Encephalopathy
Encephalopathy means any disorder or disease of the brain, especially chronic degenerative conditions. 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.
Signs and symptoms
The hallmark of encephalopathy is an altered mental state or delirium. Characteristic of the altered mental state is impairment of the cognition, attention, orientation, sleep–wake cycle and consciousness. An altered state of consciousness may range from failure of selective attention to drowsiness. Hypervigilance may be present; with or without: cognitive deficits, headache, epileptic seizures, myoclonus or asterixis.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, ataxia, tremor. Other neurological signs may include involuntary grasping and sucking motions, nystagmus, jactitation, and respiratory abnormalities such as Cheyne-Stokes respiration, apneustic respirations and post-hypercapnic apnea. Focal neurological deficits are less common.
Wernicke encephalopathy can co-occur with Korsakoff alcoholic syndrome, characterized by amnestic-confabulatory syndrome: retrograde amnesia, anterograde amnesia, confabulations, poor recall and disorientation.
Anti-NMDA receptor encephalitis is the most common autoimmune encephalitis. It can cause paranoid and grandiose delusions, agitation, hallucinations, bizarre behavior, fear, short-term memory loss, and confusion.
HIV encephalopathy can lead to dementia.
Types
There are many types of encephalopathy. Some examples include:- Mitochondrial encephalopathy: Metabolic disorder caused by dysfunction of mitochondrial DNA. Can affect many body systems, particularly the brain and nervous system.
- Glycine encephalopathy: A genetic metabolic disorder involving excess production of glycine.
- Hepatic encephalopathy: Arising from advanced cirrhosis of the liver.
- Hypoxic ischemic encephalopathy: Permanent or transitory encephalopathy arising from severely reduced oxygen delivery to the brain.
- Static encephalopathy: Unchanging, or permanent, brain damage.
- Uremic encephalopathy: Arising from high levels of toxins normally cleared by the kidneys—rare where dialysis is readily available.
- Wernicke's encephalopathy: Arising from thiamine deficiency, usually in the setting of alcoholism.
- Hashimoto's encephalopathy: Arising from an auto-immune disorder.
- 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, 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: 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, impaired locomotion or coordination, and a 100% mortality rate. Includes bovine spongiform encephalopathy, scrapie, and kuru among others.
- Neonatal 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 often resulting in permanent brain damage and nervous system disorders.
- Encephalomyopathy: A combination of encephalopathy and myopathy. Causes may include mitochondrial disease or chronic hypophosphatemia, as may occur in cystinosis.
- Creutzfeldt–Jakob disease.
- HIV encephalopathy.
- Sepsis-associated encephalopathy.
- Epileptic encephalopathies:
- * Early infantile epileptic encephalopathy.
- * Early myoclonic epileptic encephalopathy.
- Gluten encephalopathy: Focal abnormalities of the white matter are appreciated through magnetic resonance. Migraine is the most common symptom reported.
Toxicity from chemotherapy
permanent severe global encephalopathy. Ifosfamide can cause
a severe encephalopathy. Bevacizumab and other anti–vascular endothelial growth factor medication can cause posterior reversible encephalopathy syndrome.
Diagnosis
s, cerebrospinal fluid examination by lumbar puncture, brain imaging studies, electroencephalography, and similar diagnostic studies may be used to differentiate the various causes of encephalopathy.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 varies according to the type and severity of the encephalopathy. Anticonvulsants 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.Sympathomimetic drugs can increase motivation, cognition, motor performance and alertness in persons with encephalopathy caused by brain injury, chronic infections, strokes, brain tumors.
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.
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.Terminology
Encephalopathy is a difficult term because it can be used to denote either a disease or finding.When referring to a finding, encephalopathy refers to permanent 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.
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 encephalopathies, are invariably fatal, but other encephalopathies are reversible and can have a number of causes including nutritional deficiencies and toxins.