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.