Muscle ultrasound as a tool for respiratory assessment in patients with LAMA2-MD

Background: LAMA2-muscular dystrophy (LAMA2-MD) is an autosomal recessive disease, and the most common form of congenital muscular dystrophy (CMD). Most of the patients develop a form of disease characterized by inability to achieve walking capacity, multiple joint deformities, respiratory insufficiency, and some degree of dysphagia. However, there is a gravity spectrum, and some patients never achieve sitting position, while others can walk unassisted. There are still no adequate biomarkers to assess disease progression, and muscle ultrasound can be a useful tool, and also complement the assessment of respiratory and swallowing function.

Objective: Evaluate, through muscular ultrasound, the function of the respiratory muscles, tongue muscles and correlate them with respiratory function, degree of dysphagia, disease severity and age.

Methods: Ten patients with genetically confirmed LAMA2-MD were divided according to motor severity and evaluated. Muscle ultrasound of tongue, respiratory and paravertebral muscles were made. For muscles comparable to bone echo, the 4-point Heckmatt scale was used, for the others the classifications were hypoechoic, slightly hyperechoic, or very hyperechoic. Patients underwent respiratory function assessment and underwent neuromuscular disease swallowing status scale (NdSSS).

Results: 2 patients had severe presentation and were not able to sit without support. They presented geniohyoid and genioglossus muscles very hyperechoic, had level 3 NdSSS dysphagia and required gastrostomy. They both had very affected external oblique, internal oblique and transverse muscles, but presented normal diaphragm, with normal thickening. They had altered polysomnography. 4 patients had maximum motor ability to sit without support and were under six years old. They presented geniohyoid and genioglossus muscles slightly hyperechoic, affected external oblique muscle with normal internal oblique and transverse muscles and normal diaphragm, with normal thickening. They all had total lung capacity (TLC) above 50% and level 7 NdSSS. 3 patients had classic disease presentation but were older than twelve years old. They presented geniohyoid and genioglossus muscles highly hyperechoic, affected external oblique, internal oblique and transverse muscles, with normal diaphragm, with normal thickening. They all had TLC below 35% and level 7 NdSSS.

Conclusions: US can be used as a tool to evaluate disease progression and contribute to the assessment of respiratory function and dysphagia in LAMA2-MD.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
18 September 2023