Parkinson's disease

Parkinson's disease
Parkinson's disease
Other names	Idiopathic or primary parkinsonism, hypokinetic rigid syndrome, paralysis agitans, shaking palsy
	1880s illustration of Parkinson's disease (PD) Intermediate PD
Specialty	Neurology
Symptoms	Tremor, bradykinesia, rigidity, postural instability, dysautonomia, depression, anxiety, sleep abnormalities
Complications	Falls, dementia, aspiration pneumonia
Usual onset	Age over 60
Duration	Long-term
Risk factors	Family history, dyspepsia, general anesthesia, pesticide exposure, head injuries
Diagnostic method	History and neurologic examination, medical imaging, dopamine levels in urine
Differential diagnosis	Dementia with Lewy bodies, progressive supranuclear palsy, essential tremor, antipsychotic use, fragile X-associated tremor/ataxia syndrome, Huntington's disease, dopamine-responsive dystonia, Wilson's disease
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. Symptoms typically develop gradually and non-motor issues become more prevalent as the disease progresses. The motor symptoms are collectively called parkinsonism and include tremors, bradykinesia, rigidity as well as postural instability (i.e., difficulty maintaining balance). Non-motor symptoms develop later in the disease and include behavioral changes or neuropsychiatric problems such as sleep abnormalities, psychosis, anosmia, and mood swings.

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 like positron emission tomography can support the diagnosis. Parkinson's 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 Parkinson's 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. There is little evidence 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.