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Management of spasticity
Spasticity is a velocity-dependent increase in tone after upper motor neuron damage; it is treated only when it harms function, care or comfort — and in steps: remove triggers, stretching and splints, oral drugs, focal treatment with botulinum toxin or a nerve block, and for severe generalised spasticity — an intrathecal baclofen pump.
Why it matters in the exam
The exam asks about measurement (the Modified Ashworth Scale — 0, 1, 1+, 2, 3 and 4; the Tardieu scale, which compares slow and fast stretch and distinguishes spasticity from fixed contracture), drug mechanisms and side effects, and the choice between generalised and focal treatment. Spasticity is not always harmful: sometimes it helps standing and transfers. Factors that worsen spasticity: urinary infection, constipation, pressure injuries, an ingrown nail, pain and tight clothing — so they are looked for first.
Oral drugs: baclofen (GABA-B agonist) — drowsiness and weakness, and sudden withdrawal can cause seizures and hallucinations; tizanidine (alpha-2 agonist) — drowsiness, low blood pressure and liver injury, so liver tests are checked; dantrolene (acts in the muscle itself on calcium release) — liver injury, but less effect on cognition, so it is sometimes useful after brain injury; diazepam (GABA-A) — drowsiness and dependence. Intrathecal baclofen (pump) suits patients with severe generalised lower limb spasticity, after a test dose; sudden interruption (pump or catheter failure) causes life-threatening withdrawal — high fever, severe spasticity, muscle breakdown and altered consciousness.
Focal treatment: botulinum toxin A injections block acetylcholine release (cleaving SNAP-25); the effect starts after a few days, peaks after weeks and lasts about three months, and re-injection is not given sooner than about 12 weeks to reduce antibody formation. A phenol or alcohol nerve block (for example the obturator nerve for hip adduction or the musculocutaneous nerve for elbow flexion) — acts fast and is cheap, but in a mixed nerve can cause pain and unpleasant sensation. Surgery: tendon lengthening and release, and selective dorsal rhizotomy in children with diplegic CP. Every treatment is combined with stretching, splints and serial casting.
Key points
- Spasticity — velocity-dependent increase in tone.
- Look for triggers first.
- Modified Ashworth and Tardieu for measurement.
- Generalised — oral drugs; focal — botulinum toxin.
- Baclofen — never stop suddenly; intrathecal withdrawal is life-threatening.
Summary table
| Treatment | Mechanism | Main use | Side effect or trap |
|---|---|---|---|
| Oral baclofen | GABA-B | Generalised, spinal-origin spasticity | Sudden withdrawal — seizures and hallucinations |
| Tizanidine | Alpha-2 | Generalised spasticity | Liver injury, low blood pressure |
| Dantrolene | In muscle — calcium release | When cognition matters | Liver injury |
| Botulinum toxin A | Blocks acetylcholine release | Focal spasticity | Peak after weeks; do not repeat sooner than about 12 weeks |
| Intrathecal baclofen | GABA-B in the spinal cord | Severe generalised spasticity | Life-threatening withdrawal on failure |
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Sources
- AAN Practice guideline update: Botulinum neurotoxin for the treatment of blepharospasm, cervical dystonia, adult spasticity and headache, 2016 — Adult spasticity
- Braddom's Physical Medicine and Rehabilitation, 6th edition (2021) — Spasticity
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.