What is Parkinson’s Disease?

Parkinson’s disease (PD) is a progressive, neurological disorder that causes unintended or uncontrollable body movements. So this disease affects the body’s motor system, showing non-motor symptoms like stiffness, tremors, difficulty walking, rigidity, slowing, unbalancing, etc. Along with such non-motor symptoms, it may lead to the development of problems like apathy, depression, anxiety, fatigue, forgetfulness, etc. Parkinson’s disease is prevalent as part of the Parkinsonian syndromes, a progressive group of mental disorders affecting the nervous system and the body parts controlled by nerves.

Parkinson’s disease causes the death or impairment of specific neurons in the basal ganglia area of the brain. Neurons in this region produce dopamine neurotransmitter, which is responsible for the movement or motor system of the body and governs the movement of the body parts. In Parkinson’s disease, the production of norepinephrine is also hindered. Norepinephrine is a chemical messenger produced from the end of the nerves and responsible for controlling the various functions related to blood flow. The non-motor symptoms in PD are because of the deficit of this chemical messenger. A person with Parkinson’s disease is also observed with the abnormal accumulation & aggregation of the misfolded proteins known as alpha-synuclein in the form of Lewy bodies. The root cause of PD is still not understood completely. That is why PD is sometimes referred to as “idiopathic parkinsonism”.

Symptoms

The main symptoms of PD are non-motor symptoms (autonomous dysfunctions like constipation, and urinary dysfunctions), neuropsychiatric disorders (changes in mood, cognition, depression, behaviour, or thinking), and sensory (mainly changes in the sense of smell) and sleep disorders. These symptoms appear late in PD.

Causes

PD is not identified completely, but some researchers believe that PD is a combined effect of environmental concerns and genetic characteristics. Though, only 10% of cases make up for related genetic causes of PD.

At least 11 autosomal dominant and nine autosomal recessive gene mutations are implicated in the development of Parkinson’s. The autosomal dominant genes have SNCA, PARK3, UCHL1, LRRK2, GIGYF2, HTRA2, EIF4G1, TMEM230, CHCHD2, RIC3, and VPS35. Autosomal recessive genes have PRKN, PINK1, PARK7, ATP13A2, PLA2G6, FBXO7, DNAJC6, SYNJ1, and VPS13C.

Non-genetic causes are mainly environment-related, which includes the association of various drugs, beverages, tobacco, and other chemicals with the person. Drug-induced Parkinsonism is usually reversed by stopping the offending agent, such as chlorpromazine, promazine, haloperidol, benperidol, metoclopramide, and tetrabenazine. MPTP is a drug that causes irreversible Parkinsonism and is commonly used in animal-model research. Low urate concentrations in the blood are associated with an increased risk of PD. It is believed that a person exposed to pesticides has more affinity toward acquiring this condition. On the other side, a smoker, coffee drinker, or tea drinker is at a lower risk of PD.

Diagnosis

PD can be diagnosed by neurological examination and symptoms along with the patient’s medical history. No laboratory tests can be used to analyse PD for non-genetic causes, as several other conditions can also have similar symptoms. There is a need for a different medication, although the symptoms are identical, because of various root causes.

An autopsy of the midbrain is carried out for the final Parkinson’s disease diagnosis. The Lewy bodies in a neuron’s midbrain sections are considered a conclusion for a person with PD. CT scan of the individual neurons’ midbrain sections is considered, and susceptibility weighted imaging sequences at a magnetic field strength of at least 3T) can demonstrate the absence of the characteristic ‘swallow tail’ imaging pattern in the dorsolateral substantia nigra. Neuromelanin-MRI can discriminate a person with Parkinson’s from healthy subjects.

The Society of Movement Disorders-The Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) is the primary tool for healthcare providers to classify this disease. MDS-UPDRS examines four different areas of how Parkinson’s disease affects you:

Part 1: Non-motor Experiences of everyday living experience (interview and self-report questionnaire): In this part, cognitive dysfunction, hallucinations and mental illness, depression, anxiety, indifference, sleep disorders, persistent drowsiness, pain and other sensations, urinary problems, constipation problems, malaise, dopamine dysregulation syndrome, etc. examine the body’s non-motor dysfunction

Part 2: Motor experiences of daily living experience: In this part, you can talk, spit, drool, chew, swallow, eat, change clothes, hygiene-related activities, handwriting, hobbies, and related activities, go to bed, get out of bed/car/chair, balance. Coping with physical motor dysfunction, such as talking, walking, freezing, etc.

Part 3: Motor Examination (ratings): Healthcare providers use this section to determine the exercise-related effects of Parkinson’s disease. Criteria measure effectiveness based on your speaking style, facial expressions, stiffness, walking and speed, balance, movement speed, tremors, and more.

Part 4: Motor complications (interview): In this section, your healthcare provider will determine how the symptoms of Parkinson’s disease affect your life. This includes the length of time each day you have specific symptoms and whether those affect how you spend your time.

Prevention

PD is not a curable disease because there are no medications to rule out the effects of PD on the brain and nervous system. Prevention is possible through various daily activities such as exercise. Exercise can reduce your chances of getting PD, and coffee and tea can reduce the risk of PD, coffee research results though are inconsistent, and no beneficial effects have been demonstrated. Results on fats and fatty acids are unpredictable, and various studies have reported protective, increased risk, or no effect. Antioxidants like vitamins C and E have been suggested to protect against disease. There is preliminary evidence that anti-inflammatory and calcium channel blockers may be protective. Non-steroidal anti-inflammatory drugs reduce the incidence of PD by up to 15% in the early stages of use.

Treatment

Because PD is an incurable disease, certain activities and medications can help manage symptoms. In some cases, brain surgery can also be done. Dopamine deficiency is a significant cause of Parkinson’s symptoms, so available medications that raise dopamine levels can help relieve or reduce the frequency of symptoms.

Levodopa is the primary therapy for Parkinson’s disease. Nerve cells convert Levodopa into dopamine, replenishing the brain’s depleted supply. Medications might lessen the typical adverse effects of levodopa therapy. Carbidopa increases the quantity of Levodopa and reduces the side effects of Levodopa therapy, including symptoms like nausea, vomiting, low blood pressure, and restlessness. People with Parkinson’s should not stop taking Levodopa without telling their doctor. Sudden drug discontinuation can cause serious side effects such as immobility and difficulty breathing. Your doctor may prescribe other medications given below to treat the symptoms of Parkinson’s disease:

A dopamine agonist that stimulates the production of dopamine in the brain
Enzyme inhibitors increase the amount of dopamine by slowing down the enzymes that break down dopamine in the brain (e.g., MAO-B inhibitors, COMT inhibitors)
Amantadine to reduce involuntary movements
Anticholinergic agents that reduce tremor and muscle stiffness

Lesion surgeries and deep brain stimulation are the two primary categories of PD surgery (DBS). A doctor may advise deep brain stimulation if a patient has Parkinson’s disease and does not react well to treatment.

A portion of the brain is surgically implanted with electrodes connected to a tiny electrical device implanted in the patient’s chest. Many Parkinson’s disease symptoms associated with exercise might be prevented by using devices and electrodes that painlessly stimulate specific regions of the brain that regulate movement. The thalamus, globus pallidus, or sub-thalamic nucleus are the areas that DBS or lesions are intended to affect. A nerve stimulator, a type of medical apparatus used in DBS, transmits electrical impulses to some brain areas.

DBS is recommended for people with Parkinson’s disease whose motor variability and tremors are not well controlled by dosing or who are intolerant to dosing. Other less common surgical treatments involve deliberately creating lesions to prevent overactivity in some subcortical regions. For example, an incision in the globus pallidus surgically destroys the globus pallidus to control dyskinesia.

An exercise program is recommended for people with Parkinson’s disease. Some evidence suggests that rehabilitation can improve language and mobility problems, but there is less research and of mediocre quality. Regular exercise with or without physiotherapy helps maintain and improve mobility, flexibility, strength, walking speed, and quality of life. Compared to a self-monitoring exercise programme at home, following an exercise programme under the guidance of a physiotherapist further improves motor symptoms, mental and emotional function, daily activities, and quality of life. Clinical exercise has improved individuals with Parkinson’s disease’s overall quality of life.

Patients with significant medical problems, such as Parkinson’s disease, might get specialist medical care called palliative care. By reducing the signs, discomfort, and stress associated with Parkinson’s disease, this field aims to enhance the quality of life for those with the condition and their family. Since Parkinson’s disease cannot be fully cured, all therapies are palliative and aim to slow the illness’s progression and enhance the quality of life.

Conclusion

Parkinson’s is a neurological disorder associated with the body’s movement-related activities and cognitive functions. PD is a non-curable disease, but medication, therapy, and surgery are known to manage PD symptoms, slow down the progression of the condition, and enhance the quality of life. Some practices as a precaution can be taken as per available knowledge.