Myasthenia gravis: descriptive analysis of life-threatening events in a recent nationwide registry.

BACKGROUND AND PURPOSE

Myasthenia gravis (MG) may become life-threatening if patients have respiratory insufficiency or dysphagia. This study aimed to determine the incidence, demographic characteristics, risk factors, response to treatment and outcome of these life-threatening events (LTEs) in a recent, population-based sample of MG patients.

METHODS

A retrospective analysis of MG patients who presented with an LTE between 2000 and 2013 was performed. Participants were identified from a neuromuscular diseases registry in Spain that includes 648 patients with MG (NMD-ES).

RESULTS

Sixty-two (9.56%) patients had an LTE. Thirty-two were classified as class V according to the MG Foundation of America, and 30 as class IVB. Fifty per cent were previously diagnosed with MG and median duration of the disease before the LTE was 24 months (3-406). The most common related factor was infection (n = 18). All patients received intravenous human immunoglobulin; 11 had a second infusion and six had plasma exchange. Median time to feeding tube removal was 13 days (1-434). Median time to weaning from ventilation was 12 days (3-176), and it was significantly shorter in late onset MG (≥50 years) (P = 0.019). LTEs improved <2 weeks in 55.8% but did not improve until after 1 month in 20% of patients. Four patients died. No other factors influenced mortality or duration of LTEs.

CONCLUSIONS

The percentage of LTEs in MG patients was low, particularly amongst those previously diagnosed and treated for the disease. The significant percentage of treatment-resistant LTEs indicates that more effective treatment approaches are needed for this vulnerable sub-population.