[Congenital neuromuscular diseases with neonatal respiratory failure excluding myotonic dystrophy type 1 and infantile spinal muscular atrophy. Diagnosis strategy according to a 19-child series].

UNLABELLED: Apart from spinal muscular atrophy (SMA) and myotonic dystrophy type 1 (DM1), congenital neuromuscular diseases with early neonatal symptoms mean diagnostic and prognostic challenges mainly when infants require ventilatory support.

OBJECTIVES: Consider a standardized strategy for infants suspected of congenital neuromuscular disease from analysis of the literature and retrospective experience with floppy and ventilatory support-dependent infants, after exclusion of well-known diseases (DM1, SMA).

PATIENTS AND METHODS: Floppy infants requiring ventilatory support in their 1st month of life, but showing no evidence of DM1, SMA, Prader-Willi syndrome, or encephalopathy. The retrospective multicenter study was based on the response of regional referent neuropediatricians in the Reference Centre for Neuromuscular Diseases of Greater Southwest France to an inquiry about prenatal and perinatal history, investigations, diagnosis, and outcome of the child and family. It was conducted between 2007 and 2012.

RESULTS: Among the 19 newborns studied, all had severe hypotonia. Prenatal and perinatal features were similar. Their outcome was generally severe: the median survival as measured by the Kaplan-Meier method was 6.9 months. Thirteen children died at a median age of 61 days; ten of them were treated with a palliative procedure. Five children had achieved respiratory independence but suffered from a small delay in motor development. Among the three children who continuously required ventilatory support, only one survived (follow-up period: 23 months); he was the only one undergoing tracheostomy in the cohort. Diagnostic processes were different, leading to pathological and genetic diagnosis for only six infants. There was only histological orientation for seven and no specific diagnostic orientation for the last six. These difficulties have led us to propose an exploration process based on the literature.

CONCLUSION: This study highlights difficulties in obtaining a diagnosis and a precise prognosis for floppy ventilated infants. An exploration-standardized process for infants suspected of congenital neuromuscular diseases was made in order to standardize procedures. It could be used as a tool for all professionals involved.