2026 ICD-10-CM Diagnosis Code G04.1Tropical spastic paraplegia

ICD-10-CM Codes›G00–G99›G00-G09›G04

ICD-10-CM G04.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G04.1 is a billable ICD-10-CM diagnosis code for tropical spastic paraplegia. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as disease caused by Deltaretrovirus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Paralysis (other than cerebral palsy).

Code Identity

ICD-10-CM Code
G04.1
Billable Status
Yes — Valid for Submission
Code Describes
Tropical spastic paraplegia
Short Description
Tropical spastic paraplegia
Same as the full description in the CMS dataset.
Parent Code
G04
Encephalitis, myelitis and encephalomyelitis

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG00-G09Inflammatory diseases of the central nervous system
CategoryG04Encephalitis, myelitis and encephalomyelitis
This CodeG04.1Tropical spastic paraplegia

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disease caused by Deltaretrovirus
  • Human T-cell lymphotropic virus 1-associated myelopathy
  • Human T-lymphotropic virus 1 infection
  • Infection caused by Human T-lymphotropic virus

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Paraplegia(lower)
      • spastic
        • tropical
    • Paraplegia(lower)
      • tropical spastic

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS008
Paralysis (other than cerebral palsy)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Encephalitis

Encephalitis is inflammation (swelling) of the brain. It can happen when an infection or medical condition that affects the brain activates your immune system. The inflammation can cause a wide range of symptoms. In extreme cases, it can lead to brain damage, stroke, or even death.

The full article covers:

  • What is encephalitis?
  • What causes encephalitis?
  • Who is more likely to get encephalitis?
  • What are the symptoms of encephalitis?
  • How is encephalitis diagnosed?
  • What are the treatments for encephalitis?
  • Can encephalitis be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G04.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
344.1 Paraplegia NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G04.1Overview

Is G04.1 (Encephalitis, myelitis and encephalomyelitis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report tropical spastic paraplegia on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G04.1?

Under the General Equivalence Mappings, tropical spastic paraplegia converts to ICD-9-CM 344.1 (paraplegia NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.