Myasthenia gravis and Schmidt syndrome.

We describe a 47 year old woman with a 30-year history of generalized myasthenia gravis whose condition had been stable and well controlled on a combination of pyridostigmine and ephedrine until she presented. At this time she gave a 2 month history of weakness, nausea, vomiting and more recently intermittent confusion. Investigations confirmed both primary hypothyroidism and primary adrenal failure (Schmidt syndrome). The autoimmune aetiology of these three conditions was confirmed by positive acetylcholine receptor, adrenal and thyroid microsomal antibodies.