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ICD-10 Guide
ICD-10 CodesChapter 1: Certain infectious and parasitic diseasesB00.5

B00.5

Billable

Herpesviral encephalitis

Chapter 1:Certain infectious and parasitic diseases

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

Code Description

ICD-10 B00.5 is a billable code used to indicate a diagnosis of herpesviral encephalitis.

Key Diagnostic Point:

Herpesviral encephalitis is a severe neurological condition primarily caused by the herpes simplex virus (HSV), most commonly HSV-1. It is characterized by inflammation of the brain, leading to symptoms such as fever, headache, seizures, confusion, and altered mental status. The condition can progress rapidly, often resulting in significant morbidity and mortality if not treated promptly. Diagnosis typically involves clinical evaluation, imaging studies such as MRI, and laboratory tests including PCR for HSV DNA in cerebrospinal fluid (CSF). Treatment usually consists of antiviral therapy, primarily acyclovir, which is most effective when initiated early in the course of the disease. Complications can include long-term neurological deficits, seizures, and in severe cases, death. Vaccination against HSV is not currently available, making awareness and early intervention critical in managing this condition.

Code Complexity Analysis

Complexity Rating: High

High Complexity

Complexity Factors

  • Differentiating between types of herpes viruses (HSV-1 vs. HSV-2)
  • Need for precise documentation of neurological symptoms
  • Requirement for laboratory confirmation via CSF analysis
  • Potential for co-infections with other viral pathogens

Audit Risk Factors

  • Inadequate documentation of clinical findings
  • Failure to document laboratory results supporting the diagnosis
  • Misclassification of the type of herpes virus involved
  • Inconsistent coding of associated neurological symptoms

Specialty Focus

Medical Specialties

Neurology

Documentation Requirements

Detailed neurological examination findings, imaging results, and laboratory tests.

Common Clinical Scenarios

Patients presenting with acute onset of seizures, altered mental status, or fever.

Billing Considerations

Ensure thorough documentation of neurological deficits and response to treatment.

Infectious Disease

Documentation Requirements

History of exposure, laboratory confirmation of HSV, and treatment protocols.

Common Clinical Scenarios

Patients with suspected viral encephalitis requiring antiviral therapy.

Billing Considerations

Document any co-infections and the rationale for antiviral choice.

Coding Guidelines

Inclusion Criteria

Use B00.5 When
  • According to ICD
  • 10 guidelines, B00
  • 5 should be used when there is confirmed herpesviral encephalitis
  • Documentation must support the diagnosis with clinical findings and laboratory results

Exclusion Criteria

Do NOT use B00.5 When
  • Exclusion criteria include other viral encephalitides that may present similarly

Related ICD-10 Codes

Related CPT Codes

87491CPT Code

Herpes simplex virus (HSV) DNA, PCR

Clinical Scenario

Used for confirming diagnosis in suspected cases of herpesviral encephalitis.

Documentation Requirements

Document the clinical rationale for testing and results.

Specialty Considerations

Ensure that the testing aligns with the clinical presentation.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of herpesviral encephalitis, improving the accuracy of data collection and reimbursement processes. The granularity of ICD-10 codes helps in better tracking of disease prevalence and outcomes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of herpesviral encephalitis, improving the accuracy of data collection and reimbursement processes. The granularity of ICD-10 codes helps in better tracking of disease prevalence and outcomes.

Reimbursement & Billing Impact

reimbursement processes. The granularity of ICD-10 codes helps in better tracking of disease prevalence and outcomes.

Resources

Clinical References

  • •
    CDC - Herpes Simplex Virus

Coding & Billing References

  • •
    CDC - Herpes Simplex Virus

Frequently Asked Questions

What are the common symptoms of herpesviral encephalitis?

Common symptoms include fever, headache, seizures, confusion, and altered mental status. Patients may also exhibit focal neurological deficits.