Pat De Paolo February 22, 2011
Parkinson’s diseaseis a progressive degenerative disorder of the central nervous system. Parkinson’s destroys the myelin sheath around axons which disrupts nerve impulses in the brain. The most obvious symptoms include shaking, rigidity, slowness of movement, and difficulty with walking. Later stages of the disease may result in behavioral problems. Parkinson’s idiopathic, meaning it has no real known cause. Some people do have genetic factors that may lead to PD.
The areas of the brain associated are the basal ganglia. The main symptoms of Parkinson’s disease result from reduced activity of dopaminesecreting cells due to apoptosis in the substantia nigra. The most characteristic pathological finding in PD is an accumulation of Lewy bodies in the substantia nigra and several other brain regions. The loss of the important neurotransmitter dopamine disturbs the delicate balance of other neurotransmitters such as noradrenaline, serotonin, acetylcholine, GABA and glutamate in the basal ganglia circuit. This causes a neurotransmitter change that affects voluntary control as well as ANS functions.
Several genetic mutations that cause PD have been found. Genes identified are alpha-synuclein (SNCA), and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) to name a couple. Most people with these genetic mutations will develop Parkinson’s. A diagnosis of Parkinson’s disease is usually made based on the medical history and neurological examinationof the patient. The doctor conducts an interview and looks at key motor symptoms, while attending to other possible symptoms that would exclude a diagnosis of PD because PD has a varied set of causes and symptoms so every case is unique. There is no definitive test for diagnosis, but finding Lewy bodies during autopsy has traditionally been considered thenormal routine. There is no cure for Parkinson’s disease, but medications, surgery and multidisciplinary management can provide relief from the symptoms of PD. The main types of drugs useful for treating motor symptoms are levodopa, dopamine agonists and MAO-B inhibitors. The progress and stage of the disease determines which drug would be the most useful. Treatment in the initial stage aims at the start of L-DOPA treatment which may be delayed by using other medications such as MAO-B inhibitors and dopamine agonists, in the hope of delaying the onset of dyskinesias. In the second stage the aim is to reduce symptoms while controlling fluctuations of the response to medication. If this is ineffective, surgery and deep brain stimulation can be of use. Surgery was more common previously to the discovery of levodopa but now it is used in cases that cannot be controlled with drugs. Other treatments such as diet and rehabilitation have been used but are widely ineffective.