Encephalopathy

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Encephalopathy

Encephalopathy /?n?s?f?'l?p??i/ literally means disorder or disease

Disease

A disease or medical condition is an abnormal condition of an organism that impairs bodily functions, associated with specific symptoms and Medical signs....
of the brain

Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
.

ome million contexts it refers to permanent (or degenerative) brain injury, and in others it is reversible. It can be due to direct injury to the brain, or illness remote from the brain. In medical jargon it can refer to a wide variety of brain disorders with very different etiologies, prognoses and implications.

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Encyclopedia

Encephalopathy /?n?s?f?'l?p??i/ literally means disorder or disease

Disease

A disease or medical condition is an abnormal condition of an organism that impairs bodily functions, associated with specific symptoms and Medical signs....
of the brain

Brain

Terminology

In some million contexts it refers to permanent (or degenerative) brain injury, and in others it is reversible. It can be due to direct injury to the brain, or illness remote from the brain. In medical jargon it can refer to a wide variety of brain disorders with very different etiologies, prognoses and implications. For example, prion

Prion

A prion is an infectious disease that is comprised entirely of a reproduction, mis-folded protein. The mis-folded form of the prion protein has been implicated in a number of diseases in a variety of mammals, including bovine spongiform encephalopathy in cattle and Creutzfeldt-Jakob disease in humans....
diseases, all of which cause transmissible spongiform encephalopathies

Transmissible spongiform encephalopathy

Transmissible spongiform encephalopathies are a group of progressive conditions that affect the brain and nervous system of animals. According to the most widespread hypothesis they are transmitted by prions, though some other data suggest an involvement of a Spiroplasma infection....
, are nearly always fatal and have an infectious origin, but other encephalopathies are reversible and can be caused by nutritional deficiencies, toxins, and several other causes.

Types

There are many types of encephalopathy. Some examples include:

Mitochondrial encephalopathy
MELAS

Mitochondrial encephalopathy lactic acidosis with stroke-like episodes, abbreviated to MELAS is one of the family of mitochondrial cytopathies, which also include MERRF, and Leber's Hereditary Optic Atrophy....
- Metabolic disorder caused by dysfunction of mitochondrial DNA. Can affect many body systems, particularly the brain and nervous system.
Glycine encephalopathy
Glycine encephalopathy

Glycine encephalopathy, also known as non-ketotic hyperglycinemia or NKH, is an autosomal recessive metabolic disorder characterized by abnormally high levels of the amino acid glycine....
- A pediatric metabolic disorder
Hepatic encephalopathy
Hepatic encephalopathy

Hepatic encephalopathy is a potentially-reversible neuropsychiatric abnormality in the setting of liver failure, whether chronic , or acute liver failure....
- Arising from advanced cirrhosis of the liver
Hypoxic ischemic encephalopathy
Cerebral hypoxia

Cerebral hypoxia refers to deprivation of oxygen supply to brain tissue. Mild or moderate cerebral hypoxia is sometimes known as diffuse cerebral hypoxia....
- 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
Wernicke's encephalopathy

Wernicke encephalopathy is a syndrome characterised by ataxia, ophthalmoplegia, confusion, and impairment of short-term memory.It is caused by lesions in the medial thalamic nuclei, mammillary bodies, periaqueductal and periventricular brainstem nuclei, and superior cerebellar vermis, often resulting from inadequate intake or absorption of t...
- Arising from thiamine deficiency, usually in the setting of alcoholism
Hashimoto's encephalopathy
Hashimoto's encephalopathy

Hashimoto's Encephalopathy is a very rare condition associated with Hashimoto's Thyroiditis. Hashimoto's Encephalopathy is a neuroendocrine disorder....
- Arising from an auto-immune disorder
Hypertensive encephalopathy - Arising from acutely increased blood pressure
Lyme encephalopathy - Arising from the Borrelia Burgdorferi bacteria.
Toxic encephalopathy
Toxic encephalopathy

Symptoms Toxic encephalopathy has a wide variety of symptoms. The most prominent characteristic of toxic encephalopathy is an altered state of mind....
- 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
Transmissible spongiform encephalopathy

Transmissible spongiform encephalopathies are a group of progressive conditions that affect the brain and nervous system of animals. According to the most widespread hypothesis they are transmitted by prions, though some other data suggest an involvement of a Spiroplasma infection....
- A collection of diseases all caused by prions, and characterized by "spongy" brain tissue (riddled with holes), impaired locomotion or coordination, and a high fatality rate. Includes bovine spongiform encephalopathy
Bovine spongiform encephalopathy

Bovine Spongiform Encephalopathy , commonly known as Mad-Cow Disease , is a fatal, neurodegenerative disease in cattle, that causes a spongy degeneration in the brain and spinal cord....
(mad cow disease), scrapie
Scrapie

Scrapie is a fatal, degenerative disease that affects the nervous systems of sheep and goats. It is one of several transmissible spongiform encephalopathies , which are related to bovine spongiform encephalopathy and chronic wasting disease of deer....
, and kuru
Kuru (disease)

Kuru also known as "Mad Human Disease" is an incurable degenerative neurological disorder that is a type of transmissible spongiform encephalopathy found in humans....
among others.

Causes

Encephalopathy alters brain function and/or structure. It may be caused by an infectious agent (bacteria, virus

Virus

A virus is a Optical microscope#Limitations of light microscopes infectious agent that is unable to grow or reproduce outside a host cell . Viruses infect all cellular life....
, or prion

Prion

Metabolism

Metabolism is the set of chemical reactions that occur in living organisms in order to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments....
or mitochondrial

Mitochondrion

In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryote cell . These organelles range from 0.5–10 micrometers in diameter....
dysfunction, brain tumor

Brain tumor

A brain tumor is an abnormal growth of cells within the brain or inside the skull, which can be cancerous or non-cancerous .It is defined as any cranium tumor created by abnormal and uncontrolled Mitosis, normally either in the brain itself , in the cranial nerves , in the brain envelopes , skull, pituitary and pineal gland, or spread from...
or increased intracranial pressure

Intracranial pressure

Intracranial pressure, , is the pressure in the cranium and thus in the brain tissue and cerebrospinal fluid ; this pressure is exerted on the brain's intracranial blood circulation vessels....
, exposure to toxins (including solvents, excess animal protein, drugs, alcohol

Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
, paints, industrial chemicals, and certain metals), radiation, trauma, poor nutrition, or lack of oxygen

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
or blood flow to the brain.

The hallmark of encephalopathy is an altered mental state. Depending on the type and severity of encephalopathy, common neurological symptoms are loss of cognitive function, subtle personality changes, inability to concentrate, lethargy, and depressed consciousness. Other neurological signs may include myoclonus

Myoclonus

Myoclonus is brief, involuntary twitching of a muscle or a group of muscles. It describes a medical sign and, generally, is not a diagnosis of a disease....
(involuntary twitching of a muscle or group of muscles), asterixis

Asterixis

Asterixis is a tremor of the wrist when the wrist is extended , sometimes said to resemble a bird flapping its wings. Also called "liver flap", it can be a sign of hepatic encephalopathy, damage to brain cells due to the inability of the liver to metabolize ammonia to urea....
(abrupt loss of muscle tone, quickly restored), nystagmus

Nystagmus

Pathologic nystagmus is a form of involuntary eye movement. It is characterized by alternating smooth pursuit in one direction and saccadic movement in the other direction....
(rapid, involuntary eye movement), tremor, seizure

Seizure

An epileptic seizure is a transient symptom of abnormal, excessive or synchronous neuronal activity in the brain. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms ....
s, jactitation (restless picking at things characteristic of severe infection), and respiratory abnormalities such as Cheyne-Stokes respiration (cyclic waxing and waning of tidal volume), apneustic respirations, and post-hypercapnic apnea.

Diagnosis

Blood test

A blood test is a medical laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick....
s, spinal fluid examination by lumbar puncture

Lumbar puncture

In medicine, a lumbar puncture is a diagnostic and at times therapeutic procedure that is performed in order to collect a sample of cerebrospinal fluid for biochemistry, microbiology, and cytology analysis, or occasionally as a treatment to relieve increased intracranial pressure....
, imaging studies, electroencephalograms

Electroencephalography

Electroencephalography is the recording of electrical activity along the scalp produced by the firing of neurons within the brain. In clinical contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, usually 20-40 minutes, as recorded from multiple electrodes placed on the scalp....
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.

Therapy

Treatment varies according to the type and severity of the encephalopathy. Anticonvulsant

Anticonvulsant

The anticonvulsants are a diverse group of pharmacology used in the treatment of epilepsy seizures. Anticonvulsants are also increasingly being used the treatment of bipolar disorder, since many seem to act as mood stabilizers....
s may be prescribed to reduce or halt any seizures. Changes to diet and nutritional supplements may help some patients. In severe cases, dialysis or organ replacement surgery may be needed.

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. Some encephalopathies can be fatal.

Encephalopathy

Terminology

Types

Causes

Diagnosis

Therapy

Prognosis

See also