Causes and risk factors
There are 2 main types of this disorder – Thomsen disease – symptoms are apparent since infancy up to 3 years of age. Becker disease – symptoms begin to develop later from 4-12 years of age. It is a congenital condition caused due to genetic mutation.
Clinical presentation
The muscles are unable to quickly relax after contracting. After a few repetitions, the muscle relaxes and the movement becomes normal. The child will usually look muscular and well-built. Symptoms such as difficulty in swallowing, gagging, breathlessness, or tightening of the chest at the beginning of exercise, and stiff movements are observed. Frequent falling occurs. Difficulty in opening eyelids after strenuous contraction or crying is seen. It may be associated with muscle hypertrophy, stiffness, or transient weakness.
Investigations
Medical history by the patient and clinical examination by the doctor helps in diagnosis. Genetic testing to identify the defective gene. Electromyography to study the electrical activity of the muscles. Biopsy of the muscle is recommended.
Treatment
Treatment involves muscle relaxants. Physiotherapy, occupational therapy will also help in managing the condition. In case of swallowing difficulties, nutrition through nasogastric tube or intravenous route is helpful.
Complications
Complications such as chronic joint problems, frequent choking, gagging, or trouble swallowing in an infant, aspiration pneumonia, weakness of the abdominal muscles, injury due to falls can occur.
When to Contact a Doctor
One must consult a doctor if the child has symptoms such as stiff movements, difficulty in swallowing, gagging, breathlessness, or tightening of the chest.
Prevention
Genetic counseling of the couples who want to conceive and who have a family history of myotonia congenita can prevent the disease.
Systems involved
Musculoskeletal system, CNS, GIT, respiratory system
Organs involved
Skeletal muscles around legs, hands, throat, trachea
