detection of intrathecal synthesis of measles-specific antibodies in CSF is crucial for diagnosis. 6
- Neuroimaging demonstrates periventricular white matter abnormalities, with marked cerebral atrophy in advanced stages. 7
Important Clinical Caveats
Do not confuse the three distinct measles-related encephalitic illnesses: 1, 6
- Acute encephalitis or acute disseminated encephalomyelitis during acute measles infection
- Subacute encephalopathy around 6 months post-infection in immunocompromised patients
- SSPE occurring years later in immunologically normal individuals
Vaccination does not cause SSPE—it prevents it. The CDC and ACIP definitively state that MMR vaccine does not increase SSPE risk, and when rare cases occur in vaccinated children, evidence indicates they had unrecognized measles infection before vaccination. 6, 5
Prognosis and Prevention
SSPE is life-threatening in most affected individuals with no cure, though some patients (approximately 6%) may experience prolonged spontaneous remission. 8, 7 Treatment focuses on symptomatic control with antiepileptic drugs (particularly carbamazepine for seizures and abnormal movements) and immunomodulation, though evidence from randomized trials is lacking. 3, 7
Measles vaccination remains the only effective prevention strategy for SSPE, and widespread vaccination has essentially eliminated SSPE from countries with high vaccination coverage. 2, 5 Until measles is eradicated globally, individuals of all ages remain at risk. 3, 9