Parkinsons Flashcards
Describe the pathophysiology of Parkinsons
Degeneration of the dopamine producing neurons in the substantia nigra leading to a hypokinetic state
Where is the substantia nigra located?
The pars compacta of the basal ganglia
What is the biggest risk factor?
Age
Over the age of 60 increases your risk
List some risk factors for developing Parkinson’s:
Male >60y/o Rural living Pesticide exposure Previous head injury Beta blocker use
What protein is found in Lewy bodies associated with Parkinson’s?
Alpha-synuclein protein
How is the alpha-synuclein gene inherited
Autosomal dominant
What are the main motor symptoms of Parkinsons
Bradykinesia (unilateral initially) Shuffling gait Pill rolling tremor Rigidity Postural Instability - stooping
List some of the non-motor related features of Parkinson’s:
Inability to sleep Hallucinations Expressionless face GI dysfunction Cognitive impairment Pain Fatigue Olfactory dysfunction
What is a prodromal, non-motor clinical symptom that should make you suspicious of Parkinson’s?
Anosmia / Hyposmia
i.e. loss or reduced sense of smell
What are some of the neuro-psych complications of Parkinson’s?
Depression
Parkinson’s dementia
Hallucinations
What investigations should be done for Parkinson’s?
No specific investigations to diagnose PD
Only carry out investigations to eliminate other potential DDx
What is first line treatment for Parkinson’s with motor symptoms?
Levodopa
What is the mechanism of action in Levodopa?
Is the inactive form of dopamine - crosses the blood brain barrier and is converted to dopamine, increasing the overall levels
What medications should be avoided in older patients and why?
Dopamine agonists
Can induce hallucinations and delirium
What is the main principle of drug management in PD?
Symptomatic treatment
There is no neuroprotective or disease modifying agents available for PD
What can be given to treat a tremor?
Anticholinergics e.g. clozapine
Be careful when prescribing to elderly
What groups of people other than the elderly should you be wary of prescribing dopamine agonists and levadopa to?
WHY?
Patients with history of addiction, OCD and impulsive personalities
Impulsive behaviors can occur as a s/e of these drugs
What drug must be combined/ prescribed alongside levodopa?
Describe its mechanism of action:
Carbidopa
A dopa-decarboxylase inhibitor which catalyses the conversion of levodopa to dopamine
What should you consider doing if a patient develops hallucinations?
Lower their dose of levodopa
If that doesn’t work prescribe an atypical anti psychotic
What drugs can induce “Parkinsonism”
Any drugs which inhibit dopamine production e.g. anti psychotics
What other class of drugs can be used in early Parkinson’s?
MAO-B inhibitors
e.g. rasagiline
Other than medication, how else can Parkinson’s be managed?
Physiotherapy
Deep Brain stimulation
Basal ganglia ablation
Give an example of a Dopamine Agonist:
Ropinirole
Pramipexole
What are some of the S/E’s of Levodopa and dopamine agonists:
Nausea Oedema Daytime somnolence Hallucinations Motor complications e.g. response fluctuations and dyskinesia
What drug can be given if dyskinesia’s are not be controlled effectively by levodopa and dopamine agonists?
Amantadine Hydrochloride
What is the mechanism of action of amantadine hydrochloride?
Amantadine is a weak dopamine agonist with modest antiparkinsonian effects.
What chronic diseases are contraindications for amantadine therapy?
Gastric ulcers
epilepsy
What are some (uncommon) severe side effects of amantadine that need to be aware of?
Psychosis
Neuroleptic malignancy syndrome
Seizures
Tremor
What is the classic triad of symptoms in Parkinson’s?
Resting tremor
Bradykinesia
Rigidity
