Table 1.
Comparison of episodes of myasthenic crisis with AChR-Abs and seronegative patients
| Myasthenic crises | AChR-positive (n = 159) | Seronegative (n = 17) | P value | Odds ratio |
|---|---|---|---|---|
| Age | 66.5 ± 16.3 (14–89) | 54.3 ± 14.5 (25–81) | 0.0037 | |
| Male/female | 99 (62.3%)/60 (37.7%) | 7 (41.2%)/10 (58.8%) | 0.12 | 0.42 |
| Pulmonary disease | 38 (23.9%) | 2 (11.8%) | 0.37 | 0.42 |
| Heart disease | 61 (38.4%) | 5 (29.4%) | 0.60 | 0.67 |
| Diabetes mellitus | 48 (30.2%) | 2 (11.8%) | 0.16 | 0.31 |
| Tumour (other than thymoma) | 24 (15.1%) | 0 (0%) | 0.13 | 0.16 |
| Dialysis | 1 (0.6%) | 0 (0%) | 1.00 | 3.02 |
| Smoker | 16 (10.1%) | 2 (11.8%) | 0.69 | 1.19 |
| Alcohol addicted | 5 (3.1%) | 2 (11.8%) | 0.14 | 4.11 |
| ≥ 3 diseases (kidney, heart, lung, diabetes, tumour) | 21 (13.2%) | 0 (0%) | 0.23 | 0.18 |
| Myasthenia gravis | ||||
| Early onset | 22 (13.8%; 1 unknown) | 10 (58.8%) | < 0.0001 | 8.90 |
| Late onset | 136 (85.5%) | 7 (41.2%) | 0.0001 | 0.12 |
| Paraneoplastic MG (Thymoma) | 53 (33.3%) | 3 (17.6%) | 0.27 | 0.43 |
| Thymus hyperplasia | 5 (3.1%) | 5 (29.4%) | 0.0009 | 12.83 |
| Number of myasthenic worsenings/crises before present myasthenic crisis | 0.7 ± 1.3 | 0.9 ± 1.3 | 0.49 | |
| Time between first diagnosis and crisis (years) | 3.1 ± 4.4 (0–18.2) | 8.2 ± 7.6 (0–22) | < 0.0001 | |
| MGFA-classification before crisis | ||||
| First manifestation of MG | 38 (23.9%) | 3 (17.6%) | 0.77 | 0.68 |
| Class I | 8 (5.0%) | 1 (5.9%) | 1.00 | 1.18 |
| Class II | 44 (27.7%) | 4 (23.5%) | 1.00 | 0.80 |
| Class III | 40 (25.2%) | 4 (23.5%) | 1.00 | 0.92 |
| Class IV | 16 (10.1%) | 2 (11.8%) | 0.69 | 1.19 |
| Unknown | 13 (8.2%) | 2 (11.8%) | ||
| Status before crisis | ||||
| Independent at home | 73 (45.9%) | 7 (41.2%) | 0.80 | 0.82 |
| At home dependent on help | 23 (14.5%) | 3 (17.6%) | 0.72 | 1.27 |
| In a care facility or hospital | 49 (30.8%) | 7 (41.2%) | 0.42 | 1.57 |
| Unknown | 14 (8.8%) | 0 (0%) | ||
| Cause of crisis | ||||
| Infection | 80 (50.3%) | 8 (47.1%) | n.s | |
| First episode | 36 (22.6%) | 3 (17.6%) | ||
| Poor treatment compliance | 14 (8.8%) | 0 (0%) | ||
| Intake of contraindicated medication | 2 (1.2%) | 0 (0%) | ||
| Idiopathic/unknown | 32 (20.1%) | 6 (35.3%) | ||
| Therapy | ||||
| IVIG | 93 (58.5%) | 4 (23.5%) | 0.009 | 0.22 |
| Plasma exchange/immunoadsorption in total | 75 (47.2%) | 10 (58.8%) | 0.45 | 1.60 |
| PE or IA as first line therapy | 60 (37.7%) | 10 (58.8%) | 0.12 | 2.34 |
| IVIG + plasma exchange or immunoadsorption | 30 (18.9%) | 1 (5.9%) | 0.31 | 0.27 |
| Continuous pyridostigmine infusion | 61 (38.4%) | 5 (29.4%) | 0.60 | 0.67 |
| Complications | ||||
| CPR | 19 (11.9%) | 2 (11.8%) | 1.00 | 0.98 |
| Pneumonia | 86 (54.1%) | 9 (52.9%) | 1.00 | 0.95 |
| Sepsis | 32 (20.1%) | 3 (17.6%) | 1.00 | 0.85 |
| Outcome | ||||
| Days of mechanical ventilation at ICU | 19.2 ± 19.5 (1–119) | 16.2 ± 15.8 (1–55) | 0.54 | |
| Days at ICU | 22.0 ± 20.5 (1–135) | 17.6 ± 15.2 (3–56) | 0.42 | |
| Days in hospital | 30.8 ± 21.4 (3–144) | 29.9 ± 16.5 (3–71) | 0.87 | |
| In-hospital mortality | 16 (10.1%) | 2 (11.8%) | 0.69 | 1.19 |
Age, “Days of mechanical ventilation at ICU”, “Days at ICU”, “Days in hospital” and “Time between first diagnosis and crisis (years)”are depicted as mean ± Standard Deviation and range, other parameters are total number with percentage in brackets. MGFA Myasthenia Gravis Foundation of America, MG Myasthenia Gravis, IVIG Intravenous Immunoglobulin, PE Plasma exchange, IA Immunoadsorption, CPR Cardio Pulmonal Resuscitation, n.s. not significant. t test was used for statistical analysis of age-differences and for comparison of “Days of mechanical ventilation at ICU”, “Days at ICU” and “Days in hospital”. For other parameters Fisher`s exact test with odds ratio was used. Significant result (p ≤ 0.05) are shown in bold letters