Drug-induced esophageal injury - Histopathological study in a rabbit model

The purpose of this animal study was to investigate the histopathologic consequences of esophageal exposure to a variety of medications known to be injurious to the human esophagus. Twenty-four New Zealand white rabbits were utilized. Tablets or control plastic beads were secured to a silk suture thread and positioned in the rabbit esophagus through a proximal esophagostomy and a gastrostomy. Test medications were allowed to dissolve passively on the surface of the esophageal mucosa in the anesthetized rabbits. After 1 hr of drug exposure, the rabbits were killed and the esophagus removed and examined. No gross abnormalities were detected with the exception of a mild degree of erythema at some of the exposure sites. All medications and control beads produced microscopic mucosal changes when compared to suture controls. The beads and test medications caused thinning of the epithelium and increased subepithelial edema (P < 0.05). Two changes, however, were unique to animals exposed to test medications: fraying and/or splitting of the epithelium and the presence of balloon cells (P < 0.05). Balloon cells represent damaged squamous epithelial cells recognizable by their distended, globoid shape. The prevalence of balloon cells ranged from 22% to 89% of sites exposed to drug and was most commonly associated with potassium. Of all drugs reported to cause injury to the human esophagus, potassium chloride has been reported to produce the most severe lesions, including esophageal stricture and perforation. The finding of balloon cells associated with all test drugs, in contrast to their absence in specimens exposed to control suture and beads, provides strong indication that balloon cells are an early marker of chemical injury.