Botulism Germ Eases Problem of Swallowing By Michael Purdy A deadly toxin made by food-poisoning bacteria can help people who have trouble swallowing food, according to a new study at the Johns Hopkins Medical Institutions. Hopkins physicians injected small amounts of botulinum toxin, produced by the germ that causes botulism, to treat patients with achalasia, a disorder that prevents food from entering the stomach. The disorder affects the lower esophageal sphincter, a ring of muscle that normally relaxes to let food into the stomach. In achalasics, this muscle remains contracted and blocks the passage of food. The disorder afflicts 1 in 10,000 people. Results of the new study, published in the March 23 issue of the New England Journal of Medicine, show that the treatment brought immediate relief to 19 of 21 achalasia patients treated in the study. For two-thirds of the patients, relief lasted at least six months. Botulinum toxin blocks the chemical signals that nerves send to muscles, in effect paralyzing the muscles. Doctors have previously used the toxin to treat spasms of muscles under conscious control, like muscles in the neck and the eyelids. The new Hopkins study is the first example of the technique being applied to smooth muscles--muscles not under conscious control. "These results are very encouraging," said Pankaj Pasricha, assistant professor of medicine and primary author of the report. Dr. Pasricha plans to test whether larger amounts of toxin will provide patients with longer relief and whether patients build up resistance to the toxin after many treatments. For the study, Dr. Pasricha first threaded a special viewing instrument called an endoscope into the esophagus, the tube leading from mouth to stomach. He then used a long needle to inject either a placebo or botulinum toxin into the lower esophageal sphincter. These muscles normally relax to let food enter the stomach but stay contracted at all other times to keep food from coming back up. "This failure to relax causes swallowing difficulty, regurgitation, and complications like weight loss, food in the lungs and, eventually, weakening of the esophagus's ability to pump food," Dr. Pasricha said. "Patients are miserable." Surgical treatments for achalasia are available, but they can sometimes leave the sphincter too weak to prevent stomach acid from coming back up from the stomach. In contrast, botulinum toxin injection, a non-surgical, outpatient procedure, relaxes the sphincter without disabling it completely. Dr. Pasricha's study of botulinum toxin was funded by the American Society of Gastrointestinal Endoscopy, the American College of Gastroenterology and the Johns Hopkins General Clinical Research Center. Co-authors on the study were William Ravich, Thomas Hendrix, Samuel Sostre, Bronwyn Jones and Anthony M. Kalloo, all of the Division of Gastroenterology.
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