Ultrasound imaging of the abdominal muscles may help in the differential diagnosis of late-onset Pompe disease (LOPD) from myotonic muscular dystrophy type 1 (DM1), according to a study.
Patients with LOPD had significantly reduced abdominal muscle thickness compared to patients with DM1 (P =.028). Two-thirds of the abdominal muscles in the patients with LOPD were observed to have severely increased echogenicity (Z score >4) compared to only 11.25% in the DM1 group.
The findings were published online in the journal Frontiers in Neurology.
“Our study suggests that muscle ultrasound could be an efficient screening tool [for] assessing myopathic changes and disease-specific patterns that could help physicians with differential diagnosis of neuromuscular diseases. Trunk muscles could offer a preliminary opportunity for a differential diagnosis between LOPD and DM1,” wrote Hung-Chou Kuo, of the Chang Gung University College of Medicine in Taoyuan, Taiwan, and colleagues.
Read more about Pompe disease differential diagnosis
The researchers assessed patients with LOPD. The cohort of LOPD patients consisted of all men, who were between 24 and 31 years of age. The study cohort also included 10 patients with DM1, of whom there were 7 women and 3 men with ages ranging from 23 to 59 years. All patients underwent ultrasonography as well as muscle testing.
When comparing individual abdominal muscles, the bilateral rectus abdominis, external oblique, and transverse abdominis, as well as the left internal oblique muscles, had significantly different Z scores between the LOPD and DM1 groups.
In contrast to the abdominal muscles, muscles of the extremities were relatively unaffected in the patients with LOPD with the biceps brachii and triceps having normal and relatively normal values, respectively. Most patients with DM1 had increased echogenicity of the biceps and triceps, in contrast. Flexor digitorum profundus and superficialis muscles were largely unaffected in patients with LOPD, but mild to moderately affected in patients with DM1.
The rectus femoris muscles were found to be abnormal in both patient groups with most patients with LOPD having moderate to severe increases in echogenicity while patients with DM1 varied from mild to severe increases. Tibialis anterior muscles were mostly unaffected in patients with LOPD but moderately to severely affected in patients with DM1.
The ultrasonographic values were also found to be correlated with motor function of the trunk muscles including abdominal muscle strength, Medical Research Council sum score, trunk control test, and trunk impairment score total scores.
Hsieh PC, Chang CW, Ro LS, Huang CC, Chi JE, Kuo HC. Ultrasonography of abdominal muscles: differential diagnosis of late-onset Pompe disease and myotonic dystrophy type 1. Front Neurol. 2022;13. doi:10.3389/fneur.2022.944464