Delay and misdiagnosis in adult myasthenia gravis: A case report

ABSTRACT

Myasthenia gravis (MG) is a rare autoimmune disorder characterised by fluctuating and variable combination of muscle weakness and fatigue. Most cases are due to T-cell mediated autoantibodies against post-synaptic acetylcholine receptors (AChR-Ab), thus preventing acetylcholine from binding and signalling skeletal muscle to contract. 1 The annual incidence is 7-23 new cases per million. 1 It can occur at any age but with two peaks; an early- onset (20-40 years) female-predominant and a late-onset (60-80 years) male-predominant peak. MG is classified into ocular and generalised (80%). More than half the patients initially present with ptosis and diplopia but half will progress to generalised disease with involvement of bulbar, limb and respiratory weakness. Those presenting as generalised MG can also develop eye signs later. 1 It is important to recognise MG early because it is highly treatable. Untreated disease leads to permanent weakness. 2 Treatment reduces mortality from life- threatening myasthenic crisis. 1,3 Misdiagnosis leads to potentially harmful interventions and inappropriate management. 4,5 Diagnosis in late-onset MG is easily missed 2,3,4,5 because of overlapping symptoms with other diseases common in the elderly. We report a case of delay and misdiagnosis in an elderly patient with co-morbidities.