B05.0 Measles complicated by encephalitis

Name of the Condition

• Measles complicated by encephalitis

Summary

Measles complicated by encephalitis is a severe neurological complication of measles, characterized by inflammation of the brain. It represents a rare but serious manifestation of the measles virus infection, often occurring within days to weeks after the onset of the rash. The condition requires prompt medical attention due to its potential for significant morbidity and mortality.

Causes

Measles complicated by encephalitis is caused by the measles virus, a member of the Paramyxoviridae family. The virus triggers an inflammatory response in the brain, leading to encephalitis. This complication may arise from direct viral invasion of the central nervous system or an autoimmune reaction to the infection.

Risk Factors

• Lack of vaccination or incomplete immunization against measles.
• Age, with children under 5 years or adults over 20 years at increased risk.
• Immunocompromised states, such as HIV/AIDS, chemotherapy, or chronic steroid use.
• Malnutrition or vitamin A deficiency, which may exacerbate neurological involvement.

Symptoms

• High fever, often persisting beyond the typical measles rash duration.
• Altered mental status, including confusion, lethargy, or irritability.
• Seizures or convulsions.
• Headache, stiff neck, or photophobia.
• Focal neurological deficits, such as weakness or abnormal movements.

Diagnosis

Diagnosis involves clinical evaluation of neurological symptoms in the context of a recent measles infection. Laboratory tests may include cerebrospinal fluid (CSF) analysis to detect inflammatory changes, viral PCR for measles RNA, and neuroimaging (e.g., MRI or CT) to assess brain involvement. Exclusion of other causes of encephalitis is also critical.

Treatment Options

Treatment focuses on supportive care, including managing seizures, reducing fever, and addressing intracranial pressure. Antiviral therapies are not typically effective, and corticosteroids may be considered in select cases. Hospitalization in an intensive care setting is often necessary for severe cases.

Prognosis and Follow-Up

Prognosis varies, with some patients recovering fully while others may experience long-term neurological sequelae, such as cognitive impairment or motor deficits. Follow-up care includes monitoring for residual symptoms and rehabilitation as needed. Outcomes depend on the severity of brain injury and timely intervention.

Complications

• Permanent neurological damage, including cognitive or motor impairments.
• Increased risk of secondary infections due to immunosuppression.
• Long-term disability or reduced quality of life.
• In rare cases, death, particularly in unvaccinated or immunocompromised individuals.

Lifestyle & Prevention

• Ensure up-to-date measles vaccination to prevent primary infection.
• Avoid contact with infected individuals during outbreaks.
• Maintain good nutrition, including adequate vitamin A intake, to support immune function.
• Practice hygiene measures, such as handwashing, to reduce transmission risk.

When to Seek Professional Help

Seek immediate medical attention if symptoms of encephalitis develop, such as severe headache, confusion, seizures, or altered consciousness, especially in the context of a known or suspected measles infection.

Tips for Medical Coders

Document the presence of encephalitis as a complication of measles clearly in the medical record. Ensure the diagnosis is supported by clinical findings, laboratory results, or imaging. Code B05.0 is specific for measles complicated by encephalitis and should be used when this complication is confirmed.