Sensitivity of Diagnostic Tests and Therapeutic Outcome in Ocular Myasthenia Gravis

PURPOSE: To compare the sensitivity of various diagnostic tests, and to assess the efficacy of therapy in the management of myasthenia gravis (MG). METHODS: Thirty-two patients with ocular findings with MG were examined by Stimulated Single Fiber Electromyograhy (SFEMG), Repetitive Nerve Stimulation (RNS) test, Edrophonium (Tensilon) test, anti-acethylcholine receptor antibody titer. We also studied retrospectively clinical characteristics and efficacy RESULTS: Mean age of patients was 32 years (range 1 to 63 years). Twenty (62.5%) were females and 12 (37.5%) were males. Mean duration of symptoms was 17 months (range 5 months to 10 years). Associated ocular findings were ptosis 31 eyes (97%), diplopia 20 eyes (63%), and ocular limitation 19 eyes (59%). The value of diagnostic sensitivity was 97% in SFEMG, 94% in tensilon test, 75% in RNS test, and 69% in anti-acetylcholine receptor antibody assay. Nine of 10 cases who were treated with thymectomy and pyridostigmine were markedly improved. Eight cases (25%) subsequently developed generalized type of myasthenia gravis. CONCLUSIONS: Ptosis and diplopia were most frequently associated with ocular myasthenia gravis. For diagnosis of ocular myasthenia gravis, SFEMG or tensilon test was the most sensitive test. Thymectomy combined with pyridostigmine bromide seemed to be an effective therapeutic modality.

Comparison of Usefulness of Laboratory Tests in Diagnosis of Myasthenia Gravis / 영남의대학술지

PURPOSE: This study was undertaken to evaluate the clinical usefulness of Tensilon test, repetitive nerve stimulation test(RNST), single fiber EMG(SFEMG) test and acetylcholine receptor antibody(AchR Ab) assay for making diagnosis of myasthenia gravis(MG). METHOD: These tests were performed in 21 MG patients which were classified into 11 ocular, 5 mild generalized, 4 moderate generalized, and 1 chronic severe MG. RESULT: The overall positivity of Tensilon test, SFEMG and AchR Ab was 95%, 87%, and 76% respectively. The overall positivity of RNST was 67%; 38% on flexor carpi ulnaris, 43% on adductor digiti quinti and 62% on orbicularis oculi muscles. The positivity of each test was higher in generalized MG group than in ocular MG group. But we could observe the statistically significant difference only in the RNST(p<0.05). CONCLUSION: Tensilon test showed the highest positivity in all MG groups. So we would like to recommend the Tensilon test for the diagnosis of MG at first, followed by RNST and AchR Ab assay, and SFEMG would be indicated to MG group which showed relatively low postivity in other tests.