English

Abstract

Myasthenia gravis is a neuro-muscular junction disorder characterized by skeletal muscle weakness and fatiguability. It is due to a decrease in the number of available acetylcholine receptors at the neuromuscular junction as a result of antibody mediated autoimmune attack. Weakness of muscles may involve cranial and somatic musculatures. Weakness resembling myasthenia gravis may occur in other conditions as a result of drug, endocrine disease of thyroid, certain malignancies, bacterial toxins and also by non-autoimmune mechanisms involving the neuromuscular junction. The weakness may involve all the skeletal muscles of the body but the distribution of weakness has a characteristic pattern and there is a diurnal variation of symptoms. If the weakness of respiratory muscles becomes so severe as to require respiratory assistance, then it is called myasthenic crisis. The myasthenia may be generalized one involving all the groups of muscles or it may involve the extra ocular muscles and facial muscles. Sometimes the bulbar muscles alone may be involved and the condition is called bulbar myasthenia gravis. In some of the patients, (anti-AchR) Acetyl choline receptor antibodies may be positive and in some it will be negative. In some of the patients, anti-muscle specific tyrosine kinase antibodies will be positive and negative in some of the patients. CONCLUSION : 1. In our study, the commonest age group of presentation of myasthenic crisis is the fourth decade (36%). 2. Male predominance (56%) was noted in our study. 3. The most common predisposing factor is the respiratory infection (28%). 4. In three patients, the presenting symptoms of myasthenia gravis was crisis itself. 5. The mean duration of onset of myasthenia gravis to the onset of crisis was 439.36 days. 6. The duration of myasthenia gravis does not influence the occurrence of myasthenic crisis. 7. Our patients presented with predominant bulbar symptoms with respiratory distress. 8. Ventilator associated pneumonia and other respiratory complications influenced the outcome of treatment of myasthenic crisis. 9. 32% of thymectomised patients had myasthenic crisis. 10. Higher age is a risk factor and younger age is a favourable factor for good outcome. 11. Duration of myasthenia gravis have no role on the outcome of crisis. 12. The better survival rate in ventilated patients outweigh the preventable ventilator related complications.