Download Idiopathic Parkinson`s disease

Idiopathic Parkinson’s Disease handout
Dr Sabrina Akhtar
Definition:
Idiopathic Parkinson’s disease (IPD) is a degenerative, progressive disease affecting
the basal ganglia. It is classified as a movement disorder under the akinetic-rigid
syndromes. Classical features of these syndromes include slowed movement and
increased tone.
Parkinsonism is the clinical definition of several underlying pathologies that can
cause Parkinson’s-like symptoms such as:
-
Resting tremor
Rigidity
Bradykinesia
Postural instability
These are also the main symptoms of IPD. IPD is the most common form of
parkinsonism.
Aetiology:
-
Unknown aetiology.
Several postulated theories: cigarette smoking, MPTP link (by-product of
illicit stimulant drug production) and genetic factors.
Pathology:
IPD arises as a result of:
i) Reduced dopaminergic output from the substantia nigra (due to depletion of
pigmented dopaminergic neurons).
ii) Development of inclusion bodies (Lewy bodies in nigral cells).
iii) Degeneration in other basal ganglia nuclei.
Depletion of pigmented
dopaminergic neurons in
SN
Reduced dopaminergic
output from SN
Inclusion bodies (Lewy
bodies) develop in
nigral cells
Degeneration in
other basal
ganglia nuclei
Neurons in subthalamic nucleus
become more active than usual in
inhibiting activation of the cortex
Bradykinesia
Clinical features:
 Resting tremor- present at rest and when distracted. Diminished on action.
 Rigidity- cogwheel rigidity (mainly upper limbs) and lead pipe rigidity
(mainly lower limbs).
 Bradykinesia- difficulty initiating movement/ poor rapid, fine movements
(especially of fingers)/ facial immobility/reduced spontaneous blinking
(serpentine stare).
 Postural instability- loss of reflexes to maintain upright posture. May develop
retropulsion.
 Gait- shuffling + festinating.
 Speech- monotone/soft/rapid/indistinct.
 Cognitive- cognitive impairment (1/3 of patients)/ depression.
 GI- Constipation/heartburn/dribbling/ dysphagia/weight loss.
 Others- micrographia/greasy skin.
Investigations:
o Clinical diagnosis.
o <50 years: Test for Wilson’s disease.
o CT head scan if:
 Pyramidal/cerebellar/autonomic involvement.
 Diagnosis is in doubt.
Differential diagnoses:
Parkinson-plus syndromes are a group of neurodegenerative disorders that have
features in addition to typical IPD symptoms (i.e. resting tremor, bradykinesia,
rigidity, postural instability). It is important to distinguish these from IPD as typically
these syndromes have very little response to conventional therapy for IPD (i.e.
dopamine replacement therapy), especially vascular parkinsonism.
Management:


Multi-disciplinary team management.
Medical treatment is delayed until clinically necessary because of unwanted
delayed effects with Levodopa therapy which include worsening of tremor and
bradykinesia and the ‘on-off phenomenon’.
Management
Medical
Surgical

Levodopa + peripheral decarboxylase inhibitor.
Others:
-Dopamine receptor agonists (Bromocriptine/Cabergoline).
-Amantadine.
-Rivastigmine (cognitive changes).
-Antioxidant compounds (Vitamins C & E- possible neuroprotective
agents).
Stereotactic thalamotomy.
Multi-disciplinary
Physiotherapy
Reduce rigidity & correct abnormal posture.
Speech therapy
Dysarthria/dysphonia.
Neuropsychiatric
SSRI’s for depression.