Parkinson’s Disease Flashcards
What is Parkinsonism?
A neurologic syndrome exhibiting symptoms like tremor, rigidity, bradykinesia, and postural instability
Parkinsonism is not Parkinson’s disease and typically responds poorly to pharmacologic intervention.
What are the primary neurotransmitters affected in Parkinson’s disease?
Dopamine (inhibitory) and acetylcholine (excitatory)
These neurotransmitters are involved in motor control within the basal ganglia.
What are the characteristic symptoms of Parkinson’s disease?
- Tremor
- Rigidity
- Bradykinesia
- Postural instability
These symptoms can progress and worsen over time.
What is the average age of onset for Parkinson’s disease?
60 years old
The risk of developing Parkinson’s disease increases with age.
What is the prevalence of Parkinson’s disease among individuals aged 80 and older?
1–3%
This prevalence indicates an increased risk with advancing age.
How does dopamine loss in Parkinson’s disease compare to normal aging?
Dopamine loss occurs at a much greater rate in Parkinson’s disease
Normal aging involves a slow progressive loss of dopamine.
What is the role of caffeine in relation to Parkinson’s disease?
Caffeine is an adenosine A2A receptor antagonist believed to reduce the risk of developing PD
Studies have shown a correlation between coffee consumption and reduced PD risk.
What is the genetic predisposition for Parkinson’s disease?
Up to 6% of cases are linked to known genes; 15% have a family history of PD
Genetic factors contribute to the risk but are not the sole cause.
What are some environmental factors associated with Parkinson’s disease?
- Pesticides
- Herbicides
- Heavy metals
- MPTP exposure
These factors can contribute to neurodegeneration.
What are the two major strategies for treating Parkinsonism?
- Increase brain dopaminergic activity
- Decrease central cholinergic activity
Both strategies aim to alleviate symptoms of Parkinsonism.
What is Levodopa’s role in treating Parkinson’s disease?
Levodopa is a dopamine precursor that can cross the blood-brain barrier
It must be administered with carbidopa to reduce side effects.
What are the common peripheral effects of Levodopa?
- Anorexia
- Nausea
- Vomiting
- Tachycardia
- Hypotension
These side effects are due to peripheral dopamine formation.
What is the function of carbidopa when administered with Levodopa?
Carbidopa inhibits the peripheral conversion of Levodopa to dopamine
This combination reduces the dose of Levodopa needed and minimizes side effects.
What is bradykinesia?
Slowed movements, a hallmark symptom of Parkinson’s disease
A diagnosis of Parkinson’s disease requires the presence of this symptom.
True or False: Parkinsonism can be caused by exposure to certain neuroleptic drugs.
True
Neuroleptic drugs can lead to symptoms similar to Parkinson’s disease.
What are Lewy bodies?
Abnormal cytoplasmic deposits within neuronal cell bodies, associated with Parkinson’s disease
These deposits are immunoreactive for the protein α-synuclein.
Fill in the blank: The presence of _______ is indicative of Parkinson’s disease.
Lewy bodies
What are some non-motor symptoms of Parkinson’s disease?
- Depression
- GIT disturbances
- Urinary problems
- Skin problems
These symptoms can significantly affect the quality of life.
What is the role of the substantia nigra in Parkinson’s disease?
Destruction of dopaminergic neurons in the substantia nigra leads to decreased dopamine in the corpus striatum
This results in impaired motor control.
What is the absorption site and half-life of Levodopa?
Absorbed rapidly from the small intestine; half-life is 1 to 2 hours.
What are common peripheral adverse effects of Levodopa?
- Anorexia
- Nausea
- Vomiting
- Tachycardia
- Ventricular extrasystoles
- Hypotension
What causes mydriasis in relation to Levodopa?
Adrenergic action on the iris.
What are some central nervous system (CNS) effects of Levodopa?
- Visual hallucinations
- Auditory hallucinations
- Abnormal involuntary movements (dyskinesias)
- Mood changes
- Depression
- Psychosis
- Anxiety
What effect does pyridoxine (B6) have on Levodopa?
Increases peripheral breakdown of Levodopa, diminishing its effectiveness.
What can occur when Levodopa is administered with non-selective monoamine oxidase inhibitors (MAOIs)?
Hypertensive crisis due to enhanced catecholamine production.
What is a possible consequence of abruptly withdrawing Levodopa?
Neuroleptic malignant syndrome.
What enzymes metabolize dopamine?
- Monoamine oxidase (MAO)
- Catechol-o-methyl transferase (COMT)
What are the COMT inhibitors used in Parkinson’s disease?
- Tolcapone
- Entacapone
What is the main difference between Tolcapone and Entacapone?
Tolcapone inhibits COMT in both periphery and brain; Entacapone acts only in the periphery.
What are the irreversible and selective inhibitors of MAO-B?
- Selegiline
- Rasagiline
What is the risk associated with high doses of Selegiline and Rasagiline?
Hypertensive crisis with tyramine-containing foods and serotonin syndrome with tricyclic antidepressants.
What type of drugs are bromocriptine and pergolide?
Ergot-derived dopamine agonists.
What are the newer non-ergot dopamine agonists?
- Pramipexole
- Ropinirole
- Apomorphine
What is a significant side effect of apomorphine?
Used in severe and advanced stages of Parkinson’s disease.
What are common side effects of non-ergot dopamine agonists?
- Nausea
- Hallucinations
- Insomnia
- Dizziness
- Constipation
- Orthostatic hypotension
What is the mechanism of action of Amantadine in Parkinsonism?
Increases synaptic dopamine levels by increasing presynaptic release and decreasing reuptake.
What are some adverse effects of Amantadine?
- Nausea
- Insomnia
- Ankle edema
- Livedo reticularis
- Restlessness
- Agitation
- Confusion
- Hallucinations
What are the central anticholinergic drugs used for drug-induced Parkinsonism?
- Trihexiphenidyl
- Procyclidine
- Benztropine
- Orphenadrine
- Biperiden
True or False: Antimuscarinic agents are more efficacious than levodopa.
False.
What can anticholinergic drugs induce as side effects?
- Mood changes
- Xerostomia
- Constipation
- Visual problems
