Management of Measles-Induced Encephalitis in Older Children with Mature BBB
Measles encephalitis in older children requires supportive care only, as no specific antiviral therapy has proven efficacy for acute measles encephalitis in immunocompetent patients, though ribavirin may be considered in immunocompromised cases. 1, 2
Immediate Diagnostic Approach
Confirm the diagnosis through:
- CSF PCR for measles virus 1
- Serum and urine measles-specific IgM antibodies 3, 4
- Nasopharyngeal secretions for measles virus antigen detection 2
- MRI imaging as the preferred modality (more sensitive than CT for detecting encephalitic changes) 1
- EEG to assess for abnormalities (present in most cases, though nonspecific) 4
The mature blood-brain barrier status does not change the diagnostic or management approach, as measles virus can cross the BBB at any age through mechanisms independent of BBB maturity. 5, 6
Treatment Strategy
Supportive care remains the cornerstone:
- Seizure management with appropriate anticonvulsants as needed 7, 4
- Fever control and hydration 3
- Monitoring for increased intracranial pressure 1
- Treatment of secondary bacterial infections (particularly pneumonia) with antibiotics 3
- Vitamin A supplementation: 200,000 IU orally for children over 12 months, repeated on day 2 for complicated measles 3
No proven antiviral therapy exists for acute measles encephalitis in immunocompetent children. 1, 2 The guidelines explicitly state that aciclovir is not indicated for measles encephalitis, unlike HSV or VZV encephalitis. 1
Special Considerations for Immunocompromised Patients
If the child is immunocompromised (HIV, chemotherapy, post-transplant):
- Consider intravenous ribavirin, though evidence is limited and outcomes remain poor 2, 7
- Extend diagnostic workup to include other opportunistic pathogens (CMV, EBV, toxoplasma) 1
- Brain biopsy may be necessary if diagnosis remains uncertain after one week, particularly with focal imaging abnormalities 1, 7
- Measles inclusion body encephalitis (MIBE) should be considered in severely immunocompromised patients, which typically occurs within 1 year of measles exposure or vaccination 7
Prognosis and Follow-up
Most immunocompetent older children (ages 5-9) with measles encephalitis recover completely with supportive care alone. 4 In the Spanish series, all seven children aged 5-9 years showed good evolution with normal development at 5-year follow-up, despite EEG abnormalities that took 1-18 months to normalize. 4
However, encephalitis remains the most common cause of long-term sequelae from measles and occurs in approximately 1 per 1,000 measles cases. 3, 6 Permanent brain damage can occur, and the case fatality rate for measles in the United States is 1-2 per 1,000 reported cases. 3
Monitor for subacute sclerosing panencephalitis (SSPE): This rare but uniformly fatal late complication typically presents 6-8 years after the initial measles infection. 8, 3 The risk is approximately 4-11 per 100,000 measles-infected individuals, with higher risk in those infected at younger ages. 8, 5
Critical Pitfall to Avoid
Do not assume older age at measles infection eliminates SSPE risk. The Advisory Committee on Immunization Practices definitively states that measles at any age carries SSPE risk, and vaccination remains the only effective prevention strategy regardless of age. 8 The mature BBB does not protect against either acute encephalitis or the development of SSPE years later. 5