Respiratory function and sleep in children with myotonic dystrophy type 1

Myotonic dystrophy type 1 (Steinert disease): 29 years of experience at a tertiary pediatric hospital

BACKGROUND

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder caused by the expansion of a noncoding triplet repeat.

METHODS

A cross-sectional study was performed to characterize pediatric patients with DM1 followed in a tertiary hospital over the last 29 years, comparing the congenital and the childhood/juvenile-onset forms.

RESULTS

Thirty-seven patients (59.5 % male) were included, with a median age at the latest assessment of 16.8 years and a median follow-up of 7.7 years. Eleven patients were lost to follow-up, and two died. Twenty-five had congenital DM1 (CDM1), and this form had significantly higher triplet repeat length, history of polyhydramnios, lower median age at diagnosis, and first and last assessment. Common symptoms included distal skeletal muscle weakness (75.7 %) and facial involvement (94.6 %), along with dysphonia/dysarthria (73.0 %) and myotonia (73.0 %). Delayed independent ambulation frequency was significantly higher for CDM1 cases. Skeletal deformities affected 54.1 %, with talipes equinovarus and scoliosis occurring exclusively in CDM1 patients. Cognitive deficit was present in 75.7 % of cases. Polysomnograms revealed seven cases of obstructive sleep apnea and two of hypoventilation. Noninvasive ventilation was used in nine cases, and three had recurrent respiratory infections. The cardiovascular system was affected in 21.6 % of cases. Gastrointestinal issues included constipation (24.3 %), feeding difficulties (16.2 %), and cholelithiasis (5.4 %). Cataracts, epilepsy, and diabetes mellitus were reported in two cases each.

CONCLUSION

Our study highlights the diverse spectrum of severity and multiorgan involvement of DM1 in pediatric patients. It underscores the importance of establishing a pediatric-specific standard of care to enhance health outcomes through comprehensive multidisciplinary management.

Sleep in pediatric neuromuscular disorders

Sleep disordered breathing (SDB) is prevalent among children with neuromuscular disorders (NMD). The combination of respiratory muscle weakness, altered drive, and chest wall distortion due to scoliosis make sleep a stressful state in this population. Symptomatology can range from absent to snoring, nocturnal awakenings, morning headaches, and excessive daytime sleepiness. Sequelae of untreated SDB includes cardiovascular effects, metabolic derangements, and neurocognitive concerns which can be compounded by those innate to the NMD. The clinician should have a low threshold for obtaining polysomnography and recognize the nuances of individual disorders due to disproportionately impacted muscle groups such as hypoventilation in ambulating patients from diaphragm weakness. Non-invasive or invasive ventilation are the mainstay of treatment. In this review we explore the diagnosis and treatment of SDB in children with various NMD.