Parkinson's: causes, symptoms, treatment and prevention
Parkinson's is the most common neurodegenerative disease after Alzheimer's. It is estimated that approximately 1% of people over 60 suffer from this disorder.
Even though it is believed that Parkinson's disease has genetic causes and therefore can hardly be prevented or cured, there are treatments able to relieve their symptoms and delay the physical and cognitive deterioration that entails, especially medicines such as levodopa.
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What is Parkinson's disease?
Parkinson's disease affects regions of the brain that produce dopamine, a neurotransmitter that allows voluntary and precise (fine) movements in addition to other functions not related to motor skills.
The main symptoms of this disease, described by James Parkinson in 1817, include quakes at rest, muscle stiffness and the impairment of speech and walking.
Parkinson's usually starts between 50 and 60 years , although it is not uncommon for it to start from the 30s. The course of this disease is chronic and usually causes severe disability in the person who suffers after about 10 years.
While some treatments can relieve symptoms, once developed Parkinson's disease has no cure.
Causes of this pathology
The symptoms of Parkinson's are a consequence of the degeneration of subcortical brain structures . The destruction of dopaminergic neurons of the basal ganglia, especially of the region known as "substantia nigra", hinders multiple cognitive and motor functions.
The causes of Parkinson's disease they are unknown . It is known that there is a genetic component, since 15% of people diagnosed have close relatives who also suffer or have suffered this disorder.
The development of Parkinson's is probably due to the combination of mutations in several genes . Exposure to some toxins, such as those present in pesticides, herbicides and heavy metals, is also considered a risk factor, although the importance of these environmental factors seems less than that of genetics.
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symptom
The first symptoms of Parkinson's disease usually include slight tremors that intensify progressively . The same happens with the rest of symptoms, which are also related to movement.
Other early signs are the stiffness of the arms when walking, the difficulties in articulating sounds and the lack of facial expression (the "mask face" characteristic of this disease).
Subsequently all these symptoms will worsen as the degree of brain involvement increases, evolving in many cases to the diagnosis of dementia caused by Parkinson's disease.
1. Rest tremors
Rest tremors are slow and wide and occur in a part of the body that is not making any movement . They are very characteristic of Parkinson's disease, to the point that in many cases they are called "parkinsonian tremors".
They usually start in one of the hands, but as the disease progresses they spread to both arms and can also affect the legs and head.
In general, rest tremors occur along with muscle rigidity and motor slowness, and occur to a lesser extent during voluntary movements.
2. Muscular rigidity
The increase in muscle tone that occurs as a result of Parkinson's disease in turn leads to stiffness in the muscles, which limits movements and causes pain .
It is characteristic of Parkinson's that we know as "cogwheel stiffness", which means that when another person moves the affected limbs of the patient they stop, showing excessive resistance, as if there was something that hinders the joints. However, the problem is not in the joints, but in the patterns of muscular activation that the nervous system orders in real time.
3. Bradicinesia (motor slowness)
Parkinson's disease progressively hinders movements, especially those of the extremities. This decreases the ability to perform simple manual tasks , which are being carried out more slowly every time. It also makes it harder to sit up and walk.
On the other hand, the difficulties caused by these motor difficulties also cause that there is little disposition to move, so that the motor symptoms are added a psychological effect that overlaps with the previous.
4. Loss of automatic movements
The involvement of the basal ganglia causes a progressive loss of automatic movements in people with Parkinson's. This is manifested in the absence of flicker, smile and arm swing when walking .
5. Problems of posture and balance
In Parkinson's disease, postural reflexes are affected, resulting in a bent and flexed posture which in turn causes lack of balance or postural instability, facilitating falls and making travel more difficult. In addition, in the case of falls, avoid falling to the ground with all the weight and then get up also costs more.
6. Impairment of the march
One of the most visible consequences of the motor problems we have mentioned are the changes in the march. People with Parkinson's they usually take shorter steps, they drag their feet and they move their arms less when walking.
The difficulties occur in all the phases of the march, so that not only the fact of walking is complicated, but also the ability to start walking, to turn and to stop.
7. Difficulties in speech
Some of the most common speech problems in Parkinson's cases are the decrease in volume and the difficulties in pronouncing , derived from motor affectations in the articulatory organs.
Likewise the prosody is altered, the speech can be accelerated (taquifemia) and some words and phrases can be compulsively repeated (palilalia). These symptoms seem to be more frequent in cases in which Parkinson's disease has dementia.
As a result, the social life of the person is damaged, and sometimes predisposes to seek isolation.
8. Dementia
The alterations caused by Parkinson's in the brain can cause it to develop a specific form of dementia of this disease .
Dementia is diagnosed in 20-60% of Parkinson's cases, although in the rest a lower degree of cognitive deterioration can also occur. Dementia caused by Parkinson's disease is especially likely if the patient is a male, his age is advanced, the onset of his disorder has been late or does not respond well to medication.
In comparison with Alzheimer's disease, the most common cause of severe cognitive impairment, in motor dementia, motor alterations have greater relevance at the beginning. This it's due to the dopamine deficit own of Parkinson's. On the contrary, cognitive symptoms are more intense in the early stages of Alzheimer's.
However, as the Parkinsonian deterioration progresses cognitive symptoms such as memory loss and delusions increase. The different types of dementia differ less between them when they are in advanced stage.
Prevention and treatment
It is not clear if the onset of this disease can be prevented. Some studies suggest that consumption of caffeine and green tea reduces the risk of Parkinson's.
It has also been related the practice of moderate intensity aerobic exercise in adulthood with a lower chance of developing this disease in old age. However, for the time being it has not been possible to confirm the preventive efficacy of the sport, and the same happens with caffeine and green tea.
Once Parkinson's disease has developed, its symptoms can be relieved using different types of treatment. The management of this disorder is mainly carried out with medication that increases the levels of dopamine in the body.
Levodopa is the most commonly used drug to treat Parkinson's, especially in its initial phases . This compound increases the concentration of dopamine. As the disease progresses, levodopa may lose effectiveness, in which case it is replaced by dopamine agonists such as pramipexole and ropinirole.
Other forms of treatment, such as surgery, are less effective than levodopa and similar drugs. Physical exercise and relaxation techniques also help maintain mobility to a greater extent, delaying the progress of Parkinson's disease.
