Clinical and laboratory profiles of patients with myasthenia gravis
| Seropositive | Seronegative | ||
|---|---|---|---|
| (n = 57) | MuSK positive (n = 4) | MuSK negative (n = 9) | |
| CT, computed tomography; MGFA, clinical classification by Myasthenia Gravis Foundation of America; MCD, mean consecutive difference; MuSK, muscle specific kinase. *p<0.05, compared with seropositive patients; †undetermined in three patients. | |||
| Age: year, mean (range) | 50 (22–84) | 40 (29–53) | 49 (20–65) |
| Age of onset: year, mean (range) | 47 (22–84) | 33 (22–45) | 43 (17–64) |
| Male:female | 19:38 | 0:4 | 3:6 |
| MGFA, mean (SD) | 2.4 (0.8) | 2.8 (1.0) | 2.0 (0.7) |
| a:b | 34:14 | 2:2 | 7:1 |
| Positive edrophonium test | 94% | 75% | 44%* |
| Thymic mass on CT | 39% | 0%* | 0%* |
| Thymus pathology† | |||
| Normal | 9/36 (25%) | 3/4 (75%) | 6/6 (100%) |
| Hyperplasia | 4/36 (11%) | 1/4 (25%) | 0/6 (0%) |
| Thymoma | 20/36 (56%) | 0/4 (0%) | 0/6 (0%) |
| Treatment | |||
| Thymectomy | 63% | 100% | 67% |
| Corticosteroid | 56% | 100% | 45% |
| Myasthenic crisis | 4% | 75%* | 11% |