| prognosis = Varies depending on cause and severity
| frequency =
| frequency =
| deaths =
| deaths =
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}}
'''Encephalopathy''' ({{IPAc-en|ɛ|n|ˌ|s|ɛ|f|ə|ˈ|l|ɒ|p|ə|θ|i}}; from {{lang-grc|ἐνκέφαλος}} "brain" + πάθος "suffering") means any disorder or [[disease]] of the [[brain]], especially chronic [[Neurodegeneration|degenerative]] conditions.<ref name="BMA">{{cite book |author=The British Medical Association (BMA) |date=2002 |title=Illustrated Medical Dictionary |publisher=A Dorling Kindersley Book |page=199 |isbn=978-0-75-133383-1}}</ref> In modern usage, encephalopathy does not refer to a single disease, but rather to a [[syndrome]] of overall brain dysfunction; this syndrome has many possible organic and inorganic causes.
{{Short description|A broad term for any brain disease that alters brain function or structure}}
'''Encephalopathy''' is a general term used to describe any disorder or disease of the brain that alters its function or structure. The hallmark of encephalopathy is an altered mental state, but the condition can present with a wide range of neurological symptoms. Encephalopathy can be caused by a variety of factors, including infections, metabolic or mitochondrial dysfunction, brain trauma, toxic exposure, and lack of oxygen or blood flow to the brain.
==Signs and symptoms==
==Types of Encephalopathy==
The hallmark of encephalopathy is an [[Altered state of consciousness|altered mental state]] or [[delirium]]. Characteristic of the altered mental state is impairment of the cognition, attention, [[Orientation (mental)|orientation]], [[Circadian rhythm|sleep–wake cycle]] and [[consciousness]].<ref name="OehmichenNeuropathology"/> An altered state of consciousness may range from failure of selective attention to drowsiness.<ref name="Larner2016"/> [[Hypervigilance]] may be present; with or without: cognitive deficits, [[headache]], [[epileptic seizure]]s, [[myoclonus]] (involuntary twitching of a muscle or group of muscles) or [[asterixis]] ("flapping tremor" of the hand when wrist is extended).<ref name="Larner2016">{{cite book|author=A.J. Larner|title=A Dictionary of Neurological Signs|url=https://books.google.com/books?id=yUoWDAAAQBAJ&pg=PA112|date=2016|publisher=Springer|isbn=978-3-319-29821-4|pages=112}}</ref>
Encephalopathy can be classified into several types based on the underlying cause:
===Metabolic Encephalopathy===
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]], [[hypomimia]], problems with movements (they can be clumsy or slow), [[ataxia]], [[tremor]].<ref name="OehmichenNeuropathology">{{cite book|author1=Manfred Oehmichen|author2=Roland N. Auer|author3=Hans Günter König|title=Forensic Neuropathology and Associated Neurology|url=https://books.google.com/books?id=aU-xIHy53j4C&pg=PA611|date=2006|publisher=Springer Science & Business Media|isbn=978-3-540-28995-1|pages=611}}</ref> Other neurological signs may include involuntary grasping and sucking motions, [[Pathologic nystagmus|nystagmus]] (rapid, involuntary eye movement), [[jactitation (medicine)|jactitation]] (restless picking at things characteristic of severe infection),{{citation needed|date=November 2012}} and respiratory abnormalities such as [[Cheyne-Stokes respiration]] (cyclic waxing and waning of tidal volume), [[apneustic respirations]] and [[hypercapnia|post-hypercapnic]] [[apnea]]. Focal neurological deficits are less common.<ref name="Larner2016"/>
[[Metabolic encephalopathy]] is caused by systemic illness that affects the brain's metabolism. Common causes include liver failure, kidney failure, and severe electrolyte imbalances. [[Hepatic encephalopathy]] is a well-known form of metabolic encephalopathy resulting from liver dysfunction.
===Toxic Encephalopathy===
[[Wernicke encephalopathy]] can [[Wernicke–Korsakoff syndrome|co-occur with Korsakoff alcoholic syndrome]], characterized by amnestic-confabulatory syndrome: [[retrograde amnesia]], [[anterograde amnesia]], [[confabulation]]s (invented memories), poor recall and disorientation.<ref name="Association2006">{{cite book|author=American Psychiatric Association|title=American Psychiatric Association Practice Guidelines for the Treatment of Psychiatric Disorders: Compendium 2006|url=https://books.google.com/books?id=zql0AqtRSrYC&pg=PA210|year=2006|publisher=American Psychiatric Pub|isbn=978-0-89042-385-1|pages=210}}</ref>
[[Toxic encephalopathy]] results from exposure to toxic substances, such as heavy metals, drugs, or alcohol. Chronic exposure to these substances can lead to permanent brain damage.
===Hypoxic-Ischemic Encephalopathy===
[[Anti-NMDA receptor encephalitis]] is the most common autoimmune encephalitis. It can cause paranoid and [[grandiose delusions]], agitation, [[hallucination]]s (visual and auditory), bizarre behavior, fear, short-term [[Amnesia|memory loss]], and confusion.<ref name="AutoimmuneEnc">{{cite journal | vauthors = Bost C, Pascual O, Honnorat J | title = Autoimmune encephalitis in psychiatric institutions: current perspectives | journal = Neuropsychiatr Dis Treat | volume = 12 | issue = | pages = 2775–2787 | date = 2016 | pmid = 27822050 | pmc = 5089825 | doi = 10.2147/NDT.S82380 }}</ref>
[[Hypoxic-ischemic encephalopathy]] occurs when the brain is deprived of adequate oxygen supply, often due to cardiac arrest, respiratory failure, or complications during childbirth.
===Infectious Encephalopathy===
[[HIV-associated neurocognitive disorder|HIV encephalopathy]] can lead to [[dementia]].
[[Infectious encephalopathy]] is caused by infections that affect the brain, such as [[encephalitis]] or [[meningitis]]. These infections can be viral, bacterial, or fungal in origin.
===Wernicke's Encephalopathy===
== {{anchor|Types}} Causes==
[[Wernicke's encephalopathy]] is a neurological disorder caused by thiamine (vitamin B1) deficiency, often associated with chronic alcoholism.
There are many types of encephalopathy. Some examples include:
==Symptoms==
The symptoms of encephalopathy can vary widely depending on the type and severity of the condition. Common symptoms include:
* [[MELAS|Mitochondrial encephalopathy]]: Metabolic disorder caused by dysfunction of mitochondrial DNA. Can affect many body systems, particularly the brain and nervous system.
* Altered mental status
* [[Glycine encephalopathy]]: A genetic metabolic disorder involving excess production of glycine.
* Confusion
* [[Hepatic encephalopathy]]: Arising from advanced cirrhosis of the liver.
* Memory loss
* [[Cerebral hypoxia|Hypoxic ischemic encephalopathy]]: Permanent or transitory encephalopathy arising from severely reduced oxygen delivery to the brain.
* Personality changes
* Static encephalopathy: Unchanging, or permanent, brain damage.
* Seizures
* [[Uremic toxin|Uremic]] encephalopathy: Arising from high levels of toxins normally cleared by the kidneys—rare where dialysis is readily available.
* Muscle weakness
* [[Wernicke's encephalopathy]]: Arising from thiamine (B<sub>1</sub>) deficiency, usually in the setting of alcoholism.
* Tremors
* [[Hashimoto's encephalopathy]]: Arising from an auto-immune disorder.
* Difficulty speaking or swallowing
* [[Anti-NMDA receptor encephalitis]]: An auto-immune encephalitis.
* [[Hyperammonemia]]: a condition caused by high levels of [[ammonia]], which is due to inborn errors of metabolism (including [[urea cycle disorder]] or [[multiple carboxylase deficiency]]), a diet with excessive levels of [[protein]], deficiencies of specific nutrients such as [[arginine]] or [[biotin]], or organ failure.
* [[Hypertensive encephalopathy]]: Arising from acutely increased blood pressure.
* [[Chronic traumatic encephalopathy]]: Progressive degenerative disease associated with multiple concussions and other forms of brain injury.
* [[Lyme encephalopathy]]: Arising from Lyme disease bacteria, including ''[[Borrelia burgdorferi]]''.
* [[Toxic encephalopathy]]: A form of encephalopathy caused by chemicals, often resulting in permanent brain damage.
* [[Toxic-Metabolic encephalopathy|Toxic-metabolic encephalopathy]]: A catch-all for brain dysfunction caused by infection, organ failure, or intoxication.
* [[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]] (mad cow disease), [[scrapie]], and [[Kuru (disease)|kuru]] among others.
* [[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]] 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]]. Causes may include [[mitochondrial disease]] (particularly [[MELAS]]) or chronic [[hypophosphatemia]], as may occur in [[cystinosis]].<ref>{{cite journal |vauthors=Müller M, Baumeier A, Ringelstein E, Husstedt I |title= Long-term tracking of neurological complications of encephalopathy and myopathy in a patient with nephropathic cystinosis: a case report and review of the literature |journal=J Med Case Reports |volume=2 |pages=235 |year=2008 |pmid= 18644104 |doi=10.1186/1752-1947-2-235 |pmc=2491650}}</ref>
* [[HIV-associated neurocognitive disorder|HIV encephalopathy]] (encephalopathy associated with HIV infection and AIDS, characterized by atrophy and ill-defined white matter hyperintensity).
* [[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).
* [[Epilepsia|Epileptic]] encephalopathies:
** Early infantile epileptic encephalopathy (acquired or congenital abnormal cortical development).
** Early [[Myoclonic epilepsy|myoclonic epileptic]] encephalopathy (possibly due to metabolic disorders).
* [[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.<ref name="LosurdoPrincipi2018">{{cite journal| vauthors=Losurdo G, Principi M, Iannone A, Amoruso A, Ierardi E, Di Leo A et al.| title=Extra-intestinal manifestations of non-celiac gluten sensitivity: An expanding paradigm | journal=World J Gastroenterol | year= 2018 | volume= 24 | issue= 14 | pages= 1521-1530 | pmid=29662290 | doi=10.3748/wjg.v24.i14.1521 | pmc=5897856 | type=Review }} </ref>
=== Toxicity from chemotherapy ===
Chemotherapy medication, for example, [[fludarabine]] can cause a
permanent severe global encephalopathy.<ref name="HarrisonsNeurology"/> [[Ifosfamide]] can cause
a severe encephalopathy (but it can be reversible with stopping use of the drug and starting the use of [[methylene blue]]).<ref name="HarrisonsNeurology"/> [[Bevacizumab]] and other [[Anti–vascular endothelial growth factor therapy|anti–vascular endothelial growth factor medication]] can cause posterior reversible encephalopathy syndrome.<ref name="HarrisonsNeurology">{{cite book |author=Ed. Stephen L. Hauser, S. Andrew Josephson |edition=3rd |date=2013 |title=Harrison's Neurology in Clinical Medicine |isbn=978-0-07-181501-7 |page=438}}</ref>
==Diagnosis==
==Diagnosis==
[[Blood test]]s, [[cerebrospinal fluid]] examination by [[lumbar puncture]] (also known as spinal tap), [[brain imaging]] studies, [[electroencephalography]] (EEG), and similar diagnostic studies may be used to differentiate the various causes of encephalopathy.
Diagnosing encephalopathy involves a combination of clinical evaluation, laboratory tests, and imaging studies. A thorough medical history and physical examination are essential. Blood tests, lumbar puncture, and imaging studies such as [[MRI]] or [[CT scan]] may be used to identify the underlying cause.
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.
==Treatment==
==Treatment==
Treatment varies according to the type and severity of the encephalopathy. [[Anticonvulsant]]s may be prescribed to reduce or halt any seizures. Changes to diet and nutritional supplements may help some people. In severe cases, [[dialysis]] or organ replacement surgery may be needed.
Treatment of encephalopathy focuses on addressing the underlying cause. For example, metabolic encephalopathy may require correction of electrolyte imbalances, while infectious encephalopathy may require antimicrobial therapy. Supportive care, including hydration, nutrition, and management of symptoms, is also crucial.
[[Sympathomimetic drug]]s can increase [[motivation]], [[cognition]], motor performance and alertness in persons with encephalopathy caused by [[brain injury]], chronic infections, strokes, [[brain tumor]]s.<ref name="Sadock2008">{{cite book|author1=Benjamin J. Sadock|author2=Virginia A. Sadock|title=Kaplan & Sadock's Concise Textbook of Clinical Psychiatry|url=https://books.google.com/books?id=ubG51n2NgfwC&pg=PA78|year=2008|publisher=Lippincott Williams & Wilkins|isbn=978-0-7817-8746-8|pages=78}}</ref>
When the encephalopathy is caused by untreated [[celiac disease]] or [[non-celiac gluten sensitivity]], the [[gluten-free diet]] stops the progression of brain damage and improves the headaches.<ref name="LosurdoPrincipi2018" />
==Prognosis==
==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]]. Some encephalopathies can be fatal.
The prognosis of encephalopathy depends on the underlying cause and the timeliness of treatment. Some forms of encephalopathy, such as those caused by reversible metabolic disturbances, may resolve completely with appropriate treatment. Others, particularly those involving significant brain damage, may result in permanent neurological deficits.
==Terminology==
==Related pages==
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).
* [[Encephalitis]]
* [[Meningitis]]
When referring to a finding, encephalopathy refers to permanent (or degenerative)<ref>{{DorlandsDict|three/000035088|encephalopathy }}</ref> 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.
* [[Hepatic encephalopathy]]
* [[Wernicke's encephalopathy]]
When referring to a disease, encephalopathy refers to a wide variety of brain disorders with very different etiologies, prognoses and implications. For example, [[prion]] diseases, all of which cause [[Transmissible spongiform encephalopathy|transmissible spongiform encephalopathies]], are invariably fatal, but other encephalopathies are reversible and can have a number of causes including nutritional deficiencies and toxins.
==See also==
*[[Brain damage]]
*[[Neuroscience]]
*[[Neurological disorder]]
*[[Psychoorganic syndrome]]
==References==
{{reflist}}
* Adapted from: {{cite web |url=http://www.ninds.nih.gov/disorders/encephalopathy/encephalopathy.htm |title=NINDS Encephalopathy Information Page |author=Office of Communications and Public Liaison |date=9 November 2010 |publisher=[[National Institute of Neurological Disorders and Stroke]], [[National Institutes of Health]] |access-date=2005-09-01 |archive-url=https://web.archive.org/web/20090323180350/http://www.ninds.nih.gov/disorders/encephalopathy/encephalopathy.htm |archive-date=2009-03-23 |url-status=dead }}
== 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.
A broad term for any brain disease that alters brain function or structure
Encephalopathy is a general term used to describe any disorder or disease of the brain that alters its function or structure. The hallmark of encephalopathy is an altered mental state, but the condition can present with a wide range of neurological symptoms. Encephalopathy can be caused by a variety of factors, including infections, metabolic or mitochondrial dysfunction, brain trauma, toxic exposure, and lack of oxygen or blood flow to the brain.
Metabolic encephalopathy is caused by systemic illness that affects the brain's metabolism. Common causes include liver failure, kidney failure, and severe electrolyte imbalances. Hepatic encephalopathy is a well-known form of metabolic encephalopathy resulting from liver dysfunction.
Toxic encephalopathy results from exposure to toxic substances, such as heavy metals, drugs, or alcohol. Chronic exposure to these substances can lead to permanent brain damage.
Hypoxic-ischemic encephalopathy occurs when the brain is deprived of adequate oxygen supply, often due to cardiac arrest, respiratory failure, or complications during childbirth.
Diagnosing encephalopathy involves a combination of clinical evaluation, laboratory tests, and imaging studies. A thorough medical history and physical examination are essential. Blood tests, lumbar puncture, and imaging studies such as MRI or CT scan may be used to identify the underlying cause.
Treatment of encephalopathy focuses on addressing the underlying cause. For example, metabolic encephalopathy may require correction of electrolyte imbalances, while infectious encephalopathy may require antimicrobial therapy. Supportive care, including hydration, nutrition, and management of symptoms, is also crucial.
The prognosis of encephalopathy depends on the underlying cause and the timeliness of treatment. Some forms of encephalopathy, such as those caused by reversible metabolic disturbances, may resolve completely with appropriate treatment. Others, particularly those involving significant brain damage, may result in permanent neurological deficits.
