Transient neonatal myasthenia gravis is a rare disease; it affects an estimated 15% of all babies born to myasthenic mothers. Since the condition was first described by Strickroot, Schaeffer, and Bergo (1942), reports have appeared in English of 42 patients, 4 of whom died in the neonatal period.Intestinal smooth muscle hypertrophy is extremely rare in infancy and childhood; to our knowledge only 2 cases have been recorded (Pritchard and Hillier, 1920;Guthrie, 1945). We present a further case of intestinal smooth muscle hypertrophy in an infant dying soon after delivery from a myasthenic mother who had been treated with large doses of neostigmine throughout pregnancy. A possible relationship between the two is considered.Case Report A woman of 37 who had been myasthenic since the age of 20 had a thymectomy when she was 22. Her first two pregnancies were terminated because of deterioration in her disease. The first and second trimesters of her third pregnancy were uneventful. She was admitted to St. Mary's Hospital at 36 weeks with ruptured membranes and draining slightly meconium-stained liquor, but not in labour. Her treatment was 45 mg. neostigmine hourly throughout pregnancy, pyridostigmine 60 mg. every 3-4 hours as required after admission, atropine 0 6 mg. orally with the first daily dose of neostigmine and once during the evening. A myasthenic crisis occurred, during which she stopped breathing, became cyanotic, and comatose. A period of anoxia ensued before a tracheostomy was performed, because of difficulty in maintaining an airway. She never regained consciousness and died 35 hours later. Necropsy showed multiple recent infarcts of the brain and thrombi in both arteries and veins supplying the infarcted areas.A limp cyanosed infant with a heart rate of 60 beats a minute was delivered by caesarean section 4 hours after the initial episode. Mucus and liquor were sucked out of the mouth and oxygen was given by face mask. Only 3 gasps occurred in the first 5 minutes, but despite an improvement in colour the heart rate remained the same; so the infant was intubated and oxygen was given by Received October 12, 1965. * Present address: Department of Pathology, Derbyshire Royal Infirmary, Derby. intermittent positive pressure. No further spontaneous respiration occurred. Neostigmine 0 -1 mg. and lobeline gr. 1/40 were given intravenously at 9 minutes with no response, the heart stopped at 15 minutes.Necropsy. The infant, weight 3 * 02 kg., crown heel length 49 cm., had no external evidence of disease. The cerebral white matter and meningeal vessels were moderately congested. The heart (42 g.) was enlarged to twice its normal weight because of gross hypertrophy and dilatation of the right ventricle and moderate hypertrophy of the left ventricle. The valves, septa, and great vessels were normal. The lungs were small (weight 27 g., expected weight 55 g.) and very congested. The left lung had interstitial emphysema on its cardiac surface.The peritoneal cavity contained amber fluid, and there was considerable retrop...
