Congenital paramyotonia

Introduction to congenital accessory myotonia Congenital paramyotonia (congenital paramyotonia) was first described by Eulenburg (1886) and Rich (1894), hence the name Eulenberg disease. basic knowledge The proportion of sickness: 0.003%-0.005% Susceptible people: children Mode of infection: non-infectious Complications: Dysphagia, neonatal asphyxia

Causes of congenital accessory myotonia

(1) Causes of the disease

Congenital accessory myotonia is an autosomal dominant hereditary disease. It is now a sodium channel disease of skeletal muscle. Its pathogenic gene is located in SCN4A of 17q23.1~25.3 (alpha subunit encoding skeletal muscle sodium channel). Gene mutations primarily affect sodium channel inactivation.

(two) pathogenesis

The dysfunction of the sarcolemmal sodium channel of this disease is caused by the temperature of the limb contact when the ambient temperature is lowered, the water temperature is slightly lower than the body temperature, and the resting membrane potential of the sarcolemma is lowered during the cold period, and the membrane is depolarized due to the opening of the sodium ion channel. The increase of sodium ions in the cells interferes with the uptake of calcium ions in the sarcoplasmic reticulum after muscle contraction, and thus the muscle rigidity occurs. The cause of the abnormal ion channel of the disease lies in the macromolecular protein constituting the ion channel, which changes its space with temperature. The configuration has changed.

Muscle biopsy showed that the size of muscle fibers was different, there were vacuoles inside, and histochemical staining showed hypertrophy of type II muscle fibers, sometimes unable to distinguish the type of muscle fibers.

Congenital accessory myotonia prevention

Avoid cold and overwork, pay attention to the dangers of children swimming in cold water; relax exercise after strenuous activities, rest, and prevent muscle rigidity and muscle weakness.

Congenital accessory myotonic complications Complications dysphagia in neonates with dysphagia

Children may be at risk of swimming in cold water; eating cold food can induce throat rigidity, resulting in difficulty swallowing and suffocation.

Congenital diaphragmatic tonic symptoms common symptoms weakness facial muscle tonic paralysis

1. Most patients have an onset at an early age.

2. Outstanding symptoms

The characteristic is that when the degree of cold is not enough to affect the normal person's activity, the muscle rigidity and weakness of the whole body occur, and the symptoms are aggravated after the continuous contraction of the muscles in the cold environment, and the abnormal muscle rigidity is particularly obvious, and the facial and the muscles of both hands are obviously affected, therefore, the patient It is difficult to blink after being cold. In a warm environment, there is no difficulty in relaxing after muscle contraction. It only appears after slamming the tongue muscle. After eating cold food, it can induce muscle rigidity in the throat.

3. Main signs

Patients may have paroxysmal soft palate, which is easy to induce after cold and exercise. Before the onset of muscle weakness, muscle rigidity may increase first, which is called parathyroid tonic periodic paralysis. The distribution of muscle weakness is mainly in the proximal muscle. Minutes to days, toughness and weakness are aggravated after the event. This feature is in stark contrast to congenital myotonia, which is why Eulenburg calls dominance. In some families, there is only weakness, but no rigidity. The weakness is similar to the primary periodic spasm, which can be induced by oral potassium. Physical examination: visible muscle hypertrophy.

4. Electromyography examination shows strong myoelectric discharge during non-paralysis, and electrical rest is more common during paralysis.

Examination of congenital accessory myotonia

1. Serum muscle enzyme test helps to differentiate the diagnosis.

2. Serum electrolyte examination helps to differentiate the diagnosis.

3. Cold water induction test The hand and forearm are immersed in cold water at 11 ~ 13 ° C for several minutes to 40 minutes. If it can induce muscle rigidity and muscle weakness, it is helpful for diagnosis.

4. EMG examination helps to differentiate the diagnosis.

5. Muscle biopsy helps to differentiate the diagnosis.

Diagnosis and diagnosis of congenital accessory myotosis

diagnosis

Congenital accessory myotonia can be diagnosed according to the characteristics of muscle rigidity and muscle weakness after cold stimulation. When the diagnosis is difficult, it can be used as a cold water induced test to help diagnose, or ice water or ice can be placed on one side of the patient. On, after a few minutes, if the symptoms of myotonia appear, the limbs will be placed in warm water or hot water bottle. After a few minutes, the symptoms of myotonia disappear, and the diagnosis of the tonic muscle can be established.

Differential diagnosis

The disease needs to be identified with the following diseases:

Congenital muscle rigidity

The muscle hypertrophy of this disease is obvious, the degree of muscle rigidity is heavier, and it can not be relaxed immediately after exerting force. However, after repeated exertion, this phenomenon can gradually disappear. After repeated activity, the muscles of the accessory muscles are aggravated or muscle weakness, and congenital muscle rigidity is rarely. Combined with the symptoms of periodic paralysis, it is more likely to cause myogenic potential during electromyography. When using the cold-induced test, the myoelectric activity is recorded in the adductor or the abductor muscle, such as congenital myotonia, slightly moving the electrode. It can cause the release of myotonic potential, the duration is longer than room temperature, and after 4 to 5 consecutive contractions, the results are the same, and the dorsal muscles can not cause the release of muscle tonic potential when forcefully moving the electrode or strong slamming. After continuous contraction The amplitude of the motor unit is significantly reduced, and the electrical activity that continues to contract rapidly disappears and is electrically rested, and muscle rigidity occurs.

2. Atrophic myotonia

The age of onset of the disease is relatively late, there are muscle atrophy, endocrine and nutritional disorders can be identified.

3. Periodic

Because congenital accessory muscle rigidity often combined with paroxysmal soft palate, it must be distinguished from it. It can be used as a potassium load test. After taking potassium, it can induce hyperthermia with elevated potassium and potassium. If it is not related to potassium administration, it is Paramuscular tonicity, if the muscle weakness occurs after taking potassium, the normal potassium is normal, the normal periodic sputum of potassium, such as glucose insulin test can induce muscle weakness, low potassium periodic paralysis, induced by cold and muscle rigidity The muscle weakness is the rigidity of the accessory muscle.

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