Diaphragmatic myasthenia in mother and child

A 28 year old patient with ocular myasthenia for 2 y gave birth to a baby with diaphragmatic weakness. Following delivery the mother developed severe weakness of the diaphragm and required assisted ventilation. The baby recovered spontaneously and the mother responded to treatment with plasma exchange and immunosuppression. Neither mother nor baby responded to anticholinergic drugs and in neither serum were acetyl choline receptor antibodies detected.