ICD-10-CM Code G93.40

Encephalopathy, unspecified

Version 2021 Billable Code

Valid for Submission

G93.40 is a billable code used to specify a medical diagnosis of encephalopathy, unspecified. The code is valid for the fiscal year 2021 for the submission of HIPAA-covered transactions. The ICD-10-CM code G93.40 might also be used to specify conditions or terms like encephalopathy associated with aids, encephalopathy due to and following cardiopulmonary bypass, encephalopathy due to disease caused by severe acute respiratory syndrome coronavirus 2, encephalopathy due to prosaposin deficiency, encephalopathy due to radiation damage, encephalopathy, intracerebral calcification, retinal degeneration syndrome, etc

Short Description:Encephalopathy, unspecified
Long Description:Encephalopathy, 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 G93.40 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:

  • Encephalopathy associated with AIDS
  • Encephalopathy due to and following cardiopulmonary bypass
  • Encephalopathy due to disease caused by Severe acute respiratory syndrome coronavirus 2
  • Encephalopathy due to prosaposin deficiency
  • Encephalopathy due to radiation damage
  • 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-related epilepsy with encephalopathy
  • Static encephalopathy

Clinical Information

  • CHRONIC TRAUMATIC ENCEPHALOPATHY-. degenerative brain disease linked to repetitive brain trauma. progressive symptoms may include memory loss; aggression; or depression.
  • BRAIN INJURIES TRAUMATIC-. a form of acquired brain injury which occurs when a sudden trauma causes damage to the brain.
  • ACUTE FEBRILE ENCEPHALOPATHY-. acute onset of fever accompanied by seizures cerebral inflammation and a change in mental status e.g. confusion disorientation and coma.
  • BRAIN DAMAGE CHRONIC-. a condition characterized by long standing brain dysfunction or damage usually of three months duration or longer. potential etiologies include brain infarction; certain neurodegenerative disorders; craniocerebral trauma; anoxia brain; encephalitis; certain neurotoxicity syndromes; metabolic disorders see brain diseases metabolic; and other conditions.
  • BRAIN DISEASES-. pathologic conditions affecting the brain which is composed of the intracranial components of the central nervous system. this includes but is not limited to the cerebral cortex; intracranial white matter; basal ganglia; thalamus; hypothalamus; brain stem; and cerebellum.
  • BRAIN DISEASES METABOLIC-. acquired or inborn metabolic diseases that produce brain dysfunction or damage. these include primary i.e. disorders intrinsic to the brain and secondary i.e. extracranial metabolic conditions that adversely affect cerebral function.
  • HYPOXIA BRAIN-. a reduction in brain oxygen supply due to anoxemia a reduced amount of oxygen being carried in the blood by hemoglobin or to a restriction of the blood supply to the brain or both. severe hypoxia is referred to as anoxia and is a relatively common cause of injury to the central nervous system. prolonged brain anoxia may lead to brain death or a persistent vegetative state. histologically this condition is characterized by neuronal loss which is most prominent in the hippocampus; globus pallidus; cerebellum; and inferior olives.
  • BRAIN ISCHEMIA-. localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. this frequently occurs in conjunction with brain hypoxia hypoxia brain. prolonged ischemia is associated with brain infarction.
  • EPILEPSIES MYOCLONIC-. a clinically diverse group of epilepsy syndromes characterized either by myoclonic seizures or by myoclonus in association with other seizure types. myoclonic epilepsy syndromes are divided into three subtypes based on etiology: familial cryptogenic and symptomatic.
  • HEPATIC ENCEPHALOPATHY-. a syndrome characterized by central nervous system dysfunction in association with liver failure including portal systemic shunts. clinical features include lethargy and confusion frequently progressing to coma; asterixis; nystagmus pathologic; brisk oculovestibular reflexes; decorticate and decerebrate posturing; muscle spasticity; and bilateral extensor plantar reflexes see reflex babinski. electroencephalography may demonstrate triphasic waves. from adams et al. principles of neurology 6th ed pp1117 20; plum & posner diagnosis of stupor and coma 3rd ed p222 5
  • CREUTZFELDT JAKOB SYNDROME-. a rare transmissible encephalopathy most prevalent between the ages of 50 and 70 years. affected individuals may present with sleep disturbances personality changes ataxia; aphasia visual loss weakness muscle atrophy myoclonus progressive dementia and death within one year of disease onset. a familial form exhibiting autosomal dominant inheritance and a new variant cjd potentially associated with encephalopathy bovine spongiform have been described. pathological features include prominent cerebellar and cerebral cortical spongiform degeneration and the presence of prions. from n engl j med 1998 dec 31;33927
  • KERNICTERUS-. a term used pathologically to describe bilirubin staining of the basal ganglia; brain stem; and cerebellum and clinically to describe a syndrome associated with hyperbilirubinemia. clinical features include athetosis muscle spasticity or hypotonia impaired vertical gaze and deafness. nonconjugated bilirubin enters the brain and acts as a neurotoxin often in association with conditions that impair the blood brain barrier e.g. sepsis. this condition occurs primarily in neonates infant newborn but may rarely occur in adults. menkes textbook of child neurology 5th ed p613
  • KURU-. a prion disease found exclusively among the fore linguistic group natives of the highlands of new guinea. the illness is primarily restricted to adult females and children of both sexes. it is marked by the subacute onset of tremor and ataxia followed by motor weakness and incontinence. death occurs within 3 6 months of disease onset. the condition is associated with ritual cannibalism and has become rare since this practice has been discontinued. pathologic features include a noninflammatory loss of neurons that is most prominent in the cerebellum glial proliferation and amyloid plaques. from adams et al. principles of neurology 6th ed p773
  • LEIGH DISEASE-. a group of metabolic disorders primarily of infancy characterized by the subacute onset of psychomotor retardation hypotonia ataxia weakness vision loss eye movement abnormalities seizures dysphagia and lactic acidosis. pathological features include spongy degeneration of the neuropile of the basal ganglia thalamus brain stem and spinal cord. patterns of inheritance include x linked recessive autosomal recessive and mitochondrial. leigh disease has been associated with mutations in genes for the pyruvate dehydrogenase complex; cytochrome c oxidase; atp synthase subunit 6; and subunits of mitochondrial complex i. from menkes textbook of child neurology 5th ed p850.
  • LEUKOENCEPHALOPATHY PROGRESSIVE MULTIFOCAL-. an opportunistic viral infection of the central nervous system associated with conditions that impair cell mediated immunity e.g. acquired immunodeficiency syndrome and other immunologic deficiency syndromes; hematologic neoplasms; immunosuppression; and collagen diseases. the causative organism is jc polyomavirus jc virus which primarily affects oligodendrocytes resulting in multiple areas of demyelination. clinical manifestations include dementia; ataxia; visual disturbances; and other focal neurologic deficits generally progressing to a vegetative state within 6 months. from joynt clinical neurology 1996 ch26 pp36 7
  • PRIONS-. small proteinaceous infectious particles which resist inactivation by procedures that modify nucleic acids and contain an abnormal isoform of a cellular protein which is a major and necessary component. the abnormal scrapie isoform is prpsc prpsc proteins and the cellular isoform prpc prpc proteins. the primary amino acid sequence of the two isoforms is identical. human diseases caused by prions include creutzfeldt jakob syndrome; gerstmann straussler syndrome; and insomnia fatal familial.
  • WERNICKE ENCEPHALOPATHY-. an acute neurological disorder characterized by the triad of ophthalmoplegia ataxia and disturbances of mental activity or consciousness. eye movement abnormalities include nystagmus external rectus palsies and reduced conjugate gaze. thiamine deficiency and chronic alcoholism are associated conditions. pathologic features include periventricular petechial hemorrhages and neuropil breakdown in the diencephalon and brainstem. chronic thiamine deficiency may lead to korsakoff syndrome. adams et al. principles of neurology 6th ed pp1139 42; davis & robertson textbook of neuropathology 2nd ed pp452 3
  • DEMENTIA VASCULAR-. an imprecise term referring to dementia associated with cerebrovascular disorders including cerebral infarction single or multiple and conditions associated with chronic brain ischemia. diffuse cortical and subcortical subtypes have been described. from gerontol geriatr 1998 feb;311:36 44
  • AIDS DEMENTIA COMPLEX-. a neurologic condition associated with the acquired immunodeficiency syndrome and characterized by impaired concentration and memory slowness of hand movements ataxia incontinence apathy and gait difficulties associated with hiv 1 viral infection of the central nervous system. pathologic examination of the brain reveals white matter rarefaction perivascular infiltrates of lymphocytes foamy macrophages and multinucleated giant cells. from adams et al. principles of neurology 6th ed pp760 1; n engl j med 1995 apr 6;33214:934 40
  • GERSTMANN STRAUSSLER SCHEINKER DISEASE-. an autosomal dominant familial prion disease with a wide spectrum of clinical presentations including ataxia spastic paraparesis extrapyramidal signs and dementia. clinical onset is in the third to sixth decade of life and the mean duration of illness prior to death is five years. several kindreds with variable clinical and pathologic features have been described. pathologic features include cerebral prion protein amyloidosis and spongiform or neurofibrillary degeneration. from brain pathol 1998 jul;83:499 513; brain pathol 1995 jan;51:61 75
  • ENCEPHALOPATHY BOVINE SPONGIFORM-. a transmissible spongiform encephalopathy of cattle associated with abnormal prion proteins in the brain. affected animals develop excitability and salivation followed by ataxia. this disorder has been associated with consumption of scrapie infected ruminant derived protein. this condition may be transmitted to humans where it is referred to as variant or new variant creutzfeldt jakob syndrome. vet rec 1998 jul 25;14341:101 5
  • PRION DISEASES-. a group of genetic infectious or sporadic degenerative human and animal nervous system disorders associated with abnormal prions. these diseases are characterized by conversion of the normal prion protein to an abnormal configuration via a post translational process. in humans these conditions generally feature dementia; ataxia; and a fatal outcome. pathologic features include a spongiform encephalopathy without evidence of inflammation. the older literature occasionally refers to these as unconventional slow virus diseases. from proc natl acad sci usa 1998 nov 10;9523:13363 83
  • HYPERGLYCINEMIA NONKETOTIC-. an autosomal recessive metabolic disorder caused by deficiencies in the mitochondrial glycine cleavage system.
  • MYOCLONIC EPILEPSIES PROGRESSIVE-. a heterogeneous group of primarily familial epilepsy disorders characterized by myoclonic seizures tonic clonic seizures ataxia progressive intellectual deterioration and neuronal degeneration. these include lafora disease; merrf syndrome; neuronal ceroid lipofuscinosis; sialidosis see mucolipidoses and unverricht lundborg syndrome.
  • NEUROTOXICITY SYNDROMES-. neurologic disorders caused by exposure to toxic substances through ingestion injection cutaneous application or other method. this includes conditions caused by biologic chemical and pharmaceutical agents.
  • ARSENIC POISONING-. disorders associated with acute or chronic exposure to compounds containing arsenic arsenicals which may be fatal. acute oral ingestion is associated with gastrointestinal symptoms and an encephalopathy which may manifest as seizures mental status changes and coma. chronic exposure is associated with mucosal irritation desquamating rash myalgias peripheral neuropathy and white transverse mees lines in the fingernails. adams et al. principles of neurology 6th ed p1212
  • MERCURY POISONING NERVOUS SYSTEM-. neurologic disorders associated with exposure to inorganic and organic forms of mercury. acute intoxication may be associated with gastrointestinal disturbances mental status changes and paraparesis. chronic exposure to inorganic mercury usually occurs in industrial workers and manifests as mental confusion prominent behavioral changes including psychosis dyskinesias and neuritis. alkyl mercury poisoning may occur through ingestion of contaminated seafood or grain and its characteristic features include polyneuropathy; ataxia; vision loss; nystagmus pathologic; and deafness. from joynt clinical neurology 1997 ch20 pp10 15
  • LEAD POISONING NERVOUS SYSTEM CHILDHOOD-. neurologic disorders occurring in children following lead exposure. the most frequent manifestation of childhood lead toxicity is an encephalopathy associated with chronic ingestion of lead that usually presents between the ages of 1 and 3 years. clinical manifestations include behavioral changes followed by lethargy; convulsions; hallucinations; delirium; ataxia; and vomiting. elevated intracranial pressure hypertension intracranial and cerebral edema may occur. from adams et al. principles of neurology 6th ed p1210 2
  • HYPERTENSIVE ENCEPHALOPATHY-. brain dysfunction or damage resulting from sustained malignant hypertension. when blood pressure exceeds the limits of cerebral autoregulation cerebral blood flow is impaired brain ischemia. clinical manifestations include headache; nausea; vomiting; seizures; altered mental status in some cases progressing to coma; papilledema; and retinal hemorrhage.
  • LYME NEUROBORRELIOSIS-. nervous system infections caused by tick borne spirochetes of the borrelia burgdorferi group. the disease may affect elements of the central or peripheral nervous system in isolation or in combination. common clinical manifestations include a lymphocytic meningitis cranial neuropathy most often a facial neuropathy polyradiculopathy and a mild loss of memory and other cognitive functions. less often more extensive inflammation involving the central nervous system encephalomyelitis may occur. in the peripheral nervous system b. burgdorferi infection is associated with mononeuritis multiplex and polyradiculoneuritis. from j neurol sci 1998 jan 8;1532:182 91
  • HYPOXIA ISCHEMIA BRAIN-. a disorder characterized by a reduction of oxygen in the blood combined with reduced blood flow ischemia to the brain from a localized obstruction of a cerebral artery or from systemic hypoperfusion. prolonged hypoxia ischemia is associated with ischemic attack transient; brain infarction; brain edema; coma; and other conditions.
  • SEPSIS ASSOCIATED ENCEPHALOPATHY-. acute neurological dysfunction during severe sepsis in the absence of direct brain infection characterized by systemic inflammation and blood brain barrier perturbation.

Convert G93.40 to ICD-9

Code Classification

  • Diseases of the nervous system (G00–G99)
    • Other disorders of the nervous system (G89-G99)
      • Other disorders of brain (G93)

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

Brain Diseases

The brain is the control center of the body. It controls thoughts, memory, speech, and movement. It regulates the function of many organs. When the brain is healthy, it works quickly and automatically. However, when problems occur, the results can be devastating.

Inflammation in the brain can lead to problems such as vision loss, weakness and paralysis. Loss of brain cells, which happens if you suffer a stroke, can affect your ability to think clearly. Brain tumors can also press on nerves and affect brain function. Some brain diseases are genetic. And we do not know what causes some brain diseases, such as Alzheimer's disease.

The symptoms of brain diseases vary widely depending on the specific problem. In some cases, damage is permanent. In other cases, treatments such as surgery, medicines, or physical therapy can correct the source of the problem or improve symptoms.

  • Basal ganglia dysfunction (Medical Encyclopedia)
  • Brain abscess (Medical Encyclopedia)
  • Brain surgery (Medical Encyclopedia)
  • Central pontine myelinolysis (Medical Encyclopedia)
  • Cerebral spinal fluid (CSF) collection (Medical Encyclopedia)
  • EEG (Medical Encyclopedia)
  • Hepatic encephalopathy (Medical Encyclopedia)
  • Pseudotumor cerebri (Medical Encyclopedia)
  • Wernicke-Korsakoff syndrome (Medical Encyclopedia)

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