2026 ICD-10-CM Diagnosis Code G93.40Encephalopathy, unspecified

ICD-10-CM Codes›G00–G99›G89-G99›G93

ICD-10-CM G93.40
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G93.40 is a billable ICD-10-CM diagnosis code for encephalopathy, unspecified. 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
G93.40
Billable Status
Yes — Valid for Submission
Code Describes
Encephalopathy, unspecified
Short Description
Encephalopathy, unspecified
Same as the full description in the CMS dataset.
Parent Code
G93.4
Other and unspecified encephalopathy

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG89-G99Other disorders of the nervous system
CategoryG93Other disorders of brain
This CodeG93.40Encephalopathy, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Axonal neuropathy
  • CNTNAP2-related developmental and epileptic encephalopathy
  • Congenital axonal neuropathy with encephalopathy
  • Encephalopathy due to and following cardiopulmonary bypass
  • Encephalopathy due to COVID-19
  • Encephalopathy due to prosaposin deficiency
  • Encephalopathy with AIDS
  • Encephalopathy, intracerebral calcification, retinal degeneration syndrome
  • Epileptic encephalopathy with global cerebral demyelination
  • Ischemic encephalopathy
  • Myoclonic epilepsy in non-progressive encephalopathy
  • RAVINE syndrome
  • Renal tubulopathy with encephalopathy and liver failure syndrome
  • SCN8A developmental and epileptic encephalopathy
  • Static encephalopathy

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.

    • Encephalopathy(acute)

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

  • Acute Motor and Sensory Axonal Neuropathy|Acute Motor And Sensory Axonal Neuropathy|Acute Motor-Sensory Axonal Neuropathy|Acute Motor-Sensory Axonal Neuropathy

    a subtype of guillain-barre syndrome that targets sensory motor axons, and is characterized by acute onset of quadriparesis, distal sensory loss, areflexia, and respiratory insufficiency.

  • Acute Motor Axonal Neuropathy|AMAN

    a subtype of guillain-barre syndrome that targets motor axons, and is characterized by symmetric limb weakness, diffuse areflexia, facial and oropharyngeal muscle weakness, and respiratory insufficiency.

  • Axonal Neuropathy

    any nerve disorder affecting the axon of a nerve.

  • GAN wt Allele|GAN1|Giant Axonal Neuropathy (Gigaxonin) Gene|Gigaxonin wt Allele|KLHL16

    human gan wild-type allele is located in the vicinity of 16q24.1 and is approximately 65 kb in length. this allele, which encodes gigaxonin protein, is involved in both ubiquitination and neurofilament structure. mutation of the gene is associated with giant axonal neuropathy.

  • Giant Axonal Neuropathy

    a rare inherited disorder affecting the neurofilaments. it is caused by mutations in the gan gene. it is characterized by the presence of abnormally large nerve cell axons. signs and symptoms include difficulty walking, sensory disturbances, lack of motor coordination and abnormal reflexes in the limbs.

  • Spinocerebellar Ataxia, Autosomal Recessive, with Axonal Neuropathy 2|AOA2|Ataxia with Oculomotor Apraxia Type 2|SCAN2

    an autosomal recessive condition caused by mutation(s) in the setx gene, encoding probable helicase senataxin. it is characterized by juvenile onset progressive cerebellar ataxia, axonal sensorimotor peripheral neuropathy, and increased concentrations of serum alpha-fetoprotein. oculomotor apraxia is common, but is not always present.

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

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

Convert G93.40 to ICD-9-CMHistory

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

ICD-9-CM
348.30 Encephalopathy NOS
Exact Match The mapping is direct, with no qualifiers.

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 G93.40Overview

Is G93.40 (Other and unspecified encephalopathy) a billable code?

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

What MS-DRG does G93.40 group to?

When encephalopathy, unspecified 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 G93.40?

Under the General Equivalence Mappings, encephalopathy, unspecified converts to ICD-9-CM 348.30 (encephalopathy NOS). The mapping is a direct match.

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.