introduction
Parkinson's disease (PD) similarly recognized as the motor system disorders, refers to illness which is very noticeable by its nerve cells loss (neurons) in the human brain. The cause for the loss of cells continues to be unknown. However, the damage is connected to predominately dopamine producing dopaminergic in the cells of the human brain (Obeso et al., 2010).
Neurons produce dopamine (Fig 1) which is a chemical that transmits communication among substantia nigra and the best parts of the brain to control the human brain movement (Uysal‐Cantürk 2018).
A chemical unrestricted by nerve cells to connect with other cell nerves just like the rest of neurotransmitters. It has numerous roles in the brain and other helpful purposes such as reasoning, attention, working memory, and learning, control of the muscle and balance of the body because of the loss and impaired substantia nigra neurons (Braak et., al 2004).
Fig1: shows normal movement and movement disorders.
‘Substantia nigra’ (substance black) is the absorption of neurons in a detailed area of the brain and this is due to its darkness compared to other regions and they gradually disappear. The ‘substantia nigra’ is part of the Basal Ganglia and controls movement, connects to the motor cortex (Carroll 2017).
Epidemiology
Parkinson’s disease is one of the furthermost common Neurological disorder, it is broadminded adult-onset disease 1% of all Americans over the average age 60 years (Lee et., al 2016). Incidence increases with age, very uncommon under the age of 40 meaning the very first symptoms don’t usually start before the age of 50 and above (Lee et.al 2016).
Estimated figure 7 to 11 million persons living with Parkinson’s disease worldwide and statistically Albania has the highest percentage of patients with the PD where 900 people out of 10,000 people (Tysnes et., al 2017).
In the United Kingdom, the estimated figure is about 1 in 600 people affected by PD and there are 126,000 people in the country with the disease and these cases were reported in 2015/17 (Tysnes et., al 2017).
Regardless of the age, PD is more prevalent in males than females with a ratio of 3:2 notably risk factors such as neuroprotection toxicant exposure, head trauma, by estrogen, mitochondrial dysfunction, or X linkage of genetic risk factors (Wooten et.al 2004).
Categories of Parkinson’s Disease.
Types of Parkinson disease are well known as parkinsonism from Parkinson’s-like syndromes and Parkinson disease itself. No final test for any of the existing types of Parkinson’s, nonetheless with the help of neurological exam, patient history, visualize studies and physical exam do give findings.
Parkinson’s Plus Syndromes
It has some similar symptoms of Parkinson’s disease, such as atrophy and weakness of the muscles, important memory, the problem with the behaviors, inappropriate movement of the eye control, autonomic dysfunction (Alain et., al 2017).
Besides the above similarities, Parkinson’s plus syndrome include Lewy bodies, dementia, supranuclear palsy which is progressive, degeneration of cortico-basal and the treatment used to treat PD is not as effective in treating Parkinson’s plus syndrome plus the shorter period of survival with the syndrome (Alain et.al 2017).
Secondary Parkinson's Disease
A recognizable source of PD can be seen in approximately 11% of patients and with an identifiable cause, these patients can be analyzed as having secondary Parkinson's (Alain et.al 2017). Tests such as CT scans and MRI, as well as blood and urine used as the test to help and work out the causes and give more information (Alain et.al 2017).
Here the main symptoms of PD include tremors, slow movements, stiffness and balance problems. While the illness is not treatable, there are medicines that mimic dopamine and help with slowness, tremors, and stiffness (Fig 1). medications are being explored that may help slow the development of the disease (Alain et.al 2017).
Aetiology.
Until today, the clear etiology of PD is still pending, 90% of the symptoms and signs are due to loss of neurons that produce a chemical messenger in the brain known as dopamine (Jacobs et., al 2016). Once the dopamine levels decline, that’s when the irregular brain activity occurs while leading to symptoms of PD. Some of these causes may be as follows;
Environmental triggers.
Although the risk is moderately small, being in contact with certain toxins is likely to increase the chances of later Parkinson disease (Jacobs et., al 2016).
Risk factors.
Many risk factors influence PD, which eventually leads it to neurodegeneration diseases, such as Age, Family history, Exposure to well water, Rural living–possible link to exposure to pesticides, Certain professions, such as healthcare workers, farmers, teachers and Male sex (Jacobs et., al 2016).
Additionally, other risk factors are a result of life choices, such as age and genetics. As people grow older they are at higher risk of PD possibly due to aging which puts the neurons at risk to the extent of a minor change in protein mitochondrial or digestion function which pushes the cells over the edge (Fig 1) leading to catastrophic cell death (Pahwa et., al 2007).
Fig 1. Shows Changes within SN neurons with advancing age.
Genes.
Genetically, six to eleven genetic factors have related to PD, About 10% to 16% of PD. Having a first step relative to PD increases the chances of getting PD perhaps 2 or 3-fold which is possibly a 4% generation risk (Pahwa et.al 2007).
Pathophysiology.
The pathological trademark of PD is the Lewy body, complete predominantly of alpha-synuclein and other damaged proteins (Rocha et.al 2018).
The signs and symptoms of PD are large as for result of the loss of dopaminergic neurons in the ‘substantia nigra’ of the midbrain. Furthermore, signs will appear after 70% to 80% of the cells results to be decreased or die (Rocha et.al 2018).
Cell death results to lead to abnormal activity in the basal ganglia, which generally causes the motor signs of the disease (Rocha et.al 2018). Parkinson's disease has also been linked with Enlarged oxidative stress, Protein combination (alpha-synuclein), Mitochondrial dysfunction and Proteasomal dysfunction (Rocha et.al 2018).
Symptoms.
Although Parkinson's is measured as a complicated condition with several possible symptoms. people have with PD may experience several of non-motor and motor symptoms which decrease the value of life.
Motor symptoms (Physical).
They can affect a good number of activities such as writing, eat, sleeping. Generally, one first start experiencing symptoms on one side of the body and as time goes on it moves to other parts of the body (McDonald et al 2017). Later during the disease, because a significant amount of the ‘’substantia nigra’’ neurons have already been gone missing or reduced and the way they develop is different for each person (McDonald et al 2017).
Bradykinesia.
Most symptoms of PD are physically seen (Fig 2) particularly in the later stages of the disorder, for example; loss of involuntary movement is mostly frustrating mostly because it is unpredictable; the patient can be moving and before you know it he/she can’t move (McDonald et al 2017).
Predominantly in future of the disorder, patients may experience the abrupt failure to walk, characteristically lasting less than a minute, whereby most patients have complained about their feet to feel like glue on the ground ‘’like not moving’’ (Schrag et.al 2017).
It is known as freezing gait and this may or most cases lead to dangerous falls (McDonald et al 2017). many results to be dependent on the wheelchair (Aarsland, Bronnick et al. 2007).
Tremor. The tremor usually starts in the jawbone and foot or the hand is being affected first, Tremor also affects any other part of the body (McDonald et al 2017). A tremor refers to a movement which is uncontrollable that distresses a part of the human body, it is also the main symptom for PD patients (McDonald et al 2017).
In 65% of patients with PD, the tremor can affect just one specific part of the body or side, mostly in the beginning with the illness and in the later stage, the tremor becomes widespread (McDonald et al 2017).
Rigidity. Rigidity arises in response to signals from the brain, the gentle balance of opposing muscles is disturbed. The muscles stay continuously tensed and thin for the patient to start feeling stiff and weak (Aarsland, Bronnick et al. 2007). Rigidity can be increased by muscular resistance to the passive choice of gesture (Schrag et.al 2017).
Fig 2: Shows most symptoms of Parkinson’s disease.
Postural instability. Injury in balance and management causes patients to lean onward or backward to drop effortlessly. Once the patient knocks either front or trying to walk, she or he will lean backward. As the illness progresses, patients may be walking with a series of quick (Schrag et.al 2017).
Non-Motor Symptoms
These symptoms could be treated with a suitable therapy. symptoms can’t be predicted which could affect the patient individually. None of those symptoms are deadly, nonetheless affects the quality of life.
Depression (psychiatric). Independent System and understanding all appear in either early or later stage of the illness, even earlier other signs are observed (Aarsland, Bronnick et al. 2007).
Still, it could not be served, for example, sleep disturbance, the chemical imbalance within the brain, and sexual arousal may all appear later during the illness (Aarsland, Bronnick et al. 2007). luckily, depression could be effectively treated with antidepressant drugs.
Dysphagia. At a later stage of the illness, Muscles which are used to swallow tends to work less efficiently. most cases saliva and food teed to collect in the mouth and the back of the throat which could result into choking (Schrag et.al 2017). Drugs like Levodopa most likely to help with the problem.
Emotional changes. Most PD patients result to be insecure and fearful. They normally live an isolated life, rarely socializes. Others end up irritable. loss of memory and thinking slow may occur, While the volume to reason remnants complete. Whether persons suffer from dementia from PD is a contentious area still being studied (Brooks 2012).
Dysarthria. Approximately 50% of all PD patients have issues with their speech. They normally express too gently or in a drone, hesitate before speaking or repeat the same words even speak too fast. Such problems are calmed by the speech therapist (Brooks 2012).
Cognitive changes
These changes affect patients on daily bases and sometimes more than, the motor (physical) effects of PD. Even if scientists and doctors are progressively identifying the importance of speaking intellectual and other non-motor symptoms, could still mainly attention on treating physical signs and most changes can stay untreated or treated (Aarsland, Bronnick et al. 2007).
Thinking. Slowness (Bradyphemia). with the ability of thinking may occur. patients could need much time to respond intelligently. The patient takes longer to process information (Aarsland, Bronnick et al. 2007).
Bradyphemia can be misunderstood as intentional behavior, lack of attention, nevertheless it is significant to know that changes in the brain are the source of the symptom (Aarsland, Bronnick et al. 2007).
Memory. Memories with PD patients are relatively modest, some patients will be struggling to recall some events such as where and when occurred if not being helped (Brooks 2012). Resistance patients can be able to remember information way much better if they are given multiple choices to choose from (Brooks 2012).
Language. Verbal changes are rare in PD patient significantly, nevertheless, refined changes may still happen. Patients don’t normally involve themselves in conversations as often. These changes can be misunderstood as insignificance and result in deprived communication (Schrag et.al 2017).
Depression and Dementia. These two are other likely cause of cognitive changes in patients with PD, with dementia as people age, the danger of a liberal decline in the ability to think and recall increases (Brooks 2012)
Diagnosis.
The diagnosis is clinical for PD by observing symptoms such as tremor, postural instability, and stiffness of the muscle). No biomarkers or confirmatory diagnostic tests accessible yet for PD (Brooks 2012).
Normally symptoms of Parkinson’s disease will only consider PD’s diagnosis by a trained physician by using a specialised brain scan (available in the UK) normally used and after the examination has at least more than one core motor signs of Parkinson’s (Fig 3) which includes anxiety, depression, tiredness, slow movements, memory loss and tremor or shaking and this normally begins in the hands (Brooks 2012).
Fig 3: illustrates DaT or PET scan.
There several ways scientists and physicians have been exploring to classify biomarkers for the PD to manage earlier diagnosis and the treatment for the PD disease process (Schrag et.al 2017). Presently, all therapies used for the disease indicates the improvement of symptoms and signs without decelerating the illness growth (Schrag et.al 2017)
The dopamine transporter (DaT) scan been helping (Fig 3) depends on one’s symptoms, not all the people need the DaT scan to Determine the diagnosis right. In case of uncertain PET and DaT scan can be more useful (McDonald et al 2017).
Treatment.
There are different choices of treatment depends on the type and stage of the PD such as medicine and surgery to manage the signs and symptoms (Nord et.al 2017). Even if there is no actual cure and the cause still unknown.
Drug therapies
Dopamine (dopaminergic) is the most mutual therapy used by many (Nord et.al 2017). Such as levodopa unlike dopamine which can’t cross the blood-brain barrier by its self (Fig 4) but it’s quicker to leave a levodopa in the brain cells and once in the brain levodopa can be changed by Dopa-decarboxylase most importantly within nigrostriatal neurons (Moreadith et.al 2017).
Fig 4: Depicts the sites of action of different medications used in PD.
Levodopa is managed with carbidopa because of it inhibitor and it is the main drug used to treat PD (Moreadith et.al 2017). therefore, the drug must be supervised carefully to decrease symptoms of the motor to avoid neuropsychiatric complications (Moreadith et.al 2017).
Surgery
With surgery, the brain tissues are carefully destructed (lesioning) and it is so common in old patients who have a one-sided tremor which is large (Thevathasan and Gregory 2010). Because of the high risk of compilations, this method is always seen as the last option.
Deep Brain Stimulation (DBS)
This is the main surgery therapy used for treating PD to help with the movement associated problems, it doesn’t cure but it helps (Thevathasan and Gregory 2010). Surgeons place a battery device which transports electrical stimulation into the brain and it targets movement control and avoiding tremor (Thevathasan and Gregory 2010).
Future views.
Clinicians and scientists are working together to discovery prevention or treatment technique. Scientists (researchers) are also seeking day and night to understand who is more likely to develop the disease. Furthermore, researchers are learning the genetic and ecological features which escalate the chance of a diagnosis.
Conclusion
Due to the slow loss of neurons which produces dopamine that causes an imbalance in the brain hence leading to signs and symptoms of tremor which results in Parkinson’s disease. The diagnosis of PD is made mainly on clinical bases and the treatment its self is through oral drugs which are targeted to take over dopamine. As a disorder harshness deteriorates and side-effects of the therapy result exceptionally inferior, more essential therapies such as Drug therapies, DBS and surgical lesioning are all discovered. Researchers may disclose helpful treatment in the future.