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Alterations of the Peripheral Nervous System. Myasthenia Gravis Introduction. Myasthenia Gravis. Definition: -chronic, immune neurological disease -defect in transmission of nerve impulses at the neuromuscular junction -antibodies attack acetylcholine receptors.
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Alterations of the Peripheral Nervous System Myasthenia Gravis Introduction
Myasthenia Gravis • Definition: -chronic, immune neurological disease -defect in transmission of nerve impulses at the neuromuscular junction -antibodies attack acetylcholine receptors
Populations at RiskRisk Factors • Peak onset: 20 – 30 yrs. Old • Females are 3X > Males • About 20 per 100,000 affected* • Not hereditary ( small familial incidence) • Thymus gland often abnormal (hyperplasia) • Strong association between MG and hyperthyroidism *http://www.myasthenia.org/amg_whatismg.cfm
Clinical Manifestations • Muscle weakness within voluntary muscles -ptosis -abnormal vision -difficulty chewing/swallowing -weakness of arms and legs -chronic muscle fatigue -possibly difficulty breathing
Diagnostic Tools • Tensilon test (anticholinesterase) edrophonium chloride:med will enhance neurotransmission shows marked muscle tone improvement for about 4-5 mins. ANTIDOTE for Tensilon: Atropine Sulfate • EMG (electromyography): muscle response decreased with repeated stimulation
Diagnostic Tools • Thyroid function tests: some MG patients have increase • Serum protein electrophoresis: evaluate for immunologic disorders • Acetylcholine receptor antibodies test-elevated