Parkinson's Disease Flashcards
How is Parkinson’s diagnosed?
Bradykinesia +1 of: - 4-6 Hz tremor - Mucular rigidity - Postural instability ASSYMETRICAL
If these symptoms are bilateral, how does this change the diagnosis?
More likely to be SECONDARY PARKINSONISM caused by drugs (e.g. neuroleptics, antiemetics), CVD, infections etc
Name some non-motor symptoms of parkinson
- REM behaviour disorder (acting out dreams) and other sleep disorders - Reduction in olfactory function (ANOSMIA IN 90%!!!!) - Depression/anxiety/hallucinations - Parasthesia - Fatigue - Sexual dysfunction - Bladder dysfunction
If you see a patient with rapid onset parkinsonism and dementia, what is the most likely diagnosis?
Lewy Body Dementia
What is Parkinson’s Disease?
A progressive neurodegenerative disease with two main features: 1. Loss of pigmented dopaminergic neurons in the substantia nigra 2. Increase in Lewy Bodies
Name some other relevant motor features of PD
Dysphagia Dysarthria Hypersalivation Blurred vision Micrographia Dystonia Stooped posture Shuffling gate Freezing Festinant FALLS
What does festinant mean?
Having short stride and quickened gait
What is a parkinson plus syndrome?
A group of syndromes that exhibit the same symptoms as parkinsons but with additional features: - Multiple system atrophy - Corticobasal degeneration - Progressive supranuclear palsy
What are the typical pre-motor symptoms?
- Impaired olfaction - REM behaviour disorder - Depression - Constipation
What imaging technique is used in parkinson diagnosis?
SPECT - measures loflupane (DaTSCAN) uptake in presynaptic dopamine transporters
What does a DaTSCAN look like in a PD patient?
More like .. than the usual “
What are the pros and cons of DaTSCANS?
PRO - high sensitivity and specificity CON - expensive
Describe the onset and progression of PD
Insidious onset (latent period can be up to 3 decades) Long clinical course (10-30 years) Incurable, decreased life expectancy
What are the four stages in the McMahon model of PD?
Diagnosis (1.6 years) Maintenance (5.9 years) Complex (4.9 years) Palliative (2.2 years)
Name the 7 classes of drugs used to treat PD?
- L-dopa - Dopamine agonists - MAOB inhibitors - COMPT inhibitors - Amantadine - Anticholinergics - Oestrogen
Name two examples of L-Dopa with decarboxylase inhibitor
Madopar, Sinemet
Name two examples of MAOB inhibitors
Selegiline, Rasagiline
Name three examples of dopamine agonists
Ropinirole, Pramipexole, Rotigotine
How do L-Dopa and decarboxylase inhibitors work?
L-dopa is converted to dopamine in the brain
How do COMT inhibitors work, and what is an example?
Entacapone They stop L-dopa from being converted to 3-0 methydopa (must be used alongside)
How do MAOB inhibitors work?
They stop dopamine from being converted to its inactive metabolite
Which of the drug treatments is best for symptom control?
L-dopa, however it has motor complications, unlike the others
Why is L-Dopa used in older patients and dopamine agonists used in younger ones?
L-dopa is the best for symptomatic treatment but DAs are best in delaying onset of motor complications
Which members of the MDT are involved in Parkinsons care?
PD nurse specialist, physiotherapy, occupational therapy, SALT, support groups
What drug is primarily used in early PD?
MAOB inhibitors (best at stopping progression of disease, but not that good at symptom control)
What medications should be stopped when prescribing for PD?
Dopamine-blocking agents: - Neuroleptics - Antiemetics - Sodium valproate - CCBs
If a PD patient starts experiencing hallucinations from their meds, what can be given to them?
Quetiapine
How does Amantadine work?
Stimulates release of dopamine
What is the pharmacology of L-Dopa?
- Absorbed from small bowel - Motor symptoms improve 20-70%
What are the short term side effects of L-Dopa?
GI - nausea, vomiting, decreased appetite Psychiatric - confusion, hallucinations, delusions Cardiovascular - postural hypotension Sleep disorders - somnolence, insomnia, vivid drea nightmares
What are the long term side effects of L-Dopa?
DYSKINESIAS - Abnormal involuntary movements RESPONSE FLUCTUATIONS - end-of-dose deterioration and unpredictable on/off switching PSYCHIATRIC - confusion, hallucinations
What is the pharmacology of Dopamine agonists?
- Act directly on D1/D2 postsynaptic receptors in the striatum
Which dopamine agonists are administered by which routes?
Ropinirole - oral Rotigotine - transdermal Subcutaneous - apomorphine
What are the side effects of dopamine agonists?
- Nausea, vomiting, loss of appetite - Postural hypotension - Confusion, hallucinations - Somnolence - Impulse control disorders (hypersexuality, gambling etc)
What is the pharmacology of MOAB inhibitors?
- Irreversible inhibitors - Decrease dopamine breakdown so that there is more in the synaptic cleft NB - in practice these are rarely used alone as they have a weak clinical effect
What are the side effects of MOAB inhibitors?
Nausea, vomiting, confusion
What is an important drug interaction to be aware of in reference to MOAB inhibitors?
Interact with anti-depressants –> SEROTONIN SYNDROME
What is the pharmacology of COMT inhibitors?
Inhibit COMT so that more levodopa is available to cross the BBB
What are the side effects of COMT inhibitors?
Nausea, vomiting, confusion DIARRHOEA AND DISCOLOURATION OF BODY FLUIDS Increased dyskinesias
What is the pharmacology of amantadine?
Antiviral, NMDA receptor antagonist causing increased release of dopamine
When is amantadine used?
In the later stages of disease to treat dyskinesias (however do not use in the elderly as it causes confusion)
What are the side effects of amantadine?
- Confusion - Halluciantions, pscyhosis - Livedo reticularis (skin condition) - Ankle oedema
What is the pharmacology of anticholinergics?
Decrease the effects of relative ACh excess, that occurs due to dopaminergic deficiency
What are the side effects of anticholinergics?
Cognitive impairment Dry mouth, blurred vision, constipation, urinary retention, dizziness
When are anticholinergics used?
In the young, to combat tremor
