Parkinson’s Disease
The nervous system is a complicated system of the human body that establishes the body’s essential functions besides coordinating and regulating its activities. This review of the literature attempts to summarize the neural underpinnings of PD. The review looks at the pathophysiology of the illness, including how genetics, environment, and protein misfolding play a part in its progression. The review also looks at the many diagnostic criteria for Parkinson’s disease and some of its clinical symptoms, including tremors, stiffness, and bradykinesia. The pathology of PD is complicated and comprises different factors such as, environmental, epigenetic, and genetic. The potential risk factors associated with PD include drugs, environmental toxins, brain microtrauma, pesticides, genomic defects, and cerebrovascular damage. It also focuses on contemporary Parkinson’s disease management approaches, including pharmaceutical and non-pharmacological interventions, including physical therapy. The literature review emphasizes the need for additional studies to enhance the standard of living for the patients by better understanding the disease mechanisms, creating new treatments, and understanding the disease.
Introduction
The nervous system is a complicated system of the human body that establishes the body’s essential functions besides coordinating and regulating its activities. The nervous system comprises the peripheral and central nervous systems. The Central Nervous system consists of the brain and the spinal cord. It is the central processing station, whereas the peripheral nervous system comprises other neural elements and conveys sensory info between the tissues, muscles, and nerves in other body parts of the brain. Neurological disorder is a disease that affects the Central Nervous System due to physical injury of the spinal cord, nerves, or brain. The other causes of the condition may result from changes in certain biochemical elements or even maybe unknown in some states (Rizk et al.,2018). Neurological disorders significantly impact an individual’s quality of life, and their management and treatment can be challenging. Therefore its management is crucial, and the patients should be well cared for.
Neurological disorders are widely distributed among the aged, and they are expressed mainly as abnormalities of thought, behavior, or feeling and may cause distress. They include dementia(Parkinson’s disease(PD), Huntington’s disease, Alzheimer’s disease(AD)), and other contributed ailments, Cerebrovascular conditions such as migraine or stroke and other headache disorders; degenerative disorders such as neuroinfectious, multiple sclerosis, and brain tumors. Neurological disorders like HD, PD, and AD exhibit different extracellular and intracellular variations. This literature review focuses on the neural basis of Parkinson’s disease, a common neurological disorder affecting several people worldwide (Rizk et al.,2018). It also explores the underlying neural mechanisms resulting in the development of PD, as well as current and emerging treatment options.
Overview and epidemiology of Parkinson’s disease(PD)
Parkinson’s disease(PD) is among the broadly studied neurological disorders. It is a chronic condition with evolving layers of complexity. It is linked with non-motor and motor symptomatology, which makes it hard to treat the condition. There are 4.5 to 19 cases of PD per 100,000 people worldwide each year (Church, 2021). Approximately one million individuals in the United States suffer from PD, and about 60,000 new cases are reported annually. The worldwide prevalence is approximately ten million individuals. The condition mainly occurs in persons above 60 years old (Church, 2021). Most cases of PD occur within this age group sporadically and as a result of etiologies, such as oxidative stress and neuroinflammation, intra – cellular alteration and clumping, genetic disorder, mitochondrial activity, environmental variables, and failure of the immune system to function properly are some of the causes of PD. It’s interesting to note that certain genes are frequently linked to PD cases in younger people.
The actual cause of Parkinson’s disease is unfamiliar; It is believed to be a complicated interplay of genetic and environmental variables, though. Together with differences in technique and case ascertainment, the large disparity in incidence estimates can be attributed to the population’s age distribution. Risk factors and genetic backgrounds influence the differences in the prevalence of PD. Patients suffering from PD before age 40 are generally described as having early-onset PD. The young-onset begins between 21 and 40 years, while juvenile Parkinsonism begins before age 20 (Sonne et al., 2020). Genetic studies have shown that most juvenile and young-onset cases result from inheritance or genetic origin, while others are sporadic. The late-onset condition can also be of genetic component. Even though PD historically impacts individuals of both genders equally, data published recently shows that a greater percentage of men, with a male-to-female ratio of 9:1, are impacted by this condition. Around 1% of those over 60 are affected by PD, which affects males more frequently than women. The prevalence of PD increases with age, with an estimated 1 in 100 adults over 65 affected.
Parkinson’s disease affects people worldwide. Approximately 2% of people worldwide suffer from PD by their eighties (Moghaddam et al., 2017). Regional figures indicating the variations in both prevalence reflect the existence of elements that may be demographic,health-care related, environmental, and genetic.
Neuroanatomy of Parkinson’s Disease
Understanding the neurobiology and progression of Parkinson’s disease has advanced significantly in scientific circles. The degenerative process of the disease involves a number of brain regions, from the brain stem to the cortex. As a component of the basal ganglia circuitry, the substantia nigra (SN), a midbrain dopaminergic nucleus, is critical in regulating motor behavior and reward expectations. Parkinson’s disease (PD) motor impairments are largely caused by the nigrostriatal pathway, which connects the SN to the forebrain (Sonne et al., 2020). These extensions move through the medial forebrain bundle to leave the SN and connect to various neuronal groups via the basal ganglia, a collection of interconnected subcortical nuclei that control and modulate roles including voluntary movement, reward-related functions, emotions, and cognitive planning in addition to learning and cognition. The SN is generally viewed as a crucial component of these tasks and the substantial input into the basal ganglia circuitry (Sonne et al., 2020). When the subcortical nuclei are destroyed such as during neurodegeneration or stroke, several neurological disorders can ensue, including Huntington’s disease, PD, Tourette syndrome, obsessive-compulsive disorder, attention-deficit hyperactivity, and schizophrenia. PD is brought on by damage to the substantia nigra’s dopaminergic neurons., and dopamine-supplementation strategies can be used to treat the symptoms of this disorder.
Neurotransmitter Systems in Parkinson’s Disease
Histologically, PD is charcaterised by the accretion of α-synuclein particles called Lewy bodies. The main symptoms of PD are non-motor manifestations, such as REM sleep behavior problems, cognitive deficits, and stress, together with motor symptoms with the sign combination of rigidity, bradykinesia, and tremor (Moghaddam et al., 2017). The substantia nigra’s dopaminergic neurons gradually disappear as PD progresses. Nevertheless, serotonergic and other nondopaminergic neural systems are also involved. Dementia, sleep disturbances, depression, and anxiety, are among the non-motor symptoms and complications associated with Serotonergic dysfunction. This condition lowers the patient’s quality of life. Understanding how the serotonergic system interacts with other neurotransmitter systems is particularly important for understanding the pathology of the disorder. Changes in how the dorsal raphe nucleus functions have been connected to mobility issues and neuropsychiatric illnesses since it is one of the largest clusters of serotonin-producing neurons.
Risk factors associated with Parkinson’s Disease.
The pathology of PS is complicated and comprises different elements, such as, environmental, epigenetic, and genetic factors. The potential risk factors associated with PD include drugs, environmental toxins, brain microtrauma, pesticides, genomic defects, and cerebrovascular damage. Just 10-15% of instances of Parkinson’s disease (PD) are early-onset familial cases, and the rest are idiopathic, indicating that environmental and non-genetic factors are important in the etiology of PD (Emamzadeh & Surguchov, 2018). Dopaminergic cell death may result from exposure to environmental toxins. The buildup of heavy metals in the SN increases the chances of suffering from PD. Increased oxidative stress in the dopaminergic cells could result from exposure to heavy metals, hence causing PD.
In most cases, PD is idiopathic, and approximately 15% of the patients have a first-degree relative with this disorder. Mutations in various genes, such as LRRK2, α-syn, PINK1, DJ-1, Parkin, GBA1, and VPS35 are associated with PD. Besides mutation in these different genetic loci, trinucleotide repeats and polymorphisms are identified as Parkinson’s disease genes or susceptibility elements. Epigenetics are chromatin alternations, such as histone post-translational modifications and DNA methylation that change the gene expression without transforming the DNA sequence. These changes can be passed from parent to offspring, although ecological aspects such as chemical, physical, and nutritional factors can also influence epigenetics (Emamzadeh & Surguchov, 2018). There is mounting evidence that the sporadic form of Parkinson’s disease is significantly influenced by environmental factors in both its onset and progression forms.
Symptoms of Parkinson’s Disease
Dopaminergic neuronal cell loss in the substantia nigra par compact portion of the midbrain is the primary cause of Parkinson’s disease (PD). Although symptoms typically develop gradually, diagnosis might be difficult (Church, 2021). PD is a motor system condition with four cardinal symptoms: stiffness, bradykinesia, tremor, and postural unsteadiness. Conversely, non-motor symptoms are invisible, although many individuals show them (Church, 2021). The most common non-motor signs are visible in the earliest stages of PD including, including urinary dysfunction, constipation, psychosis, depression, sleeping disorders, and apathy. The disease’s motor and non-motor-related signals are associated with reduced dopaminergic production.
Gaps in Existing knowledge
The second most well-known neurodegenerative disease affecting people over 60 is Parkinson’s disease. However, until recently, the study of the causes and methods for treating Parkinson’s disease (PD) progressed gradually(Wang et al., 2020). Many research gaps still need to be filled, even though noteworthy advancement has been achieved in comprehending the neurological reasons for Parkinson’s disease (PD). The specific mechanisms through which several genetic and environmental aspects cause PD are still unknown, even though they are potential risk factors for the disease. Several studies to the importance of other cell types, like astrocytes and microglia, in the etiology of PD and the well-known function of dopaminergic neuron damage in the onset of PD.
Parkinson’s study has historically ignored the study of varied populations; hence the field is seriously affected. By failing to deal with PD diagnosis and care in different communities, a tiered PD therapy system has risen in which specific ethnic and racial populations do not receive timely diagnosis and a lack of experienced PD care. Clinical trial recruitment in nonwhite populations is still low, which affects the ability of the PD study groups to make these wrongs right. Limited clinical differences studies on women have also been limited compared to men. By focusing solely on PD biology in men, PD scholars still need to get the chance to learn about molecular biology and genetics of PD in other groups leads to limited data and understanding of the PD in diverse groups (Rajan et al., 2020). Over the past twenty years, scientists have attempted to study PD, although the understanding has been gleaned from the findings in sporadic and familial types of PD. Aspects of the therapeutic applicability and transferability of genetic findings to other morally scattered populations are still unknown.
Several evidence streams claim that the immune system is intricated in the occurrence of PD. However, further research is required on the subject of efficient biomarkers, a particular immunological target linked to the start and progression of PD , and the role of immune cell dysbiosis in the gut in PD (Tan et al., 2020). Clinical issue of the disorder are: the incapability to make a decisive diagnosis at the preliminary stages and challenges in envisaging how the disorder progresses. Biomarkers are essential in the diagnosis, prognosis, and nursing of PD. Although, there are several gaps in the study of biomarkers for PD. There has been much interest in the unfulfilled need to find accurate biomarkers for first diagnosis and intervention of the PD cause. However, researchers have only tried a few reported biomarkers in clinical practice. Biomarker investigations have usually emphasized discovering novel identities, while attempts to investigate such biomarkers further are rare(Li & Le, 2020). Combining different reliable biomarkers improves the sensitivity and specificity over a single approach that is not accurate for this complicated neurodegenerative disorder(Li & Le, 2020). Therefore, there is a need to bring up-to-date the new establishment of promising biomarker detection and PD and deliberate on the appropriate method to evaluate and assess the biomarkers’ diagnostic or prognostic value.
Key Debates and Controversies
There are various controversies and debates surrounding Parkinson’s disorder. PD is a common clinical condition with several causes and symptoms (Bloem et al., 2021b), although scientists have not clearly defined the initial cause of PD. The majority of Parkinson’s disease instances seem to be sporadic, while some cases are known to be brought on by particular genetic abnormalities. Some scientists have stated that iron deposition is involved in the etiology (Mochizuki et al., 2020b). The relative role of hereditary and environmental variables in the onset of the disease is a topic of discussion among researchers. In several populations, 3 to 5% of PD is explained by genetic factors associated with common PD genes, representing monogenic PD. In comparison, 90 genetic risk variations generally describe 16 to 36% of the genetic risk of non-monogenic PD (Bloem et al., 2021). Other studied causes of PD include constipation, and having a family member suffering from PD.
The definition and diagnostic standards for Parkinson’s disease are still up for controversy, especially in its early stages, when motor symptoms may be nonexistent or minimal. The development of diagnostic criteria and examination, on an objective quantification, either as part of a proper technique or ad hoc. Currently, scientists are developing wearable technologies and new sensors depending on objective measurement procedures (Monje et al., 2019). Despite several attempts to professionally and successfully diagnose the disorder, several scientists have suggested extending the scope of the diagnosis of Parkinson’s disease to include non-motor symptoms or to include biomarkers.
Treatment and management of Parkinson’s disease
Worldwide, more than six million individuals have this disorder. PD is a complicated disorder; hence allied health involvement from experts is essential. The aims of treatment of PD vary from individual to individual, hence the need for personalized management (Bloem et al., 2021). The examination and history are used to make the diagnosis. History includes prodromic features (constipation, sleep disorder, rapid eye movement, and hyposmia), characteristic movement challenges(slowness, stiffness, tremor), and cognitive or psychological issues(anxiety, depression, and cognitive decline). Examination shows bradykinesia with rigidity, tremor, or both.
PD has several variations with varied prognoses. Persons with diffuse malignant subtypes have protruding early nonmotor and motor symptoms, faster disorder development, and poor response to medication. People with mild motor-predominant PD show mild symptoms such as good responsiveness to dopaminergic medications and slower disorder development. The are other people with intermediate subtypes. The treatment of PD is symptomatic to all patients, and it focuses on enhancement in nonmotor(cognition, sleep, mood, constipation) and motor (bradykinesia, rigidity, tremor) symptoms. The are no treatments that modify the disease. Initial motor problems are often alleviated by dopamine-based therapies. Dealing with non-motor symptoms necessitates nondopaminergic techniques (cholinesterase inhibitors for cognitive, selective serotonin reuptake inhibitors for psychiatric disorders). Rehabilitation treatment and exercise are used in conjunction with pharmaceutical medicines. Those who encounter issues like worsened signs and efficient cognitive deficits when a medication dose depletes drug-resistant tremors, and dystonia are utilize cutting-edge therapy (carbidopa enteral suspension or deep brain stimulation). Calming care is a component of the therapy.
Conclusion
In conclusion, millions of people worldwide have Parkinson’s disease, a complicated neurological ailment. The literature review has provided a better comprehension of the numerous facets of PD, such as its etiology, clinical symptoms, and current management approaches. Parkinson’s disease is among the public neurodegenerative conditions which are heterogenous and have rapidly and gradually progressive subtypes. The causes of PD vary from genetic and sporadic factors; hence should be managed. The review also emphasizes the need for more investigation into the disease’s underlying causes in order to create novel treatments and enhance the standard of living for the patients. Overall, it shows that managing Parkinson’s disease effectively requires primary diagnosis, appropriate management, and patient-centered care.
References APA
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