What Is Spasticity?

Overview

Spasticity is one of the constituent symptoms of upper motor neurone syndrome (UMNS). These constituent symptoms form a collection of clinical manifestations which characterise UMNS and ultimately describe changes in the behaviour of the muscles and nerves, which are most frequently the result of disease or injury.^1,2,3 The other constituent symptoms include muscle weakness, hyperreflexia and clonus. Spasticity describes a state of increased muscle ‘tone’ coupled with increases in the muscle tendon's reflexes.^1,2 It is what is known as a ‘positive’ sign in that positive signs are those where there is an exaggerated function compared to a healthy individual.^1,2,3 ‘Tone’ is a complex term, and its level can often be subjective according to the person assessing it, but typically it can be described as the level of tension felt in the muscle whilst it is in a state of relaxation.³ 

As part of this condition, you may experience changes to the way in which your muscles move or contract, including cramping or the feeling of extreme tightness in your muscles that can be painful.³ Spasticity also involves the excessive muscle reflex/response to external stimulation, however its symptoms may also be completely involuntary and unpredictable without provocation.^1,3 

Although not completely understood, it is believed that spasticity occurs when there is some form of damage to how the nerves respond to a stimulus.^1,3 In spasticity the mechanisms in place that normally control your reflexes are altered, meaning that the messages sent between your nerves, spinal cord and your muscles are affected.^1,3 In spasticity, you may experience an increased ‘excitability’ of signals, meaning you are more sensitive to stimulation, and your muscle’s response is disproportionately large in relation to the signal.^1,3

Causes of spasticity

Spasticity can be linked to a number of different conditions affecting your central nervous system including:

• Multiple Sclerosis (MS) 
• Stroke
• Spinal cord injury, damage or lesions
• Cerebral Palsy²

Signs and symptoms of spasticity 

Spasticity can present in a variety of ways. The way in which spasticity may physically present varies between different people and has the potential to cause what are known as extensor or flexor symptoms.

Flexor symptoms involve your joints being flexed and your limbs being locked in this bent position. Meanwhile, with extensor symptoms, you may struggle to bend your limbs, and your legs may be locked in a straight position. Both of these have the potential to make everyday movement difficult, and tasks as simple as sitting upright may be incredibly uncomfortable. 

The symptoms can affect a variety of muscles across your body; however, they typically tend to favour the muscles of the legs.^1,3 Although spasticity, as described above, follows the path of causing ‘positive’ sign neurological symptoms, it also has the ability to cause the feeling of weakness in your muscles.^1,3 Understandably, your mobility may be negatively affected by cramping with a simultaneous loss of muscle strength. 

Diagnosis

The diagnosis of spasticity relies heavily on a physical assessment by a suitably trained medical professional. Unfortunately, there are no obvious blood tests to help form a confident diagnosis of spasticity. Despite this, there are a number of supporting investigations that can be carried out to identify spasticity and its potential cause: 

• The gold standard of diagnosis is neurological assessment. A full neurological exam will be carried out, involving assessing the function of your nervous system by carrying out a variety of physical tests. For example, the presence of the ‘clasp-knife’ phenomenon can be used as a key indicator of upper motor neuron disease, as is the case in people with spasticity. In clasp-knife, when another person attempts to move your limb, initially, the limb resists the enforced movement greatly, then suddenly gives way.
• MRI scan of the brain and spinal cord. This diagnostic test will be used to image your brain and spinal cord in order to identify potential physical causes of your symptoms, such as a stroke or a lesion within the central nervous system.

Management and treatment of spasticity

Management of spasticity will involve a variety of approaches, and will likely call upon the input of various healthcare professionals including doctors, pharmacists, physiotherapists and occupational therapists among others.^4,5 Spasticity treatment is best managed by combining a number of different methods to get the most out of treatment and to minimise the impact spasticity has on your life.^(4,5) Your treatment should be tailored to your specific goals and will take these into account as well as your ongoing response to treatment.

Medications:

Medications can play a pivotal role in the treatment of spasticity.^4,5 Although covering all options is outside the scope of this article, commonly used medicines may include:

• Baclofen – is commonly taken as a tablet that works by affecting the communication impulses between the nervous system and the muscles to prevent spasticity symptoms.^4,5 For some people whose spasticity is very troublesome to manage, baclofen may be administered continuously, using a pump that delivers the medication directly into the spinal canal.^4,5
• Diazepam – another frequently used medication for managing muscle spasms and spasticity is the benzodiazepine diazepam.^4,5 This medication may prove effective, especially if your symptoms interfere with sleep, as it improves your spasms whilst also making you feel sleepy or relaxed.^4,5 This, however, is not always ideal, and there are, unfortunately, a number of side effects and considerations regarding use that your medical team will have to consider when giving medications of this type.^4,5
• Botulinum toxin or Botox treatment – is given as an injection into muscles affected by spasticity. It works by preventing signals from being transmitted to the problematic muscle, which then prevents the exaggerated muscle contraction observed in spasticity.^4,5 This has a number of advantages in that it can be used locally on a specific site whilst avoiding some of the unwanted effects on your body as a whole.^4,5 The effects tend to last for a few months at a time, so you may require top-up injections periodically to ensure the effect is maintained.^4,5
• Cannabinoids – are medications that are related to the well-known drug cannabis and may also be an option for treatment in specific agreed cases of spasticity (as in those due to Multiple Sclerosis).^4,6 These are not the same as the cannabis that people smoke but do contain a refined version of the same ingredient or a very closely related active ingredient.^4,6 This is usually taken in the form of an oral spray under the brand name Sativex ^(4,6)  

Physiotherapy or physical interventions:

Physiotherapy input will play a crucial role in improving your symptoms and providing you with the tools to best manage your spasticity. You will engage in a program put together by a team of physiotherapists that involves a variety of exercises and stretches to help you get the most out of your mobility.^4,5,7 As well as this, they may be able to advise on posture or positioning to reduce the risk of experiencing spasticity.^4,5,7

Similarly, input from occupational therapists may allow you to better manage your day-to-day tasks by allowing adjustments to be made in terms of how your house is set up to help you carry out your daily activities^.7 

Surgical intervention may be suggested in certain cases. The procedure termed rhizotomy involves isolating the nerves related to your spasticity and then damaging them to prevent the signals linked to your symptoms from being sent. This may take place in the form of a surgical procedure or may involve the injection of a chemical that causes the death of the problematic nerve.^4,5 This is noted to be a more sensitive topic in children affected by spasticity, and its use should be very carefully evaluated by your medical team due to the risk of potential complications.^4,5

Complications

Spasticity may be linked to a number of unfortunate consequences that may include:

• Pain and discomfort
• Impacts on the ability to carry out normal day-to-day tasks
• problems with growth (especially in children or adolescents) and potential deformities of limbs
• Dislocation of joints
• Pressure sores 
• Urinary tract infections
• Constipation 
• Effects on mental wellbeing due to the associated stigma^4,8

As well as the condition itself, there may be a number of complications associated with treatment. Each form of treatment will carry its own individual adverse effects, which may range from minor and temporary to severe and permanent. It is important to consult your healthcare team for guidance on any specific adverse effects that may be linked to your individual care. Ultimately, your healthcare team will try their best to mitigate these where they can. 

In terms of the medications used for treatment, these may carry the potential for adverse effects such as drowsiness, dependence, or even liver damage in rare cases. 

Complications that may be linked to interventions such as physiotherapy, surgery or botox injections could include pain, infection, unintentional nerve damage or even changes in the sensation or the perception of pain.^4,5,9 

Summary

Although spasticity has the potential to be a debilitating condition, there are a number of options for its effective management. Spasticity may present differently in different people and is linked to a variety of medical conditions. The stigma surrounding spasticity is not to be underestimated, and if you are faced with any concerns about your condition, reaching out to your relevant healthcare provider and/or charities will allow you to obtain the support you need.