Botulinum toxin and hemiplegia

10 mins read

Botulinum toxin (also known as Botox) injections are frequently offered to children with hemiplegia as part of their movement therapy programme. They act to reduce the stiffness or 'spasticity' of the muscles, improving range and function and decreasing discomfort.

In this article

What is botulinum toxin?

Botulinum toxin (also known as Botox) injections are frequently offered to children with hemiplegia as part of their movement therapy programme. They act to reduce the stiffness or ‘spasticity’ of the muscles, improving range and function and decreasing discomfort.

You may have been referred by your child’s physiotherapist or paediatrician to a team of health professionals to be assessed for botulinum toxin treatment. This team will have set realistic, individual and functional goals for your child. If you all agree that botulinum toxin would be beneficial, you will be given a date for your child’s admission to hospital as a day case.

This information has been written to help you understand why your child has been recommended botulinum toxin, and also answer common queries about how it works, side effects and possible safety concerns. We hope it will leave you feeling prepared, informed and better able to support your child through the process.

How do the injections work?

Children with hemiplegia have problems controlling movement. The brain is unable to control muscle activity by telling the reflexes to turn off. Because of these problems, some muscles have difficulty coordinating movement and generally lack the ability to relax.

Botulinum toxin reduces the stiffness of these muscles by preventing the nerve from over-stimulating the muscle. This allows tight muscles to relax, so that they can stretch and grow. Doing this may help to reduce the risk of permanent stiffening of the joints and help control pain.

In upper limbs, botulinum toxin treatment can improve the appearance of the affected arm and hand, which can be very important to children. It can be used to try and improve reaching and grasping and reducing thumb in palm position. Although botulinum toxin is not licensed for use in the upper limb (the child’s arm, wrist or fingers), it is prescribed by doctors because it can be a useful treatment as it allows them to be stretched. You can read more about this kind of ‘accepted unlicensed use’ below.

In the leg it is most often used in calf (where its use is licensed) and hamstring muscles by reducing knee flexion and foot posturing (such as toe walking or intoeing) and so promoting a more balanced and fluid gait. Splints are often better tolerated once the foot is more relaxed. You can read more about the treatments that are often used alongside botulinum toxin below.

These improvements to function and comfort may allow surgical intervention to be delayed or even avoided in some children.

How do I know if botulinum toxin injections are right for my child?

The key to finding the right treatment for children with hemiplegia is to consider each child as an individual within their family environment. Different treatments will be appropriate at different times for different children. Your child’s age, degree of motor difficulties and functional abilities must guide the decision as to whether botulinum toxin injections are appropriate.

How can I prepare for the treatment?

The aim of these interventions is to maximise the effect of the injections. They are likely to involve significant commitments of time and effort so it is important that you and your child feel prepared and informed.

It is also important to try and manage your expectations of the treatment and be aware that the effects can never be guaranteed. It is disappointing for everyone when the treatment is not as successful as hoped or when beneficial effects start to wear off. Make sure you talk to the team in charge of your child’s treatment and have clear, realistic expectations about what is involved and what the outcomes might be.

What happens on the day of treatment?

Every hospital and unit will have their own way of working and so procedures are likely to vary. Make sure you ask your doctor about anything that you’re not sure of at the assessment.

It is important to minimise the emotional impact of having injections for your child, and appropriate sedative medication should be discussed. Some children may need a general anaesthetic, but others will prefer a local anaesthetic, often combined with some sedation. Most children prefer a degree of sedation, but what is right for your child will depend on your and their feelings. Sedation can be given by mouth, intravenously or inhaled. Again, discuss the options with the team helping you with your child.

Some practitioners will use ultrasound scanning or other ways of guiding needle placement, but not all teams routinely provide this. It will depend on the individual practitioner and unit. However, the medical team involved should always have experience in the management of hemiplegia and the administering of botulinum toxin.

What happens after the injections?

It is usual for you to go and see your child’s treatment team again about one month after the injections are performed. This is to see whether there should be any other changes to the movement programme. You will then usually be seen again between two and six months after this to discuss ongoing management.

The frequency and timing of injections depends on the individual child and the assessing team. Generally, where they are beneficial, injections are repeated annually until benefit is no longer seen.

Continuation of botulinum toxin therapy depends on whether the functional goals that were set during the assessment were reached during the treatment period. Treatment should be stopped if no improvements are seen.

How long do the effects of botulinum toxin last?

Botulinum toxin takes effect gradually within a few days to a few weeks. The peak of muscle relaxation occurs after about one month. The muscle activation is back to its previous levels four months after the injection. However, the benefits seen in daily use of the limb may actually last longer as the muscle has had a good long period of being stretched during physiotherapy. The improvements can therefore last for anything up to a year.

How do botulinum toxin injections work with other treatments?

Botulinum toxin injections are not a stand-alone treatment and should only be considered as part of a wider management programme. Botulinum toxin treatment works by reducing muscle tone, allowing the muscles in the targeted area to relax for approximately 12-16 weeks.

In order to make the most of this ‘window of opportunity’, your child’s therapy plan should carefully consider what other treatment options can be used during this time. This could include serial casting of a joint, splinting, occupational therapy and physiotherapy. This focused combination of treatments aims to improve motor skills and can bring about meaningful benefits for individual children.


Unless your child is in pain, it is particularly important that there is a period of muscle strengthening after the injections. The Association of Paediatric Chartered Physiotherapists (APCP) have produced their own guidelines on post-botulinum toxin treatment programmes.

Your child’s physiotherapist will be able to advise you of the type and frequency of physiotherapy required. It is important to focus on strengthening muscles, just as much, if not more than stretches.

Occupational therapy

An occupational therapist might also be able to recommend some specific changes to your child’s daily routine in order to incorporate greater involvement of the treated muscles. It is generally accepted now that a pulse of specific therapy after injections is very beneficial.


Splinting involves the application of foot or ankle orthoses in order to help prevent unwanted and uncontrolled movements that result from muscle imbalance and increased tone in the lower leg and ankle. Hand or arm splints do similar things in the upper limb.

Serial casting

Serial casting is a non-surgical approach aimed at reducing muscle tightness around a joint that is limiting functional mobility. A well-padded cast is applied and removed on a regular basis to gradually increase the range of motion in the affected joint. When serial casting is used at the same time as botulinum toxin injections, the casts are changed more frequently and stay on for less time than when used alone. A physiotherapy programme is used alongside this treatment to increase effectiveness.

Can adverse effects occur?

As with all medicines there are possible adverse effects, but treatment is generally well-tolerated. In clinical studies the common side-effects were leg muscle weakness, falls, abnormal walking, incontinence, diarrhoea and vomiting. If you see any side effects, they are usually mild and temporary.

The information leaflet in your medicine pack tells you more about the possible side-effects. If side-effects occur you should tell the doctor, or report them at

All medicines have to demonstrate their quality, safety and effectiveness to the medicines evaluation authorities before they are approved for use in the UK. All trial results, whether positive or negative, have to be submitted to the authorities before approval. After authorisation for use in the UK, the side effects of medicines are monitored through a variety of systems and you and your doctor can report any problems you encounter.

What is ‘accepted unlicensed use’?

Some medicines needed by doctors for their young patients do not have a licence for use in children because, for complex ethical and practical reasons, clinical trials in young children have not been carried out.

Other medicines, like botulinum toxin, have uses approved from clinical trials conducted in children for a specific disease or illness, but not in other conditions, which remain unlicensed. When botulinum toxin is injected in muscles other than the calf muscles of children, where its use is licensed, then this is unlicensed use of the medicine.

Doctors can, at their discretion, prescribe medications for an unlicensed use if there is agreement within the medical profession for it to be used in that way in clinical practice. There are a number of international guidelines, called consensus statements, which doctors can use to make decisions about the use of botulinum toxin.

This should be explained to you as part of the ‘informed consent’ that is obtained before the injections take place.

Why might botulinum toxin not work for my child?

Physiological changes to muscles, for example those that develop with age, may mean that injections might not work or become less effective. A few children develop a tolerance to the injections, which also decreases their effectiveness. It is very important that a skilled multidisciplinary team is involved in assessing and reviewing the results, as too much botulinum toxin, given too often, can be just as functionally limiting as none at all.

Does it matter how old my child is?

Botulinum toxin is only licensed for use in children with cerebral palsy aged two years or older. It is usually recommended that injections are started at as young an age as is feasibly possible. Younger children generally have a more significant response to botulinum toxin therapy because we all stiffen up with age.

Treatment is usually continued until the assessing team feels there would be no further need or no continued benefit. This is often midway through primary school for the lower limbs, and in the teenage years for the upper limbs. Unless your child has a dystonic hemiplegic cerebral palsy, there is generally little benefit in repeat injections beyond the pre-teen growth spurt.

Botulinum toxin treatment works differently on different children and you can never guarantee the results. It is important to always consult closely with a specialist.

Related information

Download our factsheet Botulinum toxin and hemiplegia [PDF]