Parkinson's disease

Parkinson's disease
Other names	Parkinson disease, idiopathic or primary parkinsonism, hypokinetic rigid syndrome, paralysis agitans, shaking palsy
A. 1880s illustration of Parkinson's disease (PD) B. Mild motor-predominant PD C. Intermediate PD D. Diffuse malignant PD
Specialty	Neurology
Symptoms	Main: Tremor, bradykinesia, rigidity, postural instability (collectively known as parkinsonism) Other: Dysautonomia, depression, anxiety, sleep abnormalities
Complications	Falls, dementia, aspiration pneumonia
Usual onset	Age over 60[1][2]
Duration	Long-term
Risk factors	Family history, dyspepsia, general anesthesia, pesticide exposure, head injuries
Diagnostic method	Based on symptoms,[1] medical imaging
Differential diagnosis	Dementia with Lewy bodies, progressive supranuclear palsy, essential tremor, antipsychotic use,[3] fragile X-associated tremor/ataxia syndrome, Huntington's disease, dopamine-responsive dystonia, Wilson's disease[4]
Prevention	Physical activity, nicotine, caffeine
Treatment	Physical therapy, deep brain stimulation[1]
Medication	L-DOPA, COMT inhibitors, AAAD inhibitors, dopamine agonists,[5] MAO-B inhibitors
Prognosis	Near-normal life expectancy
Frequency	8.5 million (2019)[6]
Named after	James Parkinson

Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease of mainly the central nervous system that affects both the motor and non-motor systems of the body. The symptoms usually emerge slowly, and, as the disease progresses, non-motor symptoms become more common. Usually symptoms include tremors, slowness of movement, rigidity, and difficulty with balance, collectively known as parkinsonism. Parkinson's disease dementia, falls and neuropsychiatric problems such as sleep abnormalities, psychosis, mood swings, or behavioral changes may also arise in advanced stages.

Most cases of Parkinson's disease are sporadic, but a few contributing factors have been identified. Pathophysiology is characterized by progressively expanding nerve cell death originating in substantia nigra, a midbrain region that supplies dopamine to the basal ganglia, a system involved in voluntary motor control. The cause of this cell death is poorly understood but involves alpha-synuclein aggregation into Lewy bodies within the neurons. Other possible factors involve genetic and environmental mechanisms, medications, lifestyle, and previous conditions.

Diagnosis is mainly based on signs and symptoms, usually motor-related, found via neurological examination, though medical imaging like neuromelanin MRI can support the diagnosis. Usual onset is in people over 60 years of age, of whom about one percent are affected. In those younger than 50, it is termed "early-onset PD".

No cure is known; treatment aims to lessen symptoms. Initial treatment typically includes L-DOPA, MAO-B inhibitors, or dopamine agonists. As the disease progresses, these medications become less effective and produce a side effect marked by involuntary muscle movements. Diet and certain forms of rehabilitation have shown some effectiveness at improving symptoms. Deep brain stimulation has been used to reduce severe motor symptoms when drugs are ineffective. There is little evidence for treatment of the non-movement-related symptoms, such as sleep disturbances and mood instability. The average life expectancy is near-normal.