Case 7 - Parkinson's Flashcards
Outline the pathophysiology behind Parkinson’s Disease
Degradation of dopaminergic neurons in the substantia nigra –> dopamine deficiency –> motor symptoms of PD
What % of dopaminergic neurons in the substantia nigra must be depleted before motor symptoms of PD arise?
50% depletion
What % of Parkinson’s disease is thought to be genetic?
10-15%
List 4 risk factors for Parkinson’s Disease
- Lifestyle: smoking, obesity, high iron, low vitamin D
- Environmental: exposure to manganese and other substances
- History of TBI
(note that PD is considered idiopathic)
What is the typical age of onset and course of Parkinson’s disease?
Age of onset ~60 years old
Progressive over ~10 years
List 4 key clinical features of Parkinsonism (TRAP)
Tremor (resting)
Rigidity
Akinesia / bradykinesia
Postural instability
Mutations in which 4 genes can increase someone’s risk of developing PD?
SNCA gene (encodes alpha-synuclein)
GBA gene (most common)
Dardarin LRRK2 gene (most common cause of DOMINANTLY inherited PD)
Parkin PARK2 gene (most common cause of RECESSIVELY inherited PD)
List 4 clinical features that may appear during the Parkinson’s prodrome
- Constipation (earliest symptom!)
- Mood disorders (anxiety, depression, apathy)
- Anosmia
- Sleep disturbances (REM sleep behaviour disorder, restless leg syndrome)
The motor symptoms of Parkinson’s are usually ________ and ____________ (more prominent on one side).
The motor symptoms of Parkinson’s are usually UNILATERAL and ASYMMETRICAL (more prominent on one side).
Parkinsonism is due to impairment of which neural network? What is the function of this network?
Parkinsonism results from impairment of the extrapyramidal system
The function of the extrapyramidal system is to facilitate involuntary muscle function (e.g. reflexes, posture, coordination)
List 3 Parkinson-plus syndromes and a differentiating factor about each
- Vascular Parkinsonism: symmetric and limited to lower limbs, with no tremor
- Multiple system atrophy (MSA): symmetric, autonomic dysfunction is the first symptom
- Corcticobasal degeneration: alien limb phenomenon, upper limb apraxia as first symptom
For each of the 4 cardinal features of Parkinsonism (TRAP) explain how they are examined and how they can be accentuated
RESTING TREMOR - subsides on voluntary movements but increases with stress.
RIGIDITY - increased and persistent resistance to passive movement (cogwheel rigidity: ‘stalls’ when moved). Rigidity is also responsible for stooped posture and hypomimia.
AKINESIA/BRADYKINESIA - slowed movements in combination w/decreased amplitudes/speed when moving (e.g. when asked to perform rapidly alternating movements with the affected limb, the movements decrease in speed and amplitude)
POSTURAL INSTABILITY - imbalance, tendency to fall. Evaluated using the pull test.
Describe the gait abnormalities seen in a Parkinson’s patient
- SHUFFLING gait (with quickened, shortened steps)
- REDUCED arm swing
- FESTINATION: small, increasingly quick steps
- FREEZING: sudden inability to start or continue movements
- PROPULSION: forward-leaning posture (increased falls risk)
Rapid gait with short steps, interrupted by stopping and freezing
What is the froment manoeuvre?
The patient is asked to perform repetitive movements in the contralateral extremity (e.g., opening and closing of the left fist if the right side is examined) → subclinical rigidity becomes more pronounced and may be detected.
Which primitive reflex may be elicited in people with Parkinson’s disease?
Glabellar reflex
tapping between the eyebrows causes the patient to blink PERSISTENTLY
Handwriting in someone with Parkinson’s disease can become…?
Reduced (micrographia)
List 4 autonomic symptoms of Parkinson’s Disease
- Oily skin
- Sexual dysfunction
- Urinary urgency
- Orthostatic hypotension
List 4 neuropsychiatric symptoms of Parkinson’s Disease
- Depression
- Cognitive problems
- Apathy
- Behavioural changes (irritability, impulsivity)
How is Parkinson’s disease diagnosed?
CLINICALLY: Parkinsonism is a syndrome diagnosed by BRADYKINESIA, PLUS one of the following features:
- Rigidity
- Tremor (4 to 6 Hz)
- Postural instability (not caused by primary visual, vestibular, cerebellar or proprioceptive dysfunction)
Name 4 features that SUPPORT a diagnosis of Parkinson’s Disease (eTG).
- Unilateral rest tremor
- Excellent response to levodopa
- Progressing disorder w/persistent asymmetry
How can bradykinesia be elicited in a physical exam?
Decrementing bradykinesia
e.g. repetitive pronation and supination, opening and closing the fingers, closing the hands into a fist
Explain the difference between lead-pipe and cogwheel rigidity
Lead-pipe rigidity refers to a hypertonic state throughout the range of movement. Immediate resistance to reversal of direction of movement about a joint.
Cogwheel rigidity easier to detect and more common in the upper extremities. Combination of lead-pipe rigidity with tremor.