Seronegative myasthenic crisis: a multicenter analysis

Myasthenic crisis (MC) is a life-threatening condition for patients with myasthenia gravis (MG). Seronegative patients represent around 10–15% of MG, but data on outcome of seronegative MCs are lacking. We performed a subgroup analysis of patients who presented with MC with either acetylcholine-receptor-antibody-positive MG (AChR-MG) or seronegative MG between 2006 and 2015 in a retrospective German multicenter study. We identified 15 seronegative MG patients with 17 MCs and 142 AChR-MG with 159 MCs. Seronegative MCs were younger (54.3 ± 14.5 vs 66.5 ± 16.3 years; p = 0.0037), had a higher rate of thymus hyperplasia (29.4% vs 3.1%; p = 0.0009), and were more likely to be female (58.8% vs 37.7%; p = 0.12) compared to AChR-MCs. Time between diagnosis of MG and MC was significantly longer in seronegative patients (8.2 ± 7.6 vs 3.1 ± 4.4 years; p < 0.0001). We found no differences in duration of mechanical ventilation (16.2 ± 15.8 vs 16.5 ± 15.9 days; p = 0.94) and length of stay at intensive care unit (17.6 ± 15.2 vs 17.8 ± 15.4 days; p = 0.96), or in-hospital mortality (11.8% vs. 10.1%; p = 0.69). We conclude that MC in seronegative MG affects younger patients after a longer period of disease, but that crisis treatment efficacy and outcome do not differ compared to AChR-MCs.

[Low incidence of SARS-CoV-2 infections in healthcare workers at a tertiary care hospital : Results of a prospective serological cohort study of the first and second COVID‑19 pandemic wave]

Hintergrund

Mitarbeiter im Gesundheitswesen mit Kontakt zu COVID‑19-Patienten sind einem erhöhten Risiko einer Infektion mit SARS-CoV‑2 ausgesetzt. Ziel dieser seroepidemiologischen Studie war es, das Infektionsrisiko für Klinikmitarbeiter eines Maximalversorgers zu evaluieren.

Methodik

Im Rahmen einer prospektiven Kohortenstudie wurden von März bis Juli 2020 (1. Welle) bei unmittelbar in der Versorgung von COVID‑19-Patienten eingesetzten Mitarbeitern im Abstand von jeweils 2 Wochen serologische Untersuchungen auf Antikörper gegen SARS-CoV‑2 durchgeführt. Von Dezember 2020 bis Februar 2021 (2. Welle) fand eine erneute Untersuchung des Antikörperstatus statt.

Ergebnisse

Die Seroprävalenz von Antikörpern gegen SARS-CoV‑2 betrug am Studienende im Februar 2021 5,1 %. Die kumulative Inzidenz betrug nach einer medianen Beobachtungsdauer von 261 Tagen 3,9 %.

Schlussfolgerung

In der untersuchten Kohorte von Klinikmitarbeitern, die in der Akutversorgung von COVID‑19-Patienten eingesetzt werden, fand sich unter den angewandten Hygiene- und Schutzmaßnahmen ein niedriges und mit der Gesamtbevölkerung vergleichbares Risiko einer SARS-CoV-2-Infektion.

MuSK-antibodies are associated with worse outcome in myasthenic crisis requiring mechanical ventilation

Myasthenic crisis (MC) is a life-threatening condition for patients with myasthenia gravis (MG). Muscle-specific kinase-antibodies (MuSK-ABs) are detected in ~ 6% of MG, but data on outcome of MuSK-MCs are still lacking. We made a subgroup analysis of patients who presented with MC with either acetylcholine-receptor-antibody positive MG (AchR-MG) or MuSK-MG between 2006 and 2015 in a retrospective German multicenter study. We identified 19 MuSK-AB associated MCs in 15 patients and 161 MCs in 144 patients with AchR-ABs only. In contrast to patients with AchR-AB, MuSK-AB patients were more often female (p = 0.05, OR = 2.74) and classified as Myasthenia Gravis Foundation of America-class IV before crisis (p = 0.04, OR = 3.25). MuSK-AB patients suffer more often from multiple chronic disease (p = 0.016, OR = 4.87) and were treated more invasively in terms of plasma exchanging therapies (not significant). The number of days of mechanical ventilation (MV) (43.0 ± 53.1 vs. 17.4 ± 18; p < 0.0001), days on an intensive care unit (ICU) (45.3 ± 49.5 vs. 21.2 ± 19.7; p < 0.0001), and hospital-length of stay (LOS) (55.9 ± 47.6 vs. 28.8 ± 20.9 days; p < 0.0001) were significantly increased in MuSK-MC. Remarkable is that these changes were mainly due to patients with MusK-ABs only, whereas patients' outcome with both antibodies was similar to AchR-MCs. Furthermore, our data showed a shortened duration of MV after treatment with plasma exchanging therapies compared to treatment with intravenous immunoglobulin in MuSK-MCs. We conclude that MuSK-AB-status is associated with a longer need of MV, ICU-LOS, and hospital-LOS in MC, and therefore recommend early initiation of a disease-specific therapy.