Pain is a common, but perhaps unexpected, non-motor symptom of Parkinson's disease (PD). Up to 75 percent of people can experience some form of discomfort during the course of their disease. Unfortunately, this symptom is often under-recognized and therefore undertreated.
Many Potential Causes of Pain in Parkinson's Disease
Some types of pain are due to Parkinson's motor or non-motor symptoms, others to the underlying disease itself. Some pain or discomfort can't be linked directly to PD but is still fairly common. A list of top causes of pain in people with Parkinson's includes:
- Muscle stiffness: Motor symptoms, such as rigidity and slowness of movement can lead to aching and pain, which may result in decreased mobility and even more pain. Stiffness may be generalized over the entire body or localized to one region, such as the shoulder, arm or leg. Sometimes an uncontrolled tremor can trigger pain.
- Dystonia: Dystonia is a prolonged, involuntary muscle contraction that causes an abnormal posture. It can affect any body part, but typical examples in PD are foot cramping or curling under of the toes. Dystonia most often arises in the morning or during "off" times, when medication is not working optimally and Parkinson's symptoms return.
- Dyskinesia: Dyskinesia is abnormal, involuntary movement that may develop with long-term use of levodopa (in conjunction with a longer duration of disease). Dyskinesia usually occurs when Parkinson's symptoms are otherwise controlled (i.e., during "on" times). The movements can be a writhing, wriggling or fidgeting-type motion.
- Central pain: In PD, the brain regions that process sensation and pain may not work correctly, which can result in a syndrome called "central pain." The symptoms of central pain vary widely from person to person. Pain can be widespread, affecting the whole body, or focused on one area. It may be a constant burning sensation or an intermittent sharp burst of pain.
- Abdominal pain: The majority of people with Parkinson's experience constipation or stomach upset at some point, many times even before diagnosis. Constipation can range from a minor nuisance to a condition that causes severe bloating and discomfort. (Watch a webinar on constipation.)
- Musculoskeletal pain: Because of decreased mobility, postural changes, falls and sometimes fractures, Parkinson's can cause muscle and bone achiness. Many people also have lower back pain and even associated sciatica (pain, tingling and numbness radiating down the back of one leg).
- Joint pain: Arthritis isn't part of Parkinson's per se. But both conditions are more common with aging so their pains can be difficult to differentiate. Hand, knee, hip and lower back joints often are stiffened by arthritis.
- Neuropathy: Damage to peripheral nerves (those that carry sensation to the hands and feet) can manifest as numbness, tingling or burning. This sort of neuropathy can be caused by a number of conditions, including diabetes and vitamin B deficiencies.
Pain, like most non-motor (and motor) symptoms, can fluctuate. When talking about their Parkinson's, people who live with the disease describe good days and bad days. Physical and emotional stress, as well as lack of sleep, fatigue and depression can exacerbate pain. Pain in Parkinson's, no matter where it's coming from, also is generally worse during "off" times (periods when PD symptoms return because medications aren't working ideally).
Multiple Approaches to Pain Management in Parkinson's
A few basic tenets for treating pain in Parkinson's are to:
- Identify the source of the pain, if possible,
- Optimize control of motor symptoms,
- Incorporate exercise,
- Use non-pharmacologic methods, if helpful,
- Add pain medication as necessary.
If pain arises, discuss it with your movement disorder specialist, who can assess your Parkinson's, evaluate for causes other than PD (even minor infections can worsen Parkinson's symptoms and pain), and direct appropriate treatment.
If motor symptoms are not controlled, pain may not be adequately controlled either. If "off" time, dyskinesia or dystonia are contributing to or causing pain, dopamine medication adjustments are likely to be the initial strategy for pain management. Additional therapies for dystonia may include botulinum toxin (Botox) injections into the affected muscles, or oral drugs, such as muscle relaxants.
Exercise can be beneficial for most pain (and constipation), even though this may be the last thing you feel like doing. A physical or occupational therapist can help you craft a personalized regimen, and family members and friends can keep you accountable.
Non-pharmacological pain treatments include massage therapy, mindfulness and meditation techniques, acupuncture, and heat or cold application. These may be used on their own or in combination with medication.
For musculoskeletal and other pain, anti-inflammatories may be recommended. For severe pain, low doses of opioids may be prescribed. Opioids can cause constipation, though, so they must be used cautiously. For central or neuropathic pain, particularly when depression is present (and even when it's not), certain antidepressants often can ease symptoms.
A multidisciplinary team approach for pain management may be necessary. In addition to your movement disorder specialist, providers may include physical or occupational therapists, psychiatrists and even pain management experts. Each of these practitioners targets a different aspect of the pain.
Active Research into Several Aspects of Parkinson's Pain
Researchers are working to better understand the mechanisms behind pain in Parkinson's so that it can be more effectively addressed. They are looking for objective measurements, such as brain imaging, to diagnose and monitor pain, and to evaluate response to treatment. (Right now this can only be done subjectively, or by asking a person to rate their pain using a numerical or visual scale.) And, they're investigating several drugs and deep brain stimulation for their potential benefits in treating Parkinson's disease pain.