Complex Regional Pain Syndrome

68 Complex Regional Pain Syndrome

Erik Hansen and Jonathan Isaacs

68.1 Patient History Leading to the Specific Problem

A 53-year-old otherwise healthy Caucasian woman presented with a history of chronic left wrist pain due to late-stage scaphoid nonunion advanced collapse wrist arthritis (Fig. 68.1). Having failed nonoperative treatment, she agreed to undergo triquetrum and scaphoid excision with lunocapitate and hamate fusion as well as carpal tunnel release (Fig. 68.2). She was discharged home following the operation and noted worsening pain and swelling on postoperative day 1. She was evaluated and sent to the emergency room where she was found to have significant swelling and erythema diffusely involving the back of her wrist and hand. Her sutures were removed and a hematoma evacuated. Cultures were sent and she was empirically started on antibiotics.

Despite negative cultures, she returned 3 days later with continued severe pain and swelling and was given an oral steroid taper and referred to hand therapy for edema control. Over the ensuing weeks, she was followed closely and noted to have worsening swelling with erythema and intermittent sensations of temperature sensitivity. Additionally, physical examination revealed hyperhidrosis, “shiny and tight” appearing skin, hypersensitivity to non-noxious stimuli, and disproportionate edema and discoloration over her fingers (Fig. 68.3). Reduced range of motion was most notable in her digits. She did not demonstrate further physical findings or serological markers indicative of infection. Despite aggressive therapy and evolving successful arthrodesis, gains in pain control and mobility were modest.

68.2 Anatomic Description of the Patients Current Status

The patient presented with disproportionate postoperative pain and hyperesthesia extending beyond the surgical field. Classical signs of complex regional pain syndrome (CRPS) including diffuse erythema, swelling, and soft-tissue changes were noted shortly after surgery and did not abate with routine interventions such as elevation, therapy, and even oral steroids. CRPS is a pain syndrome that affects the upper and lower extremities and is of unknown etiology and often presents after seemingly minor trauma, fracture, surgery, or rarely may develop spontaneously. There is an estimated incidence rate of 26.2 per 100,000 person-years. The syndrome most commonly affects Caucasian females with a 2 to 4:1 female-to-male ratio. There may be a genetic component with recent genomic data showing a possible predisposition in association with HLA-DQ1 and HLA-DR3. Severe, intense pain within a week of the injury/intervention, as seen in our patient due to the postoperative hematoma formation, may also be a risk factor or indicator for the development of CRPS.

The syndrome is evident by abnormalities of the sensory and motor function of the extremity as well as with autonomic disruption. The diagnosis is one of exclusion in addition to noting specific signs and symptoms in conjunction with a published criterion (Budapest diagnostic criteria [Box. 68.1]). Imaging is generally of minimal use in assisting with diagnosis due to the difficulty in differentiating posttraumatic, disuse, or age-related changes with that of changes from CRPS, though radiographic imaging may show severe osteopenia with patchy demineralization and subperiosteal resorption of the bones in the affected extremity. Magnetic resonance imagery and triple-phase bone scintigraphy have been used and may show changes in bony edema or local blood flow patterns. Bone scan in particular is a commonly obtained imaging modality, as periarticular tracer signal uptake in multiple joints of the affected extremity in phase 3 of the test had been considered pathognomonic. A meta-analysis comparing MRI, bone scan, and plain radiographs showed bone scans had a high sensitivity and negative predictive value, indicating the study is best used to rule out CRPS in patients with a low suspicion of having the condition.

68.2.1 Classification and Pathogenesis

CRPS is divided into three types: CRPS type I (formerly known as reflex sympathetic dystrophy), CRPS type II (also known as causalgia), and CRPS NOS (not otherwise specified). CRPS type II is characterized by injury to a peripheral nerve with associated abnormalities noted on nerve testing (including anatomic distribution sensory loss, focal percussion sign, electromyography, and nerve conduction studies). CRPS NOS includes patients who only partially meet the above-listed diagnostic criteria but whose condition is not otherwise better explained by another pathologic process. Our patient in question had trophic and autonomic changes such as hypersensitivity, cutaneous discoloration, cold sensations, hyperhidrosis, and edema with shiny-appearing skin. Based on her signs and symptoms, she was diagnosed with CRPS type I. The specific pathogenesis of this condition is unknown, but there is evidence of an elevated inflammatory state with central and peripheral sensitization leading to increased activity of afferent nociceptors and alterations in sympathetic activity.

68.3 Recommended Solution to the Problem

CRPS is a complicated problem without a straightforward solution or treatment. The management of this condition requires a multidisciplinary and multimodal approach. Additionally, early diagnosis with early treatment initiation may reduce the severity and longevity of the syndrome. The main goal of treatment is restoration of the functional use of the extremity. Other endpoints include pain control, return to work, and improved quality of life. There are ample data indicating the importance of physical and occupational therapy as a vital early and first-line intervention. These modalities improve range of motion, function, edema control, and pain when utilized in the acute setting. A recent Cochrane review showed some supporting evidence for graded motor imagery and mirror therapy in providing improved pain and function in this patient population. These modalities should be used in all patients with findings consistent with CRPS.

Vitamin C is a supplement that has been given prophylactically in high doses after several studies have shown its effectiveness in lowering a patient’s risk of developing CRPS after injury, surgery, or other mechanisms that may increase the possibility of the patient to develop the syndrome. It should be noted that Ekrol et al published a double-blind randomized controlled trial of 336 patients in which vitamin C or a placebo was given prophylactically following distal radius fractures. They found no difference in outcomes or incidence of CRPS between the groups. This was supported by a meta-analysis by Evaniew et al. However, given the low cost and risk of this intervention, it is often still given and recommended for prophylaxis.

Pharmacological therapy is an additional important treatment modality for established CRPS. An extensive list of medications have been used and studied in the treatment of this condition (Box 68.2).

Box 68.2 Medications for Use in Treatment of

Nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids: These are used to treat the inflammatory component of the syndrome. Oral steroids are most often given in short-term tapers in the acute setting since only limited benefit has been found in patients with long-standing CRPS.

Dimethyl sulfoxide: Free radical scavenger given topically as a 50% cream has shown some benefit in certain populations of patients with CRPS. Side effects include a garliclike taste or odor after administration, hypersensitivity reactions, and local pain.

Antiepileptic medications: Gabapentin (maximum 1,800 mg daily) and pregabalin (300–600 mg daily) are most often prescribed and a Cochrane review noted that these medications might provide relief in some patients with neuropathic pain. The study noted insufficient data to recommend the use of other antiepileptic medications.

Antidepressant mediations: Often used in the treatment of neuropathic pain, with tricyclic antidepressants (TCAs) being the most common. Amitriptyline is the most studied and the most commonly used medication. It has the most anticholinergic effect of the TCAs, which causes sedating effects. The serotonin–norepinephrine reuptake inhibitors venlafaxine and duloxetine have also been used.

Opioids: Commonly used in the acute treatment of all pain.

Bisphosphonates: It is most commonly used in early CRPS in patients with changes seen on bone scan. Its mechanism of action for pain relief has not been fully determined. It may function by modulating inflammatory response early in the disease process or through its antiosteoclastic properties by reducing bone turnover.

Muscle relaxants (cyclobenzaprine, baclofen, methocarbamol): Beneficial in patients with concomitant muscle spasms.

Topical medications: EMLA and capsaicin creams, and Lidoderm patches.

Ketamine: An anesthetic N-methyl-D-aspartate receptor blocker has been shown to be effective in reducing pain in some patients with CRPS.

Dec 2, 2021 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Complex Regional Pain Syndrome
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