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, depressive, anxiety, sleep disorder
Complications	Falls, dementia, aspiration pneumonia
Usual onset	Age over 60[1][2]
Duration	Long-term
Causes	Unknown
Risk factors	Family history, dyspepsia, general anesthesia, pesticide exposure, head injuries[3]
Diagnostic method	Based on symptoms,[1] medical imaging
Differential diagnosis	Dementia with Lewy bodies, progressive supranuclear palsy, essential tremor, antipsychotic use,[4] fragile X-associated tremor/ataxia syndrome, Huntington's disease, dopamine-responsive dystonia, Wilson's disease[5]
Prevention	Physical activity, nicotine, caffeine
Treatment	Physical therapy, deep brain stimulation[1]
Medication	L-DOPA, COMT inhibitors dopamine agonists,[6] MAO-B inhibitors
Prognosis	Near-normal life expectancy
Frequency	8.5 million (2019)[7]
Named after	James Parkinson

Parkinson's disease (PD), or simply Parkinson's, is a long-term neurodegenerative disease of mainly the central nervous system that affects both the motor system and non-motor systems. The symptoms usually emerge slowly, and as the disease progresses, non-motor symptoms become more common. Usual symptoms are tremor, 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 arise in advanced stages.

Most of the cases of Parkinson's disease are idiopathic but a few contributing factors have been identified. Pathophysiology is characterized by nerve cell death in the locus coeruleus and substantia nigra, latter being a midbrain region that supplies dopamine to the basal ganglia which are involved in voluntary motor control. The cause of this cell death is poorly understood but includes the alpha-synuclein aggregation into Lewy bodies within the neurons. Other possible factors involve genetic and environmental mechanisms as well as medications, lifestyle or 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, and treatment aims to mitigate 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 where 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.