Parkinson's disease is a specific movement disorder characterized by muscle rigidity, tremor and slowing of physical movement. Since it has been discovered experts are looking for the best possible medication or combination of medication that should relieve the symptoms of this serious condition. Unfortunately, today, there is still no cure for Parkinson's disease. Treatment centers on the administration of medication which relieve symptoms. Mechanism of the disease
Parkinson disease is caused by the damages of the dopamine pathways in the brain. There are four major dopamine pathways in the brain:
1. The nigrostriatal pathway, which mediates movement and is the most conspicuously affected in early Parkinson's disease.
2. The mesocortical,
3. The mesolimbic,
4. The tuberoinfundibular.
These pathways are associated with several functions such as volition and emotional responsiveness; desire, initiative, reward; sensory processes, maternal behavior. Reduction in dopamine along the non-striatal pathways is the likely explanation for much of the neuropsychiatric pathology associated with Parkinson's disease.
Symptoms of Parkinson%26rsquo;s disease
Since Parkinson disease primaily affects movement, in most cases, we are talking about motor symptoms. However, there are many other non-motor symptoms such as disorders of mood, behavior, thinking, and sensation. Here are the most common symptoms of Parkinson;%26rsquo;s disease:
%26bull; Tremor
%26bull; Rigidity
%26bull; Bradykinesia and akinesia
%26bull; Postural instability
%26bull; Shuffling: gait is characterized by short steps, with feet barely leaving the ground, producing an audible shuffling noise
%26bull; Decreased arm swing
%26bull; Stooped, forward-flexed posture. In severe forms, the head and upper shoulders may be bent at a right angle relative to the trunk
%26bull; Festination: a combination of stooped posture, imbalance, and short steps.
It leads to a gait that gets progressively faster and faster, often ending in a fall
%26bull; Gait freezing
%26bull; Dystonia which is characterized by abnormal, sustained, painful twisting muscle contractions
%26bull; Festinating speech which is excessively rapid, soft and poorly-intelligible
%26bull; Drooling: most likely caused by a weak, infrequent swallow and stooped posture.
%26bull; Impaired ability to swallow
%26bull; Masked facies
%26bull; Difficulty rolling in bed or rising from a seated position
%26bull; Micrographia
%26bull; Impaired fine motor dexterity and coordination
%26bull; Impaired gross motor coordination
%26bull; Overall loss of accessory movements
%26bull; Depression:
%26bull; Anxiety or panic attacks
%26bull; Apathy or abulia
%26bull; Slowed reaction time
%26bull; Executive dysfunction
%26bull; Dementia
%26bull; Memory los
%26bull; Medication effects
%26bull; Excessive daytime somnolence
%26bull; Initial, intermediate, and terminal insomnia
%26bull; Disturbances in REM sleep
Risk factors for developing Parkinson%26rsquo;s disease
%26bull; Age
Age is still one of the main risk factors for Parkinson's disease.
%26bull; Heredity
Having one or more close relatives with Parkinson's increases the chances of developing this disease the disease, although the risk is still less than 5 percent.
%26bull; Sex
Men are more likely to develop Parkinson's disease than women.
%26bull; Exposure to pesticides and herbicides
Exposure to herbicides and pesticides puts you at slightly increased risk of Parkinson's.
%26bull; Reduced hormone levels (Estrogen)
Some recent studies have proven that reduced estrogen levels may increase the risk of developing Parkinson's disease. This means that menopausal women or the ones with hysterectomy done may be at higher risk.
Treatment of Parkinson%26rsquo;s disease
Medications
Although there is still no cure for Parkinson%26rsquo;s disease, some medications can help manage problems with walking, movement and tremor by increasing the brain's supply of dopamine. The medications used to treat Parkinson's disease include:
%26bull; Levodopa and carbidopa (Atamet%26reg;, Sinemet%26reg;)
Since it was first discovered, Levodopa has been considered the gold standard drug therapy for Parkinson's disease. Beside the fact that Levodopa is a natural substance found in plants and animals, it is also a precursor to brain%26rsquo;s neurotransmitter dopamine. This means that the chemical structures are similar but when injected into patient it is being converted into dopamine by nerve cells in the brain. The increase in dopamine should relieve many of the disabling symptoms of Parkinson's disease. Dopamine itself cannot be used because it doesn't cross the body's blood-brain barrier which is made up from meshwork of tightly packed cells in the walls of the brain's capillaries that screen out certain substances. Levodopa, on the other hand, does cross this barrier.
Carbidopa (Sinemet%26reg;) is a drug that causes more Levodopa to get to the brain and helps reduce some of the side effects of this therapy and it is given simultaneously with Levodopa. These medicines lose their efficiency over time which means that they need to be taken more frequently. Other side effects may include hallucinations and a drop in blood pressure when standing (orthostatic hypotension).
%26bull; Dopamine agonists
There is a class of medications called Dopamine Agonists which, unlike Levodopa, aren't changed into dopamine. Instead, their purpose is to mimic the effects of dopamine in the brain. Dopamine agonists are used both as adjuncts to Levodopa therapy and also initially in early Parkinson's disease, especially in younger adults. The side effects are almost the same to those of carbidopa-levodopa, although they are less likely to cause involuntary movements and more likely to cause hallucinations or sleepiness. These medications may also increase the risk of compulsive behaviors such as hypersexuality, compulsive gambling and compulsive overeating. Some of the medications from this class are: bromocriptine (Parlodel), pergolide (Permax), apomorphine (Apokyn), pramipexole (Mirapex) and ropinirole (Requip).
%26bull; Selegiline (Eldepryl%26reg;)
This drug is widely used with or without Levodopa therapy. It helps prevent the breakdown of both naturally occurring dopamine and dopamine formed from Levodopa by inhibiting the activity of the enzyme monoamine oxidase B (MAO-B). But, like any other drug it has its limits! Latest studies have shown that Selegiline may delay the need for Carbidopa-Levodopa treatment for about a year, and when taken with Carbidopa-Levodopa, may even enhance the drug's effectiveness.
%26bull; Catechol-O-methyltransferase (COMT) inhibitors
These medications could be extremely important and helpful because they prolong the effect of Carbidopa-Levodopa therapy. They are doing so by blocking an enzyme that breaks down dopamine. These medications include Tolcapone (Tasmar%26reg;), Entacapone and many others.
%26bull; Anticholinergics
Although Anticholinergics aren%26rsquo;t so popular anymore, these drugs were the main treatment for Parkinson's disease before the introduction of Levodopa. They were used to help control tremor in the early stages of the disease. The problem is that they were causing many side effects such as dry mouth, nausea, urine retention ( especially in men with an enlarged prostate) and severe constipation. Anticholinergics can also cause mental problems including memory loss, confusion and hallucinations. Some of the most commonly used anticholinergics are: trihexyphenidyl and benztropine (Cogentin%26reg;), Benadryl%26reg;, Amitriptyline%26reg;.
%26bull; Amantadine
Amantadine is a famous anti-viral medication but sometimes, doctors may prescribe it to provide short-term relief of mild, early-stage Parkinson's disease.
Amantadine may also be added to carbidopa-Levodopa therapy for people in the latter stages of Parkinson's disease.
%26bull; Coenzyme Q10
Q10 this is a substance produced within small structures in cells called mitochondria. This substance is essential for the cells to work normally. It transports electrons during cellular respiration, the process by which cells get their energy from oxygen. People with Parkinson's disease tend to have low levels of coenzyme Q10. That%26rsquo;s why experts are saying that coenzyme Q10 supplements may slow the progression of early-stage Parkinson's disease.
Surgery is also an option!
Neurosurgery is an option to treat Parkinson%26rsquo;s symptoms but it isn't suitable for everyone. There are strict criteria and guidelines as to who can be a candidate for surgery.
The three commonly used forms of surgery are:
%26bull; Thalamotomy %26ndash; a lesion is placed on part of the brain to alleviate some forms of tremor. Thalamotomy involves the destruction of small amounts of tissue in the thalamus which represents a major brain center for relaying messages and transmitting sensations.
%26bull; Pallidotomy %26ndash; In this procedure, an electric current is used to destroy a small amount of tissue in the pallidum. Globus pallidum is a part of the brain responsible for many symptoms of Parkinson's disease.
%26bull; Deep brain stimulation %26ndash; a deep brain stimulator is placed in the brain to control tremor which can be very helpful.
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