Neurodegenerative Disease: Parkinson's Disease

Parkinson's Disease is a neurodegenerative disorder that affects nerve cells in the brain that control muscle movement.  The disease results from the lack of the chemical messenger dopamine in the brain.  Dopamine is produced in the substantia nigra of the brain.  Parkinson

s Disease causes the cells that produce dopamine to either become impaired or die.  What sets this in motion is yet to be determined.  

Signs and Symptoms

The symptoms of PD are often described using the acronym: TRAP.

T = Tremor: The characteristic tremor of PD often begins in a hand.

R = Rigidity: Muscle stiffness often occurs in the limbs or neck.  This stiffness can be so severe that range of motion and/or pain can result

A = Akinseia: this is the lack of movement or slowness in initiating/maintaining movement.

P = Posture Instability: Characteristic bending or flexion of the body.  It is associated with difficulty in balance and disturbances when walking.

Other symptoms that can appear with the progression of the disease include the loss of automatic movements, speech changes, and dementia.

Risk Factors

There are a few known risk factors for the development of PD.  First and foremost, it is very uncommon for young adults to experience the disease and risk of development increases with the progression of age.  Also, men are more likely to develop Parkinson's Disease than women.  Finally, if you have one or more close relatives have PD your chances of developing it increase.  However, your risk is still less than 5%.  Again, what sets off the initial events towards the development of PD is still unknown.

Diagnosis

Currently there are no definitive tests towards the diagnosis of PD.  This makes it incredibly difficult to diagnosis, especially in the early stages of disease progression.  Often, a diagnosis is made based on your medical history and neurological exam.  This exam includes an evaluation of walking and coordination.  Finally, with a diagnosis, a patient will normally have 2 out of the 3 cardinal Parkinson's Symptoms as mentioned earlier:  either tremor, akinesia, or rigidity.  

Treatment Options

Currently there are two major drugs on the market to treat PD.  First, there is Levodopa.  This is a natural substance that everyone has in their bodies.  When it is taken in a pill form, it passes into the brain and is converted into dopamine.  As PD progresses, medication adjustments will have to occur due to the tendency of the drug to wear off.  Dopamine antagonists are also used to treat PD.  Unlike levodopa, these are not converted into dopamine.  Instead, they mimic the effects of dopamine causing neurons to react as if dopamine were present.  However, they are not nearly as effective in treating the symptoms of PD and are often used to smooth the on-off effect of levodopa.  Other forms of drugs are: MAO B Inhibitors, COMT Inhibitors, Anticholinergics, and Antivirals.  Accompanying drug treatment is physical therapy.  This helps to improve range of motion and muscle tone.  Finally, the most common surgical procedure to treat PD is deep brain stimulation in which an electrode is place in the area of the brain that controls movement.  Stimulation is controlled by a pacemaker-like device placed under the skin in the upper chest.  This form of treatment is often used with patients in advanced stages of the disease.   Although the above treatment options have proven to be beneficial in helping with the symptoms of PD, there still is no cure for the condition.

References:  www.mayoclinic.com