An atypical course of myasthenia gravis.

Abstract

Myasthenia gravis (MG) is a chronic neuromuscular disease which leads to varying degrees of weakness in the skeletal muscles. Some of the symptoms of the disorder include weakness of the eye muscles, difficulty in swallowing and slurred speech. When only the muscles of the eyes are affected, the illness is termed ocular myasthenia, which is often characterized by abrupt onset of diplopia and ptosis of the eyelid. In most patients with ocular-onset MG, there is a progression to involvement of other muscle groups within the first two years (generalized myasthenia). In the case reported here, a 39-year-old male of Ecuadorian descent complained of difficulty seeing, double vision, dizziness, unsteady gait, difficulty maintaining balance and fatigue for the previous two days. Neurological examination was remarkable for total external ophthalmoplegia. There was no external bulbar muscle paralysis, motor weakness, muscle wasting, sensory deficits or sphincter dysfunction. His laboratory workup was significant for elevated acetylcholine receptor antibody. He was diagnosed with ocular MG after differential diagnoses were ruled out based on the onset and presentation of symptoms, the patient's age and a normal magnetic resonance imaging exam. No signs of generalized myasthenia were detected. His symptoms improved dramatically after treatment with Acetyl cholinesterase (AchE) inhibitors and steroids, regaining much of his ocular mobility and ability to walk without gait imbalance. At follow-up visits, the patient remained healthy with no evidence development of other myasthenic signs. This case is atypical since ocular MG does not normally occur in the absence of other myasthenic forms.