What a Pain! Understanding and treating pain in PD – Webinar notes

What a Pain! Understanding and treating pain in PD – Webinar notes

In early May, the American Parkinson Disease Association (APDA) Northwest Chapter offered a webinar on understanding and treating pain in Parkinson’s disease (PD), featuring Dr. Pravin Khemani, a Movement Disorders Specialist. He discussed causes of pain in PD, treating pain by optimizing treatment of PD, and treatment strategies for pain in PD from other causes. We at Stanford Parkinson’s Community Outreach viewed the webinar and are sharing our notes.  

The webinar was recorded and can be viewed for free here.

If you have questions about the webinar, you can contact APDA Northwest Chapter by phone: 206-695-2905 or email: apdanw@apdaparkinson.org.  

One resource mentioned in the webinar is the PQRST pain assessment scale. You can download a PDF version of the scale here.

For additional terrific resources on pain in PD – including downloadable guides, links to online resources, and webinars and podcasts – visit this page on the Stanford Parkinson’s Community Outreach website.

Now… on to our notes from the webinar.

– Lauren

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What a Pain! Understanding and treating pain in PD – Webinar notes

Presented by the American Parkinson’s Disease Association, Northwest Chapter

May 8, 2020

Summary by Lauren Stroshane, Stanford Parkinson’s Community Outreach

Dr. Pravin Khemani is a Movement Disorders Specialist at Swedish Neuroscience Institute in Washington. His presentation covered causes of pain in PD, treating pain by optimizing treatment of PD, and treatment strategies for pain in PD from other causes.

What is pain?

“An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”

– International Association for the Study of Pain, 1979/2011

The experience of pain is contextual; the context for this presentation is PD, which is common but remains under-treated. Pain in those with PD is typically chronic (long-term), recurrent, and/or intermittent. Dr. Khemani’s presentation did not address acute or sudden pain, such as headache, chest pain, abdominal pain, eye pain, throat pain, etc. as these are not typical of PD and are common in the general population.

Most people are familiar with some of the non-motor symptoms associated with PD: sleep disorders, cognitive changes, mood disorders, and autonomic dysfunction are widely known. Pain should be included as another non-motor symptom of PD.

Why is pain so common in PD?

Chronic, recurrent pain is experienced by 60 to 70 percent of individuals with PD. Studies show that dysfunction in the dopamine circuits and pain pathways in the brain often degenerate in PD, leading to a higher incidence in PD. There is also a higher rate of musculoskeletal issues in PD that can also cause pain, which tend to be under-treated.

Pain seems to be felt differently in PD. There seems to be a lower threshold for feeling pain in those with PD, as well as altered pain sensation.

Dr. Khemani classified pain in PD into two categories, which will be discussed further:

  1. Pain from PD and its treatment
  2. Pain from other causes

There are many different techniques for classifying or attempting to quantify pain, but it is an inherently subjective experience and there is no way to objectively “measure” someone’s pain. The speaker finds it helpful to use the “PQRST” assessment:

  • Precipitating (and relieving) factors:
    • What makes the pain worse? What makes it better?
  • Quality
    • How would you describe the pain? What does it feel like? [Examples: dull, achy, throbbing, sharp, electric shock-like, burning, tingling, icy]
  • Radiation
    • Is the pain in one place or does it move around the body?
  • Site & severity
    • Where is the pain? On a scale of 0-10, how do you rate the pain?
  • Timing & treatment
    • When did the pain start? How often does it occur – constant or intermittent? Any relation to timing of PD medications, such as during “on” or “off” states? Are you getting treated for the pain?

The type of pain can help a healthcare provider help to differentiate possible causes and treatments. For instance, nerve pain often feels like sharp, shooting, or tingly pain, whereas muscle pain tends to be a dull, deep ache. These pain types may require different modes of management.

For those with PD, it is essential to determine if there is any relationship between the timing of the pain and the PD medications.

Pain from PD and its treatment

Pain may be due to under-treatment of PD symptoms, or from motor fluctuations. A low-dopamine state can cause substantial discomfort. Pain can sometimes be the first sign of PD, even before motor symptoms appear, but is often unrecognized because it is so common from other causes as well.

In studies, individuals with PD have described their pain as “electrical discharge,” “throbbing,” “hot and cold,” and “generalized” body pain. The pain is highly variable in perception and location, though it is usually worse on the side of the body that is more affected by motor symptoms.

How to correct pain from under-treatment? Simple: optimize dopamine treatment to improve the motor symptoms! This improves pain in about 48 percent of cases. If pain persists despite an increase in dopamine, then standard pain medications (analgesics) like ibuprofen or Tylenol are effective in 78 percent of cases.

Dystonia is abnormal, sometimes painful, muscular contraction. Those with PD sometimes experience dystonia in the hands or feet, either in the on-state or off-state. Dystonia in the feet can cause the foot to rotate, or the toes may curl; this is often painful and may make it difficult to walk safely. Hand dystonia can cause hands to curl or rotate as well.

Dyskinesias are abnormal movements that tend to be mobile, dynamic, and typically triggered by dopaminergic medication. They are not typically painful and may not even be bothersome, though in cases of severe neck or head dyskinesias, pain may occur. Dyskinesias may happen when medication is kicking in, wearing off, or reaching its peak.

The concept of a therapeutic window refers to the range of medication dosage in which a person with PD gets enough medication to feel “on,” but not so much medication that they are over-medicated and experience dyskinesias or other unpleasant side effects.

As PD progresses, the therapeutic window gets narrower: it is harder to get the balance of medication just right. Medication may wear off earlier, necessitating more frequent dosing, and may take longer to kick in. Dyskinesias may become more common. The period of getting a good “on” state shrinks, and the individual experiences longer “off” times when medication is kicking in. For those who have “off” dystonia, the periods of uncomfortable dystonia lengthen.

Treatment of motor and pain fluctuations

The first step is optimization of PD treatments: the goal is to spend more time in the “on” state without dyskinesias and less time in the “off” state.

  1. Multimedication treatment: Adding other medications rather than solely increasing the dose of levodopa is the most effective approach.
  2. Surgical treatment: Options such as Deep Brain Stimulation (DBS) or a levodopa intestinal pump may work well for some patients to reduce fluctuations.
  3. Customize for each person: Everyone is different; needs and symptoms also change over time as the disease progresses.

One technique for optimizing PD medications is fractionation: taking smaller doses more frequently. However, this significantly increases “pill burden” – the number of pills an individual has to keep track of each day – and the likelihood of mistakes or missed doses.

There are some medications that provide longer “on” time with reduced likelihood of dyskinesias.

Rytary is a newer formulation of carbidopa-levodopa that combines short-acting and long-acting levodopa into one pill. For some patients, it can replace short-acting carbidopa-levodopa (Sinemet) with fewer doses and pills per day.

Another recent option is the Inbrija inhaler, which is a version of levodopa that can be inhaled. It is intended for people with occasional wearing off and usually kicks in within 10 to 30 minutes. One advantage for those with chronic constipation or other gastrointestinal issues is that Inbrija bypasses the gut.

Other medications are frequently used in combination together. By taking smaller doses of each drug, individuals can often avoid the side effects associated with a larger dose of one. Common medication combinations include:

  • Carbidopa-levodopa, such as Sinemet or Rytary
  • Dopamine agonists (in those under the age of 60, due to risk of side effects), such as pramipexole (Mirapex)
  • COMT inhibitors, such as entacapone (Comtan)
  • Monoamine oxidase inhibitors (MAOIs), such as rasagiline (Azilect)
  • Amantadine

Dystonia does not always respond to dopaminergic medications; those with painful muscular contractions may not experience relief even when their PD medications are optimized. In those cases, injected botulinum toxin (Botox) can provide substantial relief by paralyzing or weakening the dystonic muscles with small injections that are repeated every three months.

Alternatively, other oral medications such as clonazepam or trihexyphenidyl may be useful for “refractory” dystonia that does not respond to PD medications; these drugs carry risks of side effects and are not recommended for everybody.

Deep Brain Stimulation (DBS) has been a treatment for the motor symptoms of PD for twenty years, but is increasingly being explored for other diagnoses, including pain and depression. By implanting the stimulators in different areas or “targets” within the brain, the stimulation may provide therapy for these other disorders.

Over time, pain from PD will change and evolve, so DBS would likely have to be used in conjunction with other pain management modalities, not by itself indefinitely. Currently, DBS is not recommended solely for the treatment of pain that is associated with PD.

Other types of pain associated with PD

Central pain:

  • Variable description, often electric, achy, generalized body discomfort
  • Often treated with analgesics like Tylenol, muscle relaxants, gabapentin, tricyclic antidepressants, duloxetine, or pregabalin

Akathisia:

  • A state of inner restlessness that makes it impossible to sit still
  • Treated by optimizing PD medications

Restless leg syndrome (RLS):

  • “Creepy-crawly,” “tingly,” burning, aching, or throbbing in the legs that occurs with rest and is relieved by moving the legs
  • Can cause severe sleep disturbance
  • Treated with pregabalin, gabapentin, pramipexole, rotigotine, ropinirole, opiates, and other medications

Pain and discomfort from other causes

It can be quite challenging to tease apart the true causes of pain, and determine whether they are directly related to PD or due to some other cause. A team approach is often necessary, and may include:

  • General practitioner
  • Rehabilitation specialist
  • Rheumatologist
  • Pain specialist
  • Orthopedist
  • Neurosurgeon

Musculoskeletal(MSK) disorders are very common in PD, often affecting the neck, low back, joints, and limbs. This type of pain is often described as dull, deep ache, sharp pain with movement, cramping, throbbing, or “Charlie horses.” Causes of MSK pain include past injury; wear-and-tear; inflammation of the muscles, ligaments, and connective tissues; and osteoporosis that can lead to fractures. Frozen shoulder, arthritis, scoliosis, joint and spine deformities, stooped neck, and foot problems are all common MSK disorders. Neurologists typically do not treat these kinds of pain, hence the need for a team approach. Imaging with x-rays or MRI may be helpful for diagnosis.

Regular stretching is essential for all individuals, particularly in those with PD. Medications such as analgesics, steroids, and anti-inflammatories may be used; in some cases, surgery may be necessary. Rehabilitation in the form of physical or occupational therapy can be highly beneficial.

Neuropathic pain is caused by damage to the nerves, and is usually described differently than MSK pain: tingling, numbness, burning, “pins and needles,” and “shock-like” are all common descriptors for neuropathic pain.

When nerve pain occurs in the hands and feet, typical causes are neuropathy, diabetes, or deficiencies of vitamin B-12 or folate. Radiating, often asymmetric pain may occur in the shoulder, arm, back, or legs. Nerve pain may be due to radiculopathy (“pinched nerves” at the root of the nerve) or neuropathy (damage to the nerve in the periphery, far from the root).

A neurologist or a general practitioner can treat neuropathic pain. Depending on the location of the pain, an MRI of the back or neck may rule out other potential issues. Blood tests will determine if any vitamin deficiency is present; blood sugar control is also important, if diabetes is present. Rehabilitation therapy such as physical therapy is often recommended. Oral or topical medications are often helpful, and surgery may be necessary in some cases, depending on the cause of the neuropathic pain.

Some conditions can actually accentuate pain if they are present at the same time, so it is important to recognize and try to address these conditions if they exist. Depression, stress, and anxiety go hand in hand with pain, so it is essential to ask about mood when evaluating pain. Treating the pain without treating the concurrent mood disorder will not be effective. Lack of exercise and stretching is another major contributor to pain that can be addressed. Poor quality sleep, constipation, and low blood pressure (BP) are all issues that worsen the experience of pain significantly as well. Low BP results in decreased blood perfusion to muscles and nerves, which can worsen pain.

Marijuana for pain in PD?  

We do not know the effects of the chemical components of marijuana – THC and CBD – in the brains of those with PD. Because of the lack of research in this area, Dr. Khemani does not prescribe marijuana to his patients, even though it is legal in the state where he practices.

If someone has severe pain from another cause, such as cancer, then a referral to a pain physician is appropriate and may sometimes result in recommendation for a trial of marijuana.

Main takeaways:

  • There are myriad causes of pain in PD.
  • The pain evaluation questions “PQRST” can help to identify the cause of the pain.
  • Optimization of PD treatment for both motor and non-motor symptoms is essential.
  • Multidisciplinary treatment for non-PD causes of pain is necessary too.

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Question & Answer Session

Q: Regarding DBS, is there an upper age limit?

A: No, there isn’t; what matters is your “physiological” age rather than chronological age: how healthy you are in general.  

Q: Regarding Pisa syndrome and “Charlie Chaplin” gait – why does PD cause these?

A: There are two main postural changes that can occur in PD:

  1. Mechanical bend in the spine, similar to scoliosis; this is not only specific to PD and cannot be fixed, except with surgery
  2. Camptocormia, also called Pisa syndrome, in which there is a significant forward or sideward bend in the spine due to contractions of muscles

Camptocormia falls under the category of dystonia. It can occur gradually over time and can be quite problematic for some people. Sometimes it can improve with sufficient PD treatment. Other times, it can present as a dyskinetic dystonia due to over-treatment with dopamine. One way to differentiate camptocormia from scoliosis is the ability to lay flat on the bed, which isn’t possible in mechanical issues like scoliosis but is usually possible with camptocormia

Botox isn’t very effective but is sometimes used; the muscles are too deep to be very accurate with the injections. DBS may be helpful in some cases.

Q: Regarding non-traditional, non-pharmacological approaches to pain, do you think these are helpful? (i.e. acupuncture or yoga)

A: It entirely depends on the patient; everyone is wired differently. He recommends seeing a physical or occupational therapist to evaluate the patient to figure out where the deformity or issue is coming from. Once you have done this, and are cleared, then you could consider exercises such as yoga. It is ideally best to work with someone who knows that you have PD and has some understanding of the disease. Acupuncture suggests some benefit for those with PD, though very small sample sizes in these studies. The placebo effect is very real so it can be hard to draw any clear conclusions from many of the studies looking at integrative or complementary medicine.

As long as there is no interaction with the existing PD meds or exacerbation of the existing problem, Dr. Khemani is all for trying complementary medical approaches.

Q: Are there any vitamins or nutritional supplements that can be helpful for pain?

A: Great question! We talked about osteoporosis, which is serious bone loss that can lead to fractures; osteopenia is lower bone density that can eventually become osteoporosis. People with PD are at higher risk of developing both, and are often deficient in vitamin D and calcium, important elements in bone health. Falling and stumbling – experienced by many with PD – can lead to broken bones in someone with osteopenia or osteoporosis, rather than just a minor bruise.

However, be cautious not to take excessive amounts of vitamin D, as it is fat-soluble and can build up to unhealthy levels in the body if taken in excess. Calcium can cause constipation if over-dosed as well. So, if you supplement either calcium or vitamin D, make sure you don’t exceed the recommended daily dose on the bottle.  

Vitamin B-12 and folate, as mentioned before, are important for treating neuropathic pain that is related to vitamin B-12 deficiency.

People sometimes use magnesium supplements to mitigate pain. It is also used to alleviate constipation, which is one of the most-neglected health issues in those with PD: going several days without a bowel movement. For someone with back pain, constipation can significantly exacerbate the pain, partly due to internal pressure, and partly from straining to have a bowel movement. Straining can even cause a slipped disc. Everyone should be taking measures to encourage a daily bowel movement; talk to your primary care doctor if you aren’t sure where to start.

Q: Are people with PD more prone to back pain than the general populace?

A: A variety of things can cause back pain. The most common cause in the general population is simply aging and degeneration. In PD, back pain is especially concerning because staying active and moving around is so important in this disease. We don’t want Dr. Khemani often refers his patients to the Spine Clinic at his medical center to see if rehab or other therapies may be useful, or in some cases, if surgery is warranted.

Q: Are people with PD more prone to headaches? Is it related to PD?

A: People in general are prone to headaches; we don’t have any reason currently to think they are more common in PD. The treatment would depend on what kind of headaches you are having. Fellowships to become a headache specialist are usually two years long, so there is a lot to learn about the management of headaches and it is a complex field.

There is no such thing as a PD headache, per se; if you are bothered by headaches, start with your primary care doctor. For those who experience more serious headaches such as migraines or cluster headaches, then seeing a headache specialist is likely in order.

Q: What is the best way for me, as a patient, to track my pain symptoms and provide useful information to my movement disorders specialist?

A: The “PQRST” mentioned above is absolutely key: this is what providers want to know about your pain. This tool will help you to express what you are experiencing to your provider. There are also pain tracker apps available.

A downloadable PDF mentioned at the beginning of this summary is also available here.