An Unusual Presentation of Myasthenia Gravis

BACK GROUND: Myasthenia gravis (MG) is generally a rare disorder and may thus be easily misdiagnosed. Misdiagnosis is even more likely when the presentation is atypical. OBJECTIVE: To present and discuss an unusual presentation of myasthenia gravis METHOD: A 67-year-old man presented with progressive weakness of three months duration. Full clinical and limited laboratory evaluations were carried out and therapeutic treatment embarked upon. RESULTS: Illness started with generalized weakness and inability to maintain a conversation. Illness become so severe that he could not get up from sitting position This was accompanied by development of double vision. On examination he looked generally healthy except for bilateral ptosis and presence of diplopia. The was a prompt response to an injection of neostigmine methylsulphate. Haematological, biochemical and hormonal studies yielded essentially normal results. A clinical diagnosis of myasthenia gravis was made. Patient was placed on pyridostigmine and prednisolone to which he responded very satisfactory. CONCLUSION: Typically myasthenia gravis presents with ptosis but clinicians should be aware that that is not invariable and that it may start with limb weakness.