Parkinson's and Huntingdon's Flashcards
(22 cards)
Huntingdon’s chorea presents with
- Chorea (movement disorder that causes involuntary, irregular, unpredictable muscle movements- dancing)
- Tics (suppressible- stereotyped movements)
- Psychiatric symptoms
What is the inheritance pattern of huntingdon’s
autosomal dominant
an affected individual (Xx) will have a 50% chance of having a child with it as well
explain the genetic abnormality that leads to Huntingdon’s
CAG repeat on the Huntingtin gene (chromosome 4p). it is normal to have around 28 repeats of CAG. Anywhere up of 40 means that you have the disease. The more repeats the more severe the disease.
Abnormal huntingtin protein aggregates in the cell and is associated with cell death.
what is anticipation
the signs and symptoms of some genetic conditions tend to become more severe and appear at an earlier age as the disorder is passed from one generation to the next.
diagnosis of Huntingdon’s
- Genetic testing
Genetic councillor prior to diagnostic testing
Issues around confidentiality
- Differential diagnosis
Any other cause of chorea/ tics—- always think about Wilson’s disease (autosomal recessive)
Non-drug treatments for Huntingdons
handled by MDT
- Dietician- make sure patient gets enough energy if they’re always moving
- speech and language therapist
- neurologist
- palliative care
gene therapy
drug treatment for Huntingdon’s
mainly symptom management
may not be needed if chorea doesn’t stop their day to day activities
first line: VMAT2 inhibitors—– tetrabenzine (reduces dopamine in pre-synaptic neurone)
atypical antipsychotics (block dopamine receptors)
both can cause parkinsonism symptoms
diagnostic criteria of Parkinson’s disease
msut have bradykinesia and 1 of;
Rigidity
Rest tremor
Postural instability
clinical diagnosis is made
considerations for a clinical diagnosis for parkinson’s
Apply the diagnosis of Parkinson’s
Rule out all of the things that it could be
Add in supportive things:
Starts on one side
Has a tremor associated on one side
Worse over time
Stays asymmetrical if it starts that way
Responds to levodopa medication
Long clinical cause
Look for biomarkers
motor symptoms of parkinson’s (aside from diagnositc ones)
- stooped posture
- masked face
- back rigidity
- forward tilt of trunk
- reduced arm swing
- hand tremor
- flexed albows, wrists, hip and knees
- shuffling, short stepped gait
non-motor symptoms of PD
- swallowing difficulties
- speech difficulties
- drooling
- constipation
- urinary symptoms
- gastroparesis
- weight loss/ gain
- cognitive impairment
- apathy
- hallucinations
premotor features- aid in narrowinf history to look for Parkinson’s
before bradykinesia there are neurodegeneratice processes at play
- asomnia (can’t smell)
- REM- sleep behaviour disorder (acting out deams overnight)
- constipation
- mood changes
idiopathic pathophysiology ideas
Misfolding of alpha-synuclein associated with Lewy Bodies and neuronal cell death.
Likely interplay between genetic and environmental factors (e.g., pesticides)
Neuroinflammation, problems clearing things out of cells (autophagy), mitochondrial dysfunction etc
PD and genetics
very rarely caused by genetics- when it is the cause it tends to affect people when they’re younger.
Parents of children with Gaucher’s disease are more likely to get PD (GBA homozygous
Autosomal dominant
- PARL8 (AKA LRRK2)
- SNCA (park ¼)
Autosomal recessive
- (PARK2- AKA parkin)- problem with clearing toxic proteins
Differential diagnoses for PD
Essential tremor- ask about stroke
Vascular parkinsonism- tends to affect lower body first, doesn’t respond to levodopa
Parkinson’s plus syndrome
Dementia with Lewy bodies
name 3 classes of drugs used to treat Parkinson’s
These 3 can be used as monotherapies:
- dopamine agonists
- Co-beneldopa/ Co-careldopa
- Monoamine oxidase B inhibitors
Must be given with levodopa:
- Catechol-O-methyltransferase (COMT) inhibitors
dopamine agonist definition
molecule that actiavates the dopamine receptor
levadopa will cause nausea if metobolised into dopamine in peripheral tissues.
therefore you add Benserazide and Carbidopa to prevent peripheral conversion to dopamine. they can’t cross the blood brain barrier to levodopa can be converted in the brain
monoamine oxidase is an enzyme that transporting neurotransmitters out of the synaptic cleft and back into the presynaptic terminal
advanced treatments for PD
deep brain stimulation- turn off the subthalamic nucleus
apomorphine- dopamine agonist
duodopa
it is important to keep active
