Spasticity refers to muscle stiffness as a symptom that reflects upper motor neuron damage in the pyramidal (motor) tract.
Spasticity does not necessarily require treatment. It may function as support for a limb/limbs with weakened muscle strength and enable mobility.
Drug therapy is indicated
when muscle strength is still preserved to the extent that the alleviation of spasticity does not threaten the patient's ability to walk or may even improve it
for wheelchair patients to assist in transitions and possible care procedures.
Stiffness typically appears when the muscle is quickly stretched. This initially meets strong resistance, which is released as the stretching continues.
This ”jackknife” rigidity characteristic of motor tract damage differs from the ”lead-pipe” rigidity of extrapyramidal tract disease.
In addition to spasticity, damage to the motor tract also causes
muscle weakness
increased tendon reflexes
positive Babinski's sign
spasms and cramps in the extensor or flexor muscles.
Damage to the motor tracts of the lower extremities may also cause symptoms involving bladder and bowel functions.
Urinary frequency caused by detrusor hyperreflexia
Incontinence
Investigations
The cause is usually known because spasticity develops with delay after damage to the motor tract.
If the aetiology is not known, neurological investigations are needed because the cause is always a disease or injury located in the CNS.
Drug therapy
Baclofen is more effective in spinal cord injury than in brain injury. The most significant adverse effect is drowsiness; large doses also cause confusion and hypotension.
A sufficient dose to reduce spasticity is 4-6 mg 3 or 4 times daily. Maximum daily dose is 12 mg 3 times daily. It is advisable to increase the dose gradually according to response. Reaching an effective dose is often prevented by adverse effects.
Adverse effects include drowsiness, fatigue, and dry mouth. If used in combination with antihypertensive medications, tizanidine may cause hypotension and bradycardia.
Baclofen
Normal initial dosage is 5 mg 2-3 times daily.
Average dosage is 20 to 30 mg/day.
The maximum daily dose is 75 mg.
Overdose causes muscular hypotonia which means further weakening of muscle strength.
In the most severe cases, baclofen can also be administered with a pump into the spinal canal through a catheter inserted into the intrathecal space.
Most patients using a baclofen pump have a spinal cord injury, but also patients with e.g. MS may be fitted with them.
Before the pump is installed a test phase is carried out on a hospital ward: the drug is injected through lumbar puncture on 3 consecutive days in increasing doses, monitoring the response and the adverse effects.
Clonazepam
Spasticity is occasionally associated with muscle spasms and cramps in the lower extremities and trunk. These are of short duration but painful. They can be treated with clonazepam 0.5-2.0 mg for the night.
Dantrolene
Special regulations for prescription may apply.
An effective muscle relaxant which can be used in the alleviation of particularly strong spasticity if baclofen or tizanidine do not provide sufficient treatment response
Cannabinoids
Medical cannabis is being increasingly licensed for the treatment of spasticity caused by MS, but its availability and use varies across countries.
Botulinum toxin administered in local injections is effective, but the effect is transient and the treatment must be regularly repeated if a persistent response is pursued.
The patient should be told, already at the beginning of treatment, that botulinum toxin therapy will alleviate spasticity, but will not restore the lost muscle strength or function of the limb.
A part of comprehensive management of spasticity which besides the above-mentioned drug treatments should also include simultaneous non-pharmacological, rehabilitative treatment forms. The duration of botulinum toxin treatment given for spasticity is defined already in the beginning of the treatment.
Treatment with botulinum toxin should only be given by appropriately trained physicians with experience of the therapy and of the use of the required electromyography (EMG) guidance.
Surgical treatment
The use of surgical treatments has practically ceased along with the increasing use of baclofen pump therapy.
General rehabilitative measures
Spasticity can be relieved by continuous and regular physiotherapy. Ice packs further enhance the efficacy of physiotherapy.
Regular stretching is also effective.
The extent of the spasticity depends on posture. For example, spasticity of the extensors is less pronounced in the upright position than in the supine position.
Bladder function should be closely monitored, because sensory stimuli of the lower abdomen may trigger cramps in the paralysed muscles. Detrusor hyperreflexia is treated with anticholinergic drugs and regular botulinum toxin injections.
Special attention should be paid to the prevention and treatment of urinary tract infections.
Skin care is important for a non-ambulatory patient in order to prevent pressure sores that increase spasticity.