Myasthenia

Description:

Myasthenia — the autoimmune disease causing disturbance of neuromuscular transmission and which is shown weakness and pathological fatigue of skeletal (cross-striped) muscles. Any muscle of a body can be involved in process, however it is tended to preferential damage of face muscles, lips, eyes, language, a throat and neck.  A neonatal myasthenia — the passing state which is observed at the babies who were born from mothers suffering from a myasthenia, and caused by transition through a placenta of maternal antibodies to atsetilkholinovy receptors.

Myasthenia symptoms:

The myasthenia is shown by fatigue of muscles with the accompanying weakness,    especially eye  and  the muscles  innervated  by bulbar  nerves.  Weakness of eye muscles leads to a diplopia and squint, one – or to the bilateral ptosis which is most expressed by the end of day. Weakness of facial and chewing muscles is quite often noted. Difficulties of the speech and swallowing can be revealed after more or less long conversation and meal. Weakness and fatigue of muscles of language and a nasal shade of a voice are possible. Also other cross-striped muscles of extremities and a neck can be affected what results in generalized weakness. The exhaustion of tendon jerks is defined. At repeated electric stimulation pathological fatigue of muscles, the expressed ability to recovery after short rest come to light. Lability, dynamism of symptoms with their strengthening when reading, fixing a look, sometimes to the general exercise stress are characteristic. The myasthenia can be generalized and local (damage of muscles of eyes, drinks, throats, mimic muscles or muscles of a trunk). The generalized form can be followed by respiratory frustration.
the progressing character has diseases. Myasthenic episodes (myasthenic frustration and long spontaneous remissions, short on time) and myasthenic states are possible (stable manifestations throughout considerable term). At patients with a myasthenia there can come the sharp aggravation of symptoms in the form of crisis with generalized muscular weakness, oculomotor both bulbar and symptoms (an aphonia, a dysarthtia, a dysphagy), breath disturbances, the psychomotor excitement which is replaced by slackness, and also vegetative frustration. At the same time the acute hypoxia of a brain with disorder of consciousness develops. The lethal outcome is possible.

Myasthenia reasons:

The disease is connected with antibody formation against the atsetilkholinovy receptors located on a postsynaptic membrane of a neuromuscular synapse. Long-term researches proved communication of a myasthenia with a thymus. Not the last role is played also by hereditary factors.

Treatment of the Myasthenia:

It is directed to correction of relative deficit of acetylcholine and suppression of autoimmune process. For the purpose of compensation of disorders of neuromuscular transmission use antikholinesterazny means: прозерин, ambenonium chloride, pyridostigmine bromide (Mestinonum, Kalyminum, амиридин). The choice of the optimum individually compensating dose depending on a clinical form, weight of symptomatology, associated diseases, reactions to drug is important. At pharyngeal and front and eye forms of a myasthenia are more effective pyridostigmine bromide, прозерин and an ambenonium chloride. Doses of drugs and intervals of reception are individual. Appoint chloride or оротат potassium, верошпирон, ephedrine. In hard cases enter прозерин parenterally. Reception of high doses of antikholinesterazny drugs can lead to cholinergic crisis. The main methods of treatment of this crisis are cancellation of anticholinergics and repeated administration of atropine.
At the myasthenic crisis resulting from an insufficient dose of antikholinesterazny means urgently enter прозерин intravenously and intramusculary. The ambenonium chloride can be entered in candles. Apply also ephedrine solution subcutaneously, potassium drugs intravenously. The progressing and life-threatening weakness of respiratory muscles can be observed, despite introduction of large numbers of a prozerin. The patient make an intubation or a tracheostomy, transfer to IVL. Food of patients is carried out via the nazogastralny probe. It is necessary to support balance of liquid and electrolytes, vitamins; carry out correction of disturbances of acid-base balance.
The main methods of pathogenetic treatment of patients with a myasthenia are the thymectomy, a roentgenotherapy and hormonal therapy. The surgical method (thymectomy) is shown to all patients aged up to 60 years suffering from a myasthenia, but being in satisfactory condition. It is absolutely shown at a thymus tumor. The roentgenotherapy is appointed to area of this gland after an incomplete thymectomy, at an eye form of a myasthenia, and also in the presence of contraindications to operation at patients of advanced age with a generalized form of a myasthenia. In hard cases – at a generalized myasthenia – treatment is shown by immunosuppressive drugs. Appoint corticosteroids, duration of reception of the maximum dose of corticosteroids is limited to approach of considerable improvement which allows to reduce a dose to supporting afterwards.