ICD-10 Guide

A83.5

Japanese encephalitis.

BILLABLE STATUSYes

IMPLEMENTATION DATEOctober 1, 2015

LAST UPDATED09/05/2025

Code Description

ICD-10 A83.5 is a billable code used to indicate a diagnosis of japanese encephalitis..

Key Diagnostic Point:

Japanese encephalitis (JE) is a viral infection caused by the Japanese encephalitis virus (JEV), primarily transmitted through the bite of infected mosquitoes, particularly the Culex species. It is endemic in many parts of Asia and the Western Pacific. The disease can lead to severe neurological complications, including encephalitis, which is characterized by inflammation of the brain. Symptoms typically begin with fever, headache, and vomiting, progressing to neurological manifestations such as seizures, altered consciousness, and paralysis. The case fatality rate can be as high as 30%, and many survivors may experience long-term neurological deficits. Vaccination is the most effective preventive measure against JE, with several vaccines available that are recommended for travelers to endemic areas and for individuals living in high-risk regions. The clinical management of JE focuses on supportive care, as there is no specific antiviral treatment available. Early diagnosis and intervention are crucial to improve outcomes and reduce the risk of complications.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

Differentiating JE from other viral encephalitides.
Understanding vaccination status and its implications for coding.
Documenting neurological complications accurately.
Recognizing endemic versus non-endemic cases.

Audit Risk Factors

Inadequate documentation of vaccination status.
Failure to specify the type of encephalitis.
Lack of clarity in neurological symptom documentation.
Misclassification of endemic versus non-endemic cases.

Specialty Focus

Medical Specialties

Infectious Disease

Documentation Requirements

Detailed travel history, vaccination records, and clinical symptoms.

Common Clinical Scenarios

Patients presenting with fever and neurological symptoms after travel to endemic areas.

Billing Considerations

Ensure accurate documentation of exposure history and vaccination status.

Neurology

Documentation Requirements

Neurological examination findings, imaging results, and treatment plans.

Common Clinical Scenarios

Patients with acute encephalitis symptoms requiring neurological evaluation.

Billing Considerations

Document all neurological deficits and complications for accurate coding.

Coding Guidelines

Inclusion Criteria

Use A83.5 When

According to ICD
10 guidelines, A83
5 should be used when the clinical documentation supports a diagnosis of Japanese encephalitis
It is important to include details about the patient's travel history and vaccination status

Exclusion Criteria

Do NOT use A83.5 When

Exclusion criteria include cases where the encephalitis is due to other known pathogens

Related CPT Codes

87491CPT Code

Viral RNA detection

Clinical Scenario

Used when testing for JEV in patients with suspected encephalitis.

Documentation Requirements

Document the reason for testing and clinical symptoms.

Specialty Considerations

Infectious disease specialists should ensure proper interpretation of results.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of Japanese encephalitis, improving the accuracy of epidemiological data and facilitating better tracking of cases and outcomes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of Japanese encephalitis, improving the accuracy of epidemiological data and facilitating better tracking of cases and outcomes.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of Japanese encephalitis, improving the accuracy of epidemiological data and facilitating better tracking of cases and outcomes.

Resources

Clinical References

•
CDC Japanese Encephalitis Information

Coding & Billing References

•
CDC Japanese Encephalitis Information

Frequently Asked Questions

What is the primary cause of Japanese encephalitis?

Japanese encephalitis is primarily caused by the Japanese encephalitis virus, which is transmitted through mosquito bites.

How can Japanese encephalitis be prevented?

Vaccination is the most effective way to prevent Japanese encephalitis, especially for travelers to endemic areas.

ICD-10 A83.5 is a billable code used to indicate a diagnosis of japanese encephalitis..