Small intestinal motility in myotonic dystrophy patients.

We performed jejunal manometric studies on 10 myotonic dystrophy patients who had symptoms of disordered gastrointestinal motility. Reduced peristalsis of the duodenum and proximal jejunum was noted in 1 patient who had an upper gastrointestinal series, but the small bowel was radiographically normal in 8 other patients. None of the myotonic dystrophy patients had a normal jejunal manometry. The abnormalities included low amplitude contractions during phases 2 and 3 of the migrating motor complex and after eating, as well as a higher frequency of contractions during phase 2. Retrograde propagation of phase 3 occurred in 2 patients, and interruption of contractions during phase 3 occurred in 4 patients. The incidence of tonic contractions was also higher in myotonic dystrophy patients. We conclude that (a) abnormal small intestinal motility is common in patients with myotonic dystrophy and (b) jejunal manometry is more sensitive than barium radiographic studies in detecting small intestinal motility abnormalities in this disorder.