• Ensure patients receive their usual Parkinson’s medications with the correct timing and dosage (carbidopa/levodopa half-life is approximately 2 hours).
• Avoid giving dopamine antagonists, particularly antipsychotics.
• Avoid antidopaminergic medications: nearly all antipsychotics, antiemetics such as metoclopramide and calcium channel blockers such as verapamil.
  • Quetiapine or benzodiazepines are preferred if required.
• Parkinson’s disease (PD) is complex and can lead to a variety of mood, pain and dysautonomic symptoms.

• Parkinson’s disease (PD) is the second most common neurogenerative disease in Canada, affecting about 100,000 Canadians.
• Prevalence increases with age and is expected to rise with our aging population.
• Average age of onset is 60 years, with a range from 40-70 years.
• PD affects the basal ganglia and leads to formation of intraneuronal Lewy bodies. This leads to loss of dopamine release from the substantia nigra and causes motor symptoms.
• Primary PD is typically idiopathic, but secondary PD can occur due to toxic exposures (e.g., manganese), drugs (e.g., antipsychotics), infections (e.g., post encephalitis), and metabolic causes (hypercalcemia, hyperthyroid).

• Diagnosis is clinical: requires two of:
  • Tremor is classically upper extremity, distal and asymmetric (e.g., pill rolling involving the thumb). It can progress to involve the lower extremity.
  • Rigidity can be best appreciated in the wrists. Cogwheeling may also be present
  • Bradykinesia – best appreciated in finger-to-thumb tapping, but also reduced blink, facial expression and hypophonia.
  • Postural changes – orthostatic hypotension and a slow shuffling gait present later.
• Improvement with dopaminergic medications helps strengthen the diagnosis.
• Imaging or laboratory investigations only helpful in ruling out alternative diagnoses.
• Non-motor symptoms common – may present years prior to motor symptoms:
  • Pain and fatigue,
  • mood disorders (anxiety, depression, visual hallucinations),
  • anosmia,
  • sleep disturbances or dream enactment, and
  • gastrointestinal disturbances such as constipation.

• Most common pharmacological option is dopamine agonist carbidopa/levodopa (Sinemet^®). Starting dose is generally 1 tab TID (carbidopa 100 mg/levodopa 25 mg).
  • For very frail patients a 0.5 tab starting dose can be considered.
• Other medications include: dopamine agonists rotigotine, pramipexole and ropinirole: MAO-B inhibitors such as selegiline; anticholinergics such as benztropine; NMDA antagonists such as amantadine.
• Treatments provide symptomatic relief and do not prevent progression.
• For robust patients, implantation of a deep brain stimulator may be an option.
• Important to avoid antidopaminergic medications. Includes nearly all antipsychotics, antiemetics such as metoclopramide and calcium channel blockers such as verapamil.
  • Safer alternatives include quetiapine (e.g., 12.5 mg PO), or benzodiazepines if an IV formulation is required (e.g., lorazepam 2 mg IV)

• Complications of PD that may require admission include:
  • Orthostatic hypotension: PD patients can have significant associated dysautonomia, particularly later in the disease course when orthostatic hypotension can become more prominent. Sinemet (carbidopa/levodopa) can cause hypotension about 30-60 minutes after it’s taken. Management can include compression stockings, abdominal binders, salt tablets and fludrocortisone or midodrine. Admission may be required for severe symptoms (e.g., syncope).
  • Psychosis: frequent complication later in the course of the disease as neurodegeneration progresses. Triggers include sleep disturbances and medical illness. Carbidopa/levodopa itself can lead to hallucinations. Up to 40% of patients on drug treatment may experience some form of hallucinations, most often visual. Consider involving psychiatry and/or neurology as down-titration of carbidopa/levodopa may be considered once medical causes have been ruled out.
  • Parkinsonism-hyperpyrexia syndrome: rare complication that can be considered as a form of neuroleptic malignant syndrome (NMS). It typically results from the rapid discontinuation of dopaminergic medications and leads to hyperthermia, altered mental status autonomic instability and akinesis. Treatment is supportive and similar to NMS (cooling, IV fluids, benzodiazepines), in addition to restarting dopaminergic medications.

• Transfer for specialist consultation may be required if not available at your site (e.g., psychiatry for acute psychosis)
• If deep brain stimulator (DBS) malfunction is suspected, patients should be transferred to a neurosurgical site. These patients may present with worsening Parkinson’s symptoms (e.g., akinesia, severe rigidity).

• If you suspect new-onset Parkinson’s disease, consider an outpatient referral to neurology. You can consider initiating carbidopa/levodopa for moderate motor symptoms in the interim.
• If patients are presenting with progressive dysphagia, consider whether this may represent a progression towards end of life and connect them with palliative care. Dysphagia eventually occurs in up to 80% of cases and becomes unresponsive to antiparkinsonian medications in later stages.

Most patients with Parkinson’s disease can be discharged home unless they required admission for other medical conditions. Patients should be counselled around safety if experiencing orthostatic hypotension (e.g., sitting or lying down when symptoms present). They should also be made aware of the importance of continuing a regular medication regimen.

1. Chaudhuri KR, Odin P, Antonini A, Martinez-Martin P. Parkinson’s disease: the non-motor issues. Parkinsonism & related disorders. 2011 Dec 1;17(10):717-23

   
   

2. Dorsey E, Sherer T, Okun MS, Bloem BR. The emerging evidence of the Parkinson pandemic. Journal of Parkinson’s disease. 2018 Jan 1;8(s1):S3-8.

   
   

3. Parkinson’s disease in the ED: a potpourri of hyperpyrexia, dyskinesias, psychosis, and autonomic dysfunction

   
   

4. Morgante L, Colosimo C, Antonini A, Marconi R, Meco G, Pederzoli M, Pontieri FE, Cicarelli G, Abbruzzese G, Zappulla S, Ramat S. Psychosis associated to Parkinson’s disease in the early stages: relevance of cognitive decline and depression. Journal of Neurology, Neurosurgery & Psychiatry. 2012 Jan 1;83(1):76-8

   
   

5. Kouli A, Torsney KM, Kuan WL. Parkinson’s Disease: Etiology, Neuropathology, and Pathogenesis. In: Parkinson’s Disease: Pathogenesis and Clinical Aspects [Internet]. Codon Publications; 2018 [cited 2023 May 17]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536722/

   
   

6. Canadian Guideline For Parkinson Disease, 2nd Edition. Parkinson Canada. 2019 [cited 2023 May 17]. Available from https://www.parkinsonclinicalguidelines.ca/wp-content/uploads/2019/10/canadian-guideline-for-parkinson-disease-full.pdf