Reticulospinal Tract
Inhibits muscle tone
Vestibulospinal Tract
Excites muscle tone of antigravity/extensor muscles
Damage to corticobulbar tracts in CP
- loss of reticulospinal inhabitation of muscle tone
- continued vestibulospinal excitation > increased lower extremity extensor tone
review the fibers and such
review research stuff
What are the temporary/focal medications for spasticity
- Botulinum
- Phenol (alcohol)
Types of Botulinum
- botox
- dysport
- xeomin
- myobloc
How does botulinum work?
it binds to synaptic vesicles and inhibits release of Act from pre-synaptic to post-synaptic
Therapeutic effects of botulinum conclusion
- should be used as an adjunct therapy
tell me about phenol
- Phenol
- Neurolysis – causes Wallerian degeneration of neurons
- Target larger muscle groups of lower extremity
- Obturator, tibial, hamstring branches sciatic, femoral
- Duration of action: 6 -12 months
potential complications of phenol
- Injection site infection
- Desensitization/dysesthesia followed by causalgia/neuralgia
- Local edema
- Venous thrombosis
- Compartment Syndrome
- Death
oral pharmacotherapy
- Baclofen -GABA (B)
- Benzodiazepines -Diazepam (Valium) and Clonazepam - GABA (A)
- Tizanidine - ɑ2 adrenergic agonist
- Dantrolene sodium – Ca channel blocker
Where and how does baclofen work
- Acts at the level of the spinal cord
- Binds to and activates GABA-B receptor sites, reduces tone, spasms and clonus
where is baclofen metabolized?
kidneys
What can happen with baclofen?
- can lower seizure threshold
- physiologic dependence
- Sudden withdrawal may result in rebound spasticity/ muscle spasms/ hallucinations/ confusion/ seizures/ temperature elevations
What does Diazepam do?
- Increases the effect of GABA pre and post synaptically at the spinal cord level by binding to
its Benzodiazipine receptor resulting in pre-synaptic inhibition and CNS depression
Where is Diazepam metabolized?
liver
what can Diazepam cause?
- sedation, impaired cognition, attention, coordination
- physiologic dependence
What is Clonazepam?
- Benzodiazepine - Gaba RC couple
- fast onset of action and highly effective
how does Tizanidine work?
Central and spinal blocking release of excitatory catecholamines (NE and EPI)
Where is Tizanidine metabolized?
Liver (check LFTs)
What can Tizanidine result in?
significant sedation and hypotension
* better tolerated in older patients, adults
How does Dantrolene Sodium work?
- Peripheral acting upon skeletal muscle fibers inhibiting the release of Ca++ from the sarcoplasmic reticulum affecting muscle contractile response
- Reduces spasms and clonus
- May exacerbate muscle weakness/fatigue
What is a risk with Dantrolene Sodium
Hepatotoxic effect noted in up to 2% of patients - must serially monitor LFTs
