When should I suspect Parkinson's disease?
Suspect Parkinson's disease (PD) in patients presenting with slowness, rigidity, tremor or gait disturbance. Features are usually unilateral initially, becoming bilateral as the disease progresses.
Non-motor symptoms such as depression, fatigue, reduced smell, cognitive impairment, sleep disturbance and constipation may also present early on. Balance problems, falls, dementia or dysphagia may present later in the disease.
Tremor is common but may be absent in up to 30 per cent of patients. Tremor is unilateral or asymmetrical, occurs at rest and improves on moving, and affects the distal part of an extremity (typically at the thumb and index finger, 'pill-rolling', or the wrist). However, an action tremor is occasionally seen.
Rigidity is 'lead-pipe' in the absence of tremor or 'cogwheel' if tremor is present.
What else might it be?
Other causes of parkinsonism include drugs, cerebrovascular disease, dementia with Lewy bodies, Alzheimer's, progressive supranuclear palsy and multiple system atrophy.
Other causes of tremor are essential tremor, beta-agonists, physiological tremor, cerebellar disorders, dystonic tremor and hyperthyroidism.
Essential tremor is not associated with slowness or postural instability, and is an action tremor - there is no tremor at rest. It is bilateral and symmetrical, whereas a unilateral or asymmetrical rest tremor is seen in PD.
What if a patient is taking drugs that induce parkinsonism?
Antipsychotics and anti-emetics (metoclopramide and prochlorperazine) are the usual culprits, but antidepressants, amiodarone, cinnarizine, lithium, sodium valproate and cholinesterase inhibitors can also cause drug-induced parkinsonism.
If possible, reduce or stop the drug and refer to a specialist.
What should I do if I suspect PD?
Refer quickly, and untreated, to a specialist, preferably one with particular expertise in PD (usually a neurologist or an elderly care physician).
NICE states that patients with suspected mild PD should be seen within six weeks,1 but new referrals in later disease with more complex problems require an appointment within two weeks.
CKS have based these recommendations on a NICE guideline,1 a systematic review on the clinical features for diagnosing PD,2 and narrative reviews.3-9
1. National Collaborating Centre for Chronic Conditions. Parkinson's disease: national clinical guideline for diagnosis and management in primary and secondary care. RCP, 2006. www.nice.org.uk
2. Rao G, Fisch L, Srinivasan S et al. JAMA 2003; 289: 347-53.
3. Ng D. West J Med 1996; 165: 234-40.
4. Frank C, Pari G, Rossiter J. Can Fam Physician 2006; 52: 862-8.
5. Hirose G. J Neurol 2006; 253(Suppl 3), iii22-iii24.
6. Rao S, Hofmann, L, Shakil A. Am Fam Physician 2006; 74: 2,046-54.
7. Alves G, Forsaa, E, Pedersen K et al. J Neurol 2008; 255(Suppl 5): 18-32.
8. Jankovic J. J Neurol Neurosurg Psychiatry 2008; 79: 368-76.
9. Weintraub D, Comella C, Horn S. Am J Manag Care 2008; 14(2 Suppl): S40-8.
- Reliable, evidence-based answers to real-life clinical questions, from the NHS Clinical Knowledge Summaries in association with GP. See www.cks.nhs.uk