CNS 2 - Neurodegenerative Flashcards
Define neurodegeneration and name the four major neurodegenerative diseases
- progressive loss of neuronal function, typified by cell death and protein aggregates
- Alzheimer’s, Parkinson’s, Huntington’s, ALS
What two diseases are Lewy bodies associated with?
Inclusion bodies associated with Parkinson’s and Diffuse Lewy Body disease (a form of dementia)
What are the major symptoms of Parkinson’s disease?
resting tremor, bradykinesia or akinesia, muscular rigidity, postural instability, dementia
A patient comes into your primary care office with complaints of tremors throughout the day. You narrow the differential down to either Parkinson’s or essential tremor. What are some things you will test to decide which is the correct diagnosis?
During history/physical assess whether tremor is:
- symmetric (ET) or asymmetric (PD)
- moving (ET) or resting (PD)
- faster (ET) or slower (PD)
You’re on the medicine service and one of your patients has been vomiting all day. You prescribe prochloperazine and check back a few hours later. The vomiting has stopped but the nurses are worried because now the patient has muscular rigidity, bradykinesia, and a resting tremor. What happened? What other things can induce this reaction?
Parkinsonism, a sudden onset of idiopathic PD-like symptoms
Can be caused by:
stoke, brain trauma, anesthesia, encephalitis, meningitis, antipsychotics, anti-emetics, intoxication, CO poisoning, chemical toxicity
What enzyme converts L-DOPA to dopamine, and what drug inhibits this process?
Aromatic AA decarboxylase (AAD), inhibited by carbidopa in the periphery
What enzyme converts dopamine to 3,4-dihydroxyphenylacetic acid (DOPAC), and what drug inhibits this process?
MAO-B, inhibited by selegiline or rasagiline
What enzyme converts dopamine to 3-Methoxytyramine, and what drug inhibits this process?
COMT, inhibited by entacapone or tolcapone (mostly in periphery)
The net effect of PD is to suppress the extrapyramidal system via the direct and indirect DA pathway. How does this cause symptoms?
decreased ability to initiate voluntary movements and increased involuntary movements
One of your patients, a 48 yo male, has been recently diagnosed with Parkinson’s disease and states that he read on the internet that Sinemet (carbidopa + levidopa) is the best treatment and is wondering why you haven’t prescribed it to him yet. What do you say?
This med combo is very effective for 2-5 years, but the effectiveness decreases after that. Also, dyskinesias develop after 5-8 years of treatment. Because the patient is young, you are trying to effectively control his symptoms and slow his disease without sinemet first
One of your patients, a 48 yo male, has been recently diagnosed with Parkinson’s disease. You decide to prescribe a dopamine receptor agonist that is selective for D2. You live in England. What are your options and their major side effects?
- Pramipexole (SE: compulsive behavior via D3 in nucleus accumbens)
- Ropinorole (SE: sudden daytime sleep attacks)
- Rotigotine (transdermal patch, not in US)
Your patient with PD has been on levodopa/carbidopa therapy for awhile but comes to the office because this morning she woke up and found herself severely immobile (practically frozen!). What drug do you use to rescue her from this “off time,” and what drug must you give her first to prevent severe emesis?
Apomorphine, a SQ injection of DA receptor agonist
Pre-administer trimethobenzamide or domiperidone
What PD symptoms are anticholinergics effective in treating?
tremor, drooling
What is the clinical use of amantidine?
reduces the dyskinesias that can be associated with long term levidopa use
You’re on neurology rounds and your attending asks you whether you think a PD patient could be a candidate for deep brain stimulation. What is something you have to be sure of before you say yes?
must be still responsive to levodopa/carbidopa therapy!
- stimulates subthalamic nucleus
