Parkinson's disease
| Parkinson's disease | |
|---|---|
| Other names |
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A. 1880s illustration of Parkinson's disease (PD) B. Mild motor-predominant PD C. Intermediate PD D. Diffuse malignant PD | |
| Specialty | Neurology |
| Symptoms |
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| Complications |
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| Usual onset | Age over 60[1] |
| Duration | Long-term |
| Risk factors | |
| Diagnostic method |
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| Differential diagnosis |
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| Treatment | Supportive measures & control of symptoms, physical therapy, deep brain stimulation, medication |
| Medication | Levodopa, COMT inhibitors, AAAD inhibitors, dopamine agonists, MAO-B inhibitors |
| Prognosis | No known cure; near-normal life expectancy. |
| Frequency | 0.2% (Canada) |
| Named after | James Parkinson |
Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor and non-motor systems. The motor symptoms are collectively called parkinsonism and include tremors, bradykinesia (slowness in inititating movement), rigidity, and postural instability (difficulty maintaining balance). Non-motor symptoms such as dysautonomia (autonomic nervous system failures), sleep abnormalities, anosmia (decreased ability to smell), and behavioral changes or neuropsychiatric problems, such as cognitive impairment, psychosis, and anxiety, may appear at any stage of the disease. Symptoms typically develop gradually and non-motor issues become more prevalent as the disease progresses.
Most Parkinson's disease cases are idiopathic, though contributing factors have been identified. Pathophysiology involves progressive degeneration of nerve cells in the substantia nigra, a midbrain region that provides dopamine to the basal ganglia, a system involved in voluntary motor control. The cause of this cell death is poorly understood, but involves the aggregation of alpha-synuclein into Lewy bodies within neurons. Other potential factors involve genetic and environmental influences, medications, lifestyle, and prior health conditions.
Diagnosis is primarily based on signs and symptoms, typically motor-related, identified through neurological examination. Medical imaging techniques such as positron emission tomography can support the diagnosis. PD typically manifests in individuals over 60, with about one percent affected. In those younger than 50, it is termed "early-onset PD".
No cure for PD is known, and treatment focuses on alleviating symptoms. Initial treatment typically includes levodopa, MAO-B inhibitors, or dopamine agonists. As the disease progresses, these medications become less effective and may cause involuntary muscle movements. Diet and rehabilitation therapies can help improve symptoms. Deep brain stimulation is used to manage severe motor symptoms when drugs are ineffective. Little evidence exists for treatments addressing non-motor symptoms, such as sleep disturbances and mood instability. Life expectancy for those with PD is near-normal, but is decreased for early-onset.