Complex regional pain syndrome: which treatments show promise?

Journal of Family Practice, July, 2005 by Anna Quisel, James M. Gill, Peter Witherell

Practice recommendations

* Treatments for CRPS type 1 supported by evidence of efficacy and little likelihood for harm are: topical DMSO cream (B), IV bisphosphonates (A) and limited courses of oral corticosteroids (B). Despite some contradictory evidence, physical therapy and calcitonin (intranasal or intramuscular) are likely to benefit patients with CRPS type 1 (B).

* Due to modest benefits and the invasiveness of the therapies, epidural clonidine injection, intravenous regional sympathetic block with bretylium and spinal cord stimulation should be offered only after careful counseling (B).

* Therapies to avoid due to lack of efficacy, lack of evidence, or a high likelihood of adverse outcomes are IV regional sympathetic blocks with anything but bretylium, sympathetic ganglion blocks with local anesthetics, systemic IV sympathetic inhibition, acupuncture, and sympathectomy (B).

In last issue of the JOURNAL OF FAMILY PRACTICE, we discussed diagnosis of CRPS type 1 ("Complex regional pain syndrome underdiagnosed," 2005; 54: 524-532). Once other conditions have been ruled out, a primary care practitioner can diagnose CRPS type 1 right in the office using clinical findings and the patient's report of symptoms. Similarly, primary care practitioners can provide most of the best treatments for CRPS type 1. In fact, evidence indicates that no benefit has been proven from more invasive treatments such as sympathectomy which continue to be included in recommendations by experts. (1)

* Evidence for intervention less than compelling

A review of the literature on treating CRPS type 1 raises a question: is there any evidence that treatment makes a difference in outcomes that matter to patients, such as returning to work, regaining functionality of the affected limb, or resolution of pain? The large discrepancy between the high rates of CRPS type 1 documented in prospective studies of post-traumatic patients and the low rates of diagnosis of CRPS type 1 in actual practice suggests that most cases of CRPS type 1 resolve without being diagnosed and treated. This is not proven because, unfortunately, the natural history of persons diagnosed in the first 9 weeks after injury is not known (2)

Are there benefits to early treatment?

From the clinician's perspective, persons diagnosed with CRPS type 1 early appear more likely to respond to treatment. There is an "off-quoted contention that results of early treatment will be better than those when the pain is treated late." (2) Yet, the great majority of these patients may have improved just as readily without treatment. For the few cases of undiagnosed CRPS type 1 that will persist to become chronic and treatment resistant, it is unknown whether early treatment would have been preventive (2) or how clinicians could distinguish these cases early enough to target them for treatment.

Intriguing but limited data exist for using preventive therapies in all at-risk patients. One prospective cohort study documented a lower rate of CRPS type 1 in stroke patients who underwent early inpatient rehabilitation, compared with patients in earlier studies who rarely received early rehabilitation. This finding indirectly suggests a possible preventive effect of physical/occupational therapy (LOE: 3, cross-study comparison)) Luckily, early inpatient rehabilitation in stroke patients has become the standard of care, which may prevent many cases of CRPS type 1 as a side effect.

It also appears that injury to a newly hemiplegic arm may contribute to the shoulder-hand syndrome; a study that alerted patients and care-takers to the risk of injury reduced the rate of shoulder hand syndrome from 27 to 8% (LOE: 2, lower-quality RCT).4 Among post-traumatic patients with wrist fracture, a double-blind randomized placebo controlled trial (n=115) of vitamin C 500 mg tabs initiated upon diagnosis of fracture and continued for 50 days resulted in a marked decrease of CRPS type 1 from 22% in the placebo group to 7% in the vitamin C group (relative risk=0.17) (LOE: 1, high-quality RCT). (5) These results have not been tested in subsequent trials, however.

Guideline recommendations: Physical and psychological therapy, pain management

Many treatments for CRPS have been tried and are summarized without a systematic or evidence-based approach to the literature in a consensus statement released in 2002 by an interdisciplinary expert panel (LOE: 3, consensus guideline). (1) These guidelines suggest rapid initiation of multidisciplinary treatment with advancement to higher levels of intervention if no benefit from initial therapy occurs in 2 weeks. Simultaneous physical rehabilitation, psychological therapy, and pain management are recommended.

Rehabilitation through physical therapy and occupational therapy starts with desensitization and stress loading, progresses to increasing flexibility with gentle active range of motion and stretching, and eventually to normalization of use.

Psychological therapy starts with teaching patients that 1) pain sensations in CRPS type 1 do not indicate tissue damage, and 2) reactivation of the affected limb is important. With persistent symptoms, clinical psychological assessment is recommended, eventually followed by cognitive behavioral therapy.