Neurology · Year 3 · from Neurology

Case 1: Parkinson's Disease

Patient Demographics

  • Age: 67 years
  • Sex: Male
  • Occupation: Retired engineer

Chief Complaint

"My hand shakes and I've been moving slower."

History of Present Illness

The patient's wife first noticed his right hand trembling about 2 years ago, initially only at rest. Over time, she has observed that he moves more slowly - he takes longer to button his shirt, his handwriting has become smaller (micrographia), and he shuffles when walking. He has had several near-falls because his feet seem to "stick" to the floor when turning. His voice has become softer and monotone. He reports constipation for years and loss of sense of smell. He also has vivid dreams where he acts out (REM sleep behavior disorder). No family history of Parkinson's disease. No antipsychotic use.

Neurological Examination Findings

Mental Status:

  • Alert, oriented, cooperative
  • Mildly reduced verbal fluency
  • Hypomimia (masked facies) - reduced facial expression
  • Hypophonia - soft, monotonous speech

Cranial Nerves:

  • Reduced olfaction (CN I)
  • Decreased blink rate
  • Otherwise intact

Motor Examination:

  • Tremor:
  • Right hand: 4-5 Hz rest tremor, "pill-rolling" quality
  • Tremor decreases with action, increases with distraction (counting backward)
  • Mild left hand tremor at rest
  • Rigidity:
  • Right arm: Cogwheel rigidity at wrist and elbow
  • Left arm: Mild rigidity
  • Neck: Axial rigidity
  • Bradykinesia:
  • Right finger taps: Slow, decremental amplitude
  • Right hand opening/closing: Slow, fatigues quickly
  • Left side: Mildly affected
  • Strength: 5/5 throughout (rigidity is not weakness)

Reflexes:

  • 2+ symmetric
  • Plantar responses flexor bilaterally

Postural Stability:

  • Positive pull test - retropulsion with several steps to recover

Gait:

  • Stooped posture
  • Reduced arm swing, more pronounced on right
  • Short, shuffling steps
  • Difficulty initiating gait (start hesitation)
  • Festination (progressively faster, shorter steps)
  • En bloc turning (takes 5+ steps to turn)

Diagnostic Criteria

UK Brain Bank Criteria for Parkinson's Disease:

  1. Bradykinesia PLUS at least one of: rigidity, rest tremor, postural instability (YES - all present)
  2. Supportive features: Unilateral onset (YES), rest tremor (YES), progressive course (YES), asymmetric (YES), excellent response to levodopa (to be tested)
  3. Exclusion criteria: No repeated strokes, head injury, encephalitis, neuroleptic use, MPTP exposure, cerebellar signs, early dementia, Babinski signs

Neuro Workup

  • Clinical diagnosis - imaging not required if classic presentation
  • MRI Brain: Normal (rules out vascular parkinsonism, NPH)
  • DaTscan (dopamine transporter SPECT): Reduced uptake in bilateral striatum, right > left (confirms nigrostriatal degeneration) - ordered if diagnosis uncertain

Diagnosis

Parkinson's Disease - Hoehn and Yahr Stage 2.5 (bilateral involvement with mild postural instability)

Management

Pharmacological Treatment:

  1. First-line: Carbidopa/Levodopa (Sinemet) 25/100 TID
  • Most effective symptomatic treatment
  • Start low, titrate slowly
  1. Adjuncts:
  • MAO-B inhibitor (rasagiline 1 mg daily) - mild symptomatic benefit, possibly disease-modifying
  • Dopamine agonist (pramipexole, ropinirole) - younger patients to delay motor complications
  • Anticholinergic (trihexyphenidyl) - for tremor-predominant, use cautiously in elderly

Motor Complications (anticipate with long-term levodopa):

  • Wearing off - add COMT inhibitor (entacapone) or increase frequency
  • Dyskinesias - reduce individual doses, add amantadine
  • On-off fluctuations - consider extended-release formulations

Non-Motor Symptom Management:

  1. Constipation: Fiber, hydration, polyethylene glycol
  2. RBD: Melatonin, clonazepam (low dose)
  3. Depression: SNRI, SSRI
  4. Orthostatic hypotension: Compression stockings, fludrocortisone, midodrine

Non-Pharmacological:

  1. Physical therapy - gait training, balance exercises
  2. Occupational therapy - ADL modifications
  3. Speech therapy - LSVT LOUD for hypophonia
  4. Exercise - associated with improved outcomes

Advanced Therapies (for motor fluctuations):

  1. Deep brain stimulation (STN or GPi)
  2. Levodopa intestinal gel (Duopa)
  3. Apomorphine continuous infusion

Clinical Image

Image Description: DaTscan (dopamine transporter SPECT) showing reduced tracer uptake in the bilateral putamen with a comma-shaped appearance, consistent with nigrostriatal degeneration in Parkinson's disease.

Attribution: Image from Radiopaedia.org, Case courtesy of Dr. Yuranga Weerakkody. Licensed under CC BY-NC-SA 3.0. Source: https://radiopaedia.org/cases/parkinsons-disease-datscan

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