Esophageal impaction in BHE rats.

Spontaneous esophageal impaction was observed in 33 BHE rats, aged 6 to 26 months, from 157 rats which died or were killed when moribund due to spontaneous conditions. The clinical course lasted less than 48 hours and included weakness, excessive salivation, forward head motions, matting of chin and perioral hair with bedding material, followed by recovery or death. In some animals, the clinical episodes reoccurred. The esophagus was dilated (up to 7.0 mm) and impacted with bedding or food. The caudal half of the esophagus was affected more than the cranial half. The esophageal muscle was thin and pale at the site of impaction. Histologically, there was esophageal myodegeneration.