History
Ms. Yau is a 40-year-old lady. She is an ex-smoker and ex-regular drinker. She has a history of impaired fasting glucose and hyperlipidemia. She has no family history of neuromuscular diseases.
She presented with a 6-month history of variable, fatigable nasal speech, difficulty in swallowing, bilateral droopy eyelids, double vision and neck drop.
Physical examination
Physical examination was pertinent for marked dysphonia, fatigable and asymmetrical bilateral ptosis, multidirectional diplopia, neck flexion weakness, and symmetrical proximal limb weakness.
Investigation
The serum level of anti-acetylcholine receptor antibody was elevated.
Repetitive nerve stimulation test and a contrast CT of the thorax were pending.
Thought process
The pathology was likely localized to the neuromuscular junction or muscle level.
Given the variable and fatigable symptoms and signs, myasthenia gravis was the most likely diagnosis. The history did not suggest botulism, and the clinical syndrome did not match that of Lambert-Eaton myasthenic syndrome. Muscle pathology is typically expected to be either fixed or progressive.
Next steps
Ms. Yau was treated with intravenous immunoglobulins and Mestinon. There was a marked clinical response, although significant bulbar symptoms remained.
Despite not being in a myasthenic crisis by definition, the treatment alternative of plasma exchange was discussed for more rapid symptomatic control.
Ms. Yau preferred medical treatment and was initiated on moderate-dose prednisolone. Steroid-sparing agents would be started after the need for thymectomy has been clarified.