Barnett Graham Carly Kruchten-Sheridan Poev Touch
Thursday Sept. 14 2006 Group #5 Lab Session 2 - Movement Disorders
1. What are the cardinal symptoms of Parkinson's disease? How is Parkinsonian tremor different from essential tremor (describe both tremors)? The cardinal symptoms of Parkinson's disease are: -tremor (unilateral which later turns into bilateral) -bradykinesia (slowed movements) -akinesia (rigidity, loss of voluntary movements) -impairment of postural reflexes and postural instability. Parkinsonian tremors are usually unilateral (one sided) that becomes bilateral (both sided) when the patient is at rest. These are slow tremors that are associated with the decrease of dopaminergic neurons in Substantia Nigra. Essential tremors differ from Parkinsonian tremors whereas they are usually bilateral and faster than tremors seen with Parkinson's disease. Essential tremors are also present with certain postures or movements. The finger to nose test (FTN) is seen w/o dysenergia (jerky movement). This tremor can either be familial or due to certain drug exposure such as caffeine or amphetamines. 2. What is the mainstay therapy for Parkinson's disease? Describe at least 2 major side effects. The mainstay therapy for Parkinson's disease is to give levodopa often combined with carbadopa. Levodopa is transformed into dopamine once it crosses the blood-brainbarrier and can have it affect by stimulating dopaminergic neurons. One problem with this therapy is that patients can develop a tolerance to it and with therefore have to increase the dose in order to see the same level of effect. Another problem is that this medication has a tendency to wear on and off. The patient can also have dyskinesia and dystonia symptoms.
3. How do dopamine agonists work and how are they different in the mechanism of action from the mainstay therapy (describe mechanisms of both)? Dopamine agonists work by directly stimulating the dopaminergic neurons in the brain. Levodopa is transformed into dopamine once it crosses the blood-brain-barrier and can have it affect by stimulating dopaminergic neurons. Dopamine agonists differ by stimulating the nerve itself in place of dopamine which may be deficient in that person. Levodopa once changed into dopamine either before crossing or after crossing the bloodbrain-barrier can have its neurotransmitter effects anywhere dopamine can affect.
4. Describe the mechanism of action of COMT inhibitors and MAO-B inhibitors. Catechol-O-methyltransgerase (COMT) inhibitors block serum COMT from having its effect. COMT normally breakdowns dopamine or levodopa. By inhibiting this mechanism from occurring both dopamine and levodopa will remain in the system longer therefore having a longer effect. Monoamine oxidase type B (MAO-B) inhibitors the bock MAO-B in the serum from having its effect. MAO-B will normally potentate degradation of dopamine. By inhibiting the MAO-B, dopamine will remain in the system longer therefore having a longer effect.
5. Describe choreiform movements (at least 2 characteristic features). Choreiform movements are those characterized by having chorea; irregular, spasmodic, involuntary jerking or writhing movements of limbs or facial muscles, often accompanied by hypotonia. These irregular contractions appear to move from one muscle to the next rather than in a repetitive motion.
6. Describe speech of stage 5 Parkinsonian patient (at least 2-3 characteristic features). At stage 5 Parkinson's disease the patient is distinguished by having Cachectic symptoms (wasting away), they cannot stand or walk, and require constant care. Their speech if still present is unintelligible.
7. Describe progressive supranuclear palsy (2-3 characteristic features). Progressive supranuclear palsy is distinguished by ocular disturbances. The patient has a fixed gaze to their eyes usually fixed in a midline direction. They have difficulty with lateral gazes but when their head is turned for them to the right or left they can move their eyes easily to focus straight ahead. Most do not have any rhythmic tremors.
8. What is the compensation that the body makes for spasmodic torticollis? Spasmodic torticollis is an involuntary twisting and contraction of neck muscles. It occurs on either one side or the other, where a tilt to the neck usually develops. Because of this tilt the other side becomes hypertrophy to help control and stabilize the neck.
9. Describe tics (2-3 characteristic features). Tics are brief involuntary movements or sounds, they can be considered simple or complex. Simple tics are meaningless, habitual, repeated contraction of certain muscles, from as little as eye blinking or sniffing to larger and more noticeable arm or leg spasms. Complex tics usually last longer and seem to have more of a purpose and include touching certain objects, straightening ones clothes, or even repeating certain words. These movements can result in can be voluntary suppressed for only a brief period. 10. If a patient doesn't respond to levodopa, what are some other possibilities (2-3)? If the patient does not respond to levodopa any of the other pharmacological methods could be tried. This includes dopamine agonists, COMT inhibitors or MOA-B inhibitors. More extreme measures include surgery which is intended to help restore a more physiologic function in basal ganglia-thalamo-cortical circuits (thalamotomy, pallidotomy, deep brain stimulation). Newer possibilities include restorative measures to grow replacement brain material with the use of fetal or stem cell implants.