Treatment of complex regional pain syndrome type 1 in a pediatric patient using the lidocaine patch 5%: a case report

Abstract

Background

Successful treatment of complex regional pain syndrome type 1 (CRPS-1) requires a coordinated, multidisciplinary approach. Physical rehabilitation is an important component of long-term treatment. Unfortunately, patients with significant allodynia or hyperalgesia characteristic of CRPS-1 often have difficulty progressing through a physical therapy (PT) regimen. In most adults with CRPS-1, the treatment of choice is PO opioids.

Objective

This article presents a case report of the use of the lidocaine patch 5%, a targeted peripheral analgesic, in a pediatric patient and its effects on reducing pain, improving the patient's overall attitude, and facilitating compliance with ongoing PT.

Results

A 10-year-old girl developed CRPS-1 after arthroscopic surgery for a sprained ankle. Attempts at PT were unsuccessful due to inadequate pain relief from various treatment modalities. Therapy with the lidocaine patch 5% was initiated and resulted in significant pain relief, improvements in the patient's attitude, and progress with PT.

Conclusion

This case report of a child with CRPS-1 showed that therapy with lidocaine patch 5% may be efficacious in treating children with pain resulting from CRPS-1, thereby increasing the success of PT.

Introduction

Background

Complex regional pain syndrome type 1 (CRPS-1), or reflex sympathetic dystrophy, is defined as continuous pain in a portion of extremity after trauma, which may include fracture but does not involve a major nerve, and which is associated with sympathetic hyperactivity.¹

Successful treatment of CRPS-1 requires a coordinated, multidisciplinary approach, the main goal of which is functional restoration of the affected body region.² Physical rehabilitation is an important component of long-term treatment, during which the patient may undergo various interventions aimed at desensitization, restoration of motion, and building of tolerance. Unfortunately, children with significant allodynia or hyperalgesia characteristic of CRPS-1 often have difficulty progressing through a physical therapy (PT) regimen.

This case report discusses the use of the lidocaine patch 5%^∗ in a pediatric patient and its effects on reducing pain, improving the patient's overall attitude, and facilitating compliance with ongoing PT.

Case report

History and physical examination

The patient first presented at the Regional Pain Management Center (Rapid City, South Dakota) in April 1998 when she was 10 years old. The previous year, she had experienced a sprained ankle injury for which she later underwent arthroscopic surgery. When the cast was removed, the patient reported allodynia, with signs of swelling and color changes on the affected limb. Attempts at PT, including desensitization, were unsuccessful. The patient had been receiving acetaminophen (500 mg QID), ibuprofen (400 mg TID), and transcutaneous electrical nerve stimulation for symptom relief. Physical examination revealed moderate swelling over the digits of the left foot and increased hair growth on the left leg. Muscle atrophy was noted on the left calf, with allodynia present from the calf down. The patient was confined to a wheelchair at presentation. The treatment goal was to have the patient regain use of her left lower extremity.

Treatment

Therapy with gabapentin (300 mg TID), amitriptyline (25 mg at bedtime), and tramadol (50 mg q8h as needed) was initiated. Over the course of 1998, the patient also received lumbar sympathetic ganglion nerve blockade. Neither the nerve blockade nor the pharmacologic agents provided significant pain relief.

In January 1999, the patient underwent surgery for placement of a spinal cord stimulator (SCS). Initially, the SCS provided excellent coverage; by February, the patient was ambulatory with crutches. She continued to experience allodynia, with discoloration of the extremity, but the SCS improved her tolerance for PT. To further improve her mobility, the patient was fitted with a customized, spring-loaded, dorsiflexion-assist ankle-foot orthosis. Her initial session with the ankle-foot orthosis in June 2000 was difficult. The orthotic device caused intolerable pain, and the prognosis for successful rehabilitation was considered “guarded” by the physiotherapist. During this time, the patient was receiving a stable oral drug regimen that included baclofen (10 mg BID), amitriptyline (25 mg at bedtime), carbamazepine (200 mg BID), and clonazepam (0.5 mg at bedtime). However, she reported difficulty sleeping and admitted to problems both in her attitude and performance in school.

In October 2000, a trial of medications—including doxazosin mesylate (1 mg QD), zaleplon (5 mg PO at bedtime) for sleep, and the lidocaine patch 5% (1 patch/d)—was initiated. The patient's mother was instructed to apply the lidocaine patch on the affected limb, from the calf down, for 12 h/d. One week later, the physical therapist noted that the positive effect of the lidocaine patch on the patient's allodynia and pain threshold had improved her participation in PT. After 2 weeks, the therapist noted continued improvement in pain relief; the patient allowed the therapist to touch below her knee without complaint or withdrawal. The therapist was able to initiate desensitization massage and manual decongestion of edema around the patient's toes, which had not been possible before treatment with the lidocaine patch. The patient also reported that her performance in school was improving.

One month after starting therapy with the lidocaine patch, the patient could touch her leg, which she had not been able to do since the arthroscopic surgery. Both the patient and her mother agreed that the lidocaine patch was providing clinically significant pain relief. In January 2001, the patient continued to report benefit from the lidocaine patch, particularly with respect to allodynia. She continues to wear 1 lidocaine patch for 12 h/d.

Discussion and conclusions

Pain on normal touch is the most significant problem to treat in CRPS-1. In adults, one can use opioids and nerve blocks, but this is not the first line of treatment for children. Lidocaine is effective and tolerable treatment for this type of pain in both adults and children. Lidoderm provides topical (not systemic)³ relief of sensitivity associated with CRPS-1, thus allowing the patient to participate in PT.

Because it is a topical, localized treatment, one does not need to monitor blood levels of lidocaine, but only watch for systemic adverse effects of local anesthetic toxicity, such as central nervous system adverse effects, including tinnitus, metallic taste, and/or seizures, all of which are rare.³

This report is noteworthy for several reasons. First, the patient had tried many therapeutic modalities, including invasive surgical procedures, with mixed success. The guidelines recommend that treatment of CRPS-1 in children should start with the least invasive, reversible measures and progress to more invasive techniques if noninvasive therapies fail.³ The lidocaine patch 5% is a targeted peripheral analgesic that provides the pharmacologic benefits of lidocaine (ie, stabilization of neuronal membranes via inhibition of sodium channels) in a local manner, without achieving any clinically significant systemic blood levels.⁴ After application of the lidocaine patch, lidocaine penetrates the skin, soft tissue, and peripheral nerves to produce local analgesia without inducing numbness of the skin. Serum levels of lidocaine remain well below those necessary to produce cardiac activity or toxicity.⁴ Thus, the potential for systemic adverse effects and adverse drug reactions is minimal.⁴

The lidocaine patch was the first drug approved for use in postherpetic neuralgia and has been reported to have potential efficacy in treating other types of neuropathic pain, including CRPS-1.⁵ This initial report of the tolerable and effective use of the lidocaine patch 5% in a pediatric patient provides further evidence of its potential benefits in the treatment of CRPS-1.