Physiological Pathways Of Pain Relief
In the early 1960s, theories initially developed by Melzack and Wall were introduced. They proposed three features of afferent input that were signed for pain: the ongoing activity that precedes the stimulus, the stimulus-evolved activity, and the relative balance of activity in large versus small fibers. The concept of the gate control theory was introduced. Pain messages encounter nerve gates in the spinal cord that open or close depending upon a number of factors . When the gates are open, pain messages pass more easily and pain can be intense. When the gates are closed, pain messages are prevented from reaching the brain and may not even be experienced. Although the details of this process remain poorly understood, it can help to explain why various treatments are effective.
The existence of low-threshold mechanoreceptive C-tactile afferents was initially described by Vallbo et al. These afferents comprise a second anatomically and functionally distinct system that signals touch in human beings. The activation of these fibers is more closely related to limbic functions rather than cognitive and motor functions. Although rapid, accurate, and informative A touch acutely reflects the external world through cutaneous events in an exteroceptive manner, CT activation shares more characteristics with interceptive modalities. This slow, affective nature is likely to be involved in the maintenance of physical well-being.
What Causes Parkinsons Disease
Parkinsons disease occurs when nerve cells in an area of the brain called the substantia nigra become impaired or die. These cells normally produce dopamine, a chemical that helps the cells of the brain communicate . When these nerve cells become impaired or die, they produce less dopamine. Dopamine is especially important for the operation of another area of the brain called the basal ganglia. This area of the brain is responsible for organizing the brains commands for body movement. The loss of dopamine causes the movement symptoms seen in people with Parkinsons disease.
People with Parkinsons disease also lose another neurotransmitter called norepinephrine. This chemical is needed for proper functioning of the sympathetic nervous system. This system controls some of the bodys autonomic functions such as digestion, heart rate, blood pressure and breathing. Loss of norepinephrine causes some of the non-movement-related symptoms of Parkinsons disease.
Scientists arent sure what causes the neurons that produce these neurotransmitter chemicals to die.
Pain In Parkinson’s Disease
Doctors categorize pain as nociceptive, which refers to pain from tissue damage, or as neuropathic, which refers to pain that arises from the nerves. Some pain is both nociceptive and neuropathic. Most people with PD experience nociceptive pain.
This type of pain is generally localized to a specific area of the body. The most common areas for people with PD to experience pain are the neck, upper back, and the extremities . Neuropathic pain is less common in PD, although it may be caused by akathisia, an extreme restlessness.1
The pain caused by PD can generally be classified by one of five causes:
Management Of Pain In Parkinsons Disease
Issue title: Special Issue: Clinical management of Parkinsons disease: Essentials and new developments
Guest editors: Bastiaan R. Bloem and Patrik Brundin
Article type: Review Article
Affiliations: Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany | Department of Neurology, University of Ulm, Ulm, Germany | Parkinson-Klinik Ortenau, Wolfach, Germany
Correspondence: Correspondence to: Prof. Dr. Carsten Buhmann, Department of Neurology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. Tel.: +49 40 7410 52771; Fax: +49 40 7410 45780; E-mail: .
Keywords: Parkinsons disease, pain, therapy, analgetics, pathophysiology, non-motor symptoms
DOI: 10.3233/JPD-202069
Journal: Journal of Parkinson’s Disease, vol. 10, no. s1, pp. S37-S48, 2020
Abstract
Examples Of Pain Scales
Visual analog scale
A visual analog scale measures a continuum of a chosen present characteristic. For example, the experienced pain that a patient feels extends over a continuum from no pain to an extreme intensity of pain. This range of perceived pain appears continuous for the patient. Pain does not appear as an ordinary scale with jumps between the values, such as discrete, moderate, or severe. Word descriptors are only used in both ends of the line, which is usually 100 mm in length. This valuation is very subjective and best used within an individual and not between groups of individuals at the same time point. Most experts argue that a VAS at best can produce data of ordinal type. This is important to consider in the statistical analysis of VAS data. Rank ordering of scores rather than the exact values might be the best way to handle patient registrations on the 100 mm line.
Brief Pain Inventory
The Brief Pain Inventory was initially created for the purpose of measuring pain in cancer patients. It measures pain relief, pain quality, and patient perception of the cause of pain in terms of pain intensity and pain interference .
Pain In Pd: Assessment And Classification
In order that novel and optimal pharmacotherapeutic targets may be identified, a deeper understanding of the pain circuitry in PD patients who experience persistent pain is required. Since we know that unique maladaptive changes occur in central modulatory pathways that govern pain and neurodegeneration, identifying pathophysiological hallmarks for persistent pain and Parkinsons disease states, likely highly plastic and stage specific, is crucial.
Incidence And Prevalence Of Pd General Pain And Pd
Estimates of PD prevalence and incidence have provided conflicting estimates. In Europe, the annual incidence estimates range from 5/100,000 to 346/100,000. Approximately 60,000 Americans are diagnosed with PD each year. The challenges involved with differential diagnoses and other forms of Parkinsonism, as well as the long time course from initial PD-like symptoms to a correct diagnosis, are likely responsible for the discrepancy in numbers.
The reported prevalence of pain in PD and PD-related pain also varies between studies. In 2008, Negre-Pages et al estimated the prevalence of chronic pain in PD to be >60%. PD pain is often reported as heterogeneous in its clinical presentation, with a disabling effect on quality of life assessments. In 1998, the Swedish Parkinson Association reported on a survey of nonmotor symptoms comprising almost 1,000 PD respondents, revealing that pain was more common in females than males . However, general pain is also common in the population, with 18%19% in a general adult population according to the prevalence data.,
In early-stage PD, pain is rated as one of the most troublesome NMS, and it seems to affect the side of the body that was initially worst impacted by motor symptoms of the disease .
What Are The Different Types Of Pain Experienced By People With Parkinsons
Five main types of pain are common for people with Parkinsons. Multiple types may be present simultaneously or occur at different points throughout a persons path with Parkinsons. Recognizing which kind of pain is present can help you optimize treatment, as can paying attention to what activities or times of day make your pain better or worse.
Musculoskeletal pain
Musculoskeletal pain that affects muscles, bones, tendons, ligaments, and/or nerves. The pain can be localized or generalized and can fade or intensify at different times. Existing musculoskeletal pain can be exacerbated by Parkinsons.
Neuropathic pain
Rather than being caused by a physical injury, this type of pain is caused by damage to the somatosensory nervous system or a disease affecting the somatosensory nervous system, which responds to external stimuli like touch, temperature, and vibration. It tends to be fairly consistent throughout the day and is present no matter what activity youre doing. Unlike the aching you may feel when youre doing a strenuous physical activity, neuropathic pain feels more like a tingly, crawly, uncomfortable sensation.
Dystonic pain
Dystonia, the movement disorder in which involuntary muscle contractions cause repetitive or twisting motions, is often very painful. Many people with Parkinsons experience dystonia as a motor symptom, whether its localized , in multiple nearby body parts , or all over .
Akathisia
Central pain
What Are The Surgical Treatments For Parkinsons Disease
Most patients with Parkinsons disease can maintain a good quality of life with medications. However, as the disease worsens, medications may no longer be effective in some patients. In these patients, the effectiveness of medications becomes unpredictable reducing symptoms during on periods and no longer controlling symptoms during off periods, which usually occur when the medication is wearing off and just before the next dose is to be taken. Sometimes these variations can be managed with changes in medications. However, sometimes they cant. Based on the type and severity of your symptoms, the failure of adjustments in your medications, the decline in your quality of life and your overall health, your doctor may discuss some of the available surgical options.
Q Are There Any Gender Disparities In The Treatment Of Pain In Pd
Dr. Fleisher: I dont think there is any literature demonstrating gender disparities in pain treatment among patients with PD, but we do know that there are certainly gender disparities overall in the treatment of women with PD, so it would not be surprising to learn that women with PD-related pain are at a disadvantage and not getting the appropriate care that they need.
Specific Pain Syndromes In Pd
Orthostatic hypotension can cause headache or neck pain . If necessary, antihypertensive co-medication should be adjusted in accordance with recently given recommendations . Additional measures are physical exercises, fluid intake, wearing of compression stockings class two, and administration of substances such as midodrine, fludrocortisone or, in severe cases, L-threo-3,4-dihydroxyphenylserine . Camptocormia is often accompanied with pain. Prior to therapy the cause has to be differentiated . In addition to the use of pain killers, the focus is on physiotherapy. There is no specific pain medication recommended currently.
Migraine is reported less often in PD, and often associated with depression and sleep disturbances . Therefore the therapy has to focus on the comorbidities as well. The usual medication for migraine can be used, but due to an increased risk for orthostatic hypotension in PD, caution should be exercised with beta blockers .
Pain Management In Patients With Parkinsons Disease: Challenges And Solutions
This review focuses on the diagnosis and management of Parkinson-related pain. It reviews the incidence and prevalence of PD, general pain and PD-related pain, the pathophysiological pathways of pain in PD, physiological pathways of pain relief, measurements of pain, clinical diagnosis of PD-related pain, and treatment strategies.
How To Deal With The 6 Common Causes Of Leg Pain In Pd
Severe leg pain is a common complaint from people with PD. Lately, it is understood that central pain is common to Parkinsons disease, and can even be the first sign of PD, usually bilaterally. This blog post lists six causes of lower limb pain, and the importance of treating it. Treatments depend on properly identifying the source of pain. Some treatment suggestions are included.
Functional Exercise For Chronic/persistent Pain
There are some simple exercises that you can try around the house to help:
- If you experience pain in your legs, keep them strong by practising standing up and sitting down in a chair.
- If your shoulders are aching, start by loosening them with some shoulder rolling actions, then by lifting an object that is slightly weighty from a shelf, and then replacing it. This increases the range of movement in your back, shoulders and arms, and then your strength.
Who Should I See To Discuss My Parkinsons Pain
Your first point of contact should be your primary doctor. Whether that means your family doctor, neurologist, or Movement Disorder Specialist , start by asking them how to manage your pain. They may prescribe you one of the medications listed above, offer suggestions about altering your lifestyle, or refer you to a pain specialist.
Pain management specialists are physicians with specialized training in the field of evaluating, diagnosing, and treating pain; so, speaking to one of these specialists might be helpful for you. Be sure to get a referral from your primary care doctor, though, to ensure you are visiting a physician who understands the complexity of treating Parkinsons-specific pain.
Health and wellness providers like physical therapists, acupuncturists, and massage therapists can also be valuable members of your care team. Be willing to try new things and approach alternative therapies with an open mind, as no ones path with Parkinsons pain is the same. What works for someone else may not work for you and vice versa. Consider visiting different specialists to find a treatment plan that works best for you.
Standardised Testing And Powered Cohorts
Future research should control for confounding factors by standardising variables across laboratories. For example, the presence of pain should be classified according to an internationally validated scale, e.g. the KPPS. PD sub-types should be standardised according to an internationally verified method. Although there is no gold standard for sub-type classification, distinctions have been made between tremor-dominant and non-tremor-dominant sub-types, and by using UPDRS-III sub-type-based classifications. It is recommended that future studies should classify sub-types according to the German AWMF guidelines .
Shooting Pain And Paraesthesia
Radicular pain is a sharp pain that shoots down a limb and often affects fingers or toes. Paraesthesia is sometimes described as a feeling of pins and needles or perhaps numbness in a limb which has fallen asleep. Such pain is usually related to trapped nerves in the spinal cord and can feel similar to an electric shock, a tingling or a burning sensation.
Treatment: Painkillers and exercise will generally settle the pain. If not your specialist may refer you for tests such as an MRI scan to check for a trapped nerve in the spinal cord.
Q What Is The Role Of Depression In The Pain Experience In Pd
Dr. Fleisher: Depression is one of the most overlooked symptoms of PD, and it can affect over 30% of people with the disease at some point in their illness.5 I think there is a misconception that depression results from an adjustment disorder following diagnosis. While that may be partially true, patients with PD have alterations in various neurotransmittersincluding serotonin and norepinephrine in addition to dopaminethat predispose them to depression.6,7
Depression is the primary factor related to quality of life in PD and is an independent risk factor for medication nonadherence. A physician could prescribe the most comprehensive regimen to control Parkinsons symptoms, including pain, but if depression symptoms are not being addressed simultaneously, the likelihood that that person is going to take that regimen is pretty minimal.
Given the link between depression and chronic pain, patients who are depressed should be screened for chronic pain and vice versa. In my practice, we screen every patient with the Unified Parkinsons Disease rating scale , which has both a patient-reported subjective component that includes questions about depression, pain, and altered sensation, as well as an objective component that includes a physical examination and questions about potential medication adverse effects . The patient fills out the subjective component every single time they come to the office.
How Is Parkinsons Disease Diagnosed
Diagnosing Parkinsons disease is sometimes difficult, since early symptoms can mimic other disorders and there are no specific blood or other laboratory tests to diagnose the disease. Imaging tests, such as or scans, may be used to rule out other disorders that cause similar symptoms.
To diagnose Parkinsons disease, you will be asked about your medical history and family history of neurologic disorders as well as your current symptoms, medications and possible exposure to toxins. Your doctor will look for signs of tremor and muscle rigidity, watch you walk, check your posture and coordination and look for slowness of movement.
If you think you may have Parkinsons disease, you should probably see a neurologist, preferably a movement disorders-trained neurologist. The treatment decisions made early in the illness can affect the long-term success of the treatment.
Fluctuations Of Pain Experiences In Pd
Patterns of NMS fluctuations are heterogeneous and complex. Psychic NMS seem to fluctuate more frequently and severely than nonpsychic symptoms. A recent study of ten frequent NMS in advanced PD using VAS rating scales in motor-defined on- and off-states, as well as self-ratings at home, confirmed previous suspicions that increased pain in off-states and pain fluctuations correlate with a low health-related quality of life. Pain as NMS was more frequent in the off-state; more precisely, it was three to four times more common during the off-state than during the on-state.
Q Are There Any Alternative Therapies That Are Effective For Pain In Pd
Dr. Fleisher: Although alternative therapies may be helpful, there is little evidence-based research to support their use. Certainly massage therapy, anecdotally, seems to be helpful for managing pain. Small studies suggest that acupuncture might improve sleep in patients with PD, but data on the effects on pain in PD is lacking. Larger, more well-controlled and reproducible studies of these therapies are needed.
Patients frequently ask about the effects of medical marijuana in managing PD, including pain symptoms. Several studies have looked at efficacy of marijuana in PD and have found that it probably is ineffective for most PD symptoms.11 However, we just dont have enough evidence to know for sure. The most rigorous study of medical marijuana in PD showed a trend toward worsening tremor.11,12
For most people, stress and anxiety worsen tremor, and anything that relieves anxiety will improve tremor. Thus, modalities such as yoga, meditation, and mindfulness training will improve tremor. Similarly, medical marijuana may improve tremor in certain people by temporarily reducing anxiety and stress, but the evidence has not borne this out yet.
What Medications Are Used To Treat Parkinsons Disease
Medications are the main treatment method for patients with Parkinsons disease. Your doctor will work closely with you to develop a treatment plan best suited for you based on the severity of your disease at the time of diagnosis, side effects of the drug class and success or failure of symptom control of the medications you try.
Medications combat Parkinsons disease by:
- Helping nerve cells in the brain make dopamine.
- Mimicking the effects of dopamine in the brain.
- Blocking an enzyme that breaks down dopamine in the brain.
- Reducing some specific symptoms of Parkinsons disease.
Levodopa: Levodopa is a main treatment for the slowness of movement, tremor, and stiffness symptoms of Parkinsons disease. Nerve cells use levodopa to make dopamine, which replenishes the low amount found in the brain of persons with Parkinsons disease. Levodopa is usually taken with carbidopa to allow more levodopa to reach the brain and to prevent or reduce the nausea and vomiting, low blood pressure and other side effects of levodopa. Sinemet® is available in an immediate release formula and a long-acting, controlled release formula. Rytary® is a newer version of levodopa/carbidopa that is a longer-acting capsule. The newest addition is Inbrija®, which is inhaled levodopa. It is used by people already taking regular carbidopa/levodopa for when they have off episodes .
Sensory Profiling And The Potential For Mechanism
Since psychophysical testing offers the opportunity to explore the functionality of an individuals pain system under controlled settings, a comprehensive assessment of various pain processing and modulatory pathways for use as a surrogate measure of the mechanisms driving the development of persistent pain in a given population/patient cohort is possible. For example CPM deficiencies in patients with neuropathic pain can be targeted by manipulation of central noradrenergic and serotonergic transmission, where the pain-inhibiting impact of Tapentadol potentiates impaired CPM in persistent pain patients in a manner that back translates to animal studies,,. Psychophysical testing can also be used to predict analgesic treatment efficacy.
In people with PD, sensory profiling through psychophysical testing has been applied in order to provide insight of the underlying mechanisms of persistent pain. Thereafter, guidance for personalised pain medicine through mechanism-based treatments is a key goal for many chronic pain types,,,. However, a frustratingly disparate range of psychophysical trials exists in the literature for the PD patient cohort, where significant differences in the type of pain considered and methodologies employed leads to incomplete conclusions, as discussed below.
What Are The Symptoms Of Parkinsons Disease
Symptoms of Parkinsons disease and the rate of decline vary widely from person to person. The most common symptoms include:
Other symptoms include:
- Decreased facial expressions: You may not smile or blink as often as the disease worsens; your face lacks expression.
- Speech/vocal changes: Speech may be quick, become slurred or be soft in tone. You may hesitate before speaking. The pitch of your voice may become unchanged .
- Handwriting changes: You handwriting may become smaller and more difficult to read.
- Depression and anxiety.
- Sleeping disturbances including disrupted sleep, acting out your dreams, and restless leg syndrome.
- Pain, lack of interest , fatigue, change in weight, vision changes.
- Low blood pressure.
Mechanisms That Contribute To Persistent Pain In Pd
As the field progresses psychophysical testing has the potential to advance our understanding of persistent pain in PD by elucidating the mechanisms which underlie pain in PD, and in doing so, identifying subgroups of patients with susceptibility to developing persistent pain while assisting in the development and monitoring of personalised pain management strategies for these patients.
First Type Of Leg Pain Is Central Pain
This pain is described as constant burning sensation with occasional burst of sharp pain. As it was in my case, this pain is commonly exacerbated by cold and by light touch. I could not stand the sheets to touch my skin and being in a cold room sent my pain through the roof. This type is usually bilateral but it may start on the side where other Parkinsons symptoms begin. For me, it was the leg where my rest tremor began.
My Parkinson’s Story: Pain
This 10-minute video alternates between an interview with a man and and doctors. The man shares his experience with pain as a symptom of Parkinson’s disease. The doctors explain that pain is common in Parkinson’s disease, often due to rigidity or dystonia, which can be exacerbated by “off” periods. Pain caused by Parkinson’s symptoms can be relieved by Parkinson’s medications, exercise, DBS and botox injections. Pain is an invisible symptom that should be mentioned to your neurologist.
Pain In Pd: Current Treatment
Pain is a multi-dimensional experience involving sensory discriminative and affective motivational descriptive axes. As such, pain perception is inherently subjective and influenced by multiple factors. While acute pain reflects an adaptive survival mechanism, persistent pain negatively impacts the quality of life of the affected individual and serves limited evolutionarily advantage. Unfortunately a large proportion of people with PD experience persistent pain and 50% of those individuals receive no or inadequate treatment,. Therapeutic strategies that offer an improved analgesic profile remain an unmet clinical need. Clearly multi-disciplinary approaches for pain management that encompass new concepts in pathogenesis and treatment are required,.
Pain Due To Fluctuations Dyskinesia Or Dystonia
To reduce potentially pain provoking motor fluctuations and dyskinesias, the optimization of therapy aiming to smoothen dopaminergic plasma level is recommended. The use of prolonged acting dopamine agonists or substances reducing the dopamine degradation such as MAO-B or COMT inhibitors are thought to reduce painful motor fluctuations during day- and night-time as well as early-morning akinesia. PD patients with motor fluctuations, who received the finally not approved partial dopamine D2 agonist Pardoprunox as adjunct therapy to levodopa, showed in a post-hoc analysis of a RCT a greater decrease in VAS pain scores compared to placebo . Amantadine might be helpful for painful dyskinesia, but data is missing.
A second substance with a potential specific effect on pain might be safinamide. In a post-hoc analysis based on pooled data of two large RCTs, safinamide applied as add-on therapy to levodopa treatment was associated with less consumption of pain medication compared to placebo and a significant reduction of pain in two of three sub-items of the PDQ-39 scale reflecting musculoskeletal and neuropathic pain . Noteworthy, in the safinamide group a slightly higher percentage of patients had additional pain medication at study baseline. In summary, this limited benefit needs to be confirmed by dedicated future studies.