Abstract
Purpose :
To address the validity of intravenous neostigmine administration combined with prism and alternate cover test (PACT) measurement as a confirmatory diagnostic method for confusing cases of myasthenia gravis with ocular involvement.
Methods :
Neostigmine was administered intravenously in ten suspicious myasthenic diplopia patients under electrocardiographic monitoring. Distance deviation at primary position was evaluated with PACT at 5, 10, 15, 20 and 30 minutes after intravenous injection of neostigmine. Margin reflex distance and range of duction were also evaluated at each time points.
Results :
7 out of 21 patients were diagnosed as myasthenic diplopia by positive neostigmine test. Among these patients, everyone had abnormal ocular motility and 5 had ptosis. In participants who showed positive result, impairment of ocular motility was relieved invariably, but ptosis was not improved in one patient. The improvement of ocular motility had been occurred within 5 minutes in all 7 responders and the pharmacological effect reached peak at 5 to 20 minutes (mean: 13 minutes) after neostigmine administration.
Conclusions :
Intravenous neostigmine administration combined with PACT is a rapid, objective and quantifiable method in hard-to-diagnose cases of myasthenia gravis with ocular involvement. In performing neostigmine test for myasthenia gravis with ocular involvement, not only the lid position, but also ocular motility should be evaluated quantitatively to avoid a false negative result.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.