ICD-10-CM Code G31.9

Degenerative disease of nervous system, unspecified

Version 2021 Billable Code

Valid for Submission

G31.9 is a billable code used to specify a medical diagnosis of degenerative disease of nervous system, unspecified. The code is valid for the fiscal year 2021 for the submission of HIPAA-covered transactions. The ICD-10-CM code G31.9 might also be used to specify conditions or terms like acquired cerebral atrophy, autonomic nervous system disorder co-occurrent and due to neurodegenerative disorder, cerebellar degeneration, cerebral atrophy, cerebral degeneration, cerebral degeneration due to creutzfeldt-jakob disease, etc

Short Description:Degenerative disease of nervous system, unspecified
Long Description:Degenerative disease of nervous system, unspecified

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code G31.9 are found in the index:


The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Acquired cerebral atrophy
  • Autonomic nervous system disorder co-occurrent and due to neurodegenerative disorder
  • Cerebellar degeneration
  • Cerebral atrophy
  • Cerebral degeneration
  • Cerebral degeneration due to Creutzfeldt-Jakob disease
  • Cerebral degeneration due to Parkinson's disease
  • Cerebral degeneration presenting primarily with dementia
  • Chorea due to heredodegenerative disorder
  • Circumscribed atrophy of brain
  • Degenerative brain disorder
  • Degenerative disease of the central nervous system
  • Epilepsy co-occurrent and due to degenerative brain disorder
  • Frontal lobe degeneration
  • Frontal lobe degeneration with motor neurone disease
  • Frontotemporal degeneration
  • Frontotemporal dementia
  • Gemignani syndrome
  • Microphthalmia with brain atrophy syndrome
  • Parkinsonism due to heredodegenerative disorder
  • Posterior cortical atrophy syndrome
  • Prieto Badia Mulas syndrome
  • Progressive focal cortical atrophy
  • Secondary cerebellar degeneration

Convert G31.9 to ICD-9

  • 330.9 - Cereb degen in child NOS (Approximate Flag)
  • 331.9 - Cereb degeneration NOS (Approximate Flag)

Code Classification

  • Diseases of the nervous system (G00–G99)
    • Other degenerative diseases of the nervous system (G30-G32)
      • Oth degenerative diseases of nervous system, NEC (G31)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021

Information for Patients

Degenerative Nerve Diseases

Also called: Neurodegenerative diseases

Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses. Sometimes the cause is not known.

Degenerative nerve diseases include

  • Alzheimer's disease
  • Amyotrophic lateral sclerosis
  • Friedreich's ataxia
  • Huntington's disease
  • Lewy body disease
  • Parkinson's disease
  • Spinal muscular atrophy

Degenerative nerve diseases can be serious or life-threatening. It depends on the type. Most of them have no cure. Treatments may help improve symptoms, relieve pain, and increase mobility.

  • Multiple system atrophy (Medical Encyclopedia)
  • Progressive multifocal leukoencephalopathy (Medical Encyclopedia)

[Learn More]