Management of myasthenic crisis.

Sir, I read with interest the recent article by Murthy et al. It provides excellent data regarding the management and outcome of patients with myasthenic crisis. I would like to make certain observations. First, Murthy et al have utilized the neostigmine test for confirmation of diagnosis. I would like to emphasize that the edrophonium (Tensilon) test is an excellent alternative for this purpose. It may even be better as the test result is obvious in 1-2 minutes, as compared to neostigmine that requires 15-30 minutes. Tensilon test has a relatively high sensitivity and specificity, and the incidence of serious complications is only 0.16%. Secondly, it is important to differentiate myasthenic crisis from cholinergic crisis. The edrophonium test allows for this differentiation and this may help in optimizing the treatment. Thirdly, Murthy et al started all their patients on steroids prior to discharge. We agree with the approach, however, caution is required as steroids may exacerbate weakness in a subgroup of patients with myasthenia. Therefore, it is advisable to keep patients hospitalized after initiating steroids till clinical improvement begins, as exacerbations after that are unusual. Finally, Murthy et al have shown the effectiveness of lowvolume plasma exchanges in myasthenic crisis, which is similar to our observations. It is particularly important in the Indian scenario to minimize the cost of treatment. It is encouraging to note that plasmapheresis was shown to be superior to intravenous immunoglobulins in treating myasthenic crisis in an earlier study.