A disease that happens when the muscles do not relax as they should after contraction is called myotonia. This condition can affect the muscles throughout the body and cause different symptoms among people, depending on the type and severity of the disease. Doctors usually recommend medicines, physical therapy, and avoiding triggers to manage this condition.
People who suffer from this condition may not be able to let go of someone’s hand after you shake it or have problems standing up. In general, there are several types of myotonia, and all of them occur due to a genetic mutation (change). Sometimes, these genetic changes may affect other organs in the body. For example, the brain, heart, eyes, digestive tract, lungs, and others.
Types of Myotonia
Physicians have divided this health condition into 2 categories. Both categories negatively affect the electrical process that is responsible for muscle contraction.
Dystrophic Myotonia
This form of myotonia is a type of muscular dystrophy that causes muscle weakness and loss (atrophy) gradually over time. Some types of dystrophic myotonia (DM) include myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2).
Non-Dystrophic Myotonia
This type of myotonia does not impact muscle tissue structure. Check some examples below:
- Myotonia congenita (one of the most common forms of non-dystrophic myotonia)
- Paramyotonia congenita
- Sodium channel myotonia
- Hypokalemic periodic paralysis type 1 and type 2
- Andersen-Tawil syndrome
- Hyperkalemic period paralysis
What Are The Symptoms of Myotonia?
While the primary symptom is the inability to relax a muscle after contraction, it may also cause other symptoms. These include:
- Extreme tiredness (fatigue)
- Muscle weakness or stiffness that may improve with activity
- Atypical appearance of the muscles (such as hypertrophy or hypotonia)
- Paralysis (usually occurs in people with hyperkalemic periodic paralysis)
If any of the previous symptoms occur, immediately contact your healthcare professional. Otherwise, it may lead to serious complications.
Causes and Risk Factors
This condition occurs due to a change (mutation) in one of the genes that control muscle contractions. These genes negatively affect the ion channels that regulate muscle activity, causing symptoms. Moreover, all types of myotonia are caused by different gene changes. For instance, people who develop myotonic dystrophy type 1 have a mutation in the DMPK gene, but people with myotonia congenita have a change in the CLCN1 gene. While some people develop myotonia randomly, others get the abnormal genes from their biological parents.
While anyone can develop this condition, physicians have identified some factors that may elevate your risk. Examples include:
- Autosomal dominant (Thomsen disease) – In this case, there is a 50% chance of getting the abnormal gene from the only affected parent.
- Autosomal recessive (Becker disease) – When both biological parents are carriers of the abnormal genes that cause myotonia, there is a 25% chance of passing the gene to their biological children.
- Family history – If you have a sibling or parent with myotonia, your risk of developing it significantly increases.
There are also some factors that may trigger the symptoms. For example:
- Extreme cold or heat
- Inactivity or long periods of rest
- Emotional stress
- Certain foods, alcohol, or caffeine
What Are The Long-Term Effects of Myotonia?
Those who develop this condition may also experience some complications, especially if it is left untreated. Check some examples below:
- Sleep apnea
- Respiratory problems
- Cataracts
- Insulin resistance, which may lead to thyroid dysfunction and diabetes
- Chronic muscle pain
- Arrhythmia (irregular heart rhythm)
- Conduction defects
- Weakened heart muscle
- Dysphagia
- Long-term constipation
- Bloating
- Cognitive impairment
- Reduced fertility
- Increased risk of miscarriage
- Polyhydramnios
- Intellectual disability
- Male pattern baldness (androgenic alopecia)
- Atypical facial features (facial dysmorphisms)
This document does not contain a full list of complications, but you can talk with your doctor about measures to reduce the risk or even prevent them. In addition, there is no way to prevent this condition because it occurs due to a genetic change that appears randomly or is passed from the biological parents during conception. The only thing you can do is a genetic test to make sure you do not have the abnormal genes that cause myotonia. It is very important to understand the risks of having children with myotonia.
Diagnosis
In most cases, the diagnosis starts with questions about family history and symptoms and a physical examination in which doctors will look for abnormalities linked to myotonia. However, doctors will perform some tests to rule out health conditions that cause similar symptoms to myotonia. Check some of them below:
- Creatine kinase (CK) blood test – This test is done to check for an enzyme that primarily exists in the muscles. In most cases, people with myotonia have increased levels of CK.
- Electromyography (EMG) – This test helps doctors evaluate the health and function of the skeletal muscles and nerves that send signals between them and the brain.
- Genetic test – This test requires a blood sample to check for the abnormal genes that are often present in people with myotonia.
- Potassium blood tests – It is done to check for reduced or increased levels of Potassium in the blood. It often may indicate a type of myotonia.
- Short exercise test – Doctors use this test to determine how your nerves and muscles respond.
Treatment
Physicians usually prescribe different treatments for people with myotonia. It depends on several factors, including the severity and type of the condition, overall health, sex, age, and preferences. Most of the time, physical therapy is recommended for all people with myotonia, but doctors may also recommend other options. Check some examples below:
Dystrophic Myotonia Treatments
The treatment for this condition depends on the symptoms. For instance, the primary medicine used to treat this type of myotonia is Mexiletine. It is an antiarrhythmic medication, but it may help ease muscle cramps and stiffness.
Non-Dystrophic Myotonia Treatment
Besides medicines, doctors may recommend that people with this type of myotonia avoid exposure to cold temperatures and limit intense physical exercise.
Periodic Paralysis Treatment
In general, treatment for periodic paralysis includes managing Potassium levels and avoiding triggers. That’s why doctors often recommend the following options. Examples include:
- Eat meals at regular intervals
- Avoid high-carbohydrate foods
- Do not work overnight
- Get plenty of rest
- Foods high in Potassium (including beans, dried fruits, mangos, papayas, bananas, and others)
When it is not enough, physicians often prescribe Dichlorphenamide or Acetazolamide to relieve the symptoms.
Frequently Asked Questions
When should I see my healthcare provider?
This is a long-term health condition that requires regular checkups to monitor your symptoms and health. You should also know about certain unusual reactions to anesthesia. Inform your anesthesiologist about your condition if you have surgery.
What is the life expectancy of someone with myotonic dystrophy 1?
In general, the life expectancy of people with this condition varies because it depends on several factors. For example, the severity of the disease, overall health, and their response to treatment. Most people with congenital and classic forms of myotonia have a near-normal lifespan.
What Are The Symptoms of Myotonia?
Most people with this condition are unable to relax the muscles after a contraction, which causes severe muscle stiffness or spasms.
Can myotonia affect children?
Yes. Some forms of myotonia, such as congenital myotonia and congenital myotonic dystrophy, can appear during infancy or childhood. Children may experience muscle stiffness, delayed motor development, difficulty walking, or frequent falls. Early diagnosis and treatment can help improve quality of life.
Is myotonia a progressive condition?
It depends on the type. Non-dystrophic forms of myotonia often remain stable throughout life and do not significantly worsen over time. In any case, dystrophic forms, such as myotonic dystrophy, are usually progressive and may lead to increasing muscle weakness and involvement of other organs.
Can exercise help people with myotonia?
Moderate, regular exercise may help improve muscle function and reduce stiffness in some people with myotonia. However, intense physical activity can trigger symptoms in certain types of the condition. A healthcare provider or physical therapist can recommend a safe exercise plan based on the specific diagnosis.
Are there foods that can worsen myotonia symptoms?
Certain foods and beverages may trigger symptoms in some individuals. These can include foods that affect potassium levels, excessive caffeine, or alcohol. Since triggers vary among people, keeping a symptom diary may help identify foods that worsen muscle stiffness or weakness.
Can pregnancy affect myotonia?
Pregnancy may influence symptoms and requires careful monitoring, especially in women with myotonic dystrophy. Some women experience increased muscle weakness, fatigue, or pregnancy-related complications. Genetic counseling may also be recommended because some forms of myotonia can be inherited.
Is genetic counseling recommended for families affected by myotonia?
Genetic counseling is often recommended for individuals with myotonia and their family members. A genetic counselor can explain inheritance patterns, discuss the likelihood of passing the condition to children, and help families understand available genetic testing options.
Can people with myotonia live normal lives?
Many people with myotonia can lead active and productive lives, especially when symptoms are properly managed. Regular medical follow-ups, adherence to treatment plans, avoidance of triggers, and lifestyle adjustments can help reduce symptoms and improve daily functioning. If you have any other questions, ask your healthcare provider.
