Children
suffering from cerebral palsy can experience long-term and significant
improvements in their condition by taking injections of purified botulinum
toxin, researchers report.
"We analyzed
approximately 10 years of treatment information from our clinic, where
we treat a large number of children with cerebral palsy," said Dr. Marc
DiFazio, chief of the child and adolescent neurology service at Walter
Reed Army Medical Center in Washington, D.C. "We were able to show that,
over long periods and with multiple treatments, children had continued
beneficial effects with the medication."
The children
also had no serious side effects from the injections, DeFazio told United
Press International.
He presented
the research at the annual meeting of the American Academy of Neurology.
Unprocessed
botulinum toxin is the most poisonous substance known. However, botulinum
toxin in a purified and injectable form can be used safely to control a
number of conditions marked by involuntary muscle contractions.
When the purified
toxin is injected at the site of involuntary contractions, DeFazio explained,
it binds to nerve endings at the point where nerves join muscles. This
temporarily prevents the nerves from signaling the muscles to contract,
resulting in muscle relaxation.
The effect of
one set of injections can last for up to four months, he said.
The Food and
Drug Administration approved purified botulinum toxin -- marketed as Oculinum
-- in December 1989 for treatment of two eye conditions characterized by
excessive muscle contractions. The medication now is marketed under the
trade name Botox and is widely used "off-label" -- that is, it can be prescribed
at a physician's discretion without specific FDA approval for a variety
of therapeutic and cosmetic purposes.
Cerebral palsy,
or CP, is a term used to describe a group of chronic illnesses that impair
control of the muscles. It appears in the first few years of life and,
although it generally does not worsen over time, at present it has no cure.
"Following the
initiation of treatment some of the children could begin for the first
time to do things for themselves," DeFazio said. This included "feeding
themselves, using a pen to write for the first time or 'talking' with a
computer touch screen."
He adding that
with ongoing injections, most of the children were able to maintain the
gains they had realized after beginning the treatment. "The changes might
appear to be small to those who can walk or move without impairment," DeFazio
said, "but for those with cerebral palsy, they can be life-changing, both
for the children and their families."
His team analyzed
the medical records of 250 subjects, ages 1 to 16, who had been diagnosed
with CP and who had received botulinum toxin injections at Walter Reed.
Of the children in the group, 206 received multiple injections.
The researchers
tracked the progress of 148 of the children, who averaged age 2, for one
year. The result: 86 percent showed significant improvement, verified by
videotape analyses, physician evaluations, spasticity ratings and family
questionnaires.
"Parents were
typically quite pleased with the results after treatment, with approximately
90 percent reporting that their children continued to demonstrate improvement
after multiple injections," DiFazio said.
Over 80 percent
of the children tracked beyond two years of multiple injections continued
to demonstrate improvement over pre-treatment symptoms. The improvements
often were sustained longer than four months after an injection, the researchers
noted.
They said side
effects were mild and uncommon, consisting mostly of rare, flu-like symptoms
or temporary and localized muscle weakness. Drug resistance was rare.
"It is so good
to see research that will translate immediately and so crucially into the
care of these children," Nancy Clegg, a brain malfunction researcher at
Texas Scottish Rite Hospital for Children in Dallas, told UPI. "Almost
all of the children I see have cerebral palsy and, in many cases, Botox
will help a kid really be a kid for the first time."
--
Copyright 2003 by United
Press International.
All rights reserved.
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