Parkinson's Disease (cont.)

In its early stages, Parkinson's disease can resemble a number of other conditions with Parkinson-like symptoms known as Parkinsonism. These conditions include multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, Lewy body dementia, stroke, encephalitis (inflammation of the brain), and head trauma. Alzheimer's disease and primary lateral sclerosis can also be mistaken for Parkinson's disease. Other similar conditions include essential tremor, dystonic tremor, vascular Parkinsonism, and drug-induced Parkinsonism.

An early and accurate diagnosis of Parkinson's disease is important in developing good treatment strategies to maintain a high quality of life for as long as possible. However, there is no test to diagnose Parkinson's disease with certainty (except after the individual has passed away). A diagnosis of Parkinson's disease - especially in the early phase - can be challenging due to similarities to related movement disorders and other conditions with Parkinson-like symptoms. Individuals may sometimes be misdiagnosed as having another disorder, and sometimes individuals with Parkinson-like symptoms may be inaccurately diagnosed as having Parkinson's disease. It is therefore important to re-evaluate individuals in the early phase on a regular basis to rule out other conditions that may be responsible for the symptoms.

A neurologist who specializes in movement disorders will be able to make the most accurate diagnosis. An initial assessment is made based on medical history, a neurological exam, and the symptoms present. For the medical history, it is important to know whether other family members have Parkinson's disease, what types of medication have been or are being taken, and whether there was exposure to toxins or repeated head trauma in the past. A neurological exam may include an evaluation of coordination, walking, and fine motor tasks involving the hands.

Several guidelines have been published to assist in the diagnosis of Parkinson's disease. These include the Hoehn and Yahr scale and the Unified Parkinson's Disease Rating Scale. Tests are used to measure mental capacity, behavior, mood, daily living activities, and motor function. They can be very helpful in the initial diagnosis, to rule out other disorders, as well as in monitoring the progression of the disease to make therapeutic adjustments. Brain scans and other laboratory tests are also sometimes carried out, mostly to detect other disorders resembling Parkinson's disease.

The diagnosis of Parkinson's disease is more likely if:

1. at least two of the three major symptoms are present (tremor at rest, muscle rigidity, and slowness);
   
   
2. the onset of symptoms started on one side of the body;
   
   
3. symptoms are not due to secondary causes such as medication or strokes in the area controlling movement; and
   
   
4. symptoms are significantly improved with levodopa (see below).

Source: MedicineNet.com
http://www.medicinenet.com/parkinsons_disease/article.htm