Myasthenic syndrome

Myasthenic syndrome is characteristic of myasthenia gravis (Erba-Joly disease) - neuromuscular disease, accompanied by muscle weakness and fatigue.

Often it is associated with hyperplasia or a thymus tumor (up to 70% of cases), but the etiology is not fully understood. 

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Epidemiology

Most of the myasthenic syndrome occurs in women 20-30 years old, but can be in childhood and in people older than 50 years. The development of the disease is subacute or chronic.

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Pathogenesis

In the pathogenesis the leading role is played by the expansion of the synaptic cleft, up to complete destruction of the synapse, atrophic and dystrophic changes in the striated muscle.

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Symptoms of the myasthenic syndrome

The myasthenic syndrome begins with the weakness of the musculature of the eyes, pharynx, larynx with swallowing, voice, speech, rapid eye fatigue, especially when reading, less often - weakness in the extremities. All these symptoms are painless quickly pass during rest. In addition, there is a violation of endocrine glands function, primarily thyroid (hyperfunction) and adrenal (insufficiency), and mineral metabolism of potassium, which leads to heart failure. In all cases of involvement in the process of respiratory muscles, ventilation is affected.

Crises develop in colds, intoxications, hormonal changes (including pregnancy), physical or mental stresses. In this case, the myasthenic syndrome is accompanied by a sharp deterioration in the state with the generalization of the disorders. Oculomotor disorders develop, bulbar paralysis of Erba-Golodflam (aphonia, dysarthria, dysphagia, when the patient can not swallow even saliva), difficulty breathing (superficial, frequent, ineffective), cardiac dysfunction, psychoemotional disorders (agitation is replaced by apathy), vegetative disorders - mydriasis, tachycardia, weak pulse, dry skin, intestinal atony and sphincters. With rapid progression after 10-20 minutes, a stop of breathing may occur. Distinctive feature: positive reaction to proserin - after 20-30 minutes after intramuscular injection of 2-3 ml of proserine, there is a sharp decrease in symptoms.

Differentiate the myasthenic syndrome with Lambert-Eaton disease, which develops with lung carcinoma, breast, prostate, ovarian cancer: muscles, limbs and trunk are more often affected, there is no reaction to proserin. The crisis may resemble cholinergic crises in case of an overdose of anticholinesterase drugs, but in this case it is characterized by a vegetative reaction: hypersalivation, copious sweat, vomiting, profuse diarrhea, frequent urination. Keep in mind that these two crises can be combined among themselves in people using proserin.

Forms

Myasthenic syndrome may be local with the lesion of one group of muscles, more often the eyes, larynx, pharynx, mimic muscles or trunk musculature or generalized with respiratory distress or without. With the flow, the myasthenic syndrome is distinguished: a progressive form; episodes (short crisis and prolonged remission); A stable form with periods of deterioration in the form of a crisis.

[12], [13], [14]