Myoclonus is an unconscious short twitch of a muscle or group of muscles. It describes a medical sign and, generally, is not a disease diagnosis. These myoclonic twitches , jerks , or seizures are usually caused by sudden muscle contractions ( positive myoclonus ) or a brief contraction deviation ( negative myoclonus ). The most common condition in which they occur is during sleep (hypnic jerk). Myoclonic jerks occur in healthy people and are occasionally experienced by everyone. However, as they appear more diligently and become more widespread they can be a sign of a variety of neurological disorders. Hiccups are a kind of myoclonic jerk that specifically affects the diaphragm. When a seizure caused by another person is known as provoking spasm . Shiver attacks in infants fall into this category.
Myoclonic jerks can occur alone or sequentially, in a pattern or without a pattern. They can occur rarely or many times every minute. Most often, myoclonus is one of several signs in various neurological disorders such as multiple sclerosis, Parkinson's disease, Dystonia, Alzheimer's disease, Gaucher's disease, sclerosis subacute sclerosis, Creutzfeldt-Jakob disease (CJD), serotonin toxicity, some cases of Huntington's disease, some forms of epilepsy, and occasionally in intracranial hypotension.
In almost all cases where myoclonus is caused by a central nervous system disease, it is preceded by other symptoms; for example, in CJD is generally a late-stage clinical feature that arises after the patient has begun to show severe neurological deficits.
Anatomically, myoclonus can be derived from cortical lesions, subcortex or spinal cord. The presence of myoclonus over the foramen magnum effectively excludes the spinal myoclonus; Further localization relies on further investigation with electromyography (EMG) and electroencephalography (EEG).
Video Myoclonus
Signs and symptoms
Myoclonic seizures can be described as "jumps" or "surprises" experienced in a single extremity or even the entire body. The feelings experienced by the individual are described as uncontrollable jerks that are common to receiving light electric shocks. Suddenly jerking and twitching the body can often be so severe that it can cause a child to fall.
Myoclonic seizures ( myo "muscle", "clonic " jerk ") are muscle involuntary contractions suddenly. The jerky muscles consist of symmetrical jerks, mostly disguised, localized in the arm and on the shoulders and also along with the nod of the head; both arms can be thrown out and simultaneously can occur head nod. Symptoms have some variability among subjects. Sometimes the whole body may be jerked, like a surprising response. As with all general seizures, the patient is unconscious during the event but the seizures are so short that the person seems to remain fully conscious.
In epilepsy reflexes, myoclonic seizures can be caused by flashing lights or other environmental triggers (see photosensitive epilepsy).
Common examples of normal myoclonus include hiccups and hypnic shocks experienced by some asleep. Some cases of pathological myoclonus can distort movement and greatly limit a person's ability to sleep, eat, talk, and walk. Myoclonic jerks generally occur in individuals with epilepsy.
Maps Myoclonus
Type
The most common types of myoclonus include action, cortical, essential, palatal reflexes, seen in progressive epilepsy myoclonus, reticular reflex, sleep and sensitive stimuli.
Epilepsy form
- Cortical reflex Myoclonus is considered an epileptic type derived from the cerebral cortex - the outer layer, or "gray matter," of the brain, responsible for most information processing which occurs in the brain. In this type of myoclonus, jolt usually involves only a few muscles in one part of the body, but a jolt that involves multiple muscles may occur. Cortical reflex myoclonus can be intensified when patients try to move in a certain way or feel a certain sensation.
- Essential Myoclonus occurs in the absence of epilepsy or other visible abnormalities in the brain or nerves. This can happen randomly to people who do not have a family history, or among the same family members, indicating that it can sometimes be a hereditary disorder. Essential myoclonus tends to be stable without increasing severity over time. Some scientists speculate that some form of essential myoclonus may be a type of epilepsy with no known cause.
- Juvenile myoclonic epilepsy JME usually consists of twitching and muscle twitching of the upper extremity. This may include arms, shoulders, elbows, and very rarely but not limited to the legs. JME is one of the most common types of epilepsy and can affect one out of every 14 people with this disease. These seizures usually occur soon after waking up. The onset for JME can be seen around puberty for most patients. The administration of drugs that also treat various types of seizures is usually the most effective form of treatment.
- Lennox-Gastaut syndrome LGS or epilepsy encephalopathy in childhood is a rare epilepsy disorder disorder for 1-4% of epilepsy in children. This syndrome has symptoms that are much more severe ranging from multiple seizures each day, mental retardation, abnormal findings in electroencephalogram (EEG). The initial age of onset of seizures correlates with a higher risk of cognitive impairment.
- Progressive epilepsy myoclonus (PME) is a group of diseases characterized by myoclonus, epileptic seizures, tonic-clonic seizures, and other serious symptoms such as walking or talking difficulties. This rare disorder often worsens over time and is sometimes fatal. Studies have identified at least three forms of PME. Lafora disease is inherited as an autosomal recessive disorder, which means that the disease only occurs when a child inherits two copies of a damaged gene, one from each parent. Lafora disease is characterized by myoclonus, epileptic seizures, and dementia (progressive memory losses and other intellectual functions). The second group of PME diseases belonging to the cerebral storage disease class usually involves myoclonus, vision problems, dementia, and dystonia (continuous muscle contractions that cause abnormal motion or abnormal postures). Another group of PME disorders in the class of system degeneration is often accompanied by myoclonus action, seizures, and problems with balance and walking. Many of these PME diseases begin in childhood or adolescence. Treatment usually does not work for long periods of time. Reticular reflex Myoclonus is considered a common type of epilepsy originating from the brainstem, the part of the brain that connects to the spinal cord and controls vital functions such as breathing and heartbeat. Myoclonic jerks usually affect the whole body, with muscles on both sides of the body affected simultaneously. In some people, myoclonic jolts only occur on the body part, like the legs, with all the muscles in that part involved in each jolt. Reticular myoclonus reflexes may be triggered by voluntary movements or external stimuli.
Flutter diaphragm
Very rare forms include diaphragmatic flutter, Belly Dancer's Syndrome, or Van Leeuwenhoek's disease. This was first described by Antony van Leeuwenhoek in 1723, who suffered from it. This condition characterizes oral communication that sounds like a short hiccup. These muscle spasms can recur dozens of times per day. The diaphragm contraction rate is between 35 and 480 contractions per minute, with the average rate found to be 150. Studies show that possible causes include disorders of the central or peripheral nervous system, anxiety, nutritional disorders, and certain drugs. No single treatment has been shown to be effective, although blocking or destruction of the phrenic nerve may provide immediate relief when pharmacological treatment is found to be ineffective.
Only about 50 people in the world have been diagnosed with diaphragmatic flutter. One case was Chaz Moore from Colorado Springs, Colorado, interviewed by Dr. Sanjay Gupta from CNN. Patients have tried several drugs, which only use medical marijuana.
Other forms
- Action myoclonus is characterized by a muscle jerk that is triggered or intensified by voluntary movements or even intent to move. This can be exacerbated by efforts at proper and coordinated movements. Myoclonus action is the most crippling form of myoclonus and can affect the arms, legs, face, and even sound. It is often associated with tonic-clonic seizures and diffuse neuronal disease such as post-hypoxia encephalopathy, uremia, and various forms of PME, although, in cases of focal brain damage, the disease may be confined to one limb. This type of myoclonus is often caused by brain damage caused by lack of oxygen and blood flow to the brain when breathing or heartbeat is stopped temporarily. Over-excitement of the sensorimotor cortex (cortical reflex myoclonus) or reticular formation (reticular reflex myoclonus) is also a cause of myoclonus action. Serotonin and GABA neurotransmitters are thought to lead to a lack of inhibition, which is a possible explanation for why improvements were made by giving serotonin precursors. The involved systems include the cerebellodentatorubral, pyramidal, extrapyramidal, optical, hearing, posterior and plexus colon and cuneate columns, spinocerebellar tract, cranial nerve motor neurons and anterior horns, and muscle fibers.
- Palatal myoclonus is a regular rhythmic contraction of one or both sides of the back of the roof of the mouth, called the soft palate. This contraction may be accompanied by myoclonus in other muscles, including the face, tongue, throat, and diaphragm. Contractions are very rapid, occurring as often as 150 times per minute, and can survive during sleep. This condition usually appears in adults and can take place indefinitely. People with palatal myoclonus usually regard it as a minor problem; some people complain of the occasional "click" sound, the sound that makes the soft-ceiling muscles contract.
- Middle ear myoclonus occurs in the muscles of the middle ear. These muscles may include tympani and stapedius tensor muscles. This may involve the muscles that surround the Eustachian tube, which includes tensor veli palatini, levator veli palatini, and salpingopharyngeus. Patients describe it as a sound or throbbing sensation in the ear.
- Spinal myoclonus is a myoclonus derived from the spinal cord, including segmental and propriospinal myoclonus. The latter is usually because the thoracic generator produces truncal flexion jerk. This is often stimulus-induced with delays due to slow propriospinal nerve fibers.
- Stimulus-sensitive myoclonus is triggered by external events, including sound, motion, and light. Surprises can increase the sensitivity of the patient.
- Sleep myoclonus occurs during the early stages of sleep, especially during bedtime. Some forms appear sensitive to stimuli. Some people with sleeping myoclonus are rarely disturbed by it, or need care. If it is a symptom of more complex and disturbing sleep disorders, such as restless leg syndrome, it may require medical care. Myoclonus may be associated with patients with Tourette syndrome.
Cause
Benign myoclonus can occur in healthy individuals and most often caused by anything other than arbitrary muscle contractions. Myoclonus may develop in response to infection, hyperglycemic hyperosplasia, head or spine injury, stroke, stress, brain tumor, kidney or liver failure, lipid storage diseases, chemical toxicity or drugs, as a side effect of certain drugs (such as tramadol). , quinolone, benzodiazepine, gabapentin, sertraline, lamotrigine), or other disorders.
Benign myoclonic movements are usually seen during induction of general anesthesia with intravenous drugs such as etomidate and propofol. This is postulated as a result of decreasing inhibitory signals from cranial neurons. Prolonged oxygen deprivation to the brain, hypoxia, may cause posthypoxic myoclonus. People who suffer from benign fascic syndrome can often experience myoclonic jerking limbs, fingers and thumbs.
Myoclonus can occur by itself, but most often as one of several symptoms associated with various nervous system disorders, including multiple sclerosis, Parkinson's disease, Alzheimer's disease, Opsoclonus Myoclonus, Creutzfeldt-Jakob disease, Lyme Disease and lupus. Myoclonic jerks generally occur in people with epilepsy, a disorder in which electrical activity in the brain becomes irregular that leads to seizures. It is also found in MERRF (Myoclonic Epilepsy with Ragged Red Fibers), rare mitochondrial encephalomyopathy. Myoclonus can be a living condition along with Tourette's syndrome.
Jerks of the muscle group, many of the body, or a series of rapid successions, which result in people who jerk upright from a more relaxed sitting position are sometimes seen in outpatients being treated with high doses of morphine, hydromorphine, and similar drugs. , and may mark the height and/or elevation of the serum levels of these drugs quickly. The myoclonic jerks caused by other opioids, such as tramadol and pethidine, may be less benign. Drugs unrelated to opioids, such as anticholinergics, are known to cause myoclonic jerks.
Pathophysiology
Most myoclonus is caused by central nervous system disorders. Some are from peripheral nervous system injuries. Studies show some brain locations involved in myoclonus. One is in the brainstem, close to the structure responsible for the shock response, the automatic reaction to unexpected stimuli involving rapid muscle contraction.
The specific mechanisms underlying myoclonus are not fully understood. Scientists believe that some types of stimulus-sensitive myoclonus may involve too many parts of the brain that control movement. These parts are interconnected in a series of feedback loops called motor paths. This pathway facilitates and modulates communication between the brain and muscles. The key element of this communication is a chemical known as a neurotransmitter, which carries messages from one nerve cell, or neuron, to another. The neurotransmitter is released by the neuron and attaches itself to the receptor on the adjacent cell portion. Some neurotransmitters can make the receiving cells more sensitive, while others tend to make the receiving cells less sensitive. Laboratory studies show that the imbalance between these chemicals may underlie myoclonus.
Some researchers speculate that abnormalities or deficiencies in receptors for certain neurotransmitters may contribute to some form of myoclonus. Receptors that appear to be associated with myoclonus include those for two important inhibitory neurotransmitters: serotonin, which constricts blood vessels and carries on sleep, and gamma-aminobutyric acid (GABA), which helps the brain maintain muscle control. Other receptors associated with myoclonus include benzodiazepine receptors, sleep-inducing drugs, and glycine, a neurotransmitter inhibitor that is essential for controlling motor and sensory function in the spinal cord. Further research is needed to determine how these receptor abnormalities cause or contribute to myoclonus.
Treatment
Regarding more serious illness, the origin of complex myoclonus can be treated with many drugs, which have limited effects individually, but greater when combined with others acting on different pathways or brain mechanisms. Treatment is most effective when underlying causes are known, and can be treated as such. Some drugs are studied in various combinations including clonazepam, sodium valproate, piracetam, and primidone. Hormonal therapy may increase the response to antimicrocinic drugs in some people.
Several studies have shown that a 5-hydroxytryptophan (5-HTP) dose leads to an increase in patients with some type of myoclonus and PME action. The differences in 5-HTP effects in patients with myoclonus have not been described.
Many drugs used for myoclonus, such as barbiturates, phenytoin and primidone, are also used to treat epilepsy. Barbiturates slow down the central nervous system and cause a sedative or antiseizure effect. Phenytoin and primidone are effective antiepileptic drugs, although phenytoin may cause liver failure or have other long-term harmful effects in patients with PME. Sodium valproate is an alternative therapy for myoclonus and can be used alone or in combination with clonazepam. Some people have adverse reactions to clonazepam and/or sodium valproate.
When patients take some medication, suspension of drugs suspected to cause myoclonus and treatment of metabolic disorders may resolve some cases of myoclonus. When pharmacological treatment is indicated anticonvulsants are the main line of treatment. The paradoxical reaction to treatment is very important. Drugs that most people respond to in others aggravate their symptoms. Sometimes this leads to errors by increasing the dose, rather than reducing or stopping the drug. The treatment of myoclonus focuses on drugs that can help reduce symptoms. Medications used include sodium valproate, clonazepam, antivonvulsan levetiracetam, and piracetam. Clonazepam doses are usually increased gradually until the patient improves or the side effects become dangerous. Drowsiness and loss of coordination are common side effects. The beneficial effects of clonazepam may decrease over time if the patient develops tolerance to the drug.
In the form of myoclonus where only one area is affected, and even in some other form, Botox injections (OnabotulinumtoxinA) can help. The chemical messengers responsible for triggering unconscious muscle contractions are hampered by Botulinum Botox toxins.
Surgery is also an option for treatment if symptoms are caused by tumors or lesions in the brain or spinal cord. Surgery may also improve the symptoms in which the myoclonus affects the face or ear. While DBS is still being studied for use with myoclonus, In-Brain Stimulation has also been tried on those with this and other motion disorders.
Prognosis
The effects of myoclonus on an individual may vary depending on the shape and overall health of the individual. In severe cases, especially those that indicate an underlying disorder in the brain or nerves, movement can be highly distorted and limit the ability to function normally, such as eating, talking, and walking. In these cases, usually effective treatments, such as clonazepam and sodium valproate, may actually cause adverse reactions to the drug, including increased tolerance and greater need for increased doses. However, the prognosis for simpler forms of myoclonus in healthy individuals may be neutral, as the disease may cause little or no difficulty. At other times the illness begins simply, in one area of ​​the body, and then spreads.
Research
Research on myoclonus is supported through the National Institute of Neurological Disorders and Stroke (NINDS). The main focus of the research is on the role of neurotransmitters and the receptors involved in the disease. Identifying whether or not abnormalities in this pathway cause myoclonus can assist in efforts to develop drug treatments and diagnostic tests. Determining the extent to which genetics play in this disorder can cause potential treatments for their reversal, potentially correcting the loss of inhibition while increasing the mechanism in the body that will compensate for its effect.
Etymology and pronunciation
The word myoclonus uses a combination of myo - and clonus forms, indicating muscle contraction dysfunction. It's spoken or . The prevalence of variance shows the division between English American and English English. The variant emphasizing the -oc - syllable is the only pronunciation given in half a dozen major American (medical and public) dictionaries. Variants that emphasize the -clo - syllabus are given in the English English module of the Oxford Dictionary online but not in the American English module.
See also
- Periodic leg movement disorder
- benign fasciculation syndrome
- Restless legs syndrome
- Fasciculation
- Brain Zaps (SSRI withdrawal)
- Clonus
- Fahr syndrome
References
External links
- The first version of this article is adapted from the public domain NINDS Myoclonus Information Page. Please change and customize as needed.
- "Why do we twitch while we sleep?" (The Straight Dope)
- Myoclonus Fact Sheet , National Institute of Neurological Disorders and Stroke (see Apr. 5, 2005)
Source of the article : Wikipedia
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