Staying Safe and Active: Long-Term Management

Living with myotonia congenita is less about fighting the disease and more about learning to work with your body’s unique rhythms. While your symptoms are caused by a lifelong genetic mutation, they are not static; your level of stiffness and strength can change based on your environment, your activity level, and even your overall health ^[1][2].

The Importance of Planning for Surgery

The most critical safety precaution for anyone with myotonia congenita is informing your surgical and dental teams about your diagnosis. Specifically, depolarizing muscle relaxants used during general anesthesia can cause a severe muscle reaction ^[3].

• Avoid Succinylcholine: This common muscle relaxant (a depolarizing agent) can trigger intense, prolonged muscle contractions (a myotonic spasm) that make it difficult for doctors to manage your airway or perform surgery ^[4].
• Important Distinction: Myotonia congenita is distinct from Malignant Hyperthermia. While succinylcholine must be avoided, volatile (inhaled) anesthetics are not automatically prohibited. An experienced anesthesiologist will develop an individualized plan, which may involve nondepolarizing relaxants or Total Intravenous Anesthesia (TIVA), which relies on medications delivered through an IV rather than gases ^[4][5].
• Temperature Control: Keeping the operating room and your body warm is vital, as getting cold during surgery can trigger severe stiffness ^[4].

Action Step: Always carry a medical alert card or wear a bracelet that clearly states: “Myotonia Congenita: Avoid Succinylcholine and Depolarizing Muscle Relaxants.”

Exercise and the ‘Warm-Up’ Strategy

Physical activity is highly recommended for maintaining health, but it requires a “slow and steady” approach. Because of the warm-up phenomenon, your muscles will be at their stiffest during the first few minutes of any movement ^[6][7].

• Gentle Progression: Start any activity with a very low-intensity version of the movement. If you are going for a walk, begin with 5 to 10 minutes of slow, deliberate steps before picking up the pace ^[6]. Use handrails and take extra time on stairs when you first start moving.
• Avoid Sudden Bursts: Trying to sprint or lift a heavy weight suddenly can trigger “locking” or transient weakness, which may cause you to fall ^[8][9].
• Manage Fatigue: While stiffness improves with movement, true muscle fatigue does not. If you experience severe exhaustion or weakness after exercise, you may need to reduce the intensity of your workouts ^[10].

Pregnancy and Family Planning

Many people with myotonia congenita have healthy pregnancies and deliveries, but it requires specialized planning.

• Symptom Changes: Some women find that their muscle stiffness worsens during pregnancy due to hormonal changes, increased weight, or stress ^[11].
• Delivery Planning: A multidisciplinary team including a neurologist, an obstetrician, and an anesthesiologist should create a delivery plan early ^[11][3]. Neuraxial techniques like an epidural are often considered safe and effective after an individualized obstetric-anesthesia review, and your team must be prepared for the general anesthesia risks mentioned above if a C-section is required ^[11][3]. Any medication changes, like stopping mexiletine, must be made jointly by your team.
• Genetic Counseling: Since both Thomsen and Becker forms are genetic, speaking with a genetic counselor can help you understand the likelihood of passing the condition to your children. A person with Thomsen disease generally has a 50% chance of passing the variant; in Becker disease, the chance depends on the partner’s carrier status ^[11].

Environmental and Lifestyle Triggers

Your symptoms may fluctuate based on internal and external factors:

• Cold Exposure: Cold is a frequent trigger for increased stiffness. Dressing in layers and using hand warmers can help when you are outdoors ^[1].
• Stress and Fatigue: High levels of emotional stress or lack of sleep can make your muscles feel “tighter” and less responsive ^[10].
• Acute Illness: As covered in previous pages, having a fever or infection can exacerbate myotonia. If you become ill, monitor for “red flag” symptoms like dark urine, severe pain, or persistent weakness, which could indicate muscle breakdown (rhabdomyolysis); seek urgent medical evaluation (including blood tests) rather than trying to manage these at home with fluids ^[2].

By understanding these triggers and preparing for medical procedures in advance, you can significantly reduce the impact of myotonia congenita on your daily life.