parkinson

Question 1

pathophysiology?

Answer 1

dopaminergic neuron degeneration in substantia nigra of basal ganglia and locus coeruleus -> dopamine deficiency -> motor symptoms

lack of serotonin and NA -> depressive symptoms

acetylcholine surplus -> dyskinesia (no dopamine to balance out Ach so it increases)

Question 2

etiology?

Answer 2

idiopathic and occurs commonly in males over age of 60.

role of genetics:
alpha-synuclein (lewy body)
Parkin gene mutation

secondary parkinsonism as result of typical antipsychotics

Question 3

prodrome features?

Answer 3

symptoms begin with constipation, anosmia, sleep disturbances (restless leg, REM sleep behavior disorder, excessive daytime sleepiness), mood disorders like depression and anxiety

because lewy bodies begin by affecting the autonomic system then progress to olfactory bulb, basal ganglia, and brainstem by traveling through vagus nerve

Question 4

clinical features?

Answer 4

symptoms are PROGRESSIVE (> 10 years) and begin UNILATERALLY then bilaterally. The motor signs are asymmetric (one side is more pronounced than the other).

1. bradykinesia: slowed movements
2. resting tremor: pill-rolling that occurs at rest while supported against gravity and subsides with voluntary movement. most common in hands but can involve legs, jaw, lips.
3. rigidity: resistance to passive joint movement independent of speed (distinguish it from hypertonia). cogwheel rigidity when it’s combined with resting tremor.
   Froment maneuver: asking pt to perform repetitive movement with contralateral hand while examining the other hand will make rigidity more pronounced
4. postural instability: repetitive falls
   evaluated by pull test (with wall behind u and pt in front, instruct the pt to take 1-2 steps back upon pulling their shoulder to correct their balance)
5. shuffling gait with short steps and reduced arm swing
6. hypomimia (mask face, reduced facial expression)
7. autonomic: orthostatic hypotension, urine urgency)
8. depression, parkinson dementia in advanced cases

Question 5

diagnosis?

Answer 5

diagnosis is clinical with presence of parkinsonism (bradykinesia with tremor/rigidity or both)

confirmed with postmortem findings of lewy bodies.

supportive features is resting tremor and benefit from dopamine medications.

imaging not required unless diagnosis is unclear

Question 6

treatment?

Answer 6

medications don’t change the trajectory of the disease, so only initiate when it affects quality of life.

supportive: physiotherapy, fall prevention, sleep hygiene

start with monotherapy then switch or combine as needed. avoid abrupt discontinuation of medications.

1. levodopa+carbidopa: initial option esp for elderly. Most effective but high risk of dyskinesia
2. MAO-B inhibitor Selegiline: trialed as monotherapy for mild disease
3. Nonergot dopamine agonists Pramipexole, Ropinirole, Apomorphine: trialed as initial tx for younger patients
4. anticholinergics Benztropine: trialed for younger patients with chief complaint of tremor
5. deep brain stimulation for severe motor symptoms refractory to treatment
6. manage associated symptoms (depression, dementia..etc)