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 CodesQ04.5

Q04.5

Billable

Megalencephaly

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/11/2025

Code Description

ICD-10 Q04.5 is a billable code used to indicate a diagnosis of megalencephaly.

Key Diagnostic Point:

Megalencephaly, characterized by an abnormally large brain, is a congenital malformation of the nervous system. This condition can arise from various etiologies, including genetic syndromes, metabolic disorders, or environmental factors during pregnancy. Clinically, megalencephaly may present with developmental delays, seizures, and neurological deficits. It is often associated with other congenital anomalies such as hydrocephalus, where cerebrospinal fluid accumulates in the brain, leading to increased intracranial pressure. The differential diagnosis includes conditions like microcephaly, where the head is smaller than expected, and holoprosencephaly, a failure of the brain to properly divide into two hemispheres. Accurate diagnosis often requires imaging studies such as MRI or CT scans, alongside genetic testing to identify underlying chromosomal abnormalities. Management may involve multidisciplinary approaches, including neurology, genetics, and developmental pediatrics, to address the diverse needs of affected children.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in clinical presentation and associated conditions
  • Need for comprehensive documentation of neurological assessments
  • Potential overlap with other congenital brain malformations
  • Requirement for genetic testing results to support diagnosis

Audit Risk Factors

  • Inadequate documentation of associated neurological deficits
  • Failure to include genetic testing results in the medical record
  • Misclassification of megalencephaly with other brain malformations
  • Lack of clarity on the etiology of the condition

Specialty Focus

Medical Specialties

Pediatrics

Documentation Requirements

Detailed developmental assessments, neurological evaluations, and any associated comorbidities.

Common Clinical Scenarios

Assessment of developmental milestones in children with megalencephaly, management of seizures, and referrals to specialists.

Billing Considerations

Consideration of the child's overall health, including any other congenital anomalies that may impact treatment.

Genetics

Documentation Requirements

Genetic testing results, family history, and any syndromic associations.

Common Clinical Scenarios

Genetic counseling for families, interpretation of chromosomal microarray results, and discussions regarding recurrence risks.

Billing Considerations

Understanding the implications of genetic findings on prognosis and management.

Coding Guidelines

Inclusion Criteria

Use Q04.5 When
  • Follow the official ICD
  • CM coding guidelines for congenital malformations, ensuring accurate documentation of the condition's etiology and associated anomalies

Exclusion Criteria

Do NOT use Q04.5 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

96110CPT Code

Developmental screening, standardized instrument

Clinical Scenario

Used for assessing developmental milestones in children with megalencephaly.

Documentation Requirements

Document the specific developmental concerns and results of the screening.

Specialty Considerations

Pediatric specialists should ensure comprehensive evaluations are performed.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of congenital conditions like megalencephaly, improving the accuracy of data collection and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of congenital conditions like megalencephaly, improving the accuracy of data collection and reimbursement processes.

Reimbursement & Billing Impact

reimbursement processes.

Resources

Clinical References

  • •
    CDC - Birth Defects

Coding & Billing References

  • •
    CDC - Birth Defects

Frequently Asked Questions

What is the primary concern when coding megalencephaly?

The primary concern is ensuring comprehensive documentation of the condition, including any associated neurological deficits and the results of genetic testing, to support the diagnosis and appropriate coding.