The Cerebral Palsy Network

Botulinum toxin injections -- commonly known as Botox therapy -- have become a very useful tool in the treatment of a number of neurological disorders. Botulinum toxin is a protein substance that is directly injected into muscle tissue in order to stop abnormal muscular contraction. It was first used and approved over ten years ago to treat strabismus (misalignment of the eyes). Since then, it has proven effective at treating blepharospasm and hemifacial spasm. It can also provide relief for a number of other neurological disorders characterized by abnormal muscle contraction, including spasmodic torticollis, oromandibular dystonia, and spasmodic dyphonia. Ongoing clinical trials continue to find new uses of Botulinum toxin, as well as a better understanding of its potential complications and contraindications (factors that make a procedure inadvisable).

What is Botulinum toxin?
Botulinum toxin is a protein that is produced by the anaerobic bacterium Clostridium Botulinum. C. Botulinum was once known only as the culprit of the often fatal food poisoning known as botulism, which can result from eating improperly canned foods. The bacteria causes muscle paralysis by blocking the presynaptic release of the neurotransmitter acetylcholine. Normally, acetylcholine plays a vital role in sending messages from the nerves to the muscles that "tell" the muscles to move. The area where the nerve meets the muscle is called the synapse, and "presynaptic release" refers to the secretion of acetylcholine by the nerve cell. When the synaptic transmission is blocked, the muscle to which that nerve is attached becomes paralyzed.

What is Botox therapy?
Botox therapy is the direct injection of the Botulinum toxin into a specific muscle, with the aim of blocking the transfer of acetylcholine and, in so doing, alleviating muscle spasm due to too much neural activity.

There are as many as seven different types of Botulinum neurotoxin, but only type A is in clinical use at this time. It is one of the most potent neurotoxins and, indeed, one of the deadliest substances to humans. Administered safely in small amounts, however, its therapeutic advantages have proven very promising. In patients suffering from any of a number of neurological disorders that lead to uncontrollable muscle spasm and contraction, the Botulinum neurotoxin can provide relief for anywhere from 6 weeks up to many months. Over time, it appears that neurons "resprout" from the paralyzed nerve ending terminals, providing new avenues of communication with the muscle. After the neurons resprout, the muscle returns to its previously abnormal state of constant spasm.

Because of the neurons’ ability to "resprout" and re-establish communication between the nerve and muscle, Botox therapy is only a short-term fix. It needs to be readministered regularly. Unfortunately, the long-term effects (greater than 5 years) of receiving regular injections are not known at this time. Nor has its safety been determined for pregnant women, women who are breastfeeding, or children who receive chronic therapy.

Following the injections, patients generally receive some form of physical or occupational therapy, which involves stretching the muscle to lengthen the tissue and improve its function.

Side Effects
Despite any alarm triggered by the word "botulism," the Botulinum toxin is a safe and effective agent when used appropriately by physicians who are professionally trained to use it. The doses required are tiny amounts, which are very carefully injected into specific muscles.

Even very small amounts of the toxin can, however, have undesirable side effects. The main side effect is weakness in the group of muscles that is being treated. Drooping of the eyelids (ptosis) for example, can develop when blepharospasm is treated. Muscular weakness is often short-lived though. Some patients develop flu-like symptoms, but this is relatively rare.

Other clinical conditions for which Botox therapy is regularly used
Botulinum toxin is accepted treatment for a number of neurological and ophthalmisc (eye) conditions. These include strabismus, blepharospasm, hemifacial spasm, spasmodic torticollis, oromandibular dystonia, and spasmodic dyphonia.

Strabismus - is a misalignment of the eyes; the eyes appear to be looking in different directions. There are several different types of strabismus, which is usually treated surgically. Botulinum toxin can be an effective alternative to surgery for many patients, although studies comparing botox therapy and surgery have not been done.

Blepharospasm - is the involuntary forceful closure of the eyelids. Usually the first symptom is uncontrollable blinking. Eventually the eyelids remain completely closed all the time, and even though the patient’s vision may be normal they are functionally blind. When accompanied by oromandibular dystonia, the condition is known as Meiges syndrome. Injections of Botulinum toxin into muscles in the face and periocular region (around the eye) has become the treatment of choice for patients with blepharospasm.

Hemifacial spasm - Hemifacial spasm is the sudden, simultaneous contraction of the muscles on one side of the face. The spasm can subside immediately or persist for several seconds and can occur several times a day. It can be painful and embarrassing. Botulinum toxin is an alternative therapy to oral medication and surgery.

Spasmodic torticollis - Spasmodic torticollis, also known simply as torticollis, is an asymmetric muscular spasm in the neck that results in forceful turning of the head to one side. Additionally, the head may be pulled forward or backward. It is the most common of the focal dystonias (a dystonia is a state of abnormal muscle tone; blepharospasm is another dystonia and, indeed, is the second most common focal dystonia). Torticollis can accompany other movement disorders and can be very painful.

Oromandibular dystonia - Oromandibular dystonia involves continuous, bilateral (both sides) spasms of the face, jaw, neck, tongue, larynx, and in severe cases, the respiratory system. It’s usually treated with various medications, although botox therapy has proven effective for certain cases. Because there are so many different muscles involved, the therapy requires multiple injections.

Spasmodic dysphonia - Spasmodic dysphonia is the sudden interruption of speech due to a spasm of the laryngeal muscles (the vocal cords). Botulinum toxin therapy has proven effective at ameliorating the symptoms and restoring speech fluency, although one kind of spasmodic dysphonia (abductor spasmodic dysphonia) poses an airway obstruction risk if certain muscles are injected.

Miscellaneous other conditions
Preliminary reports on a variety of other conditions suggest that Botulinum toxin therapy may be an effective treatment. Stuttering (speech characterized by repetitions of sounds and words) and vocal tremor (speech characterized by quavering), for example, may be treatable with Botulinum toxin. Botulinum toxin has also been used successfully for specific types of urinary incontinence.

Credit for this report goes to the Neurology Forum. Thankyou for your efforts to provide this information to others.

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Last updated 03/24/03

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