Symptoms - Pain
Although Parkinson’s disease (PD) is most noted for its motor symptoms of tremor, bradykinesia (slowed movement), rigidity, and balance issues, up to 85 percent of people with PD also experience pain.1,2
Pain is highly subjective, based on the individual’s perception, and it can be difficult to describe. The pain experienced by people with PD is often a major complaint.
Some people with PD experience pain as an early symptom of the disease, while others experience it at later stages. For a minority of people with PD, the pain is severe and overshadows the motor symptoms of the disease.1,2
How is it categorized?
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 (arms and legs). 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:
- Musculoskeletal pain related to poor posture
- Nerve or root pain, which is commonly related to arthritis in the neck or back
- Pain due to dystonia, the prolonged twisting or contraction of a muscle group
- Discomfort due to extreme restlessness (akathisia)
- A pain syndrome known as "primary" or "central" pain that arises from the brain1
The motor symptoms of PD can frequently lead to musculoskeletal pain. Musculoskeletal pain may be felt in the hip, back, neck, or even a frozen shoulder. Musculoskeletal pain is diagnosed based on a history and physical examination.
Imaging tests, such as x-rays, bone scans, or ultrasound, may be used. Treatment is often multi-faceted, including dopaminergic therapy, physical therapy, and an exercise program that emphasizes range of motion.1
Nerve or root pain
Nerve or root pain is pain that occurs close to a nerve. It is also called neuritic or radicular pain. The most common root pain syndrome is sciatica, in which the sciatic nerve is compressed or inflamed from the L5 vertebrae and causes pain that shoots down the leg.
Diagnosis of root pain is done through a neurological exam, which may include imaging or electrodiagnostic studies. This type of pain is usually successfully treated with pain medication and a mobility program.1
Dystonia is one of the most painful symptoms of PD. Dystonia can affect the limbs, neck, face, tongue, jaw, trunk, or even the muscles in the throat that control swallowing or the vocal cords. People with PD who experience dystonia may experience their feet or toes curling painfully, an arm that twists behind the back, or the head bent forward towards the chest.
Dystonia often occurs when medications for PD, such as dopaminergic agents, are wearing off. Treatment may include changing the dosing of medication, adding physical activity to combat early morning dystonia, or injections of apomorphine under the skin.1
Some people with dystonia benefit from deep brain stimulation, a surgical procedure in which electrodes are implanted and then activated in the brain.1
Akathisia is an extreme restlessness that is experienced by some people with PD. Those who experience akathisia are unable to sit still, drive a car, or eat at a table. It often impacts a person’s sleep and ability to interact socially.1
Approximately half of the cases of akathisia in PD fluctuate with medication, and the symptoms may be relieved by additional dopaminergic treatment.1
Central pain syndromes
Central pain is one of the most severe, as it causes unexplained sensations of stabbing or burning. It is also the most rare pain syndrome experienced by people with PD. Central pain may affect the abdomen, chest, mouth, rectum, or genitalia. Treatment is often challenging and may include dopaminergic agents, painkillers, opiates, antidepressants, or antipsychotics.1
The role of depression
Chronic pain can lead to depression, and depression also increases the incidence of pain. Approximately 40 percent of people with PD experience depression.1
Depression must be considered as a contributing factor in assessing pain in people with PD and may need to be treated.1