The following is Part I of a series of columns on the topic of pain as a secondary condition for people with disabilities. This month's column provides a general overview of pain experienced by people with spinal cord injury. Future columns will explore how pain affects people with different types of disabilities.

Jennifer Rowland, Ph.D.

Pain is a commonly reported and functionally limiting secondary condition for people with many types of disabilities, including SCI. It can be classified as chronic (long-term or persistent pain) or acute (short-term with an easily identifiable cause), and severity can be measured by verbal report using a visual analog scale (i.e., numerical pain rating) and by functional limitations associated with the pain.

Pain Types

There are two basic types of pain:

1. Neuropathic Pain: also known as 'neuralgia' results from damage to the central or peripheral nervous system or from abnormal processing of central nervous system pain signals. This type of pain may present as a steady burning sensation, a 'pins and needles' feeling or as an 'electric shock.'
   
2. Nociceptive Pain: may manifest as musculoskeletal pain, and can result from mechanical, thermal or chemical trauma. Nociceptors are sensory receptors that respond to these pain types, which are specifically: a) Mechanical: respond to excess pressure; b) Thermal: activated by extreme hot or cold temperatures above 45 degrees Celsius and below 5 degrees Celsius; c) Chemical: could be from externally ingested chemicals or a physiological chemical (ie, lactic acid that could cause pain following exercise)(Kandel, Schwartz, & Jessell, 2000).

Pain Prevalence for People with SCI

Pain prevalence for people with SCI varies widely among sources (33% to 94%) and depends on the survey sample and methods used in data collection (Demirel, Hilmaz, Gencosmanglu, & Kesiktas, 1998; Siddall, Taylor, McClelland, Rutkowski, & Cousins, 1999). It is estimated that as many as two-thirds of people with SCI report having chronic pain, and up to one-third of those reporting pain classify it as severe (Ehde, Jensen, Engel, Turner, Hoffman, & Cardenas, 2003; Finnerup, Johannesen, Sundrup, Bach, & Jensen, 2001; Siddall, Yezierski, & Loeser, 2002). Chronic pain has been shown to significantly increase with age (Putzke, Barrett, Richards, & DeVivo, 2003).

Recent research on adults with SCI provides evidence that pain adversely affects social integration, and that higher pain intensity is associated with a decreased ability to perform basic activities of daily living (Jensen, Hoffman, & Cardenas, 2005) and has a negative impact on quality of life (Budh et al., 2003; Rintala, Loubser, Castro, Hart, & Fuhrer, 1998; Turner & Cardenas, 1999; Turner, Cardenas, Warms, & McClellan, 2001). Siddall, McClelland, Rutkowski, and Cousins (2003) studied 100 people with traumatic SCI to determine prevalence and characteristics of pain within five years of injury. Fifty-eight percent of the sample reported severe or excruciating pain, with musculoskeletal pain being the most commonly reported pain type. Forty-one percent of the sample reported neuropathic pain at the injury level, whereas 35% reported pain below the lesion. Visceral pain, defined as originating from the body's viscera or organs, was only reported by 5%. Overall, 81% of those studied reported pain, but there was no relationship between pain presence and lesion level, complete or incomplete SCI, or injury type. These authors concluded that, among this sample, those with neuropathic pain soon after their injury were likely to have persistent pain which could be severe.

Measuring or Quantifying Pain

Finding ways in which to accurately measure pain and its effects on quality of life is especially important. Given improvements in medical care over the past few decades that have increased survival rates for people with SCI and made aging with SCI more common (Anson & Shepherd, 1996), the issue of accurate and complete pain measurement in SCI is very important for this population.

It can be difficult to distinguish neuropathic pain from nociceptive pain, and researchers in the Department of Pain Medicine and Palliative Care, Beth Israel Medical Center in New York developed a 6-item questionnaire to assist in making this distinction:

1. Did the pain feel like pins and needles?
2. Did the pain feel hot/burning?
3. Did the pain feel numb?
4. Did the pain feel like electrical shocks?
5. Is the pain made worse with the touch of clothing or bed sheets?
6. Is the pain limited to your joints?

Answering yes to questions 1-5 indicates neuropathic pain, whereas a yes to question 6 indicates nociceptive pain.

Another method of evaluating pain has been the McGill Pain Questionnaire. This form has been used in the clinic to describe subjective pain experiences, and involves a pain rating index, descriptive pain words, and pain intensity (on a 1-5 scale). However, it is not a pain measurement tool specific to identifying pain for people with SCI or other types of disabilities.

Treating Pain

Although medications are one way of reducing pain, other strategies include improving education on ways to reduce pain by increasing self-efficacy, improving adherence to pain treatments, and identifying positive coping strategies (Ambrose et al., 2003; Cedraschi et al., 2004). Social support that involves a structure of receiving positive input from family members, friends, and caregivers, has also been shown to reduce pain (Hakkinen, 2004; Moskowitz et al., 2004).

Exercise is another potential prevention and different management tool to decrease pain among people with SCI. Future columns will explore how types of exercise can benefit people with SCI as well as people with other types of disabilities.

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Encouraging Readers to Share Pain Experiences

If you have experienced pain as a secondary condition, or have advice for others regarding ways in which you have decreased your pain, please e-mail me, Dr. Jennifer Rowland, at jenrow@uic.edu. These shared experiences could offer ideas for future column topics.