Urinary incontinence in a woman with myasthenia gravis: a demonstration of sphincter fatigue by spectral analysis of the striated urethral sphincter

Myasthenia gravis (MG) is a disorder of the neuromuscular junction caused in the majority of the patients by antibodies directed against the postsynaptic acetylcholine nicotinic receptors. The classic clinical presentation of MG has been well characterized as fluctuating muscle weaknesses affecting particular muscle groups. However, voiding dysfunction in conjunction with MG is rare. A review of the literature yielded only 7 prior reports of such a combination. Most of the reported cases involved incontinence in males after a transurethral resection of the prostate. Only 3 cases described de novo voiding dysfunction. We report about a 45-year-old female with generalized MG who developed urinary incontinence. EMG examination revealed striated urethral sphincter fatigue objectived by spectral analysis.