Poison cures

A poison used in chemical warfare is being used to treat children with cerebral palsy

Published: Friday 15 August 1997

botulinum , a toxin developed for che-mical warfare and strong enough to kill 10,000 humans with a teaspoonful, is being tested as a treatment for handicapped children in St James University Hospital, Leeds, uk. The toxin causes botulism, a form of food poisoning that leads to paralysis. One in four of those affected by the poison die if they are not treated with an antitoxin. The poison blocks nerve transmission and weakens or paralyses muscles.

After attracting the attention of experts on chemical warfare, it is being tested as a treatment for victims of cerebral palsy. Doctors say that the toxin could be injected in tiny amounts to relieve ailments caused by involuntary contraction of muscles such as blepharospasm (in which the eyes are repeatedly screwed up), squinting, and torticollis, which leads to the head being pulled over to one side.

In a pilot trial carried out in Leeds, 20 children with cerebral palsy were given the toxin. Improvement was noted in 18 and the situation of the other two did not deteriorate. But it has not been established that the improvement noticed was due to the treatment with the toxin. Doctors are unclear about how the toxin works. "It is the most lethal toxin around, yet its potential is amazing," says Tim Ubhi, coordinator of the study. "It is the biggest advance in the treatment of cerebral palsy for decades. People have been using it ad hoc for some time, but we have no firm evidence that it works."

Cerebral palsy causes contraction of muscles in children making it difficult for them to walk. Injection of the toxin relaxes the muscles and can also promote growth in children. "The evidence is that it works on selected children but it is not a catch-all solution. It is potentially a very exciting treatment but we have to be cautious," says Richard Parnell, research officer at Scope, a charity organisation for children with cerebral palsy.

To study the effects and understand the working of the toxin in greater detail, 50 children with cerebral palsy will be selected at the Leeds hospital. Half of them would be injected with the toxin. The injections will be so coded that neither the doctors nor the parents nor the children find out which children are receiving the treatment. The code will be broken after three months and the toxin will be administered to those children who did not receive it. This study will confirm the effects of the toxin and will determine its future uses.

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