Parkinson

Parkinson’s disease is a progressive neurological disorder caused by the degeneration (loss of function and death) of dopaminergic neurons in the place region of the brain called the substantia nigra. This condition is characterized by a reduction in the production of dopamine, a neurotransmitter critical for coordinating movement. It was first described in 1817 by British physician James Parkinson and named after him at his request. Parkinson’s disease is the second most common neurodegenerative disorder after Alzheimer’s disease and typically affects individuals aged 60 age and older; however it can rarely occur in younger individuals under 40 like. It is approximately twice as common in men as in women. In Türkiye, the disease affects 3 per 1000 of the population aged 15 and above and 2% of those aged 65 and older, impacting approximately 10 million people worldwide.

Key Features

Parkinson’s disease is a subtle and slowly progressing movement disorder that begins with the loss of nerve cells in the brain that produce dopamine. Dopamine is a chemical substance in the brain responsible for regulating and fine-tuning movements. Symptoms emerge when 60–80% of the dopaminergic neurons in the substantia nigra have been lost or destroyed. The disease typically begins in middle to late adulthood and progresses over a period of 15–25 years. Cases occurring at a young age (5–10%) are often associated with genetic factors. Symptoms usually start unilaterally and spread to the opposite side over the years. Parkinson’s disease is not limited to motor (movement-related) symptoms; it also affects quality of life through non-motor (non-movement) symptoms.

A visual related to Parkinson’s disease (generated by artificial intelligence)

Causes and Risk Factors

The exact cause of Parkinson’s disease is unknown, but it is believed that the degeneration of dopamine-producing cells is triggered by a combination of genetic and environmental factors. Genetic predisposition plays a significant role, particularly in early-onset cases; individuals with a family history of Parkinson’s have a higher risk than the general population. Environmental factors include exposure to chemicals such as pesticides, agricultural agents, manganese, rural living, well water consumption, and head trauma (for example from boxing). Interestingly, studies suggest that smoking and coffee consumption may reduce the risk of Parkinson’s; coffee intake is particularly highlighted as a protective factor. Age is one of the most important risk factors; the prevalence of the disease increases markedly after age 60. Additionally, male gender and diabetes comorbid conditions may also increase risk.

Symptoms

The symptoms of Parkinson’s disease are divided into two main groups: motor and non-motor, and they vary throughout the course of the disease.

A visual related to Parkinson’s disease (generated by artificial intelligence)

Motor Symptoms

• Tremor: Occurs as the initial symptom in approximately 60–70% of patients. This tremor, typically present at rest, is observed in the hands (for example during money counting), fingers, arms, legs, jaw, tongue, or lips. It intensifies during stress, anxiety, or walking but diminishes or disappears with voluntary movement.
• Bradykinesia (Slowness of Movement): Manifests as reduced amplitude of movement, difficulty initiating movement, and inability to perform rapid successive movements. Daily activities such as Button buttoning, tying bağlama, writing writing, turning in bed, and sitting up or standing become difficult. It is the fundamental finding for diagnosis.
• Rigidity: Increased muscle tone causes stiffness in the hand, foot wrist, elbow, shoulder, and neck. This situation can present as early symptoms resembling unilateral shoulder pain.
• Postural and Balance Impairment: Patients develop a stooped posture, take small small steps, show reduced arm swing during walking, and in advanced stages experience falls due to balance loss. In later stages, freezing episodes (inability to initiate movement) become more frequent.

Non-Motor Symptoms

Beyond motor symptoms, numerous other symptoms affect quality of life. These include loss of smell sense (an early sign), constipation, sleep disturbances (REM sleep behavior disorder, excessive daytime sleepiness), depression, Anxiety, orthostatic hypotension (drop in blood pressure upon standing), urinary incontinence, sexual dysfunction, increased sweating, swallowing difficulties, and in advanced stages dementia. In early stages, nonspecific complaints such as fatigue, body aches, and difficulty with fine motor tasks are also commonly reported.

A visual related to Parkinson’s disease (generated by artificial intelligence)

Stages of the Disease

Parkinson’s disease progresses through five stages, with increasing severity of symptoms and declining independence:

• Stage One: Symptoms are mild and unilateral. Mild tremor, reduced facial expression (mask face), and gait disturbances may be overlooked. Daily life is unaffected; medication needs are minimal.
• Stage Two: Symptoms become bilateral. Tremor, bradykinesia, and postural changes worsen, but the patient remains independent.
• Stage Three: Balance impairment, slowed reflexes, and falls begin. Daily tasks become more difficult, but the patient can still live independently.
• Stage Four: Movement becomes very slow, walking becomes difficult, and the patient can no longer live alone. Tremor may lessen, but speech difficulties and medication side effects become prominent.
• Stage Five: The patient is confined to a wheelchair or bed. Rigidity is severe and full-time care is required for all needs.

Diagnostic Methods

The diagnosis of Parkinson’s disease is made based on the patient’s clinical history and neurological examination; bradykinesia is an essential finding. Brain imaging techniques (MRI, CT) and blood tests are used for differential diagnosis to rule out other causes of parkinsonism such as cerebrovascular disease, tumors, or drug side effects. DaTscan is an imaging technique that uses a radioactive tracer to label dopamine cells, facilitating early diagnosis. In Türkiye, it has been available since 2018 in limited centers and is effective in distinguishing Parkinson’s from age-related or depression-related slowing and in predicting disease progression. Advanced methods such as Positron Emission Tomography (PET) and DAT-SPECT are not routinely used in clinical practice.

Treatment Methods

There is no cure for Parkinson’s disease, but various methods are used to control symptoms and improve quality of life.

Medication

The cornerstone of treatment is medications that increase dopamine levels. Dopamine precursors and dopamine agonists support dopaminergic transmission in the brain. Medications must be taken consistently and regularly; abrupt discontinuation can lead to life-threatening risks. Treatment is individualized; a drug effective in one patient may be insufficient in another. Most patients respond well to medication in the first five years, but long-term use may lead to complications such as motor fluctuations (on-off periods), involuntary movements (dyskinesia), and medication resistance.

Surgical Treatment

When medication response declines or side effects become prominent, surgical options are considered. Deep Brain Stimulation (brain pacemaker) regulates movement centers in the brain through electrical stimulation. It operates via a generator implanted in the chest wall and functions on a principle similar to a heart pacemaker. It is applied to patients under 65 years of age without dementia who initially responded well to medication. The battery lasts 5–6 years and is replaceable. Surgery does not halt disease progression but reduces required medication dosage.

Infusion Therapies

In advanced stages, oral medications are replaced by continuous subcutaneous injection infusion or intrajejunal infusion (gel-form medication pump). These methods aim to reduce motor fluctuations and dyskinesia.

Supportive Therapies

Physical therapy, exercise, and symptom-targeted additional therapies (for depression, sleep disorders) support the patient’s quality of life. Although Broad bean containing dopamine-rich foods are recommended, excessive intake may trigger involuntary movements.

Frequently Asked Questions and Misconceptions

• Is Parkinson’s genetic? Genetic predisposition is important; risk is higher in those with a family history, but environmental factors are also required.
• How long do patients live? With proper treatment, patients can live 15–25 years or longer; the disease itself is not fatal.
• Is every tremor Parkinson’s? No, unilateral resting tremor is typical, but other causes exist.
• What should the diet be like? High-fiber foods (for constipation), calcium and vitamin D (for bone health) are recommended. Antioxidants may be beneficial, but there is no conclusive data for vitamin E.
• Is loss of smell observed? Yes, it can be an early sign.

Social and Scientific Dimensions

Parkinson’s disease is an increasingly prevalent health issue due to aging populations. In Türkiye, it is estimated that 150,000 to 400,000 patients exist, with approximately 10,000 new diagnoses each year. World Parkinson’s Day on 11 April is observed to raise awareness and awareness support. Current research continues into vaccines and genetic therapies, and Parkinson’s remains the neurodegenerative disease with the best response to medical and surgical treatments. Early diagnosis is critical for slowing disease progression and extending the period of high-quality life.

Disclaimer: The content in this article is provided solely for general encyclopedic information purposes. The information here should not be used for diagnosis, treatment, or medical advice. Always consult a physician or qualified healthcare professional before making any health-related decisions. The author and SPHERE Encyclopedia assume no liability for any consequences arising from the use of this information for diagnosis or treatment purposes.