Introduction Epidemiological studies conducted in several countries have shown that the incidence of myasthenia gravis is on the increase. This is more so in the older (>50 years) population. The reasons for this increase have not been fully explained even after correcting for an ageing population and improved diagnosis. We were interested in establishing if there were different clinical and immunological features accounting for this apparent changing incidence between young and late onset myasthenia gravis. Methods and results: We have prospectively recruited 123 patients in the first 22 months of our study. So far, our data indicate that 76.27% of all newly diagnosed myasthenia patients in our region are over the age of 50 years. Around 73.5% of patients had ocular symptoms at onset and 38.5% had pure ocular myasthenia. Ptosis was the most common first symptom, followed in decreasing order of frequency by diplopia, limb weakness, dysphagia, dysarthria, difficulty with chewing and head drop.
Conclusion Further evaluation of clinical data and immunological investigations (antibodies and T regulatory cell function and T-cell repertoire) will provide useful information and possibly an explanation for this increase in late-onset myasthenia gravis.