Table of ContentsView AllTable of ContentsCausesDiagnosisTreatmentFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Causes
Diagnosis
Treatment
Frequently Asked Questions
Clonusis an abnormal reflex response that produces involuntary, repetitive, and rhythmic muscle contractions when a muscle is stretched.This abnormal reflex is typically a sign of an upper motor neuronlesion. These neurons originate in the brain’s cerebral cortex and travel down to the brain stem or spinal cord. They are responsible for motor function, muscle tone,reflexstrength, and more.Clonus can be observed throughout the body, but is most commonly seen in the biceps, triceps, patella, and ankle regions.kali9 / Getty ImagesCauses of ClonusClonus is a type of reflex. When a muscle group is stretched or stimulated,neuronsperceive that stretch and cause contraction of the same muscle group.This type of reflex is meant to protect against strains and muscle tears. With clonus, however, the normal contraction occurs not once but several times before subsiding.Clonus can be seen in a number of different diseases affecting the nervous system.Common Causes of ClonusMultiple sclerosisCerebral palsyStrokeSpinal cord injuryTraumatic brain injuryOrthopedic traumaSerotonin syndromeClonic movements can also be observed in the context ofseizures, side effects of certain medications, and chemical imbalances.Clonus and MSMultiple sclerosis (MS) is a chronic autoimmune inflammatory disease in which theimmune systemdestroys the protective sheath covering nerve cells, known asmyelin. This damage leads to miscommunications between the brain and other areas of the body, as well as a lower trigger threshold for stretch reflexes.Given the nature of the disease, people with MS often experience clonus, as well as othersymptomslike involuntary muscle spasms,tremors, muscle weakness, andspasticity. Other symptoms include sensory loss, coordination issues, and cognitive impairment.The Link Between MS and the Immune SystemClonus and SpasticitySpasticity is often seen in people with neurological diseases. It refers to abnormal muscle tightness or contraction.In addition to painful muscle spasms, spasticity can also lead to clonus, pain, permanent muscle contractures, joint deformities, and even decreased ability to performactivities of daily living.Clonus vs. MyoclonusClonus is an abnormal reflex response to a muscle being stretched. It produces rhythmic movements.Myoclonusis sudden, involuntary, irregular twitching or spasms of a muscle or group of muscles.How Clonus Is DiagnosedClonus can be observed during the physical examination portion of a medical appointment. Depending on the area affected, a healthcare provider can apply stress or “stretch” a muscle or tendon and observe the subsequent response or reflex. With clonus, the healthcare provider can then measure or count the number of involuntary contractions which occur.Once unexpected or unexplained clonus is observed, it becomes incredibly important to try and determine the cause of the neurologic issue. To get to the root cause of clonus, a healthcare provider may order:Specific blood testsMRIscan of the brain and/or spinal cordNerve conduction studiesLumbar puncture(spinal tap)Treatment for ClonusWhen it comes to managing clonus, there are several oral medications and alternative therapies that can be beneficial.While there is no “one-size-fits-all” therapy, a tailored treatment regimen managing both the symptoms and the underlying disease can increase a person’s quality of life.The treatment of clonus due to chemical imbalances, seizure, or medication side effects is to correct these acute medical problems.MedicationsThe goal of oral medications used to manage clonus due to spasticity is to relax the affected muscles and decrease rigidity. Some of these medications include:Muscle relaxants, such asbaclofenandtizanidineBenzodiazepines, such asdiazepamandclonazepamThese medications should be used with caution, as they come with side effects. These include, but are not limited to, drowsiness, dizziness, andfatigue.Other TherapiesTargeted injections of eitherbotulinum toxinA/B orphenolmay provide relief for clonus.Botulinum toxin is typically injected within the affected muscle, weakening or temporarily paralyzing specific muscles so they can not involuntarily contract. It can take up to 10 days before results are noticeable and increased range of motion and function may be observed. If successful, these injections could provide relief for several months.Unlike botulinum toxin injections, phenol injections are administered close to the affected nerve roots and immediately block nerve conduction, causing the muscle to relax.If effective, phenol injections may also provide several months worth of relief.Physical Therapy for ClonusPhysical therapy is a conservative but potentially transformative option for clonus management. A licensed physical therapist can help stretch and strengthen affected muscles, leading to increased mobility and functionality. They can also recommend if and when splints or braces may be viable options to give additional support, especially when clonus affects the lower extremities and can impeded proper mobility.SurgeryIf all other treatment options fail, a healthcare provider may recommend surgery to alleviate clonus. Surgery can either be done to release a tendon which has become inflamed and caused a contracture of the underlying muscle, or it can be done to sever the affected neuron-muscle pathway.While these surgeries may relieve clonus, they can also lead to permanent and disabling limited mobility and muscle functionality.Home Remedies for ClonusIn conjunction with other modes of treatment, the application of cold packs to affected areas and vigilant performance of at-home stretching exercises can also help reduce the severity of clonus.OutlookWhile there are several treatment options to help alleviate clonus, the severity and prognosis really depends on the underlying cause. Clonus can range from a mild annoyance to a disabling reflex.Adequate management of the underlying disease or cause, if possible, can result in minimization of clonus.SummaryClonus refers to a reflex response to a muscle stretch that produces involuntary and repetitive muscle contractions. Common causes of clonus include multiple sclerosis, cerebral palsy, spinal cord or traumatic brain injuries, and more. It is also seen in the context of certain seizures, medication side effects, or chemical imbalances.Through a thorough history and physical examination, a healthcare provider will be able to diagnose clonus and offer treatment options such as physical therapy, medications, targeted injections, and surgery. The prognosis for clonus depends on the underlying cause and how effectively it can be managed.A Word From VerywellClonus can range from inconvenient to disabling. If you are suffering from clonus, it’s important to speak with your healthcare provider about your symptoms. Management of clonus requires multi-disciplinary collaboration betweenneurologists,orthopedists, physical therapists, and others. Thankfully, there are several treatment options available which can help manage clonus.Frequently Asked QuestionsClonus refers to involuntary and repetitive muscle contractions that occur in response to stimulation. Clonus is typically due to an upper motor neuron lesion. Clonus can be observed throughout the body, but are most commonly seen in the jaw, biceps, triceps, patella, and ankle regions.A clonus test is performed when a healthcare provider applies a force or stretch to an area—the ankle, for example—and upon release of the stretch, the ankle begins involuntarily and rhythmically bobbing up and down. This is considered a positive clonus test. Resulting movements will vary based on the area being tested, but this type of movement is indicative of clonus.Clonus is a type of stretch reflex. When a muscle is being stimulated or stretched, nerve impulses from the muscle get sent to the brain, which in turn sends a message to the muscle to contract in defense. Over-stretching, an injury, or certain neurological deficits can all trigger a clonus reflex.Whereas clonus is an abnormal reflex that produces rhythmic, involuntary muscle contractions, myoclonus refers to brief and sudden involuntary muscle twitches.
Clonusis an abnormal reflex response that produces involuntary, repetitive, and rhythmic muscle contractions when a muscle is stretched.This abnormal reflex is typically a sign of an upper motor neuronlesion. These neurons originate in the brain’s cerebral cortex and travel down to the brain stem or spinal cord. They are responsible for motor function, muscle tone,reflexstrength, and more.
Clonus can be observed throughout the body, but is most commonly seen in the biceps, triceps, patella, and ankle regions.
kali9 / Getty Images
Causes of Clonus
Clonus is a type of reflex. When a muscle group is stretched or stimulated,neuronsperceive that stretch and cause contraction of the same muscle group.This type of reflex is meant to protect against strains and muscle tears. With clonus, however, the normal contraction occurs not once but several times before subsiding.
Clonus can be seen in a number of different diseases affecting the nervous system.
Common Causes of Clonus
Clonic movements can also be observed in the context ofseizures, side effects of certain medications, and chemical imbalances.
Clonus and MS
Multiple sclerosis (MS) is a chronic autoimmune inflammatory disease in which theimmune systemdestroys the protective sheath covering nerve cells, known asmyelin. This damage leads to miscommunications between the brain and other areas of the body, as well as a lower trigger threshold for stretch reflexes.
Given the nature of the disease, people with MS often experience clonus, as well as othersymptomslike involuntary muscle spasms,tremors, muscle weakness, andspasticity. Other symptoms include sensory loss, coordination issues, and cognitive impairment.
The Link Between MS and the Immune System
Clonus and Spasticity
Spasticity is often seen in people with neurological diseases. It refers to abnormal muscle tightness or contraction.
In addition to painful muscle spasms, spasticity can also lead to clonus, pain, permanent muscle contractures, joint deformities, and even decreased ability to performactivities of daily living.
Clonus vs. MyoclonusClonus is an abnormal reflex response to a muscle being stretched. It produces rhythmic movements.Myoclonusis sudden, involuntary, irregular twitching or spasms of a muscle or group of muscles.
Clonus vs. Myoclonus
Clonus is an abnormal reflex response to a muscle being stretched. It produces rhythmic movements.Myoclonusis sudden, involuntary, irregular twitching or spasms of a muscle or group of muscles.
How Clonus Is Diagnosed
Clonus can be observed during the physical examination portion of a medical appointment. Depending on the area affected, a healthcare provider can apply stress or “stretch” a muscle or tendon and observe the subsequent response or reflex. With clonus, the healthcare provider can then measure or count the number of involuntary contractions which occur.
Once unexpected or unexplained clonus is observed, it becomes incredibly important to try and determine the cause of the neurologic issue. To get to the root cause of clonus, a healthcare provider may order:
Treatment for Clonus
When it comes to managing clonus, there are several oral medications and alternative therapies that can be beneficial.
While there is no “one-size-fits-all” therapy, a tailored treatment regimen managing both the symptoms and the underlying disease can increase a person’s quality of life.
The treatment of clonus due to chemical imbalances, seizure, or medication side effects is to correct these acute medical problems.
Medications
The goal of oral medications used to manage clonus due to spasticity is to relax the affected muscles and decrease rigidity. Some of these medications include:
These medications should be used with caution, as they come with side effects. These include, but are not limited to, drowsiness, dizziness, andfatigue.
Other Therapies
Targeted injections of eitherbotulinum toxinA/B orphenolmay provide relief for clonus.
Botulinum toxin is typically injected within the affected muscle, weakening or temporarily paralyzing specific muscles so they can not involuntarily contract. It can take up to 10 days before results are noticeable and increased range of motion and function may be observed. If successful, these injections could provide relief for several months.
Unlike botulinum toxin injections, phenol injections are administered close to the affected nerve roots and immediately block nerve conduction, causing the muscle to relax.If effective, phenol injections may also provide several months worth of relief.
Physical Therapy for ClonusPhysical therapy is a conservative but potentially transformative option for clonus management. A licensed physical therapist can help stretch and strengthen affected muscles, leading to increased mobility and functionality. They can also recommend if and when splints or braces may be viable options to give additional support, especially when clonus affects the lower extremities and can impeded proper mobility.
Physical Therapy for Clonus
Physical therapy is a conservative but potentially transformative option for clonus management. A licensed physical therapist can help stretch and strengthen affected muscles, leading to increased mobility and functionality. They can also recommend if and when splints or braces may be viable options to give additional support, especially when clonus affects the lower extremities and can impeded proper mobility.
Surgery
If all other treatment options fail, a healthcare provider may recommend surgery to alleviate clonus. Surgery can either be done to release a tendon which has become inflamed and caused a contracture of the underlying muscle, or it can be done to sever the affected neuron-muscle pathway.
While these surgeries may relieve clonus, they can also lead to permanent and disabling limited mobility and muscle functionality.
Home Remedies for ClonusIn conjunction with other modes of treatment, the application of cold packs to affected areas and vigilant performance of at-home stretching exercises can also help reduce the severity of clonus.
Home Remedies for Clonus
In conjunction with other modes of treatment, the application of cold packs to affected areas and vigilant performance of at-home stretching exercises can also help reduce the severity of clonus.
Outlook
While there are several treatment options to help alleviate clonus, the severity and prognosis really depends on the underlying cause. Clonus can range from a mild annoyance to a disabling reflex.
Adequate management of the underlying disease or cause, if possible, can result in minimization of clonus.
Summary
Clonus refers to a reflex response to a muscle stretch that produces involuntary and repetitive muscle contractions. Common causes of clonus include multiple sclerosis, cerebral palsy, spinal cord or traumatic brain injuries, and more. It is also seen in the context of certain seizures, medication side effects, or chemical imbalances.
Through a thorough history and physical examination, a healthcare provider will be able to diagnose clonus and offer treatment options such as physical therapy, medications, targeted injections, and surgery. The prognosis for clonus depends on the underlying cause and how effectively it can be managed.
A Word From Verywell
Clonus can range from inconvenient to disabling. If you are suffering from clonus, it’s important to speak with your healthcare provider about your symptoms. Management of clonus requires multi-disciplinary collaboration betweenneurologists,orthopedists, physical therapists, and others. Thankfully, there are several treatment options available which can help manage clonus.
Frequently Asked QuestionsClonus refers to involuntary and repetitive muscle contractions that occur in response to stimulation. Clonus is typically due to an upper motor neuron lesion. Clonus can be observed throughout the body, but are most commonly seen in the jaw, biceps, triceps, patella, and ankle regions.A clonus test is performed when a healthcare provider applies a force or stretch to an area—the ankle, for example—and upon release of the stretch, the ankle begins involuntarily and rhythmically bobbing up and down. This is considered a positive clonus test. Resulting movements will vary based on the area being tested, but this type of movement is indicative of clonus.Clonus is a type of stretch reflex. When a muscle is being stimulated or stretched, nerve impulses from the muscle get sent to the brain, which in turn sends a message to the muscle to contract in defense. Over-stretching, an injury, or certain neurological deficits can all trigger a clonus reflex.Whereas clonus is an abnormal reflex that produces rhythmic, involuntary muscle contractions, myoclonus refers to brief and sudden involuntary muscle twitches.
Clonus refers to involuntary and repetitive muscle contractions that occur in response to stimulation. Clonus is typically due to an upper motor neuron lesion. Clonus can be observed throughout the body, but are most commonly seen in the jaw, biceps, triceps, patella, and ankle regions.
A clonus test is performed when a healthcare provider applies a force or stretch to an area—the ankle, for example—and upon release of the stretch, the ankle begins involuntarily and rhythmically bobbing up and down. This is considered a positive clonus test. Resulting movements will vary based on the area being tested, but this type of movement is indicative of clonus.
Clonus is a type of stretch reflex. When a muscle is being stimulated or stretched, nerve impulses from the muscle get sent to the brain, which in turn sends a message to the muscle to contract in defense. Over-stretching, an injury, or certain neurological deficits can all trigger a clonus reflex.
Whereas clonus is an abnormal reflex that produces rhythmic, involuntary muscle contractions, myoclonus refers to brief and sudden involuntary muscle twitches.
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Boyraz I, Uysal H, Koc B, Sarman H.Clonus: definition, mechanism, treatment.Medicinski Glasnik. 2015;12(1):19-26.Bhattacharyya K.The stretch reflex and the contributions of C David Marsden.Ann Indian Acad Neurol. 2017;20(1):1. doi:10.4103/0972-2327.199906Epilepsy Foundation.Clonic seizures.Sanders AE, Zafar N, Sharma S.Myoclonus. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.Manca M, Merlo A, Ferraresi G, Cavazza S, Marchi P.Botulinum toxin type A versus phenol. A clinical and neurophysiological study in the treatment of ankle clonus.Eur J Phys Rehabil Med. 2010;46(1):11-18.National Institute of Neurological Disorders and Stroke.Spasticity information page.
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Boyraz I, Uysal H, Koc B, Sarman H.Clonus: definition, mechanism, treatment.Medicinski Glasnik. 2015;12(1):19-26.Bhattacharyya K.The stretch reflex and the contributions of C David Marsden.Ann Indian Acad Neurol. 2017;20(1):1. doi:10.4103/0972-2327.199906Epilepsy Foundation.Clonic seizures.Sanders AE, Zafar N, Sharma S.Myoclonus. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.Manca M, Merlo A, Ferraresi G, Cavazza S, Marchi P.Botulinum toxin type A versus phenol. A clinical and neurophysiological study in the treatment of ankle clonus.Eur J Phys Rehabil Med. 2010;46(1):11-18.National Institute of Neurological Disorders and Stroke.Spasticity information page.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Boyraz I, Uysal H, Koc B, Sarman H.Clonus: definition, mechanism, treatment.Medicinski Glasnik. 2015;12(1):19-26.Bhattacharyya K.The stretch reflex and the contributions of C David Marsden.Ann Indian Acad Neurol. 2017;20(1):1. doi:10.4103/0972-2327.199906Epilepsy Foundation.Clonic seizures.Sanders AE, Zafar N, Sharma S.Myoclonus. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.Manca M, Merlo A, Ferraresi G, Cavazza S, Marchi P.Botulinum toxin type A versus phenol. A clinical and neurophysiological study in the treatment of ankle clonus.Eur J Phys Rehabil Med. 2010;46(1):11-18.National Institute of Neurological Disorders and Stroke.Spasticity information page.
Boyraz I, Uysal H, Koc B, Sarman H.Clonus: definition, mechanism, treatment.Medicinski Glasnik. 2015;12(1):19-26.
Bhattacharyya K.The stretch reflex and the contributions of C David Marsden.Ann Indian Acad Neurol. 2017;20(1):1. doi:10.4103/0972-2327.199906
Epilepsy Foundation.Clonic seizures.
Sanders AE, Zafar N, Sharma S.Myoclonus. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.
Manca M, Merlo A, Ferraresi G, Cavazza S, Marchi P.Botulinum toxin type A versus phenol. A clinical and neurophysiological study in the treatment of ankle clonus.Eur J Phys Rehabil Med. 2010;46(1):11-18.
National Institute of Neurological Disorders and Stroke.Spasticity information page.
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