Parkinson's disease: What you need to know in wake of Jesse Jackson's diagnosis

— -- Iconic American civil rights activist, politician and minister Jesse Jackson announced Friday that his doctors have diagnosed him with Parkinson’s disease – a diagnosis that he says comes after several years of symptoms.

Below are answers to some of the more common questions about this disease.

What is Parkinson’s disease?

Parkinson's disease is the second most common neurodegenerative disorder globally, after Alzheimer's disease, affecting more than 1 million people in North America. It was originally described by English surgeon James Parkinson in 1817. While the precise causes of this condition remain unknown, the disease is characterized by abnormalities in a specific region of the brain called the substantia nigra, and it results in decreased signaling of the neurotransmitter dopamine. This imbalance leads to the hallmark symptoms of this condition -- abnormal movements, such as a characteristic hand tremor, slow movements, muscle stiffening, and a decreased ability of the body’s reflexes to appropriately adjust to changes in posture. Psychiatric symptoms often include anxiety and depression. Other characteristic symptoms include walking in short, shuffling steps and decreased facial expressiveness, called “masked facies.”

Who is affected by this condition?

There are an estimated 7.5 million people worldwide living with Parkinson’s, and the risk of developing it increases with age. Approximately 41 per 100,000 persons aged 40 to 49 years has Parkinson's, compared to an estimated 1,900 per 100,000 persons over the age of 79.

What are the risk factors for Parkinson’s?

Aside from older age, the most well-established risk factor for developing Parkinson’s is having a family member who has been diagnosed with this disease, as was the case with Jackson. Men are also 1.5 times more likely to develop Parkinson’s than women. Several large studies have also found a correlation between depression and the development of Parkinson’s, though it is unknown if depression plays a causative role in the development of Parkinson’s, or if it is instead an early symptom. Other possible risk factors include exposure to certain types of pesticides and high consumption of dairy products.

How is Parkinson’s diagnosed?

Parkinson’s is diagnosed based on a patient’s clinical history and physical exam. Diagnosis is made by the when a person has Parkinsonian symptoms without any other explanation, such as another neurological disease, head trauma, or a medication that may also be causing Parkinson’s-like symptoms. There are currently no available laboratory or imaging tests that can confirm a diagnosis of Parkinson’s.

What are the treatments for this condition?

Treatments for Parkinson’s are aimed at correcting the abnormalities in brain dopamine levels and usually include a medication called levodopa or other dopamine-stimulating drugs. These drugs, however, pose a risk of causing uncontrollable movements called dyskinesia. Younger patients with Parkinson’s-associated tremor may benefit from using drugs in a class known as anticholinergics. Some patients who experience symptoms despite medications may benefit from placement of a stimulation device deep in their brains or other neurosurgical procedures. Physical therapy and speech therapy can also be used to help minimize the effects of the disease. Researchers are working on developing gene therapies or methods of neural transplantation to slow or reverse the effects of Parkinson’s, but management with medications and symptomatic support remain the current mainstay of treatment at this time.

What is the prognosis for Parkinson’s?

Neurologic changes seen in Parkinson’s are typically irreversible and may worsen as the disease progresses. The number and severity of symptoms vary from person to person, and there are currently no ways to predict which individuals will experience a rapid or slow decline. Parkinson’s itself is generally not considered to be a fatal disease in and of itself; however, the neurologic changes caused by Parkinson’s increase a person’s likelihood of dying from conditions such as pneumonia due to difficulty swallowing or trauma from falling.