Myoclonus (Muscle Twitch)

Overview

Myoclonus means a sudden and uncontrollable jerking movement. Sometimes, you feel Hiccups or sudden myoclonic jerks when falling asleep are common examples of myoclonus, which you don’t have to worry about. Myoclonus may affect a small region (focal or segmental myoclonus), such as one hand, or may produce violent jerks over the entire body (generalized myoclonus).

Different types of myoclonus occur due to nervous system disorders, such as epilepsy, metabolic issues, or reactions to medications. However, many different neurological disorders can cause myoclonus. Myoclonus dystonia is a movement disorder in which sustained muscle contractions cause twisting and repetitive movements or uncomfortable postures.

However, getting treatment for involuntary muscle twitches can help control the symptoms. Besides that, if the reason for myoclonus is unclear and can’t be treated directly, reduce its impact on your daily life.

What are the positive and negative myoclonus?

Positive and negative myoclonus are terms used to describe different characteristics or manifestations of myoclonus:

1. Positive Myoclonus: This refers to myoclonic jerks that involve an active muscle contraction, causing a sudden, brief movement or twitch. Positive myoclonus can be seen as a sudden extension or flexion of a limb or other body part.
2. Negative Myoclonus: Also known as asterixis, negative myoclonus involves a brief lapse or loss of muscle tone, resulting in a momentary decrease in muscle activity. It often appears as a brief interruption or drop in posture or movement, such as a limb dropping or a head-nodding momentarily.

Both types of myoclonus can occur in various neurological conditions and may have different underlying mechanisms and implications for diagnosis and treatment.

Types of Myoclonus (Muscles Twitch)

Myoclonus can be categorized into different types based on causes, appearance, and which muscles are affected. Here are some common types of myoclonus:

Physiological Myoclonus

Physiologic myoclonus involves quick muscle twitches followed by relaxation.

• Hiccups: Sudden contractions of the diaphragm and other breathing muscles, often caused by irritation of a nerve.

• Sleep Physiologic Myoclonus (Hypnic Jerks): Sudden muscle contractions or jerks that occur as a person falls asleep. These brief and involuntary movements sometimes accompany a sensation of falling. 

Pathological Myoclonus

• Cortical Myoclonus: Muscle twitches originate from the cerebral cortex (outer layer of the brain), often linked with epilepsy or other brain disorders.

• Subcortical Myoclonus: Muscle twitches arising from deeper brain areas like the basal ganglia, brainstem, or spinal cord.

• Cortico-Reticular Myoclonus: Involving the brainstem and cortex, usually associated with metabolic or toxic issues.

Epileptic Myoclonus

Epileptic myoclonus is the presence of myoclonus in people living with epilepsy.

• Action Epileptic Myoclonus: Voluntary movements or actions trigger muscle jerks.

• Photosensitive Myoclonus: Exposure to light commonly induces muscle involuntary jerky movements observed in specific types of epilepsy.

Myoclonic seizures are epileptic seizures in which the motor manifestation is myoclonus. The myoclonus is generalized without local onset and is usually accompanied by a generalized ictal epileptiform EEG discharge.

Progressive Myoclonus Epilepsies (PMEs)

Progressive Myoclonic Epilepsy is a group of diseases characterized by myoclonus, epileptic seizures, and other serious symptoms such as trouble walking or speaking.

• Lafora Body Disease: A rare genetic disorder causing myoclonic seizures, and worsening brain function.

• Unverricht-Lundborg Disease: An inherited form of PME characterized by myoclonic seizures and coordination problems (ataxia).

Essential Myoclonus:

Essential myoclonus occurs on its own, usually without other symptoms and without being related to any underlying illness. The cause of essential myoclonus is often unknown. Hereditary essential myoclonus starts in adulthood, causing mild muscle twitches.

However, Essential myoclonus occurs on its own without an underlying medical condition. Essential myoclonus is sometimes an inherited disorder but can also arise in people with no family history of neurological disorders. Essential myoclonus tends not to worsen over time and cognition remains normal.

Posthypoxic Myoclonus

Posthypoxic myoclonus (PHM) presents with focal or generalized, stimulus-sensitive myoclonic jerks beginning days to weeks after cardiac arrest, sometimes without reliable correlates on electroencephalography (EEG).

Opsoclonus-Myoclonus Syndrome (OMS):

A rare neurological condition featuring rapid, involuntary eye movements (opsoclonus) along with myoclonus, and lack of coordination (ataxia).

Peripheral Myoclonus

It refers to myoclonic jerks that originate from a peripheral nerve (outside of the brain and spinal cord). The common example of peripheral myoclonus is hemifacial spasm.

Palatal Myoclonus:

Palatal myoclonus (also known as palatal tremor) is a regular, rhythmic contraction of one or both sides of the rear of the roof of the mouth (soft palate). The contractions are rapid and may continue during sleep.

Spinal Myoclonus

Spinal myoclonus occurs in the spinal cord. In some instances, the myoclonic jerk involves the whole trunk of the body, beginning in the thoracic (middle) spinal segments and spreading up and down, a phenomenon known as propriospinal myoclonus.

Generalized Myoclonus

Generalized myoclonus is a type of involuntary muscle jerk that can affect the entire body simultaneously or sequentially, often caused by neurological conditions or metabolic disorders. Childhood involves multiple myoclonic seizure types that are usually difficult to control as well as cognitive impairment.

Stimulus Sensitive Myoclonus

Stimulus-sensitive myoclonus is a type of myoclonus triggered by outside stimuli such as lights, noise, or movement. It can be brought on by surprise as well.

What is Juvenile Myoclonic Epilepsy?

Juvenile Myoclonic Epilepsy (JME) is a type of epilepsy characterized by a sudden, brief myoclonic jerk or myoclonic seizure, typically occurring upon awakening. Juvenile myoclonic epilepsy often starts in adolescence and is thought to involve genetic factors influencing the brain’s electrical activity, leading to these myoclonic seizures.

With what conditions is palatal myoclonus associated?

Palatal myoclonus is often associated with neurological disorders that affect the brainstem and the connections between the brainstem and the cerebellum. Palatal myoclonus can be linked to conditions such as multiple sclerosis, brainstem strokes, trauma, tumors, or degenerative diseases like olivopontocerebellar atrophy. This condition can also be seen in patients with metabolic or infectious diseases affecting central nervous system disorders.

Causes

Here are common causes of myoclonus:

• Epilepsy and Seizure Disorders: Myoclonic jerks can be a symptom of epilepsy.

• Metabolic Disorders: Kidney or liver failure, metabolic abnormalities, or genetic disorders can lead to myoclonus.

• Neurodegenerative Diseases: Conditions like Parkinson’s disease or Huntington’s disease can cause secondary myoclonus. Secondary myoclonus can happen for a wide range of reasons. Some of these only affect your brain or other areas of your nervous system. Others can affect many systems throughout your body.

• Infections: Viral or bacterial brain infections, such as encephalitis can trigger myoclonus.

• Medication Side Effects: Certain medications affecting the central nervous system can induce myoclonus.

• Brain Lesions or Trauma: Brain tumors, strokes, or traumatic brain injury can disrupt nerve signaling.

• Disturbance in the Nervous System: A disturbance of the brain or spinal cord can cause myoclonus.

• Genetic or Hereditary Disorders: Some genetic conditions are associated with myoclonus.

• Toxic or Chemical Exposure: Exposure to toxins or certain drugs can cause myoclonus.

• Stroke and Vascular Disorders: Brain vascular issues can lead to myoclonus.

Several locations in the brain are involved in myoclonus. One is in the brainstem, close to structures that are responsible for the startle response, an automatic reaction to an unexpected stimulus involving rapid muscle contraction. The specific mechanisms underlying myoclonus are not yet fully understood. It is believed that some types of stimulus-sensitive myoclonus may involve overexcitability of the parts of the brain that control movement.

Symptoms

Myoclonus symptoms can vary in severity and frequency. These spasms can happen occasionally or repeatedly, affecting specific body areas or all muscles. The symptoms depend on the underlying cause.

Common signs of myoclonus include:

• Unexpected and sudden myoclonic jerks or spasms
• Short-lasting movement disorders
• Unable to control or predict
• Resembling sudden shock-like movements
• Varying in strength and frequency
• Affecting one part of the body or the entire body
• Disrupting normal eating, talking, or movement disorders

Myoclonus often is caused by brain damage that results from a lack of oxygen and blood flow to the brain when breathing or heartbeat is temporarily stopped. Over-excitement of the sensorimotor cortex ( cortical reflex myoclonus ) or reticular formation ( reticular reflex myoclonus ) is also a cause of action myoclonus.

What is Benign Neonatal Sleep Myoclonus?

Benign Neonatal Sleep Myoclonus is a non-epileptic condition seen in newborns, characterized by brief, jerky movements during sleep that typically resolve on their own without treatment and do not cause harm.

Define Segmental myoclonus.

Segmental myoclonus refers to a type of myoclonus where involuntary muscle jerks occur in contiguous or adjacent muscle groups, typically involving multiple muscles within a specific region or segment of the body. This contrasts with generalized myoclonus, which involves jerks affecting muscles throughout the entire body.

Myoclonus Diagnosis

After checking your body and talking about your symptoms and medical history, your neurologist may recommend specific tests to confirm if you have myoclonus:

• Blood tests: This helps find potential causes and rule out other conditions with similar symptoms.
• Electromyography (EMG): This test measures the electrical activity in your muscles.
• Electroencephalogram  (EEG): It records the electrical activity in your brain during myoclonus episodes and when there are no episodes.
• MRI (Magnetic Resonance Imaging): This scan takes detailed pictures of your brain, spinal cord, nerves, muscles, or other tissues.

Treatment

Myoclonus treatment is based on your overall health and specific symptoms.

First, your neurologist will address underlying health conditions or movement disorders, causing the myoclonus. Then, treat myoclonus to manage or reduce your muscle twitching episodes.

Common treatments for myoclonus include:

• • Clonazepam: A medication that relaxes muscles and is often used for certain types of myoclonus.
  • Epilepsy medications: Drugs like barbiturates, phenytoin, levetiracetam, valproate, or primidone can help control myoclonus.
  • Combination therapy: Sometimes using a combination of medications works better than just one.
  • Hormone therapy: This can be used along with other medications to improve treatment results.
    
  • Botox injections: These injections can be useful for myoclonus affecting facial muscles or the soft palate in the mouth.

However, there are no drugs specifically designed to treat myoclonus. Treatments for other diseases may help relieve myoclonus symptoms.

What are the treatments of cortical myoclonus?

Treatment of cortical myoclonus involves medications like antiepileptic drugs (e.g., valproic acid, levetiracetam) to reduce muscle jerks, and sometimes deep brain stimulation (DBS) for severe cases resistant to medication. The specific treatment plan for cortical myoclonus depends on the individual’s symptoms, underlying cause, and response to therapy, and it is typically tailored by a neurologist or a specialist in movement disorders.

When To See A Doctor

If you have sudden muscle jerks for the first time, visit a neurologist for consultation. The neurologist will examine you to check for underlying health issues and movement disorders. Muscle twitching all over your body every day will affect your life, causing serious damage. 

Disclaimer

This information is intended for educational purposes only and should not be considered a substitute for professional medical advice. If you have concerns about Myoclonus (Muscle Twitch) or any other medical condition, please see a doctor for an accurate diagnosis and personalized treatment suggestions.