2026 ICD-10-CM Diagnosis Code G98.8Other disorders of nervous system

ICD-10-CM Codes›G00–G99›G89-G99›G98

ICD-10-CM G98.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G98.8 is a billable ICD-10-CM diagnosis code for other disorders of nervous system. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 974 through 976. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (neither hereditary nor degenerative).

Code Identity

ICD-10-CM Code
G98.8
Billable Status
Yes — Valid for Submission
Code Describes
Other disorders of nervous system
Short Description
Other disorders of nervous system
Same as the full description in the CMS dataset.
Parent Code
G98
Other disorders of nervous system not elsewhere classified

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG89-G99Other disorders of the nervous system
CategoryG98Other disorders of nervous system not elsewhere classified
This CodeG98.8Other disorders of nervous system

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of nervous system
  • Acute nervous system disorder
  • Adenoviral nervous system infection
  • Allan-Herndon-Dudley syndrome
  • Bacterial infection of the nervous system
  • Bacterial neuritis
  • Balint syndrome
  • Chronic musculoskeletal pain due to disease of nervous system
  • Chronic musculoskeletal pain due to disorder
  • Chronic nervous system disorder
  • Delayed myelination
  • Disease of nervous system complicating pregnancy, childbirth and puerperium
  • Disorder confirmed
  • Disorder of nervous system
  • Disorder of olfactory system
  • Enteroviral neurological disease
  • Fungal neuritis
  • Hemorrhage into nerve trunk
  • Hereditary disorder of nervous system
  • Heterotopic ossification due to neurological disorder
  • Human immunodeficiency virus infection with neurological disease
  • Hypermelanosis due to nervous system disorder
  • Hypohidrosis
  • Hypohidrosis due to neurological disorder
  • Infantile multisystem neurologic, endocrine, pancreatic disease
  • Infection of peripheral nerve caused by fungus
  • Infection of peripheral nerve caused by Mucorales
  • Infectious disease of nervous system
  • Inherited metabolic disorder of nervous system
  • Lathyrus poisoning
  • Lathyrus sylvestris poisoning
  • Localized hyperhidrosis due to focal neurological disorder
  • Lower motor neuron lesion
  • Nervous system and sense organ diseases
  • Neurological complication of procedure
  • Neurological disorder caused by ethanol
  • Neurological disorder confirmed
  • Neurological disorder due to and following lumbar puncture
  • Neurological disorder due to excess intake of macronutrients
  • Neurological disorder due to excess intake of micronutrients
  • Neurological disorder due to nutrient deficiency
  • Neurological disorder treatment changed
  • Neurological disorder treatment started
  • Neurological lesion
  • Neuronal intranuclear inclusion disease
  • Pancreatic insufficiency
  • Perinatal neurological disorder
  • Pruritus due to neurological disorder
  • Space-occupying lesion of nervous system
  • System disorder of the nervous system
  • X-linked hereditary spastic paraplegia

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Nervous system disorder NOS

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.

    • Complication(s) (from) (of)
      • nervous system
    • Disease, diseased
      • nervous system
    • Disease, diseased
      • nervous system
        • specified NEC
    • Disorder(of)
      • nervous system
    • Disorder(of)
      • nervous system
        • specified NEC

Clinical ClassificationClinical

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

CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hypohidrosis

    abnormally diminished or absent perspiration. both generalized and segmented (reduced or absent sweating in circumscribed locations) forms of the disease are usually associated with other underlying conditions.

  • Grade 2 Hypohidrosis, CTCAE|Grade 2 Hypohidrosis

    symptomatic; limiting instrumental adl or mild/moderate impact on age-appropriate normal daily activity (pediatric)

  • Grade 3 Hypohidrosis, CTCAE|Grade 3 Hypohidrosis

    increase in body temperature; limiting self-care adl or severe impact on age-appropriate normal daily activity (pediatric)

  • Grade 4 Hypohidrosis, CTCAE|Grade 4 Hypohidrosis

    life-threatening consequences; urgent intervention indicated

  • Grade 2 Hypohidrosis, CTCAE|Grade 2 Hypohidrosis

    symptomatic; limiting instrumental adl

  • Grade 3 Hypohidrosis, CTCAE|Grade 3 Hypohidrosis

    increase in body temperature; limiting self care adl

  • Grade 4 Hypohidrosis, CTCAE|Grade 4 Hypohidrosis

    heat stroke

  • Grade 5 Hypohidrosis, CTCAE|Grade 5 Hypohidrosis

    death

  • Hypohidrosis

    reduced sweating. causes include burns, dehydration, radiation, and leprosy.

  • Hypohidrosis, CTCAE|Hypohidrosis|Hypohidrosis

    a disorder characterized by reduced sweating.

Patient EducationClinical

Neurologic Diseases

The brain, spinal cord, and nerves make up the nervous system. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing, or learning. You can also have problems with your memory, senses, or mood.

Read the full article at MedlinePlus

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

Convert G98.8 to ICD-9-CMHistory

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

ICD-9-CM
349.89 Cns disorder NEC
Approximate The match is approximate rather than exact.
ICD-9-CM
349.9 Cns disorder 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 G98.8Overview

Is G98.8 (Other disorders of nervous system not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other disorders of nervous system on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does G98.8 group to?

When other disorders of nervous system is the principal diagnosis on an inpatient stay, it groups to MS-DRG 974, 975, 976, with relative weights from 0.8945 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of G98.8?

Under the General Equivalence Mappings, other disorders of nervous system converts to ICD-9-CM 349.89 (cns disorder NEC) and 349.9 (cns disorder NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.