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v1.0.0
ICD-10 Guide
DiagnosesAutoimmune Encephalitis

Autoimmune Encephalitis

ICD-10 Coding for Autoimmune Encephalitis(G04.81)

PRIMARY SPECIALTYNeurology
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Autoimmune Encephalitis?
Essential facts and insights about Autoimmune Encephalitis

Key Clinical Considerations:

  • Altered mental status, seizures, and psychiatric symptoms
  • Positive autoantibody tests (e.g., NMDA receptor antibodies)
  • Neurological deficits such as memory loss or confusion

Clinical Information

Clinical Criteria & Documentation Requirements

  • Patient history including onset and progression of symptoms
  • Specific coding terminology such as 'autoimmune encephalitis' or 'anti-NMDA receptor encephalitis'
  • Examples of documentation include detailed neurological exam findings and results of imaging studies

Coding Guidelines

Usage Guidelines & Examples

  • Follow usage guidelines for autoimmune disorders
  • Common errors include misclassifying as viral encephalitis

Code Exclusions

Important Exclusions

  • Viral or bacterial encephalitis
  • Other neuroinflammatory disorders

Related ICD-10 Codes

Primary Codes
G04.81
Autoimmune encephalitis
Ancillary Codes
R94.8
Z86.59
Differential Codes
G04.90
F05

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

Neurology

Specialty Applications

  • Adults and children with suspected autoimmune conditions
  • Neurology clinics and emergency departments

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What are the documentation requirements?

Document clinical symptoms, diagnostic tests, and treatment response.

What are the billing considerations?

Ensure accurate coding to reflect the complexity of the condition and any associated treatments.