Parkinson's disease is a progressive nervous system disorder that affects movement. In Parkinson's disease, certain nerve cells (neurons) in the brain gradually break down or die. Many of the symptoms are due to a loss of neurons that produce a chemical messenger in your brain called dopamine. When dopamine levels decrease, it causes abnormal brain activity, leading to symptoms of Parkinson's disease.

Early signs may be mild and go unnoticed. Symptoms often begin on one side of your body and usually remain worse on that side, even after symptoms begin to affect both sides. Parkinson's signs and symptoms may include:

• Tremor. A tremor, or shaking, usually begins in a limb, often your hand or fingers. You may a rub your thumb and forefinger back-and-forth, known as a pill-rolling tremor. Your hand may tremor when it's at rest.
• Slowed movement (bradykinesia). Over time, Parkinson's disease may slow your movement, making simple tasks difficult and time-consuming. Your steps may become shorter when you walk.
• Rigid muscles. Muscle stiffness may occur in any part of your body. The stiff muscles can be painful and limit your range of motion.
• Impaired posture and balance. Your posture may become stooped, or you may have balance problems as a result of Parkinson's disease.
• Loss of automatic movements. You may have a decreased ability to perform unconscious movements, including blinking, smiling or swinging your arms when you walk.
• Speech changes. You may speak softly, quickly, slur or hesitate before talking. Your speech may be more of a monotone rather than with the usual inflections.
• Writing changes. It may become hard to write, and your writing may appear small.

• Freezing or being stuck in place
• Shuffling gait or dragging of one foot
• Stooped posture
• Small, cramped handwriting
• Sleep problems, insomnia
• Apathy, depression
• Lowered voice volume or tremor when speaking
• Difficulty swallowing
• Constipation
• Cognitive impairment

The cause of Parkinson's is largely unknown. Scientists are currently investigating the role that genetics, environmental factors, and the natural process of aging have on cell death and PD.

There are also secondary forms of PD that are caused by
• Medications such as
  • Antipsychotic : Haloperidol, Risperidone
  • Antiemetics : metoclopramide, Levosulpiride
  • Calcium channel blocker : Flunarizine
• Toxic exposures to carbon monoxide, cyanide
• Hypothyroidism
• Hypoparathyroidism

No specific test exists to diagnose Parkinson's disease. Neurologist will diagnose Parkinson's disease based on your medical history, a review of your signs and symptoms, and a neurological and physical examination.

Blood tests to rule out other conditions that may be causing your symptoms.
Imaging tests such as MRI, and PET scans may also be used to help rule out other disorders. Imaging tests aren't particularly helpful for diagnosing Parkinson's disease.

Parkinson's disease can't be cured, but medications can help control your symptoms, often dramatically.

• Medications :
  Almost all patients with Parkinson’s disease eventually need to take medication to help with their motor symptoms. Carbidopa/Levodopa remains the most effective symptomatic therapy and is available in many strengths and formulations. It also may be used in combination with other classes of medications including Dopamine Agonists, COMT Inhibitors, MAO Inhibitors, and Anticholinergic agents. Treatment is highly individualized and adjusted over time based on symptoms and side effects.A new method to take medication is through a drug pump that delivers a carbidopa/levodopa gel (Duopa) directly into the intestines. Surgery is required to place a small hole (stoma) in the stomach through which a tube is connected to a portable pump worn on your belt. It is designed to deliver the medicine continuously, a little at a time, to improve absorption and reduce off-times. Duopa is similar to insulin pumps used by diabetics.
• Deep Brain Stimulation :
  Some patients with Parkinson’s disease may benefit from deep brain stimulation (DBS), a surgical therapy that has been FDA approved for over a decade. DBS involves implanting an electrode into a targeted area of the brain, The electrodes are stimulated through a connection to a pacemaker-like device located under the skin in the chest. Patients that are considered good candidates for this procedure are those with a robust response to Levodopa, no significant cognitive or psychiatric problems, and no significant problems with balance. The procedure can help patients with medication-resistant tremors. It can also help patients who have significant motor fluctuations in which medication response varies during the day and dyskinesias or extra movements may occur as a side effect of medication.