Spasticity is involuntary
muscle contractions that are not coordinated with other muscles. Most muscles
in the human body come in pairs that work in opposite ways to eachother.
When one is contracted, the other is stretched. The biceps and triceps
are two such muscle pairs. When you stretch your forearm out, the triceps
is contracted and the biceps stretched - when you pull it in, the reverse
happens. The regulation of the two muscles is a complex, finely controlled
and delicate mechanism which involves sending information to the muscles
and receiving sensory feedback from them. In spasticity, the system gets
things wrong and contracts both at the same time.
Spasticity can be
very painful and, depending on the affected muscles, can result in an uncoordinated
gait, stiff or deformed posture and shortening of the range of limb movement.
It can cause permanent muscle shortening and problems around the joints
against which the two spastic muscles are supposed to move (contracture).
It can be a permanent feature or brought on by a variety of factors such
as fatigue, heat or infection.
Spasticity is a common
in a number of conditions including cerebral palsy, spinal cord injury,
stroke and multiple sclerosis.
In multiple sclerosis,
spasticity is usually caused by damage to the nerves (neurons)
that control muscles or those that collect sensory information back from
them. Reflexive spasms which are generated by the spinal
cord are not inhibited by the brain, as normal, and increased muscle
tone results. The lesions responsible are usually
in the cerebellum or the white
matter tracts that connect it to the peripheral
motor (efferent) and sensory (afferent)
nerves.
Spasticity is a very
common problem in MS. It often affects the legs although it can effect
almost any muscle pair in the body. Clonus (repetitive
muscle spasms) is often associated it.
The upside to spasticity
is that the increased muscle tone often prevents the muscular
atrophy that can occur through lack of use.
The first line of
treatment for spasticity is physical therapy
which can involve strengthening and stretching exercises and other non-invasive
procedures. If these are effective or the spasticity is mild, drug treatments
are often undesirable.
Direct drug treatments
for spasticity include:
Many people report
that cannabis works both for the muscle spasms and the pain involved with
spasticity.
Very radical treatments
are sometimes used for very severe spasticity and involve the destruction
of nerves or muscles:
A number of drug treatments
are also available to address the pain the results from spasticity.
These work by relaxing
the central nervous system (CNS)
and reduce muscle overactivity and painful spasms. They are physically
addictive drugs with a number of side-effects including drowsiness and
muscle weakness.
As with benzodiazepines,
this works on the CNS and decreases spasms, muscle tone and improves posture.
It can be pumped into the CNS via a Baclofen Pump. Baclofen has a number
of side-effects including muscle weakness, drowsiness, fatigue and nausea.
Baclofen can be interact dangerously with alcohol and other drugs. It can
also cause seizures and hallucinations if stopped suddenly.
Dantrolene works
directly on the muscular chemistry and increases passive movement, decreases
muscle tone, reduces muscle spasms, tightness and pain. It has a number
of side-effects including drowsiness, dizziness, weakness, fatigue, diaorrhea
and skin photosensitivity. It can also damage the liver in a minority of
people.
Tizanidine works
on the CNS and relaxes muscles though is less likely to cause muscle weakness
than other spasticity treatments. Side effects include drowsiness and occasionally
low blood pressure, dry mouth, dizziness, and hallucinations. As with Dantrolene
it can cause liver damage in a minority of users.
Spasticity links:
We
Move - Spasticity
Spasticity:
Innovations in Treatment
Cannabinoids
might reduce spasticity in multiple sclerosis
Treatment
of Spasticity in Multiple Sclerosis with Magnetic Stimulation
Anti-spasticity
agents for multiple sclerosis (Cochrane Review)
MS Glossary
All About Multiple Sclerosis