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Shaw Chiropractic
A Medical-Legal Newsletter for Personal Injury Attorneys
by Dr. Steven W. Shaw

New Study Explains Chronic Pain in Whiplash Syndrome

A study published in the November 1999 issue of the journal PAIN (1;83(2):229-234) adds new insight into the chronic muscular pain suffered by victims of whiplash related to automobile trauma. The study titled AGeneralized muscular hyperalgesia in chronic whiplash syndrome@ was performed by researchers from the Department of Rhumatology of Aalborg Hospital in Aalborg, Denmark

This study examined 11 sex and age matched control subjects to 11 chronic whiplash patients. The subjects were injected with hypertonic saline solution. The researchers measured muscular sensibility and referred pain patterns. Measurement instruments included visual analog scales and pressure algometry.

The authors found that pain thresholds were significant lower in chronic whiplash patients than in controls. They also found that muscular hyperalgesia and large referred pain areas were present in the whiplash patients both within and outside the traumatized area. The findings suggest that with chronic whiplash syndromes the pain generator becomes centralized rather than from the area of lesion. In lay terms, this means that the actual tissues damaged eventually become a secondary pain producer and the chronic pain is mediated by newly learned pain loops in the spinal cord, brain stem and brain. Consequently, the treatment of chronic whiplash pain by attending to the area of trauma may not address the newly developed pain generator in the central nervous system. A more thorough explanation of this changed central neural processing is beyond the scope of this newsletter. For further explanation I would recommend we speak personally.

In the paper, the authors identify some other interesting points. Below is a list of some of the more interesting observations:

- 14-42% of patients with whiplash develop chronic pain.

- The etiology and pathogenesis of whiplash syndromes are not fully understood.

- The anxiety and depression found in whiplash patients are more a consequence of chronic pain rather than a pre-existing condition.

- Ultrasonic scanning has revealed post-traumatic lesions in muscles of whiplash patients.

- In some ways, the symptoms of patients suffering from chronic whiplash pain are similar to the symptoms of patients with chronic fibromyalgia.

What are the key points of this study? First, chronic whiplash patients have significantly lower pain threshold in both injured and non-injured areas. Second, these patients also have greater area of pain, intensity of pain and duration of pain following stimuli at both injured and non-injured areas.

This new data helps to address both treating and IME doctors opinions regarding Asymptom magnification@ and Aembellishment@. These terms are often used by doctors to explain symptoms which seem inconsistent or disproportionate. The connotation is that these patients are faking. The attorney, armed with this information, should question the physician who uses these terms to determine if they are familiar with this research. The physician should examine the patient=s treatment records to see if a pattern of symptoms moving towards this chronic presentation exists. If so, the physician=s opinion may be modified from Asymptom magnification@ to Acentralized pain@ suggesting the consistency of the pain presentation with this scientifically established phenomenon.