Myasthénie

The serious myasthénie or myasthénie ( MG , in Latin myasthenia climbed = " serious weakness musculaire") is a Maladie neuromusculaire by attack of the neuro-muscular transmission involving a fluctuating weakness and a fatigability. It is one of the autoimmune diseases most known and the pathogenetic Antigène S and mechanisms were indeed elucidated. The weakness is due to the circulating Anticorps which block the receiving S of the Acétylcholine to the post-synaptic Jonction neuromusculaire, thus inhibiting the stimulating effect on the Neurotransmetteur, the acetylcholine. The myasthénie is treated by Immunosuppression and inhibiting of the cholinestérase.

History

Clinical demonstrations

Classically, fatigability makes the contraction muscular each less intense time.

The clinical demonstrations can include:

  • a Diplopia (vision doubles and/or deformed)
  • a Ptosis (falls of one or the 2 eyelids)
  • a weakness of the muscles:
    • facial
    • respiratory
    • proximaux

The attack can remain limited to the ocular muscles, then, a Thymome is frequently associated.

Diagnosis

  • Clinical examination:
It can be normal or find a fluctuating driving deficit. One seeks a fatigability (squattings, tended arms…), one frequently uses the method of the score of Osserman

  • pharmacological Tests

They show the disappearance of the symptoms under anticholinesterasic; one uses the prostigmine or the tensilon (10 Mg in IV slow). The effect occurs a few minutes after the injection with transitory clinical improvement (5 minutes for the prostigmine, 1 minute for the tensilon).
  • electric Examinations (Electromyogram or EMG)
During the repetitive stimulation of a motor nerve one finds a reduction in amplitude of the potential of action, i.e. a decrement. This test can be negative.

  • biological Examination:

In priority one seeks the rate of antibody antirécepteurs to the acetylcholine (aRach); It can be negative. One then speaks about Myasthénie séro-negative . One can also seek, especially in the event of negative result with research above: the antibodies striated anti-muscles, anti-musk antibodies.

  • to draw up a complete assessment and because of the frequent autoimmune ground within the framework of the autoimmune diseases, one can also seek: anti-thyroid antibodies (TSH) the smooth antibodies anti-muscles and antinuclear antibodies (ACAN).

  • muscular biopsy:

In the doubtful cases, it can be used to eliminate another pathology.

  • Search for a thymome

Systematic with thoracic scanner. A thymique tumor is found in 15 to 30% of the cases of myasthénie; conversely 2/3 of the carriers of thymome develop a myasthénie. The thymome can reveal signs of malignity with risk of local extension. Generally, one will find a thymique hyperplasy without thymome; finally the thymus can be normal.

  • Search for an associated autoimmune affection

Present in 10 to 15% of the cases: thyroïdite, weakens of Biermer, polyarthritis rhumatoïde, lupus…

Classification of the various stages

SCALE Of OSSERMAN MODIFIEE

  • Stage 1: myasthénie ocular pure
  • Stage 2: myasthénie generalized of average gravity with usually ocular signs but not of bulbar or respiratory sign
  • Stage 3: myasthénie generalized of average gravity with usually ocular signs and bulbar signs but without respiratory sign
  • Stage 4: myasthénie generalized rather severe with usually ocular, bulbar signs and moderate respiratory attack
  • Stage 5: myasthénie generalized severe with respiratory attack engraves

Treatment of the myasthénie

The myasthénie can be treated by inhibiting drugs of the cholinestérases like the mestinon or the mythelase. These drugs prevent the degradation of acetylcholine. Another solution in the event of thymome is the thymectomy. The other therapeutic ones, immunomodulateurs are sometimes used: intravenous general-purpose immunoglobulin perfusions even of the Corticoids more or less associated with L Imurel.

External bonds

  • ''' FRIENDLY - Association of Myasthéniques '''; Isolated and Interdependent. /French-speaking Myasthenie.com/Association dedicated to the patients of Myasthénie and to their families. Site, forum, meetings, seminars…
  • HonSelect
  • CHU of Rouen

Sources

  • muscular Myasthénie AFM
  • Dystrophy Canada
  • Online Mendelian Inheritance in Man, OMIM (TM). Johns Hopkins University, Baltimore

Random links:Duality (mathematics) | The Great Jump | Friedrich Wilhem von Bismarck | Bahige Tabbara | Netlib | Carsten_Niebuhr