CRPS Type 1 & 2: Presenting Sx May Resemble RA

CRPS is a relatively rare chronic pain disorder dominated by burning pain that is often disproportionate to the initial injury, typically triggered by an injury, surgery, or immobilization.

Diagnosis of complex regional pain syndrome (CRPS) is often delayed and subsequent orthopedic surgery often worsens the condition, according to a retrospective study published in the Scandinavian Journal of Pain.1

Analyzing data for 55 patients, Ellen Jørum, MD, PhD, and colleagues from Oslo University Hospital found that the mean time delay to CRPS diagnosis was 4 years, and that orthopedic re-operations exacerbated 80% of cases.

CRPS is a relatively rare condition with symptoms that mimic other conditions. The syndrome is dominated by constant, burning pain that is often disproportionate to the initial injury, and may also involve motor disability.The pathogenesis of CRPS is unknown. Proposed mechanisms include classic inflammation, neurogenic inflammation, and maladaptive changes in pain perception at the level of the central nervous system.

Although the debilitating form of chronic pain is typically triggered by an injury, surgery, or immobilization, some idiopathic cases have been reported. CPRS is usually confined to one limb, but can sometimes spread to other limbs or body parts.2

Rheumatoid arthritis (RA) can have signs and symptoms similar to those in CRPS. However, the symptoms of RA are typically present in multiple joints, as opposed to just a region of the body.

Debilitating Pain, Worsened By Surgery

The study population included 38 cases of CRPS with no definite nerve lesion (type 1, previously known as reflex sympathetic dystrophy), and 17 cases with a major nerve lesion (type 2, previously known as causalgia). EMG/neurography of the affected extremity provided measurements of motor function, including distal delay, conduction speed, and sensory tests.

Results showed that the mean time to CRPS diagnosis was 3.9 years (range, 6 months to 10 years). Initiating events included fractures, squeeze injuries, blunt injuries, stretch accidents, and surgery.

Many patients experienced debilitating pain — 81.5% were unable to work at all, and only 16.4% managed part-time hours. The majority (65.5%) needed help with all housekeeping activities; only 34.5% were able to participate to some degree. All had given up leisure activities and reported sleep problems.

A total of 27 patients (14 men and 13 women) underwent one to 12 surgeries over a period ranging from 6 months to several years after initial injury. The majority (81.5%; 22) reported subsequent worsening of pain; another 4 found that their pain was not altered, and only 1 reported improvement of pain.

Importantly, researchers also found that 17 of the 22 patients with worsened postsurgical pain (77%) could have been diagnosed with CRPS before surgery.

“Retrospectively, by an analysis of patients’ reports, as well as documentation in their records, based on information of pain, sensory and autonomic dysfunction, a large majority of these patients had symptoms and signs compatible with a certain or probable CRPS prior to the first post-injury surgical procedure,” the authors write.

A Diagnosis of Exclusion?

CRPS is sometimes difficult to diagnose in clinical practice, especially for physicians not familiar with the condition, says Salim Hayek, MD, a professor of anesthesiology from Case Western Reserve University School of Medicine in Cleveland, Ohio.

“The problem with CRPS is that we don’t have a biomarker for it, no blood test or imaging study that we could order and confirm that a particular patient has the diagnosis,” Dr Hayek told Clinical Pain Advisor, noting that the symptoms can often mimic other conditions and the diagnosis is often one of exclusion. 

According to Andreas Goebel, MD, a senior lecturer in pain medicine from the University of Liverpool’s Institute of Translational Medicine and chair of the development panel for UK CRPS guidelines, the study highlights an important aspect of CRPS in clinical practice.

“Non-specific pain is always a difficult situation for a surgeon, whose training is to look for a structural cause of the pain,” Dr. Goebel told Clinical Pain Advisor. “Many people come to surgeons with unexplained pain. They have limb pain and the surgeon, if they haven’t seen [CRPS] often enough, come with their general ideas of how to address that pain — and arthroscopy is one of those ways.”

“Typically, there may be something that looks a bit abnormal on imaging, so the surgeon is inclined to shave a bit of bone off. If this is a situation where CRPS is present, then it can get quite a bit worse,” Dr Goebel noted.

This article originally appeared on Clinical Pain Advisor