Identification of sleep hypoventilation in young individuals with Becker muscular dystrophy: A pilot study

Abstract

AimTo report on sleep hypercapnia in Becker muscular dystrophy (BMD) at earlier stages than ever recognized. Subjects and methodsThis retrospective study examined nocturnal hypercapnia in six young Becker muscular dystrophy (BMD) patients with deletions of one or more exons of DMD gene. Clinical information, consecutive data on forced vital capacity (FVC%), forced expiratory volume in one second (FEV1%), peak expiratory flow (PEF%), peak cough flow (PCF), average PCO2 in all-night monitoring, and left ventricular ejection fraction (LVEF) were reviewed. ResultsIn five BMD patients, including three who were still ambulant, nocturnal average PCO2 was elevated to >45 mmHg at 12–31 years of age. Noninvasive positive pressure ventilation was initiated in four patients. Gradual declines in FVC% and PEF% were evident in one BMD patient with exon 3–7 deletion, whereas these functions did not change in the remaining BMD patients. PCF, FEV1%, and LVEF were less informative for the assessment of respiratory function in this patient series. ConclusionSleep hypercapnia was present in certain BMD patients, which was unexpected from the routine pulmonary function tests. Individualized assessment of nocturnal PCO2, partly based on the deletion types, should be further explored in the clinical practice of BMD patients.