In the early stages of the disease, signs and symptoms are pretty less evident. However, as the disease progresses to more advance stages the following symptoms are prominent [7]:

• Tremors characterized by shaking hands, fingers and legs.
• Bradykinesia characterized by slowed movement making everyday simple tasks,difficult to achieve.
• Muscle stiffness sets in as the disease advances.
• Posture and balance of the individual get disrupted.
• Individuals may experience difficulty in writing due to loss of motor movements.
• Changes in the speech may occur.
• Automatic movements such as blinking, swinging arms while walking and making gestures while talking are all lost.

• Falling

  Implications for fall prediction were also explored. [ncbi.nlm.nih.gov]

• Fatigue

  […] of experienced fatigue. [ncbi.nlm.nih.gov]

  These co-morbidities include constipation, depression, fatigue, and insomnia. [foodforthebrain.org]

• Difficulty Walking

  As these symptoms become more pronounced, patients may have difficulty walking, talking, or completing other simple tasks. PD usually affects people over the age of 60. Early symptoms of PD are subtle and occur gradually. [web.archive.org]

  Tremors, rigidity, slow movement (bradykinesia), poor balance, and difficulty walking (called parkinsonian gait) are characteristic primary symptoms of Parkinson's disease. [healthcommunities.com]

• Hypersomnia

  Nadège Limousin, Eric Konofal, Elias Karroum, Ebba Lohmann, Ioannis Theodorou, Alexandra Dürr and Isabelle Arnulf, Restless legs syndrome, rapid eye movement sleep behavior disorder, and hypersomnia in patients with two parkin mutations, Movement Disorders [doi.org]

• Hyperthermia

  Methamphetamine-induced hyperthermia and dopaminergic neurotoxicity in mice: Pharmacological profile of protective and nonprotective agents. [ncbi.nlm.nih.gov]

• Hyposmia

  In our previous studies, we observed that several pre-Parkinson symptoms (eg, constipation, weight loss, and erectile dysfunction) preceded the onset of motor symptoms. 2 - 4 Hyposmia and REM sleep behavior disorder have been also consistently found to [oadoi.org]

  Hyposmia and visual hallucinations are helpful pointers in distinguishing Parkinson's disease from atypical Parkinsonism and should be specifically enquired about in the history. [ncbi.nlm.nih.gov]

• Hypophonia

  Supporting parkinsonian features include stooped posture, masked facies, micrographia (small handwriting), drooling, speech changes (eg, hypophonia or soft speech, stuttering, slurring, monotonic speech), and a shuffling, festinating gait (quick short [dx.doi.org]

  […] all of them) include: abnormal walking decreased arm swing excessive salivation feelings of depression or anxiety increase in dandruff or oily skin lack of facial expression ( hypomimia ) less frequent blinking and swallowing lowered voice volume ( hypophonia [medbroadcast.com]

  […] micrographia) Lack of facial expression Slowed activities of daily living (for example, eating, dressing, and bathing) Trouble turning in bed Staying in a certain position for a long period of time Non-motor symptoms Diminished sense of smell Low voice volume (hypophonia [cedars-sinai.org]

  Lack of facial expression Slowed activities of daily living (for example, eating, dressing, and bathing) Difficulty turning in bed Remaining in a certain position for a long period of time Nonmotor symptoms Diminished sense of smell Low voice volume (hypophonia [columbianeurology.org]

  Mechanism of action of voice therapy in Parkinson's hypophonia-a PET study. Poster presented at: the 11th Annual Meeting of the Organization for Human Brain Mapping 2005 Toronto, Ontario, Canada; 51 Farley B G, Koshland G F. [oadoi.org]

• Constipation

  This paper highlights the importance of early recognition and treatment of constipation to prevent volvulus developing and thevarious treatments currently available. [ncbi.nlm.nih.gov]

• Nausea

  Nausea (adverse effect, post‐intervention) 150 per 1000 21 per 1000 (1 to 390) RR 0.14 (0.01 to 2.60) 40 (1 study) moderate a Memantine does not increase risk for nausea. Not statistically significant. [doi.org]

  When combined with levodopa, carbidopa increases cerebral levodopa bioavailability and reduces the peripheral adverse effects of dopamine (e.g., nausea, hypotension). [aafp.org]

  If nausea becomes a problem, your GP may prescribe anti-sickness medication. A potentially serious, but uncommon, complication of dopamine agonist therapy is sudden onset of sleep. [nhsinform.scot]

  In most individuals, a daily dose of carbidopa 75 mg is sufficient to prevent nausea. [ncbi.nlm.nih.gov]

• Muscle Rigidity

  Signs and symptoms include tremor which is most pronounced during rest, muscle rigidity, slowing of the voluntary movements, a tendency to fall back, and a mask-like facial expression. [icd9data.com]

  Upon evaluation, classic parkinsonian signs of muscle rigidity, tremor, bradykinesia, freezing of gait, and cognitive decline were observed. [ncbi.nlm.nih.gov]

  Parkinson disease, also called primary parkinsonism, paralysis agitans, or idiopathic parkinsonism, a degenerative neurological disorder that is characterized by the onset of tremor, muscle rigidity, slowness in movement (bradykinesia), and stooped posture [britannica.com]

  Parkinson’s disease symptoms include muscle rigidity, tremors, and changes in speech and gait. After diagnosis, treatments can help relieve symptoms, but there is no cure. [webmd.com]

• Sialorrhea

  Since there is insufficient evidence of glycopyrrolate for the treatment of sialorrhea exceeding 1 week, the practice implication is that it is possibly useful. [ncbi.nlm.nih.gov]

  […] and impulse control disorders and related behaviors); and discuss the management of selected nonmotor symptoms of Parkinson disease, including rapid eye movement sleep behavior disorder, cognitive impairment, depression, orthostatic hypotension, and sialorrhea [doi.org]

• Increased Sweating

  sweating Urinary frequency or urgency Male erectile dysfunction As the disease gets worse, walking may become affected. [cedars-sinai.org]

  sweating Urinary frequency/urgency Male erectile dysfunction As the disease progresses, walking may become affected, causing the patient to stop in mid-stride or "freeze" in place, and maybe even fall over. [columbianeurology.org]

  sweating, vomiting, viral infection, an elevated drug level, arthralgia, tremor, anxiety, urinary tract infection, constipation, dry mouth, pain, hypokinesia, and paresthesia. 36 Adverse effects (pramipexole): In placebo-controlled trials of early PD [ncbi.nlm.nih.gov]

• Muscle Spasticity

  Hip dislocation and ankle equinus deformity are known to arise from muscle spasticity primarily. [en.wikipedia.org]

• Blepharospasm

  […] control 0000020 Visual hallucinations 0002367 5%-29% of people have these symptoms Abnormality of the foot Abnormal feet morphology Abnormality of the feet Foot deformities Foot deformity [ more ] 0001760 Apathy Lack of feeling, emotion, interest 0000741 Blepharospasm [rarediseases.info.nih.gov]

• Infrequent Blinking

  blinking, lack of facial expression, impaired postural reflexes, and gait abnormalities. [merckmanuals.com]

• Face Rigidity

  The four primary symptoms of PD are tremor, or trembling in hands, arms, legs, jaw, and face; rigidity, or stiffness of the limbs and trunk; bradykinesia, or slowness of movement; and postural instability, or impaired balance and coordination. [web.archive.org]

  Symptoms usually show up in one or more of four ways: tremor, or trembling in hands, arms, legs, jaw, and face rigidity, or stiffness of limbs and trunk bradykinesia, or slowness of movement postural instability or impaired balance and coordination. [parkinsons.org]

• Hypomimia

  Other clinical features include secondary motor symptoms (eg, hypomimia, dysarthria, dysphagia, sialorrhoea, micrographia, shuffling gait, festination, freezing, dystonia, glabellar reflexes), non-motor symptoms (eg, autonomic dysfunction, cognitive/neurobehavioral [ncbi.nlm.nih.gov]

  Other symptoms that are common in Parkinson's (though no one person will have all of them) include: abnormal walking decreased arm swing excessive salivation feelings of depression or anxiety increase in dandruff or oily skin lack of facial expression ( hypomimia [medbroadcast.com]

  Other manifestations of bradykinesia include loss of spontaneous movements and gesturing, drooling because of impaired swallowing, 25 monotonic and hypophonic dysarthria, loss of facial expression (hypomimia) and decreased blinking, and reduced arm swing [doi.org]

• Dull Facial Expression

  facial expression 0000338 Leg muscle stiffness 0008969 Lethargy 0001254 Myoclonus 0001336 Oculogyric crisis 0010553 Short attention span Poor attention span Problem paying attention [ more ] 0000736 Urinary incontinence Loss of bladder control 0000020 [rarediseases.info.nih.gov]

• Mask-like Facies

  Hallucinations Hallucination Sensory hallucination [ more ] 0000738 Hyperreflexia Increased reflexes 0001347 Hypokinesia Decreased muscle movement Decreased spontaneous movement Decreased spontaneous movements [ more ] 0002375 Hyposmia Loss of smell 0004409 Mask-like [rarediseases.info.nih.gov]

• Tremor

  Treating the patients with hand tremors is clinically difficult, because a wide range of disorders can result in hand tremors. Therefore, when treatment for hand tremors begins, various pharmacological options have to be considered. [ncbi.nlm.nih.gov]

  Tremor is the major symptom for some individuals, while for others tremor is only a minor complaint and other symptoms are more troublesome. [web.archive.org]

  Table 2 Features differentiating Parkinson’s disease from essential tremor Some patients with PD have a history of postural tremor, phenomenologically identical to essential tremor, for many years or decades before the onset of parkinsonian tremor or [doi.org]

• Bradykinesia

  Table 1 Parkinson’s disease symptoms Bradykinesia Bradykinesia refers to slowness of movement and is the most characteristic clinical feature of PD, although it may also be seen in other disorders, including depression. [web.archive.org]

  Bradykinesia and rigidity respond best, while tremor may be only marginally reduced. Problems with balance and other symptoms may not be alleviated at all. Anticholinergics may help control tremor and rigidity. [ninds.nih.gov]

• Postural Instability

  Management of postural instability is challenging as it is often resistant to dopaminergic therapy. Greater knowledge of postural control is essential to understand postural instability in PD. [ncbi.nlm.nih.gov]

  Postural instability usually develops later rather than sooner in the disease progression. The patient may need to hold onto someone to maintain balance when getting up or walking. [dx.doi.org]

  Postural instability Postural instability due to loss of postural reflexes is generally a manifestation of the late stages of PD and usually occurs after the onset of other clinical features. [doi.org]

• Resting Tremor

  Right-side resting tremor and rigidity were abolished immediately following the ultrasound energy delivery. In addition, left-side resting tremor and rigidity also improved. No adverse events occurred during the procedure. [ncbi.nlm.nih.gov]

  Characteristically, rest tremor disappears with action and during sleep. [doi.org]

• Dystonia

  SUBJECTS/PATIENTS: Six patients with Parkinson's disease with deep brain stimulation experiencing disabling foot dystonia. [ncbi.nlm.nih.gov]

• Sexual Dysfunction

  dysfunction) in women dizziness, blurred vision or fainting when moving from a sitting or lying position to a standing one – caused by a sudden drop in blood pressure excessive sweating (hyperhidrosis) swallowing difficulties (dysphagia) – this can lead [nhs.uk]

  dysfunction, decreased ability to smell, restless legs and muscle cramps. [health.harvard.edu]

  dysfunction – Cramping – micrographia (abnormally small or cramped handwriting) – a mask-like expression Refer: [Last accessed on 29/11/2017] 9. [slideshare.net]

  Sexual dysfunction. Some people with Parkinson's disease notice a decrease in sexual desire or performance. Prevention Because the cause of Parkinson's is unknown, proven ways to prevent the disease also remain a mystery. [mayoclinic.org]

So far no laboratory tests exist for diagnosing Parkinson's disease. A neurologist will diagnose the disease based on the past medial history of the affected individual followed by thorough analysis of the signs and symptoms. In addition, certain tests may also be required to rule out the possibility of any underlying disease condition. In order to arrive at an appropriate diagnosis, the neurologist will give medications meant for Parkinson's disease to the individual. If the individual benefits from the drug then the diagnosis is confirmed [8].

Parkinson's disease cannot be cured; the symptoms can be effectively managed and progression of the condition slowed down with appropriate treatment methods. Medications form an important part of treatment regime. In more advanced stages, however surgery may be advised. The following are the various medications prescribed for treating Parkinson's disease.

• Carbidopa-levodopa is one of the most effective medications for Parkinson disease. This is a natural chemical that gets converted to dopamine when it reaches the brain [9].
• Medications containing dopamine antagonists are prescribed which unlike levodopa do not get converted to dopamine but mimic the effects of the brain chemical.
• Monoamine oxidase B (MAO-B) inhibitors do not allow the breakdown of dopamine. However, this class of medication has various side effects when taken with other drugs.
• Anticholinergics help in controlling the tremors; however are seldom prescribed due to associated side effects.
• Amantadine is prescribed for short term relief from the symptoms. It is also given in association with levodopa to reduce dyskinesias that may accompany as a side effect of carbidopa-levodopa drug [10].

As the disease progresses, there is gradual loss of neurological functions in the affected individuals. Individuals who do not receive proper treatment often suffer from other secondary debilitating conditions. There is absolute loss of movement making the individual completely bed ridden for rest of the life. However, with introduction of newer generation medications, it has now been possible to effectively manage the symptoms and improve the quality of life [6].

Parkinson disease occurs due to necrosis of certain nerve cells in the brain which are responsible for producing dopamine. The exact cause that triggers the development of such a type of movement disorder is yet to be known. However, interplay of several factors such as environment and genetic are known to play a role. Genetic factors attribute to 10% cases of Parkinson disease.

Genetic factors

Certain genes have been identified to play a major role in causation of Parkinson's disease. Individuals with family history of this disease are at an increased risk of contracting it as they age.

Environmental factors

Exposure to certain toxins can predispose an individual to develop Parkinson's disease [2].

Parkinson disease is the second most common neurological disorder affecting about 7 million individuals across the globe. An estimated 1 million individuals of United States suffer from this neurodegenerative disorder [3]. Individuals aged 60 years and above fall easy prey to this disease. Men are 1.5 times more likely to contract Parkinson's disease, compared to women. Statistics have revealed that a small percentage of individuals (5 – 10%) between the age group of 20 – 50 years have been known to develop this kind of movement disorder [4].

Parkinson's disease is a result of death of neurons in the brain. These are responsible for producing dopamine. Dopamine is a chemical messenger of the brain that transmits information to control the movements in various parts of the body [5]. The inability of the neurons to produce dopamine causes motor impairment which is the major cause of disability amongst the affected individuals. It has also been found that about 60 – 80% of necrosis of the nerve cells occurs even before the preliminary signs and symptoms of Parkinson's disease occur.

Till date, no methods have been developed to prevent Parkinson's disease. Since the cause is unknown, ways to prevent the onset of the disease also remains a mystery. However, there have been some pieces of evidence suggesting the use of caffeine to help prevent Parkinson's disease.

Individuals over the age of 60 years are the most affected.The disease steadily causes disability greatly interfering with the individual’s ability to carry out daily functions. The preliminary stage of the disease may showcase little or no symptoms. Parkinson's disease cannot be cured. The symptoms can be effectively managed with appropriate medications. In some cases, surgical procedures may be required to improve the symptoms [1].

Definition

Parkinson's disease is a neurodegenerative disorder characterized by loss of neurological functions due to necrosis of the nerve cells in the brain. It is known to be the second most common neurological disorder after Alzheimer disease. Individuals above the age of 60 years are more prone to develop this condition. Parkinson's disease greatly affects the movement ability of the individuals and therefore the disease is also commonly referred to as movement disorder.

Cause

The exact factor that leads to development of Parkinson's disease is not clear. However certain genetic factors and exposure to environmental toxins is known to cause this type of neurological disorder.

Symptoms

In the initial stages, Parkinson's disease may show little or no signs at all. As the disease progresses to more advance stages, individuals experience tremors of the hands, fingers and legs. They also have difficulty in walking and their movements slow down to a great extent. Difficulty in talking is evident with slurred speech.

Diagnosis

No laboratory tests help in diagnosing the condition. A thorough examination of the signs and symptoms help in confirming Parkinson's disease.

Treatment

Medications form the basis of the treatment regime. Various classes of drugs are prescribed to keep the symptoms under control. Carbidopa-levodopa is the most effective drug for treating Parkinson's disease. It works by getting converted into dopamine once it reaches the brain.

1. Langston JW. The Parkinson's complex: parkinsonism is just the tip of the iceberg. Ann Neurol 2006; 59:591.
2. Pezzoli G, Cereda E. Exposure to pesticides or solvents and risk of Parkinson disease. Neurology. May 28 2013;80(22):2035-41.
3. Wirdefeldt K, Adami HO, Cole P, Trichopoulos D, Mandel J. Epidemiology and etiology of Parkinson's disease: a review of the evidence. Eur J Epidemiol. Jun 2011;26Suppl 1:S1-58.
4. Van Den Eeden SK, Tanner CM, Bernstein AL, et al. Incidence of Parkinson's disease: variation by age, gender, and race/ethnicity. Am J Epidemiol 2003; 157:1015.
5. Hornykiewicz O. The discovery of dopamine deficiency in the parkinsonian brain. J Neural TransmSuppl 2006; :9.
6. Jeffrey S. Biomarkers for Parkinson's Diagnostic, Prognostic. Medscape [serial online]. Available at http://www.medscape.com/viewarticle/810262.
7. Politis M, Wu K, Molloy S, et al. Parkinson's disease symptoms: the patient's perspective. MovDisord 2010; 25:1646.
8. Tolosa E, Gaig C, Santamaría J, Compta Y. Diagnosis and the premotor phase of Parkinson disease.Neurology. Feb 17 2009;72(7 Suppl):S12-20.
9. Stocchi F, Rascol O, Kieburtz K, et al. Initiating levodopa/carbidopa therapy with and without entacapone in early Parkinson disease: the STRIDE-PD study. Ann Neurol. Jul 2010;68(1):18-27.
10. Weintraub D, Sohr M, Potenza MN, Siderowf AD, Stacy M, Voon V, et al. Amantadine use associated with impulse control disorders in Parkinson disease in cross-sectional study. Ann Neurol. Dec 2010;68(6):963-8.