Myotonia

In medical terms, Myotonia is a neuromuscular condition. It is characterized by delayed relaxation of muscles after voluntary muscle contraction. It can affect any muscle type, the skeletal muscles, cardiac muscles (obvious) and smooth muscles (not obvious). The condition is usually inherited.

What happens in Myotonia?

Extra effort is required to relax the muscle soon after contraction. When the same action is repeated immediately, the condition improves as the muscles have warmed up.

Releasing the grip on objects or difficulty rising from a seated position is common with people with Myotonia. Immediately after rising from a seated position the individual may walk with a stiff, awkward gait. The posture improves after taking few steps forward. Another incidence is the time lag in opening eyes after initial tight eyelid closure.

What causes Myotonia?

Myotonia is caused by mutations in the chloride sodium or potassium channels that regulate the muscle membrane. Specific triggers that have been recognized so far include stress and exposure to cold.

What is the treatment for Myotonia?

If the condition is mild, exercise would suffice. If the condition is severe, treatment is necessary. Neurologist or medical geneticist with specific knowledge of the condition treats Myotonia. After a physical examination and a detailed family history, doctors prescribe medicines. Sodium channel blockers such as procainamide, phenytoin and mexiletine, tricyclic antidepressant drugs such as clomipramine or imipramine, benzodiazepines, calcium antagonists, taurine and prednisone are prescribed for the treatment. Physical therapy and other rehabilitative measures are recommended to help muscle function.

What is the prognosis for Myotonia?

Recognized as a chronic disorder, prescription medications when combined with physical therapy and other rehabilitative measures help alleviate symptoms later in life.

Myotonia Congenita

Myotonia Congenita is a neuromuscular genetic disease that involves progressive muscle stiffness and enlargement. This rare disorder is characterized by bouts of sustained muscle stiffness or Myotonia. The resultant muscle tensing can range from mild to severe. Myotonia Congenita occurs due to mutation of the CLCNI gene. This gene is critical in the functioning of the skeletal muscles. Therefore the mutation leads to bouts of muscle weakness. Abnormal muscle enlargement or hypertrophy is noticed in persons suffering Myotonia, even in children.

• Myotonia Congenita is an inherited condition.
  
• Myotonia Congenita is treatable.
  
• Is a non-progressive Myotonia disorder.
  
• Does not affect affected person's life span.
  
• Can affect body structure or growth patterns.
  
• Men are more affected than women.
  
• More common in northern Scandinavia, the ratio is 1:10,000 people.
  
• Muscle stiffness is more apparent in the leg muscles though it can affect face muscles and tongue.
  
• Cold, anxiety and fatigue are triggers for leg muscles stiffness.

Myotonia can affect muscles in any part of the body. In some it can affect the limbs. Some persons experience difficulty in swallowing or inability to relax their muscles quickly after contraction. Other symptoms include shortness of breath at the beginning of exercise.

Thomsen disease: In this form of the disorder, the symptoms manifest early in infancy. The main characteristic symptom of Thomsen disease is muscle stiffness or even muscle weakness after a bout of strenuous exercise. Even stress, fatigue or cold can act as triggers. The symptoms become noticeable in 2-3 years. Limbs and eyelid muscles are often affected. Thomsen disease is transmitted as an autosomal dominant trait.

Becker disease: This form of the disorder typically occurs later in life. The symptoms of Becker disease are noticed between 4-12 years. In Becker Myotonia, there is severe muscle stiffness which can often lead to mild muscle atrophy. Some medications such as beta blockers, diuretics and muscle relaxants can trigger Becker disease symptoms. Becker disease is inherited as an autosomal recessive trait.

An Electromyography is done to test the electrical activity within the muscles. Muscle biopsy is performed to check for absence of 2B fibers. CK blood test is done to check for elevated creatine kinase levels.

Myotonia Congenita Treatment

In the absence of a cure for Myotonia Congenita, a holistic approach encompassing lifestyle changes, physical therapy, and avoiding triggers is effective. Termed as the warm-up phenomenon, for most people regular exercise has been effective to relax the stiff muscles. Healthcare providers suggest making lifestyle modifications such as avoiding certain situations and physical therapy even before prescribing medications. Rehabilitative therapy to improve muscle function and relaxation techniques to reduce stress and mental discomfort which may worsen the disorder is also recommended.

Only when all these are insufficient, medications such as quinine and anticonvulsant drug such as phenytoin are prescribed. Children diagnosed with the disorder should have regular consultation with pediatric neurologist to understand and manage the disorder with the least disturbance during the growing years. Custom designed exercises, selecting suitable games and sports, avoiding foods that trigger lets children work around the symptoms and have a quality life.

Myopathy

Myopathy or muscular disease that includes muscle inflammation and muscle weakness. Myopathies affecting the skeletal muscle can have many origins - inherited, drug induced or endocrine issues. Mostly a Myopathy is transitory in nature and rarely results in complete loss of function. Muscular Dystrophy is possibly an exception in that it can be severe and sometimes even fatal if it occurs early in life.

Genetic Myopathies

These inherited Myopathies occur due to a genetic defect in the synthesis of a protein. There are many kinds in genetic Myopathies:

• Central Core Disease : Weakness in the muscles affecting hips and legs resulting in problems in running, jumping and climbing stairs
  
  
• Centronuclear Myopathy or Myotubular Myopathy : Weakness in the muscles affecting face, legs, arms and the trunk resulting in drooping upper eyelids, facial weakness or foot drop
  
  
• Myotonia Congenita : Muscles in the face, arms or legs are affected and result in muscular stiffness (myotonia) after contracting of muscles - usually after a trigger in the form of stress, fatigue, cold or a long period of no motion
  
  
• Nemaline Myopathy : Weakness in the muscles of arms, legs and the trunk resulting in poor or absent reflexes, long or narrow face, abnormal facial features
  
  
• Paramyotonia Congenita : Stiffness of muscles in the face, forearms and hands
  
  
• Periodic Paralysis : Temporary muscle weakness episodes in hypokalemic form (low calcium) as a result of vigorous exercises, intake of food high in carbohydrates, stress, alcohol, insulin, pregnancy or infection. In the hyperkalemic form (high calcium) it can occur as a result of vigorous exercises, stress, pregnancy, skipping food, high potassium levels or steroids
  
  
• Mitochondrial Myopathies : Progressive weakness of muscles in the eye (ocular myopathy) or arms and the legs or multisystem issues
  
  

Endocrine related Myopathies : Hormone deficiency can cause Myopathies. Hyperthyroid Myopathy is the result of excess secretion of thyroxine from the thyroid gland affecting muscles in the shoulders, hips or eyes. Hypothyroid Myopathy occurs when too little hormone is secreted and results in stiffness, cramps and weakness of legs and arms muscles.

Inflammatory Myopathies : Some Myopathies result in inflamed, weakened or wasted muscles. Dermatomyositis affects the connective tissue and the severity of the affected muscle loss can result in crippling movement.

Chronic muscle inflammation is called as Myositis. It is usually caused due to allergic reaction, infectious disease or rheumatism. Sometimes Myopathies are hereditary. Symptoms of Myopathy can also include cramps, spasms and stiffness. There is progressive deterioration in muscle strength resulting in pain and fatigue on walking and tripping and falling. This is not due to nerve dysfunction. Some patients might notice facial weakness, foot drop, droopy eyelids and poor reflexes in affected muscles.