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  IN THIS Article
 ::  Introduction
 ::  Case report
 ::  Discussion
 ::  Acknowledgement
 ::  References

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Year : 1985  |  Volume : 31  |  Issue : 2  |  Page : 109-11

Congenital myasthenia gravis (a case report).

How to cite this article:
Joshi R M, Bharucha B A, Mohire M D, Kumta N B. Congenital myasthenia gravis (a case report). J Postgrad Med 1985;31:109

How to cite this URL:
Joshi R M, Bharucha B A, Mohire M D, Kumta N B. Congenital myasthenia gravis (a case report). J Postgrad Med [serial online] 1985 [cited 2023 Mar 23];31:109. Available from:

  ::   Introduction Top

Myasthenia gravis is characterised by abnormal fatiguability after repeated or sustained muscle activity and improvement after rest. Peak incidence is seen in young adults but it may also occur in infancy and childhood. One can recognize three separate entities in childhood period: (a) transient neonatal myasthenia in an infant of myasthenic mother, (b) congenital or infantile myasthenia in an infant of non-myasthenic mother and (c) juvenile myasthenia similar to adult myasthenia.[3] Rarity of this condition and a good therapeutic response to neostigmine prompted us to report the following case.

  ::   Case report Top

A 15 month old male child was brought to us by his mother with a history of drooping of both eyelids, noticed since the age of 6 months, appearing late in the day but disappearing after sleep. The child was a full-term normal delivery born of a non-consanguinous marriage, and the primi-mother had noticed quickening at 26 weeks of gestation. There was no history suggestive of myasthenia in the mother. Neonatal period was uneventful and the milestones were normal upto 6 months of age but after that the child had achieved only walking with support by 15 months of age, while other developments were normal. There was no history of swallowing difficulty, aspiration or respiration difficulty except on admission when the child had signs of right upper zone pneumonitis.
On CNS examination, the child had the findings of bilateral ptosis, weak gag reflex, generalised hypotonia with weakness also of intercostal muscles and diaphragm, with depressed deep tendon reflexes.
With a clinical diagnosis of congenital myasthenia gravis in an infant of a non-myasthenic mother, the child was investigated. Neostigmine test with 0.375 mg given intramuscularly showed a good response in the form of improvement in ptosis, gag reflex, power, respiration and deep tendon reflexes.
X-ray chest showed right upper zone pneumonitis which cleared up with antibiotics.
Repeatative stimulation of the median nerve with recording of muscle action potentials from abductor pollicis brevis showed a definite decrement at 3 cps frequency. This decrement was subsequently abolished by intramuscular injection of prostigmine.
The child was put on neostigmine tablets, 5 mg 4 times a day during waking hours and he showed a good response in the form of improvements in signs.

  ::   Discussion Top

Congenital myasthenia presenting in an infant of non-myasthenic mother is rare (1% of cases).[3] Simpson[10] has postulated an auto-immune etiology of adult myasthenia gravis; but there is no association with thymoma or antibodies in congenital myasthenia, as seen in adult cases.[1],[10] Bundy[2] undertook a detailed genetic study based on available reports in the literature and some cases from 4 London hospitals and suggested an autosomal recessive pattern of inheritance. Macrae[5] recorded a case with weakness at birth in which foetal movements were markedly diminished in the last 6 weeks of pregnancy.
In an isolated case, the diagnosis may be difficult. It should be kept in mind in an infant with unexplained sucking, swallowing or respiratory difficulty, especially if with ptosis, ophthalmoplegia or hypotonia. It should be differentiated from transient neonatal myasthenia as seen in [Table 1] The diagnosis is confirmed by a response to anticholinesterase drugs. Edrophonium chloride, 0.2 mg per kg intravenously or neostigmine 0.04 mg per kg intramuscularly may be used. EMG is a helpful adjunct to the diagnosis. There is a progressive decrease in muscle response on repetitive stimulation of the nerve at low rates.
The therapy consists of oral pyridostigmine, 1 mg per kg every four hours or neostigmine, 0.3 mg/kg every 3 hours during waking hours in the day and injections before feeds if required. Streoids, immunosuppressants, plasmapheresis or thymectomy are not as helpful in these cases.[4],[6],[7],[8],[9] Drugs such as curare, gallamine, succinyl choline, quinine, quinidine, neomycine, procaine and morphine should be avoided.[3]
The course tends to be non-fluctuating and compatible with a long survival with little need for medication compared to other forms.[7] However, a number of recent reports on fatal cases due to acute bulborespiratory involvement suggests that prognosis is not always good.[3]

  ::   Acknowledgement Top

We thank the Dean, Seth G.S. Medical College and K.E.M. Hospital, Bombay, for giving us permission to publish this paper.

  ::   References Top

1.Blalock, A., Manson, M. F., Morgon, H. J. and Riven, S. S.: Myasthenia gravis and tumours of the thymic region; A report of a case in which the tumour was removed. Ann. Surg., 110: 544-561, 1939.   Back to cited text no. 1    
2.Bundey, S.: A genetic study of infantile and juvenile myasthenia gravis. J. Neurol. Neurosurg. & Psychiat., 35: 41-51, 1972.   Back to cited text no. 2    
3.Dubowitz, V.: Myasthesia gravis, In, "Muscle disorders in childhood,"-"Major Problems in Clinical Practice," Vol. XVI, Editors: A. I. Schaffer and M. Markowitz, W. B. Saunders Company Ltd., Philadelphia and London. 1978. pp. 191-201.  Back to cited text no. 3    
4.Fonkalsrud, E. W., Herrman, C. Jr. and Donald, D. M.: Thymectomy for myasthenia gravis in children. J. Paediatr. Surg., 5: 157-165, 1970.  Back to cited text no. 4    
5.Macrae, D.: Myasthenia gravis in early childhood. Pediatrics, 13: 511-519, 1954.   Back to cited text no. 5    
6.Millichap, J. G. and Dodge, P. R.: Diagnosis and treatment of myasthenia gravis in infancy and childhood. Neurology, 10: 1007-1014, 1960.  Back to cited text no. 6    
7.Sarnat, H. B., McGarry, J. D. and Lewis, J. E. I r.: Effective treatment of infantile myasthenia gravis by combined prednisone and thymectomy. Neurology, 27: 550-553, 1977.  Back to cited text no. 7    
8.Seybold, Marjorie, E.: Thymectomy in juvenile myasthenia gravis. Arch. Neurol., 25: 385-392, 1971.  Back to cited text no. 8    
9.Seybold, Marjorie, E. and Lindstrom, J. M.: Myasthenia gravis in infancy. Neurology, 31: 476-480, 1981.  Back to cited text no. 9    
10.Simpson, J. A.: Myasthenia gravis and myasthenic syndromes. In, "Disorders of Voluntary Muscle," 4th edition, editors: J. A. Walton, Churchill Livingstone, Edinburgh and London, 1981, p. 584.  Back to cited text no. 10    

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Online since 12th February '04
2004 - Journal of Postgraduate Medicine
Official Publication of the Staff Society of the Seth GS Medical College and KEM Hospital, Mumbai, India
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