The Usefulness of Ice Test for Diagnosis of Myasthenia Gravis in Patients with Ptosis

ABSTRACT

PURPOSE: To compare the results of the ice test with other diagnostic tests for the diagnosis of myasthenia gravis in patients with ptosis. METHODS: The patients included in this study presented with suspicious myasthenic blepharoptosis and visited the Department of Ophthalmology, Guro Hospital, Korea University between March 2003 and February 2004 for diagnosis. All patients received "myasthenic ptosis workup" including the ice test, edrophonium test, RNS EMG, and anti-acetylcholine receptor antibody (anti-AchR) titer test. The tests were compared for specificity, sensitivity, ease of performance, economic benefits and observed complications. RESULTS: The patients included six men and nine women with an average age of 36.9+/-2.4 yrs. Positive test results were obtained as follows Ice test 80%, edrophonium test 66.7%, RNS EMG 53.3%, and anti-AchR titer test 86.7%. Adverse effects of edrophonium test were encountered in two patients who had nausea, vomiting, and dizziness. CONCLUSIONS: The authors found that the ice test was simpler, faster, more economic, and safer than the others for diagnosing blepharoptosis caused by myasthenia gravis. Considering its relative high sensitivity and specificity, the ice test should be the first screening test given to patients with suspicious myasthenic ptosis.