Parkinson's Disease: What It Is, Symptoms, Diagnosis, and Treatment

Parkinson's disease is one of the most common neurodegenerative diseases.

It is one of the most common neurodegenerative diseases. There is a chemical substance called dopamine, which plays an important role in controlling movement in the body. In a region of the brain called the “substantia nigra,” where dopamine is produced, there is damage and loss of the dopamine-producing cells. When a certain amount of cell loss occurs, symptoms and signs start to appear in patients. The disease affects the quality of life of individuals through the symptoms it causes. It is more commonly seen in older age. Therefore, as people live longer, it is observed at higher rates.

There are many causes that can present similar symptoms to Parkinson’s disease. These are called "Parkinsonism" or "Parkinson's syndromes." Since they can occur due to different causes, they may not respond to the medications typically used in the treatment of Parkinson's disease. Some of these include Parkinson-plus syndromes and secondary (secondary) Parkinsonism, where Parkinson's symptoms are accompanied by other systemic symptoms. Secondary Parkinsonism can be caused by vascular diseases, infections, tumors, medications, and some toxic events. Therefore, it is essential to first make a differential diagnosis and plan the treatment accordingly.

What is Parkinson's Disease?

Parkinson's disease is a progressive neurological disorder that primarily causes movement-related problems. A healthy body ensures smooth and coordinated muscle movements through a substance called dopamine in the brain. This substance is produced in a region of the brain called the "Substantia Nigra." In Parkinson's disease, the cells in the "Substantia Nigra" begin to die, and the dopamine levels drop. As a result, Parkinson's disease develops.

First described as "shaking palsy" in 1817, Parkinson's disease is most commonly seen in individuals between the ages of 40 and 70. However, it occurs in about 5% of people in the 20 to 40 age range.

What Are the Symptoms of Parkinson's Disease?

Parkinson's disease is characterized by four main symptoms:

1. Slowness of movement (bradykinesia)
2. Tremors, particularly at rest (tremor)
3. Muscle rigidity and stiffness (rigidity)
4. Reduced postural reflexes

In addition to these, other systemic symptoms may be present. It is a slowly progressive brain disease.

Symptoms typically begin on one side of the body and may progress to the other side over the years. The most important symptom is slowness of movement, which also affects the patient’s gait. They may walk with small steps, and there is a reduced arm swing on the affected side, along with slow walking. When these symptoms affect the face, a reduced ability to make facial expressions may lead to a "masked face" appearance.

Tremors typically occur when the patient is at rest, most commonly in the hands, but less frequently in the feet, jaw, and lips. Despite being an important symptom, not all Parkinson's patients experience tremors.

As the disease progresses, other symptoms may appear, such as a "flexion posture" (forward and sideways bending of the body), "freezing" (difficulty initiating movement), memory issues, psychiatric symptoms, gastrointestinal problems like constipation, urinary symptoms, and sleep disturbances. Sleep disorders are commonly seen in most patients.

However, there is an early stage called the "premotor" phase in patients without Parkinson's disease, which shows signs that may indicate the future development of Parkinson's. In this stage, symptoms such as constipation, "REM sleep behavior disorder" (a sleep disorder), shouting or fear during sleep, and limb movements could indicate Parkinson’s. A loss of the sense of smell is also a potential early sign of the disease. When looking at the medical history of Parkinson’s patients, many of them have shown these symptoms. These individuals have a higher risk of developing Parkinson's disease, and such symptoms may have appeared years before the disease’s onset.

How is Parkinson's Disease Diagnosed?

The diagnosis of Parkinson's disease is made through a neurological examination. There is no specific laboratory test for the disease. Some tests may be conducted to support the diagnosis or exclude other diseases.

Is There a Cure for Parkinson's Disease?

There is no treatment that can completely stop the progression of Parkinson's disease. The disease does not shorten life expectancy, and with treatment targeting the symptoms, patients can maintain a certain quality of life for many years.

If the diagnosis is accurate, Parkinson’s disease responds very well to treatment, with over 90% of patients showing a positive response. Treatment can be classified into three categories: medication, surgical treatment, and other methods. It is crucial for all these treatment plans to be managed by an experienced neurologist, as we have a variety of effective medications available.

In medical treatment, the medications we use aim to reduce dopamine deficiency by preventing the breakdown of dopamine in the brain, ensuring it stays in the brain for longer periods, or providing drugs that mimic dopamine's effects. The most effective medication is levodopa, which is easily absorbed by the brain.

Through regular check-ups over the years, we are able to help our patients maintain a certain level of daily life. However, as the disease progresses and side effects of the medications arise, new issues may emerge.

In advanced stages, patients may experience freezing of gait, a reduction in the effect duration of medications, involuntary movements, sleep disturbances, autonomic dysfunctions (such as low blood pressure), some psychiatric symptoms, and memory loss.

For patients in advanced stages, if medications do not provide enough response or if involuntary movements develop due to medications, surgical treatment may be an option. This could include apomorphine injections (which have a short-term effect) or medication infusion via a pump that delivers the drug directly from the intestine.

Surgical treatment nowadays primarily involves placing electrodes in specific brain nuclei and sending stimuli (such as thalamic stimulation, pallidal stimulation, and subthalamic stimulation). This approach is particularly effective in some Parkinson's patients, but it is crucial to carefully decide who and how the surgery will be performed.