Botox injection

Botox is the commercial name of Botulinum toxin, which is a toxin produced by clostridium botulinum. It is the most poisonous biological substance known to man. Historically, it was found to be the cause of 'botulism' which is a paralytic condition, caused by infection with the spores or by food poisoning. The fact that the toxin causes paralysis- or in scientific terminology, inhibition of neuromuscular transmission leading to weakness of muscles, led to further discovery and the emergence of botox as a therapeutic tool. Now botox is used in the treatment of many conditions like squint, cramps, anal fissure etc and in a more sensational manner- for the disappearance of wrinkle lines.

How does botox act?

To understand the mode of action of botulinum toxin, one must know a little about what is called the neuro muscular junction. In human body, muscles are supplied by nerves by of the neuromuscular junction, where each nerve fibre ends as a small bulbous tip (called the nerve terminal) in to a small cup shaped receptacle in the muscle. The nerve transmission in this synapse is by means of release of chemicals called the neurotransmitters which combines with receptors on the muscle end thereby transmitting the nerve signal. Acetylcholine is the principal neurotransmitter at the NM junction.

Botulinum toxin has seven serotypes which all can irreversibly block the release of acetyl choline by the nerve terminal at the neuromuscular injection, blocking the synaptic transmission thereby making the muscle weak. Although the block is irreversible, the nerve terminals can sprout creating new neuromuscular junctions- which is why there is need of repeated injections when botox is used for treatment. Other than neuromuscular junctions, the toxin also acts in the nerve terminals that supply certain glands and hence can be used in condition where there is over-activity (for example in over-activity of sweat glands).

What should one know about botox injection?

Of the seven serotypes, serotype A is widely used. It is commercially available in the name of 'Botox' in US and 'dysport' in the UK. It is injected in the muscles or glands that are to be weakened- for example in an overactive gland. the dose depends on which commercial preparation is used, the bulk of the muscle to be injected, the strength of the muscle and stature of the patient. Injection is usually done with the help of electromyography.

Once injected, the effect may last from weeks to months, producing significant improvement in cosmetic appearance (wrinkles or squint) or function . However,after around 3 months, the effects decline, necessitating further doses.Thus the patients who are treated are usually carefully followed up. Over the years,repeated doses may lead to tolerance where increasing amount of the toxin is needed to bring upon the same effect- which can be due to emergence of antibodies- the body's natural defense mechanism against any foreign substance administered. So the choice of dose and frequency of Botox needs crucial medical judgement.The use of other serotypes is being explored in cases of tolerance.

Indications of botox:

Botox is finding its place in the treatment of an ever increasing list of condition. The conditions in which botox is used in a fairly successful manner are

1. Eye

• Squint: Botox injection is used to improve the alignment of eye , the effect can be both cosmetic and functional. It is also used in addition to surgery. The side effects can be transient weakness in opening eyes, double vision bleeding etc.
• Blepharospasm (involuntary closure of eyes)
• Thyroid eye disease.

2. Wry neck

• In wry neck or torticollis: Botox can give significant pain relief, improvement in head position and function. The most common side effect is a transient difficulty in swallowing which improves soon.

3. Spasm of muscles around head, neck, face , vocal cords, bladder etc

• Jaw opening and closing spasm : symptomatic improvement and prevention of complications.
• Vocal cord spasms: improvement of voice. side effects can be a transient voice change or hoarseness.
• Hemifacial spasm: Gives significant improvement. Side effect is a transient weakness of facial muscles.

4. Writer's cramp and musician's cramps.

5. Tics and tremors

• simple tics and Tourette's syndrome
• tremors

6. Parkinson's disease.

7. Spasticity:

• In children with spasticity,treatment in infancy and toddlerhood helps in walking and avoids contractures.
• in spasticity following stroke

8. Pelvic floor muscle spasm :

9. Experimentally in improving symptoms in prostate enlargement.

10. Long standing anal fissure: can be an alternative to surgery (sphincterotomy).

11. Hypersecretion of glands like excessive sweating of underarms, hand etc

12. Achalasia : used endoscopically to improve symptoms in achalasia.

13. Pain relief:

• Head ache: tension type or migraine
• Chronic low back pain
• Tennis elbow.

14. Cosmetic:

• improving frown lines
• improving wrinkles
• improving neck appearance.

Side effects of botox:

Usually botox injections are well tolerated. However the following side effects can occur:

1. Weakness of adjacent muscle: The muscles adjacent to the ones injected can remain weak which is usually transient. For example in case of wry neck, the patient may have difficulty in swallowing for a transient period of time. Unusually a generalised weakness can appear which is fortunately very rare.
2. Flu like illness: with general malaise, head ache or body ache.
3. Allergy - which is rare
4. Gall bladder dysfunction.
5. Brachial plexopathy- which is an immune mediated weakness of arms
6. Necrotising fasciitis- which is a rare but serious condition.

Remember:

Botox or Botulinum toxin is a potent and relatively safe drug.

Its effects are reversible and repeated sessions may be necessary.

Botox is being used in many conditions which previously only responded partially to medical treatment or surgery.

However in many conditions the use of Botox is only in experimental stages and further experience is needed before it could be used widely.