Lack of correlation between the ventilatory response to CO2 and lung function impairment in myotonic dystrophy patients: evidence for a dysregulation at central level.
Myotonic dystrophy Type 1 (DM1) is the most common muscular dystrophy in adults. Respiratory failure is common but clinical findings support a dysregulation of the control of breathing at central level, furthermore contributing to alveolar hypoventilation independently of the severity of respiratory weakness. We therefore intended to study the relationship between the ventilatory response to CO2 and the impairment of lung function in DM1 patients. Sixty-nine DM1 patients were prospectively investigated (43.5 ± 12.7 years). Systematic pulmonary lung function evaluation including spirometry, plethysmography, measurements of respiratory muscle strength, arterial blood gas analysis and ventilatory response to CO2 were performed. Thirty-one DM1 patients (45%) presented a ventilatory restriction, 38 (55%) were hypoxaemic and 15 (22%) were hypercapnic. Total lung capacity decline was correlated to hypoxaemia (p = 0.0008) and hypercapnia (p = 0.0013), but not to a decrease in ventilatory response to CO2 (p = 0.194). Ventilatory response to CO2 was reduced to 0.85 ± 0.67 L/min/mmHg and not correlated to respiratory muscle weakness. Ventilatory response to CO2 was neither different among restricted/non-restricted patients (p = 0.2395) nor among normoxaemic/hypoxaemic subjects (p = 0.6380). The reduced ventilatory response to CO2 in DM1 patients appeared independent of lung function impairment and respiratory muscle weakness, suggesting a central cause of CO2 insensitivity.
Department of Pulmonary Function Testing and Exercise Physiology, CHU Nancy, Nancy, F-54000, France; EA 3450 DevAH - Development, Adaptation and Disadvantage, Cardiorespiratory Regulations and Motor Control, Université de Lorraine, F-54505, France. Electronic address: m.poussel@chu-nancy.fr.
Mathias
M
Poussel
Department of Pulmonary Function Testing and Exercise Physiology, CHU Nancy, Nancy, F-54000, France; Pulmonology Department, CHU Nancy, Nancy, F-54000, France.
Catherine
C
Thil
EA 3450 DevAH - Development, Adaptation and Disadvantage, Cardiorespiratory Regulations and Motor Control, Université de Lorraine, F-54505, France; Department of Internal Medicine, CHU Nancy, Nancy, F-54000, France; Reference Centre in Neuromuscular Diseases, CHU Nancy, Nancy, F-54000, France.
Pierre
P
Kaminsky
Pulmonology Department, CHU Nancy, Nancy, F-54000, France.
Magalie
M
Mercy
Pulmonology Department, CHU Nancy, Nancy, F-54000, France.
Emmanuel
E
Gomez
Pulmonology Department, CHU Nancy, Nancy, F-54000, France; EA-7298 INGRES, Université de Lorraine, F-54505, France.
Ari
A
Chaouat
Pulmonology Department, CHU Nancy, Nancy, F-54000, France; EA-7298 INGRES, Université de Lorraine, F-54505, France.
François
F
Chabot
Department of Pulmonary Function Testing and Exercise Physiology, CHU Nancy, Nancy, F-54000, France; EA 3450 DevAH - Development, Adaptation and Disadvantage, Cardiorespiratory Regulations and Motor Control, Université de Lorraine, F-54505, France.
Bruno
B
Chenuel
D000328:Adult; D002245:Carbon Dioxide / Q000502:physiology; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000139:chemically induced; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000150:complications* / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012131:Respiratory Insufficiency / Q000150:complications* / Q000503:physiopathology*; D012132:Respiratory Muscles / Q000503:physiopathology*
D002245:Carbon Dioxide
Control of breathing; Lung function; Muscle; Myotonic dystrophy