title: Breathing pattern and central ventilatory drive in mild and moderate generalised myasthenia gravis.
abstract: BACKGROUND
  Myasthenia gravis is a specific autoimmune disease characterised by weakness and fatigue. Respiratory muscle weakness has been studied using the determination of maximal respiratory pressures, but the response of respiratory centres is not well characterised. This study was undertaken to determine the breathing pattern and the central ventilatory drive in patients with mild and moderate generalised myasthenia gravis.
  
  
  METHODS
  Twenty four patients with myasthenia gravis were studied, divided into two groups. Group 1 included 13 subjects (eight women and five men aged 23-64) with mild generalised myasthenia gravis, and group 2 was composed of 15 patients (11 women and four men aged 23-69) with moderate generalised myasthenia gravis. A control group comprised 15 healthy persons with a similar age and sex distribution. Spirometric measurements and maximal respiratory pressures were performed under basal conditions in all subjects, and the rate and depth of breathing and the inspiratory occlusion pressure in the mouth in the first 0.1 second (P0.1) were measured.
  
  
  RESULTS
  No difference was detected for parameters of breathing pattern between patients in group 1 and control subjects, although P0.1 was higher in those in group 1. Subjects in group 2 had a lower tidal ventilation, shorter inspiratory time, and a higher frequency with a higher P0.1 than control subjects.
  
  
  CONCLUSIONS
  Mild myasthenia gravis causes increased neuromuscular drive with a normal breathing pattern. Moderate myasthenia gravis is characterised by a more rapid shallow breathing pattern.
authors.affiliation: Respiratory Services, La Paz Hospital, School of Medicine, Autonoma University, Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: García Río
authors.forename: C
authors.initials: C
authors.lastname: Prados
authors.forename: E
authors.initials: E
authors.lastname: Díez Tejedor
authors.forename: S
authors.initials: S
authors.lastname: Díaz Lobato
authors.forename: R
authors.initials: R
authors.lastname: Alvarez-Sala
authors.forename: J
authors.initials: J
authors.lastname: Villamor
authors.forename: J M
authors.initials: JM
authors.lastname: Pino
mesh_terms: D000328:Adult; D000368:Aged; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000188:drug therapy / Q000503:physiopathology* / Q000601:surgery; D011239:Prednisolone / Q000627:therapeutic use; D012132:Respiratory Muscles / Q000503:physiopathology*; D013934:Thymectomy; D013990:Tidal Volume / Q000502:physiology
chemical_list: D002800:Cholinesterase Inhibitors; D011239:Prednisolone