ICD-10 Logo
ICDxICD-10 Medical Coding
ICD-10 Logo
ICDxICD-10 Medical Coding
ICD 10 CodesDiagnoses
ICD 10 CodesDiagnoses
ICD-10 Logo
ICDxICD-10 Medical Coding

Comprehensive ICD-10-CM code reference with AI-powered search capabilities.

© 2025 ICD Code Compass. All rights reserved.

Browse

  • All Chapters
  • All Categories
  • Diagnoses

Tools

  • AI Code Search
ICD-10-CM codes are maintained by the CDC and CMS. This tool is for reference purposes only.
v1.0.0
ICD-10 Guide
ICD-10 CodesB05.1

B05.1

Measles with encephalitis

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 B05.1 is a billable code used to indicate a diagnosis of measles with encephalitis.

Key Diagnostic Point:

Measles with encephalitis is a severe complication of measles, a highly contagious viral infection caused by the measles virus. Encephalitis, an inflammation of the brain, can occur in approximately 1 in 1,000 cases of measles. The condition typically manifests 7 to 10 days after the onset of the measles rash, characterized by symptoms such as high fever, seizures, confusion, and altered consciousness. The pathophysiology involves the direct invasion of the central nervous system by the measles virus, leading to neurological deficits and potential long-term complications, including cognitive impairment and motor dysfunction. Diagnosis is primarily clinical, supported by serological testing for measles-specific IgM antibodies. Vaccination against measles, typically administered as part of the MMR (measles, mumps, rubella) vaccine, is crucial in preventing this serious complication. The incidence of measles and its complications has significantly decreased in vaccinated populations, but outbreaks can still occur, particularly in unvaccinated individuals. Prompt recognition and management of encephalitis are essential to minimize neurological damage and improve outcomes.

Code Complexity Analysis

Complexity Rating: High

High Complexity

Complexity Factors

  • Requires understanding of both measles and its neurological complications.
  • Differentiation from other viral encephalitides.
  • Documentation must clearly indicate the relationship between measles and encephalitis.
  • Potential for co-morbid conditions that may complicate coding.

Audit Risk Factors

  • Inadequate documentation linking encephalitis to measles.
  • Failure to document vaccination status.
  • Misclassification of encephalitis type.
  • Inconsistent clinical findings in the medical record.

Specialty Focus

Medical Specialties

Pediatrics

Documentation Requirements

Detailed history of vaccination, clinical presentation, and neurological assessment.

Common Clinical Scenarios

Children presenting with fever, rash, and neurological symptoms following measles infection.

Billing Considerations

Consideration of age and vaccination status is critical for accurate coding.

Neurology

Documentation Requirements

Comprehensive neurological evaluation and imaging studies to assess encephalitis.

Common Clinical Scenarios

Patients with seizures or altered mental status following measles infection.

Billing Considerations

Documentation must clearly establish the link between measles and neurological symptoms.

Coding Guidelines

Inclusion Criteria

Use B05.1 When
  • According to ICD
  • 10 guidelines, B05
  • 1 should be used when encephalitis is directly related to a confirmed measles infection
  • Documentation must support the diagnosis of both measles and encephalitis, and any relevant laboratory findings should be included

Exclusion Criteria

Do NOT use B05.1 When
No specific exclusions found.

Related CPT Codes

90460CPT Code

Immunization administration

Clinical Scenario

When administering the MMR vaccine to prevent measles.

Documentation Requirements

Document vaccine type, date, and patient consent.

Specialty Considerations

Pediatricians should ensure vaccination history is accurately recorded.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of complications related to measles, such as encephalitis, improving data accuracy and enhancing epidemiological tracking of measles-related complications.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of complications related to measles, such as encephalitis, improving data accuracy and enhancing epidemiological tracking of measles-related complications.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of complications related to measles, such as encephalitis, improving data accuracy and enhancing epidemiological tracking of measles-related complications.

Resources

Clinical References

  • •
    CDC Measles Information

Coding & Billing References

  • •
    CDC Measles Information

Frequently Asked Questions

What are the symptoms of measles with encephalitis?

Symptoms include high fever, seizures, confusion, and neurological deficits following a measles infection.

How can measles with encephalitis be prevented?

Vaccination with the MMR vaccine is the most effective way to prevent measles and its complications, including encephalitis.