# Encephalopathy

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Not to be confused with [Anencephaly](/source/Anencephaly).

**Encephalopathy** (/ɛnˌsɛfəˈlɒpəθi/; Ancient Greek **ἐγκέφαλος* ()* 'brain') is any disorder or [disease](/source/Disease) of the [brain](/source/Brain), especially chronic [degenerative](/source/Neurodegeneration) conditions.[1] In modern usage, *encephalopathy* does not refer to a single disease, but rather to a [syndrome](/source/Syndrome) of overall brain dysfunction; this syndrome has many possible organic and inorganic causes.

## Types

There are many types of encephalopathy. Some examples include:

- [Mitochondrial encephalopathy](/source/MELAS): Metabolic disorder caused by dysfunction of mitochondrial DNA. Can affect many body systems, particularly the brain and nervous system.
- [Acute necrotizing encephalopathy](/source/Acute_necrotizing_encephalopathy), rare disease that occurs following a viral infection.
- [Glycine encephalopathy](/source/Glycine_encephalopathy): A genetic metabolic disorder involving excess production of glycine.
- [Hepatic encephalopathy](/source/Hepatic_encephalopathy): Arising from advanced cirrhosis of the liver.
- [Hypoxic ischemic encephalopathy](/source/Cerebral_hypoxia): Permanent or transitory encephalopathy arising from severely reduced oxygen delivery to the brain.
- [Static encephalopathy](/source/Fetal_Alcohol_Spectrum_Disorder): Unchanging, or permanent, brain damage, usually caused by [prenatal exposure to ethanol](/source/Alcohol_and_pregnancy).
- [Uremic](/source/Uremic_toxin) encephalopathy: Arising from high levels of toxins normally cleared by the kidneys—rare where dialysis is readily available.
- [Wernicke's encephalopathy](/source/Wernicke's_encephalopathy): Arising from [thiamine (B1) deficiency](/source/Thiamine_deficiency), usually in the setting of [alcoholism](/source/Alcoholism).
- [Hashimoto's encephalopathy](/source/Hashimoto's_encephalopathy): Arising from an auto-immune disorder.
- [Anti-NMDA receptor encephalitis](/source/Anti-NMDA_receptor_encephalitis): An auto-immune encephalitis.
- [Hyperammonemia](/source/Hyperammonemia): A condition caused by high levels of [ammonia](/source/Ammonia), which is due to inborn errors of metabolism (including [urea cycle disorder](/source/Urea_cycle_disorder) or [multiple carboxylase deficiency](/source/Multiple_carboxylase_deficiency)), a diet with excessive levels of [protein](/source/Protein), deficiencies of specific nutrients such as [arginine](/source/Arginine) or [biotin](/source/Biotin), or organ failure.
- [Hypertensive encephalopathy](/source/Hypertensive_encephalopathy): Arising from acutely increased blood pressure.
- [Chronic traumatic encephalopathy](/source/Chronic_traumatic_encephalopathy): A progressive degenerative disease associated with repeated head trauma, often linked to [contact sports](/source/Contact_sports).
- [Lyme encephalopathy](/source/Lyme_encephalopathy): Arising from Lyme disease bacteria, including *[Borrelia burgdorferi](/source/Borrelia_burgdorferi)*.
- [Toxic encephalopathy](/source/Toxic_encephalopathy): A form of encephalopathy caused by chemicals and prescription drugs, often resulting in permanent brain damage.
- [Toxic-metabolic encephalopathy](/source/Toxic-Metabolic_encephalopathy): A catch-all for brain dysfunction caused by infection, organ failure, or intoxication.
- [Transmissible spongiform encephalopathy](/source/Transmissible_spongiform_encephalopathy): A collection of diseases all caused by prions, and characterized by "spongy" brain tissue (riddled with holes), impaired locomotion or coordination, and a 100% mortality rate. Includes [bovine spongiform encephalopathy](/source/Bovine_spongiform_encephalopathy) (mad cow disease), [scrapie](/source/Scrapie), and [kuru](/source/Kuru_(disease)) among others.
- [Neonatal encephalopathy](/source/Neonatal_encephalopathy) (hypoxic-ischemic encephalopathy): An obstetric form, often occurring due to lack of oxygen in bloodflow to brain-tissue of the fetus during labour or delivery.
- [Salmonella](/source/Salmonella) encephalopathy: A form of encephalopathy caused by food poisoning (especially out of peanuts and rotten meat) often resulting in permanent brain damage and nervous system disorders.
- Encephalomyopathy: A combination of encephalopathy and [myopathy](/source/Myopathy). Causes may include [mitochondrial disease](/source/Mitochondrial_disease) (particularly [MELAS](/source/MELAS)) or chronic [hypophosphatemia](/source/Hypophosphatemia), as may occur in [cystinosis](/source/Cystinosis).[2]
- [Creutzfeldt–Jakob disease](/source/Creutzfeldt%E2%80%93Jakob_disease) (CJD; transmissible spongiform encephalopathy).
- [Aicardi–Goutières syndrome](/source/Aicardi%E2%80%93Gouti%C3%A8res_syndrome), a hereditary disease caused by [mutations](/source/Mutations) in the *[TREX1](/source/TREX1), [RNASEH2B](/source/RNASEH2B), [RNASEH2C](/source/RNASEH2C), [RNASEH2A](/source/RNASEH2A), [ADAR1](/source/ADAR1), [SAMHD1](/source/SAMHD1), [IFIH1](/source/IFIH1), [LSM11](/source/LSM11)*, or *[RNU7-1](/source/RNU7-1)* gene.
- [Infectious disease-associated encephalopathy](/source/Infectious_disease-associated_encephalopathy) (an umbrella term for encephalopathy related to infectious disease, not necessarily directly infecting the central nervous system)
- [HIV encephalopathy](/source/HIV-associated_neurocognitive_disorder) (encephalopathy associated with HIV infection and AIDS, characterized by atrophy and ill-defined white matter hyperintensity).
- [Sepsis-associated encephalopathy](/source/Sepsis-associated_encephalopathy) (this type can occur in the setting of apparent sepsis, trauma, severe burns, or trauma, even without clear identification of an infection).
- [Epileptic](/source/Epilepsia) encephalopathies: - Early infantile epileptic encephalopathy (acquired or congenital abnormal cortical development). - Early [myoclonic epileptic](/source/Myoclonic_epilepsy) encephalopathy (possibly due to metabolic disorders).
- [Gluten](/source/Gluten) encephalopathy: Focal abnormalities of the white matter (generally area of low perfusion) are appreciated through magnetic resonance. Migraine is the most common symptom reported.[3]
- *BRAT1* Encephalopathy: An ultra-rare autosomal recessive neonatal encephalopathy.[4]
- [Limbic-predominant age-related TDP-43 encephalopathy(LATE)](/source/Limbic-predominant_age-related_TDP-43_encephalopathy) is a type of [dementia](/source/Dementia) that is caused by mis-folded [TDP-43](/source/TDP-43) protiens. The disorder typically affects >80 year olds.

### Toxicity from chemotherapy

Chemotherapy medication, for example, [fludarabine](/source/Fludarabine) can cause a permanent severe global encephalopathy.[5] [Ifosfamide](/source/Ifosfamide) can cause a severe encephalopathy (but it can be reversible with stopping use of the drug and starting the use of [methylene blue](/source/Methylene_blue)).[5] [Bevacizumab](/source/Bevacizumab) and other [anti–vascular endothelial growth factor medication](/source/Anti%E2%80%93vascular_endothelial_growth_factor_therapy) can cause posterior reversible encephalopathy syndrome.[5]

## Signs and symptoms

The hallmark of encephalopathy is an [altered mental state](/source/Altered_state_of_consciousness) or [delirium](/source/Delirium). Characteristic of the altered mental state is impairment of the cognition, attention, [orientation](/source/Orientation_(mental)), [sleep–wake cycle](/source/Circadian_rhythm) and [consciousness](/source/Consciousness).[6] An altered state of consciousness may range from failure of selective attention to drowsiness.[7] [Hypervigilance](/source/Hypervigilance) may be present; with or without: cognitive deficits, [headache](/source/Headache), [epileptic seizures](/source/Epileptic_seizure), [myoclonus](/source/Myoclonus) (involuntary twitching of a muscle or group of muscles) or [asterixis](/source/Asterixis) ("flapping tremor" of the hand when wrist is extended).[7]

Depending on the type and severity of encephalopathy, common neurological symptoms are loss of cognitive function, subtle personality changes, and an inability to concentrate. Other neurological signs may include [dysarthria](/source/Dysarthria), [hypomimia](/source/Hypomimia), problems with movements (they can be clumsy or slow), [ataxia](/source/Ataxia), [tremor](/source/Tremor).[6] Other neurological signs may include involuntary grasping and sucking motions, [nystagmus](/source/Pathologic_nystagmus) (rapid, involuntary eye movement), [jactitation](/source/Jactitation_(medicine)) (restlessness while in bed),[citation needed] and respiratory abnormalities such as [Cheyne-Stokes respiration](/source/Cheyne-Stokes_respiration) (cyclic waxing and waning of tidal volume), [apneustic respirations](/source/Apneustic_respirations) and [post-hypercapnic](/source/Hypercapnia) [apnea](/source/Apnea). Focal neurological deficits are less common.[7]

[Wernicke encephalopathy](/source/Wernicke_encephalopathy) can [co-occur with Korsakoff alcoholic syndrome](/source/Wernicke%E2%80%93Korsakoff_syndrome), characterized by amnestic-confabulatory syndrome: [retrograde amnesia](/source/Retrograde_amnesia), [anterograde amnesia](/source/Anterograde_amnesia), [confabulations](/source/Confabulation) (invented memories), poor recall and disorientation.[8]

[Anti-NMDA receptor encephalitis](/source/Anti-NMDA_receptor_encephalitis) is the most common autoimmune encephalitis. It can cause paranoid and [grandiose delusions](/source/Grandiose_delusions), agitation, [hallucinations](/source/Hallucination) (visual and auditory), bizarre behavior, fear, short-term [memory loss](/source/Amnesia), and confusion.[9]

[HIV encephalopathy](/source/HIV-associated_neurocognitive_disorder) can lead to [dementia](/source/Dementia).[citation needed]

## Diagnosis

[Blood tests](/source/Blood_test), [cerebrospinal fluid](/source/Cerebrospinal_fluid) examination by [lumbar puncture](/source/Lumbar_puncture) (also known as spinal tap), [brain imaging](/source/Brain_imaging) studies, [electroencephalography](/source/Electroencephalography) (EEG), neuropsychological testing and similar diagnostic studies may be used to differentiate the various causes of encephalopathy.[citation needed]

Diagnosis is frequently clinical. That is, no set of tests give the diagnosis, but the entire presentation of the illness with nonspecific test results informs the experienced clinician of the diagnosis.[citation needed]

## Treatment

Treatment varies according to the type and severity of the encephalopathy. [Anticonvulsants](/source/Anticonvulsant) may be prescribed to reduce or halt any seizures. Changes to diet and nutritional supplements may help some people. In severe cases, [dialysis](/source/Kidney_dialysis) or organ replacement surgery may be needed.[citation needed]

[Sympathomimetic drugs](/source/Sympathomimetic_drug) can increase [motivation](/source/Motivation), [cognition](/source/Cognition), motor performance and alertness in persons with encephalopathy caused by [brain injury](/source/Brain_injury), chronic infections, strokes, [brain tumors](/source/Brain_tumor).[10]

When the encephalopathy is caused by untreated [celiac disease](/source/Celiac_disease) or [non-celiac gluten sensitivity](/source/Non-celiac_gluten_sensitivity), the [gluten-free diet](/source/Gluten-free_diet) stops the progression of brain damage and improves the headaches.[3]

## Prognosis

Treating the underlying cause of the disorder may improve or reverse symptoms. However, in some cases, the encephalopathy may cause permanent structural changes and irreversible damage to the brain. These permanent deficits can be considered a form of stable [dementia](/source/Dementia). Some encephalopathies can be fatal.[citation needed]

## Terminology

Encephalopathy is a difficult term because it can be used to denote either a disease or finding (i.e., an observable sign in a person).[citation needed]

When referring to a finding, encephalopathy refers to permanent (or degenerative)[11] brain injury, or a reversible one. It can be due to direct injury to the brain, or illness remote from the brain. The individual findings that cause a clinician to refer to a person as having encephalopathy include intellectual disability, irritability, agitation, delirium, confusion, somnolence, stupor, coma and psychosis. As such, describing a person as having a clinical picture of encephalopathy is not a very specific description.[citation needed]

When referring to a disease, encephalopathy refers to a wide variety of brain disorders with very different etiologies, prognoses and implications. For example, [prion](/source/Prion) diseases, all of which cause [transmissible spongiform encephalopathies](/source/Transmissible_spongiform_encephalopathy), are invariably fatal, but other encephalopathies are reversible and can have a number of causes including nutritional deficiencies and toxins.[citation needed]

## See also

- [Brain damage](/source/Brain_damage)
- [Neuroscience](/source/Neuroscience)
- [Neurological disorder](/source/Neurological_disorder)
- [Psychoorganic syndrome](/source/Psychoorganic_syndrome)

## References

1. The British Medical Association (BMA) (2002). *Illustrated Medical Dictionary*. A Dorling Kindersley Book. p. 199. ISBN 978-0-75-133383-1.

1. Müller M, Baumeier A, Ringelstein E, Husstedt I (2008). "Long-term tracking of neurological complications of encephalopathy and myopathy in a patient with nephropathic cystinosis: a case report and review of the literature". *J Med Case Rep*. **2**: 235. [doi:10.1186/1752-1947-2-235](https://doi.org/10.1186/1752-1947-2-235). [PMC 2491650](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2491650). [PMID 18644104](https://pubmed.ncbi.nlm.nih.gov/18644104)

1. Losurdo G, Principi M, Iannone A, Amoruso A, Ierardi E, Di Leo A et al. (2018). "Extra-intestinal manifestations of non-celiac gluten sensitivity: An expanding paradigm" (Review). *World J Gastroenterol*. **24** (14): 1521–1530. [doi:10.3748/wjg.v24.i14.1521](https://doi.org/10.3748/wjg.v24.i14.1521). [PMC 5897856](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897856). [PMID 29662290](https://pubmed.ncbi.nlm.nih.gov/29662290)

1. Carapancea, Evelina; Cornet, Marie-Coralie; Milh, Mathieu; De Cosmo, Lucrezia; Huang, Eric J.; Granata, Tiziana; Striano, Pasquale; Ceulemans, Berten; Stein, Anja; Morris-Rosendahl, Deborah; Conti, Greta; Mitra, Nipa; Raymond, F. Lucy; Rowitch, David H.; Solazzi, Roberta (2023-03-21). "Clinical and Neurophysiologic Phenotypes in Neonates With BRAT1 Encephalopathy". *Neurology*. **100** (12): e1234–e1247. [doi:10.1212/WNL.0000000000206755](https://doi.org/10.1212/WNL.0000000000206755). [ISSN 1526-632X](https://www.worldcat.org/issn/1526-632X). [PMC 10033164](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10033164). [PMID 36599696](https://pubmed.ncbi.nlm.nih.gov/36599696)

1. Ed. Stephen L. Hauser, S. Andrew Josephson (2013). *Harrison's Neurology in Clinical Medicine*. 3rd ed. McGraw Hill Professional. p. 438. ISBN 978-0-07-181501-7.

1. Manfred Oehmichen; Roland N. Auer; Hans Günter König (2006). [*Forensic Neuropathology and Associated Neurology*](https://books.google.com/books?id=aU-xIHy53j4C&pg=PA611). Springer Science & Business Media. p. 611. ISBN 978-3-540-28995-1.

1. A.J. Larner (2016). [*A Dictionary of Neurological Signs*](https://books.google.com/books?id=yUoWDAAAQBAJ&pg=PA112). Springer. p. 112. ISBN 978-3-319-29821-4.

1. American Psychiatric Association (2006). [*American Psychiatric Association Practice Guidelines for the Treatment of Psychiatric Disorders: Compendium 2006*](https://books.google.com/books?id=zql0AqtRSrYC&pg=PA210). American Psychiatric Pub. p. 210. ISBN 978-0-89042-385-1.

1. Bost C, Pascual O, Honnorat J (2016). "Autoimmune encephalitis in psychiatric institutions: current perspectives". *Neuropsychiatr Dis Treat*. **12**: 2775–2787. [doi:10.2147/NDT.S82380](https://doi.org/10.2147/NDT.S82380). [PMC 5089825](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5089825). [PMID 27822050](https://pubmed.ncbi.nlm.nih.gov/27822050)

1. Benjamin J. Sadock & Virginia A. Sadock (2008). [*Kaplan & Sadock's Concise Textbook of Clinical Psychiatry*](https://books.google.com/books?id=ubG51n2NgfwC&pg=PA78). Lippincott Williams & Wilkins. p. 78. ISBN 978-0-7817-8746-8.

- Adapted from: Office of Communications and Public Liaison (9 November 2010). ["NINDS Encephalopathy Information Page"](https://web.archive.org/web/20090323180350/http://www.ninds.nih.gov/disorders/encephalopathy/encephalopathy.htm). [National Institute of Neurological Disorders and Stroke](/source/National_Institute_of_Neurological_Disorders_and_Stroke), [National Institutes of Health](/source/National_Institutes_of_Health). Archived from [the original](http://www.ninds.nih.gov/disorders/encephalopathy/encephalopathy.htm) on 2009-03-23. Retrieved 2005-09-01.

## Further reading

- *The Diagnosis of Stupor and Coma* by Plum and Posner, ISBN 0-19-513898-8, remains one of the best detailed observational references to the condition.

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Adapted from the Wikipedia article [Encephalopathy](https://en.wikipedia.org/wiki/Encephalopathy) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Encephalopathy?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.