Parkinson’s Disease

Question 1

Parkinson’s disease presentation

Answer 1

This man complains of a persistent tremor. Examine him neurologically.

Question 2

Clinical signs Parkinson’s disease

Answer 2

1. Expressionless face with an absence of spontaneous movements.
2. Coarse, pill‐rolling, 3–5 Hz tremor. Characteristically asymmetrical.
3. Bradykinesia (demonstrated by asking patient to repeatedly oppose each digit onto thumb in quick succession).
4. Cogwheel rigidity at wrists (enhanced by synkinesis – simultaneous movement of the other limb (tap opposite hand on knee, or wave arm up and down).
5. Gait is shuffling and festinant. Absence of arm swinging – often asymmetrical.
6. Speech is slow, faint and monotonous.
   In addition
7. Blood pressure looking for evidence of multisystem atrophy: Parkinsonism with postural hypotension, cerebellar and pyramidal signs.
8. Test vertical eye movements (up and down) for evidence of progressive supranuclear palsy.
9. Dementia and Parkinsonism: Lewy‐body dementia.
10. Ask for a medication history.

Question 3

Causes of Parkinsonism

Answer 3

1. Parkinson’s disease (idiopathic)
2. Parkinson plus syndromes:
   a. Multisystem atrophy (Shy–Drager)
   b. Progressive supranuclear palsy (Steele–Richardson–Olszewski)
   c. Corticobasal degeneration; unilateral Parkinsonian signs
3. Drug‐induced, particularly phenothiazines
4. Anoxic brain damage
5. Post‐encephalitis
6. MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) toxicity (‘frozen addict syndrome’)

Question 4

Pathology of Parkinsonism

Answer 4

• Degeneration of the dopaminergic neurones between the substantia nigra and basal ganglia.

Question 5

Treatment of Parkinsonism

Answer 5

1. L‐Dopa with a peripheral Dopa‐decarboxylase inhibitor, e.g. Madopar/co‐beneldopa:
   ⚬⚬ Problems with nausea and dyskinesia
   ⚬⚬ Effects wear off after a few years so generally delay treatment as long as possible
   ⚬⚬ End‐of‐dose effect and on/off motor fluctuation may be reduced by modified release preparations
2. Dopamine agonists, e.g. Pergolide, Ropinirole:
   ⚬⚬ Use in younger patients: less side effects (nausea and hallucinations) and save L‐Dopa until necessary
   ⚬⚬ Apomorpine (also dopamine agonist) given as an SC injection or infusion; rescue therapy for patients with severe ‘off’ periods
3. MAO‐B inhibitor, e.g. Selegiline, inhibit the breakdown of dopamine
4. Anti‐cholinergics, can reduce tremor, particularly drug induced
5. COMT inhibitors, e.g. Entacapone, inhibit peripheral breakdown of L‐Dopa thus reducing motor fluctuations
6. Amantadine, increases dopamine release
7. Surgery; deep‐brain stimulation (to either the subthalamic nucleus or globus pallidus) helps symptoms

Question 6

Causes of tremor

Answer 6

1. Resting tremor: Parkinson’s disease
2. Postural tremor (worse with arms outstretched):
   ⚬⚬ Benign essential tremor (50% familial) improves with EtOH
   ⚬⚬ Anxiety
   ⚬⚬ Thyrotoxicosis
   ⚬⚬ Metabolic: CO2 and hepatic encephalopathy
   ⚬⚬ Alcohol
3. Intention tremor: seen in cerebellar disease