Asterixis | |
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Other names | Flapping tremor, liver flap |
Specialty | Neurology |
Asterixis (more colloquially referred to as flapping tremor) is not actually a tremor, but rather a negative myoclonus. This movement disorder is characterized by an inability to maintain a position, which is demonstrated by jerking movements of the outstretched hands when bent upward at the wrist (which can be similar to a bird flapping its wings, hence the name "flapping tremor"). [1] [2]
The tremor is caused by abnormal function of the diencephalic motor centers in the brain, which regulate the muscles involved in maintaining position. Asterixis is associated with various encephalopathies due especially to faulty metabolism. [3] The term derives from the Greek a, meaning "not" and stērixis, meaning "support" or "stable position".
Asterixis is normally asymptomatic and found during clinical examination for other reasons, but more rarely it can also be the leading symptom. [4] Usually there are brief, arrhythmic interruptions of sustained voluntary muscle contraction, causing brief lapses of posture with a frequency of 3–5Hz. It is typically bilateral, but may be asymmetric. Unilateral asterixis may occur with structural brain disease. [5]
To elicit the sign, the patient should be asked to hold constant posture against gravity. This can be done by extending the arms at 90° to the body and extending the wrists with the fingers spread. This position should be held for at least 30 seconds, and in that duration the examiner should look for intermittent loss of posture in the fingers, wrists or arms. [4]
Possible causes for asterixis are: [4]
R. D. Adams and J. M. Foley first described asterixis in 1949 in patients with severe liver failure and encephalopathy. [8] Initially Foley and Adams referred to asterixis simply as "tremor" but realized that they needed a more appropriate term. On a literature search they found a poorly described phenomenon in similar patients mentioned by German physicians called “jactitations” but the reference was vague. Foley consulted Father Cadigan, a Jesuit classics scholar, who suggested “anisosterixis” (an "negative"–iso "equal"–sterixis "firmness") but Foley shortened this to asterixis due to the former being too difficult to pronounce. They introduced the term in 1953 by way of a medical abstract and later Adams solidified its medical use as he was an author and editor of the widely influential Harrison's Principles of Internal Medicine . [9]
Creutzfeldt–Jakob disease (CJD), also known as subacute spongiform encephalopathy or neurocognitive disorder due to prion disease, is a fatal neurodegenerative disease. Early symptoms include memory problems, behavioral changes, poor coordination, and visual disturbances. Later symptoms include dementia, involuntary movements, blindness, weakness, and coma. About 70% of people die within a year of diagnosis. The name "Creutzfeldt–Jakob disease" was introduced by Walther Spielmeyer in 1922, after the German neurologists Hans Gerhard Creutzfeldt and Alfons Maria Jakob.
Central pontine myelinolysis is a neurological condition involving severe damage to the myelin sheath of nerve cells in the pons. It is predominately iatrogenic (treatment-induced), and is characterized by acute paralysis, dysphagia, dysarthria, and other neurological symptoms.
A tremor is an involuntary, somewhat rhythmic muscle contraction and relaxation involving oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the hands. In some people, a tremor is a symptom of another neurological disorder.
Wilson's disease is a genetic disorder characterized by the excess build-up of copper in the body. Symptoms are typically related to the brain and liver. Liver-related symptoms include vomiting, weakness, fluid build-up in the abdomen, swelling of the legs, yellowish skin, and itchiness. Brain-related symptoms include tremors, muscle stiffness, trouble in speaking, personality changes, anxiety, and psychosis.
Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of progressive, incurable, and fatal conditions that are associated with prions and affect the brain and nervous system of many animals, including humans, cattle, and sheep. According to the most widespread hypothesis, they are transmitted by prions, though some other data suggest an involvement of a Spiroplasma infection. Mental and physical abilities deteriorate and many tiny holes appear in the cortex causing it to appear like a sponge when brain tissue obtained at autopsy is examined under a microscope. The disorders cause impairment of brain function which may result in memory loss, personality changes, and abnormal or impaired movement which worsen over time.
Wernicke-Korsakoff syndrome (WKS) is the combined presence of Wernicke encephalopathy (WE) and alcoholic Korsakoff syndrome. Due to the close relationship between these two disorders, people with either are usually diagnosed with WKS as a single syndrome. It mainly causes vision changes, ataxia and impaired memory.
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.
Wernicke encephalopathy (WE), also Wernicke's encephalopathy, or wet brain is the presence of neurological symptoms caused by biochemical lesions of the central nervous system after exhaustion of B-vitamin reserves, in particular thiamine (vitamin B1). The condition is part of a larger group of thiamine deficiency disorders that includes beriberi, in all its forms, and alcoholic Korsakoff syndrome. When it occurs simultaneously with alcoholic Korsakoff syndrome it is known as Wernicke–Korsakoff syndrome.
Hyperammonemia, or high ammonia levels, is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to brain injury and death. It may be primary or secondary.
Alcoholic hepatitis is hepatitis due to excessive intake of alcohol. Patients typically have a history of at least 10 years of heavy alcohol intake, typically 8–10 drinks per day. It is usually found in association with fatty liver, an early stage of alcoholic liver disease, and may contribute to the progression of fibrosis, leading to cirrhosis. Symptoms may present acutely after a large amount of alcoholic intake in a short time period, or after years of excess alcohol intake. Signs and symptoms of alcoholic hepatitis include jaundice, ascites, fatigue and hepatic encephalopathy. Mild cases are self-limiting, but severe cases have a high risk of death. Severity in alcoholic hepatitis is determined several clinical prediction models such as the Maddrey's Discriminant Function and the MELD score.
Myoclonus is a brief, involuntary, irregular twitching of a muscle, a joint, or a group of muscles, different from clonus, which is rhythmic or regular. Myoclonus describes a medical sign and, generally, is not a diagnosis of a disease. It belongs to the hyperkinetic movement disorders, among tremor and chorea for example. These myoclonic twitches, jerks, or seizures are usually caused by sudden muscle contractions or brief lapses of contraction. The most common circumstance under which they occur is while falling asleep. Myoclonic jerks occur in healthy people and are experienced occasionally by everyone. However, when they appear with more persistence and become more widespread they can be a sign of various neurological disorders. Hiccups are a kind of myoclonic jerk specifically affecting the diaphragm. When a spasm is caused by another person it is known as a provoked spasm. Shuddering attacks in babies fall in this category.
Hepatic encephalopathy (HE) is an altered level of consciousness as a result of liver failure. Its onset may be gradual or sudden. Other symptoms may include movement problems, changes in mood, or changes in personality. In the advanced stages it can result in a coma.
Acute liver failure is the appearance of severe complications rapidly after the first signs of liver disease, and indicates that the liver has sustained severe damage. The complications are hepatic encephalopathy and impaired protein synthesis. The 1993 classification defines hyperacute as within 1 week, acute as 8–28 days, and subacute as 4–12 weeks; both the speed with which the disease develops and the underlying cause strongly affect outcomes.
Hyperkinesia refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both. Hyperkinesia is a state of excessive restlessness which is featured in a large variety of disorders that affect the ability to control motor movement, such as Huntington's disease. It is the opposite of hypokinesia, which refers to decreased bodily movement, as commonly manifested in Parkinson's disease.
Glycine encephalopathy is a rare autosomal recessive disorder of glycine metabolism. After phenylketonuria, glycine encephalopathy is the second most common disorder of amino acid metabolism. The disease is caused by defects in the glycine cleavage system, an enzyme responsible for glycine catabolism. There are several forms of the disease, with varying severity of symptoms and time of onset. The symptoms are exclusively neurological in nature, and clinically this disorder is characterized by abnormally high levels of the amino acid glycine in bodily fluids and tissues, especially the cerebrospinal fluid.
Intention tremor is a dyskinetic disorder characterized by a broad, coarse, and low-frequency tremor evident during deliberate and visually-guided movement. An intention tremor is usually perpendicular to the direction of movement. When experiencing an intention tremor, one often overshoots or undershoots one's target, a condition known as dysmetria. Intention tremor is the result of dysfunction of the cerebellum, particularly on the same side as the tremor in the lateral zone, which controls visually guided movements. Depending on the location of cerebellar damage, these tremors can be either unilateral or bilateral.
Hashimoto's encephalopathy, also known as steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), is a neurological condition characterized by encephalopathy, thyroid autoimmunity, and good clinical response to corticosteroids. It is associated with Hashimoto's thyroiditis, and was first described in 1966. It is sometimes referred to as a neuroendocrine disorder, although the condition's relationship to the endocrine system is widely disputed. It is recognized as a rare disease by the NIH Genetic and Rare Diseases Information Center.
Kuru is a rare, incurable, and fatal neurodegenerative disorder that was formerly common among the Fore people of Papua New Guinea. Kuru is a form of prion disease which leads to tremors and loss of coordination from neurodegeneration.The term kúru means “trembling” and comes from the Fore word kuria or guria. It is also known as the "laughing sickness" due to the pathologic bursts of laughter which are a symptom of the infection.
Raymond Delacy Adams was an American neurologist, neuropathologist, Bullard Professor of Neuropathology at Harvard Medical School and chief of neurology at Massachusetts General Hospital. Along with neurologist Maurice Victor, Adams was the author of Adams and Victor's Principles of Neurology, the 12th edition of which appeared, 50 years after the original.
Frank O. Bastian is an American physician and neuropathologist, who previously worked at Louisiana State University, moved to a university in New Orleans in 2019. He specializes in the transmissible spongiform encephalopathies (TSEs), which include, but are not limited to, Bovine spongiform encephalopathy (BSE) "Mad cow disease" in cattle, scrapie in sheep and goats, and Creutzfeldt–Jakob disease (CJD) in humans.