Myaesthenia Gravis

MYAESTHENIA GRAVIS

• Myasthenia gravis is a neuromuscular disorder characterized by weakness and fatigability of skeletal muscles.
• An autoimmune disorder mediated by anti acetylcholine receptors at post synaptic membrane and inhibits nicotinic receptors.
• Failure of transmission at many neuromuscular junctions results in weakness of muscle contraction.
• Myaesthenia gravis is antibody mediated (type II) hypersensitivity.

 Clinical Features–

• Weakness and fatigability of skeletal muscles.
• Fluctuating weakness of voluntary muscle.
• Lids and extracocular muscle of eyelid- diplopia and ptosis.
• Facial weakness produces snarling expression.
• Tongue weakness leads to dysarthric mushy quality.
• Bulbar weakness.
• Myaesthenic crisis

 Diagnosis-

• Anti- AchR radioimmunoassay
• Electrophysiological testing
• Single- fibre electromyography
• Edrophonium chloride (Enlon) 2 mg + 8 mg IV, highly probable diagnosis.

 Treatment-

• Anticholinesterases– neostigime, pyridostigmine
• Corticoidsteroids
• Plasmapharesis  and IV Ig.
• Thymectomy-

1. Surgical removal of thymoma
2. Treatment for MG.

 Drugs to avoid in Myaesthenia Gravis Patients-

• Antibiotics- aminoglycosides (streptomycin), Quinolones(ciprofloxacin), Macrolides(erythromycin)
• Beta- blocking agents- propranolol
• LA – procaine
• Magnesium
• Quinines
• Nondepolarizing muscle relaxants- tubocurarine, gallamine
• Botulinum toxin                       

• Myasthenia gravis is a neuromuscular disorder characterized by weakness and fatigability of skeletal muscles.
• An autoimmune disorder mediated by anti acetylcholine receptors at post synaptic membrane and inhibits nicotinic receptors.
• Failure of transmission at many neuromuscular junctions results in weakness of muscle contraction.
• Myaesthenia gravis is antibody mediated (type II) hypersensitivity.
• Weakness and fatigability of skeletal muscles.
• Fluctuating weakness of voluntary muscle.
• Lids and extracocular muscle of eyelid- diplopia and ptosis.
• Facial weakness produces snarling expression.
• Tongue weakness leads to dysarthric mushy quality.
• Anti- AchR radioimmunoassay
• Electrophysiological testing
• Single- fibre electromyography
• Edrophonium chloride (Enlon) 2 mg + 8 mg IV, highly probable diagnosis.

Drugs against MG-

• Antibiotics- aminoglycosides (streptomycin), Quinolones(ciprofloxacin), Macrolides(erythromycin)
• Beta- blocking agents- propranolol
• LA – procaine
• Magnesium
• Quinines
• Nondepolarizing muscle relaxants- tubocurarine, gallamine
• Botulinum toxin