A type of seizure that causes sharp and uncontrollable muscle movements is called myoclonic seizures. While most of the time, the symptoms are mild, sometimes, they may happen along with severe seizure disorders. Commonly, they happen in childhood, but they may also affect adults. Doctors often prescribe medicines to control the frequency and severity of the symptoms.
In other words, myoclonic seizures cause uncontrollable movements without any changes in the level of awareness or consciousness. This condition often affects one muscle, but may also affect a group of muscles. Rarely, the condition affect a wider part of the body. Generally, myoclonic seizures occur on their own. Some people may also develop them as a symptom of another health condition. Usually, people with other types of seizures also develop myoclonic seizures.
This type of seizure occurs quite commonly, especially in people who already have juvenile myoclonic epilepsy (JME). Myoclonic seizures are one of the primary types of seizures in people with JME. Moreover, approximately 5% to 10% of all epilepsy cases are JME.
What is The Difference between a Myoclonic Seizure and Myoclonus?
The medical term “myoclonus” is used to describe a sharp and quick muscle movement that most of the time looks like a twitch or spasm. Myoclonic seizures happen because of an underlying epileptic disorder in the brain. A disease in which there are abnormal electrical signals in the brain is called epilepsy. It negatively affects brain function.
In any case, myoclonus is not associated with any severe illness, but also common. Healthcare professionals have divided this condition into 2 categories. These include:
- Hypnic jerks – This type causes a sudden muscle twitch or spasm before falling asleep.
- Hiccups – This type of myoclonus negatively affects the diaphragm (the muscle that controls how much air the lungs hold).
How Does This Condition Affect My Body?
This health condition causes seizures that affect the electrical activity in the brain. It causes a burst of electrical activity, but it lasts only several seconds. Moreover, myoclonic seizures can affect one or both sides of the brain.
Symptoms
The main symptom of this type of seizure is sudden and uncontrolled muscle contractions. Usually, it happens in one of the following ways. Examples include:
- Positive myoclonus – In such cases, the condition causes the muscles to contract suddenly, and it often looks like a muscle spasm.
- Negative myoclonus – This type causes a sudden loss of tension in the muscles. For instance, when you drop something you were carrying, the muscles suddenly relax.
Most of the time, myoclonic seizures involve the following features or circumstances. For example:
- Brief muscle contractions – They are usually similar to those of a mild electric shock (such as from static buildup on fabric). It often causes the muscles to tighten up for a few seconds.
- Small groups of muscles – In most cases, myoclonic seizures affect small groups of muscles, including muscles in the arms, legs, or face. In rare cases, it may also affect larger areas, including the chest, back, or abdomen.
- Limited numbers – Usually, myoclonic seizures cause muscle contractions only once. Some people may have a few of these in a brief period.
- Under certain circumstances – While most people have myoclonic seizures in the morning when they wake up, some people may experience them before sleep or when they are very tired.
- In most cases, people are aware of them. In general, passing out or losing awareness of the world around you is common in multiple types of seizures, but it does not happen in myoclonic seizures. However, you may have another type of seizure that causes symptoms similar to myoclonic seizures. One of them is absence seizures.
Causes
This type of seizure happens due to epilepsy because it negatively affects the brain and signals that travel between it and the muscles. Generally, most epilepsy forms are inherited from one or both biological parents. Check below some types of epilepsy that often involve myoclonic seizures:
- Juvenile myoclonic epilepsy – This form of epilepsy often appears between 12 and 18 years and involves different types of seizures. For example, absence seizures and tonic-clonic seizures.
- Lennox-Gastaut syndrome – It is a rare and severe form of epilepsy that usually causes symptoms before the age of 10. It also causes myoclonic seizures.
- Myoclonic-astatic epilepsy – In such cases, the condition affects both sides of the body, and after a seizure, the muscles become weak.
- Myoclonic epilepsy of infancy (MEI) – While MEI often occurs before 3 years old, sometimes, it may appear as late as age 5. Usually, it causes symptoms when the child is awake.
- Progressive myoclonus epilepsy – It is a very severe form of epilepsy that usually worsens over time. It causes brain damage that negatively affects the memory, muscle control, thinking ability, and others.
Furthermore, myoclonic seizures can happen due to other causes or circumstances. Check some of them below:
- Cerebral hypoxia (lack of oxygen)
- Severe concussions
- Traumatic brain injury
- Brain tumors (including cancer)
- Degenerative brain disorders (including Alzheimer’s disease and frontotemporal dementia)
- Alcohol or drug withdrawal
- Misuse of drugs and alcohol (these include prescription medicines, recreational drugs, and even caffeine)
- Prolonged exposure to heavy metals (such as Lithium)
- Metabolic issues – For example, hypoglycemia (low blood sugar), hyperglycemia (high blood sugar), and others
- Infections – These include infections caused by parasites, fungi, viruses, and bacteria, especially meningitis or encephalitis.
Types of Myoclonus
There are some types of myoclonus that are not considered myoclonic seizures. Check some of them below:
- Subcortical myoclonus – Some types of myoclonus happen as a result of disease or damage to certain parts of the nervous system (located deeper than the outer surface of the brain).
- Peripheral myoclonus – This form of myoclonus occurs due to injuries to the peripheral nervous system.
- Lance-Adams syndrome – This syndrome happens due to complications after a period of oxygen deprivation. It occurs rarely and usually affects people who have had a heart attack, which has caused a cardiopulmonary arrest. When a cardiopulmonary arrest occurs, the heart and lungs stop working. Most of the time, people who survive cardiopulmonary arrest are saved by CPR (cardiopulmonary resuscitation). Moreover, people with this syndrome experience action myoclonus, which are uncontrollable muscle jerks.
What Are The Potential Complications of Myoclonic Seizures?
Those who develop myoclonic seizures may also experience some complications. Check some examples below:
- Unexpected jerks that can cause falls
- Status epilepticus – This complication is a medical emergency.
- Inability to walk or perform daily activities
- Cognitive decline
- Intellectual and developmental disabilities
- Other seizure types (such as generalized tonic-clonic seizures)
- Aspiration pneumonia
- JME (juvenile myoclonic epilepsy)
- Infantile spasms
- Progressive myoclonic epilepsies (PME)
This document does not contain a full list of complications, but you can consult with your healthcare professional about ways to prevent or manage them.
How to Prevent Myoclonic Seizures?
While it is not possible to prevent seizures completely, doctors may recommend some tips that can reduce the risk. Examples include:
- Avoid alcoholic beverages, prescription medicines, and recreational drugs – Misuse of any of the previous substances can cause seizures.
- Manage chronic health conditions – For example, diabetes (including both types), hyperlipidemia (high cholesterol), hypertension (high blood pressure), hyperglycemia, and others.
- Stop smoking – If you have problems with smoking cessation, discuss it with your doctor.
- Wear safety equipment to prevent head injuries. These include helmets, safety belts, and restraints.
- Avoid triggers – These include alcoholic drinks, recreational drugs, and overuse of certain prescription medicines.
Diagnosis
Most of the time, doctors start the diagnosis of this condition with a physical examination and questions about your medical history and symptoms. However, to exclude or confirm myoclonic seizure, they usually perform the following tests. Examples include:
- Electroencephalogram (EEG) – This test is used to measure the electrical activity in the brain. It is also the primary test used to diagnose myoclonic seizures.
- Blood tests to check for metabolic and blood chemistry imbalances, and infections.
- CT (computerized tomography) scans
- MRI (magnetic resonance imaging) scans
- Spinal tap (also called a lumbar puncture)
Treatment
In mild cases, doctors often prescribe rescue medicines to prevent clusters of myoclonic seizures. These include Benzodiazepines (including Clonazepam and Clobazam), anti-seizure medicines, and others. However, people who develop a moderate to severe form of myoclonic seizure may need additional treatments. Check some of them below:
- Epilepsy surgery
- Dietary changes
- Implantable devices to stimulate the vagal nerve, responsive neurostimulation, or deep brain stimulation.
Frequently Asked Questions
How soon after treatment will I feel better?
In general, the recovery time varies among people who suffer from myoclonic seizures. It often depends on the severity of the condition, gender, age, and your response to treatment.
Are myoclonic seizures contagious?
No, this type of seizure is not contagious, which means it cannot pass from one person to another.
Is a myoclonic seizure the same as epilepsy?
While these conditions are closely related, there are differences between them. Sometimes, physicians use the medical term “seizures” when they detect abnormal signals in the brain. In this case, seizures are often caused by epilepsy. In general, it is quite difficult to say without testing whether a seizure occurs due to epilepsy or not. To determine the exact cause of seizures, physicians will perform an EEG.
Can stress trigger myoclonic seizures?
Yes, emotional stress may increase the likelihood of seizures in some people with epilepsy. Stress can affect brain activity, sleep quality, and overall health, which may contribute to seizure episodes. Learning stress-management techniques may help reduce triggers.
Can lack of sleep make myoclonic seizures worse?
Sleep deprivation is a common trigger for myoclonic seizures, especially in people with juvenile myoclonic epilepsy (JME). Getting enough sleep and maintaining a regular sleep schedule can help reduce the frequency of seizures.
Can children outgrow myoclonic seizures?
It depends on the underlying cause. Some children with certain epilepsy syndromes may experience fewer seizures as they get older, while others may require lifelong treatment. A healthcare provider can explain the expected outlook based on the specific diagnosis.
Is it safe to drive if I have myoclonic seizures?
Driving regulations vary depending on where you live and how well your seizures are controlled. Many regions require a seizure-free period before a person can drive. Discuss driving safety and local requirements with your healthcare provider.
Can flashing lights cause myoclonic seizures?
For some people, especially those with photosensitive epilepsy, flashing lights, strobe lights, or rapidly changing visual patterns can trigger seizures. However, not everyone with myoclonic seizures is sensitive to light.
What should I do if I witness someone having a myoclonic seizure?
Stay calm and ensure the person is in a safe environment. Remove nearby objects that could cause injury and remain with them until the seizure ends. If the seizure lasts unusually long, occurs repeatedly without recovery, or results in injury, seek emergency medical assistance.
Can myoclonic seizures affect learning or school performance?
Some people, particularly children with epilepsy syndromes associated with myoclonic seizures, may experience difficulties with concentration, memory, or learning. Early diagnosis, appropriate treatment, and educational support can help minimize these challenges and improve academic performance. Ask your healthcare provider if you have additional questions.
