Clinical and electrophysiological features in a large cohort of myotonic dystrophy patients
Mailin Oliva1, Miguel Chuquilin Arista1
1University of Florida
Objective:
To describe clinical and electrophysiological characteristics of patients with myotonic dystrophy type I (DM1) and type II (DM2).

 

Background:

Myotonic dystrophy is characterized by different symptoms including cardiomyopathy, weakness, peripheral neuropathy, and myalgia. We reviewed the disease course of patients with DM1 and DM2 seen at our institution.

Design/Methods:

Retrospective chart review of DM patients seen at the University of Florida between 1995 and 2017. Clinical and electrophysiological features were analyzed. Chi-Square test was used for statistical analysis.

Results:
A total of 166 patients who had DM1 (n=143) or DM2 (n=23) were found. Symptom onset occurred on average earlier in DM1 (28.5 years) than DM2 (52 years). Most patients (n=165) presented with weakness (99.4%), and 80 had myalgia (48.2%). Prevalence of myalgia was significantly different between DM1 (44.8%) and DM2 (69.5%) patients (p=0.026). Neuropathy symptoms (numbness and tingling of the extremities) were more prevalent in DM2 (34.7%) than DM1 (12.6%) (p=0.0065). There was no significant difference in prevalence of sleep (excessive daytime somnolence, poor sleep) or cardiac (angina, palpitations, arrhythmia and/or EKG conduction disturbances) symptoms between DM1 (74.78% for sleep, 55.2% for cardiac) and DM2 (73.9% for sleep and 39.1% for cardiac) (p=0.926 and 0.15 respectively). Pulmonary function testing (n=64 patients) showed a restrictive pattern in 55.2% and 50% of those tested with DM1 and DM2 respectively. Electromyography was performed on 64 patients, and all 16 with DM2 had myotonic discharges compared to 87.5% of 48 with DM1.
Conclusions:

Disease onset occurs later and sensory neuropathy symptoms and myalgia are more prevalent in patients with DM2 than DM1. Up to a half of myotonic dystrophy patients can exhibit restrictive pulmonary pattern. This study provides a stronger understanding of the DM disease presentation and course in a large patient population.