Complex regional pain syndrome

Case Study: Chronic neuropathic foot pain as a result of Complex Regional Pain Syndrome (CRPS). by Bruce Werber DPM, FACFAS

Bruce Werber, DPM,FACFAS

A 54 year old female presents with sharp pain, burning, tingling and numbness at the dorsal aspect both feet, left worse than right increasing over the last 12 months. There is no history of trauma. There has been an insidious onset and intensity is not related to activity or shoe gear. Patient also notices red discoloration at dorsum of feet. There has been prior treatment with Neurontin and Lyrica without any success. Pain level reported at 6/10 on average. Pain periodically awakens patient from sleep. Life and work activities are limited by this discomfort.

PMH: hypertension, hypercholesterolemia, chronic low back pain, asthma, bronchitis, pneumonia, gastric reflux, environmental allergies, moderate overweight.

Past surgery: Cholecystectomy, hysterectomy

Social history: 2 alcohol drinks per day, and 1-2 cigarettes per day

Medications: Tenormin, Nexium, Soma, Darvocet,Catapress, Lipitor

Medication Allergies: NSaids, Neurontin, Lyrica

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Pertinent Physical Examination

Fig. 1: pre treatment photo

Vascular Exam : Widespread telangectasias or vasculitic lesions covering the dorsal feet bilateral from toes to ankle (see Fig. 1). Otherwise, vascular exam is normal, with pulses at 2/4 for dorsalis pedis and posterior tibial bilateral. Capillary refill is also normal bilateral, with limbs level and elevated. There are no prominent varicosities in the upper or lower leg bilateral.

Derm Exam: Normal except for telangectasias identified in vascular exam, hallux pinch callus bilateral.

Neuro Exam: DTR patella and achilles are diminished bilateral, positive Tinels at posterior tibial nerve (tarsal tunnel) bilateral, as well as at the deep peroneal nerve at the level of the first metatarsal cuneiform joint bilateral. Common Peroneal, Superficial peroneal are normal with percussion. Palpation of the deep peroneal nerve at the first metatarsal cunieform joint level recreates the patients pain. Raised leg exam is negative for pain or discomfort, except for tightness of the hamstring. Monofiliment testing revealed loss of discrimination from toes to mpj level, vibratory was intact

Musculoskeletal Exam: Functional hallux limitus bilateral, with decreased stiffness of the medial column bilateral, less than 5 degrees of dorsiflexion available with the first ray loaded, moderate functional ankle equinus bilateral.

Gait Analysis: Reveals inverted heel contact, perpendicular midstance to heel off, with the forefoot abducted at midstance to heel off, and a medial rolloff evident, slightly early heel off.

Imaging: No significant osseous pathology noted, there is faulting noted in the lateral exposure at the navicular cunieform joint and metatarsal cunieform joint level, similar bilateral.

Labs: Primary care physician noted all within normal limits.

IMPRESSION: Entrapment neuropathy of the deep peroneal nerve, possible vasculitis.

TREATMENT PLAN: Diagnostic nerve block of the deep peroneal nerve left.

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Summary of patients response and treatment course

Diagnostic nerve block did provide significant relief for several hours and patient noted that the vasculitic lesions disappeared around the injection site for about 24 hours.

Patient underwent surgery to decompress the deep peroneal nerve bilaterally. Patient noted significant relief of her symptoms and also noted the vasculitic lesions diminished markedly from the dorsum of her foot. The postoperative course was uneventful and patient was discharged after 12 weeks. She reported pain level was 1-2/10 on average and she was sleeping again.

Approximately 8 months after discharge, almost one year after surgery, patient returns with diffuse foot and leg pain, the vasculitic lesions have recurred and have started to spread from the dorsum of the foot to the ankle. The patient reported that they had almost disappeared entirely for several months.

Examination at this visit revealed a spread of the neuropathy, with the patient failing monofiliment testing to the entire foot, vibratory sensation is also diminished but not absent. Proprioception was intact. Now there was positive Tinels at the common peroneal nerve, superficial peroneal nerve and posterior tibial nerve with proximal radiation. No other changes noted in the physical examination. A common peroneal nerve block, provided significant relief for the patients symptoms. It was unknown what the causative etiology was.

	Fig. 2: post spinal stimulator implantation

Patient was given a course of Medrol since the pain was so severe and with the common peroneal nerve block, the patient achieved temporary relief. Patient was then referred to pain specialist, the workup found no additional findings. Physical therapy, chiropractic manipulation, and acupuncture were initiated over the course of 8-10 weeks. The patient had no response to this, but she did continue to respond to periodic nerve blocks and Medrol when the pain became overwhelming. It was thought at this time that the patient had developed Complex Regional Pain Syndrome (CRPS) presenting with painful neuropathic signs. At this time, a trial of a spinal stimulator was performed, with excellent outcome. Patient's pain diminished markedly. The vasculitic lesions gradually diminished, sensation was reported to be improved and decreased pain was noted.

Patient then had a permanent spinal stimulator implanted for the treatment of Chronic neuropathic foot pain as a result of Complex Regional Pain Syndrome (CRPS).

The patient has done well since that time. She continues to experience periodic discomfort at the lateral ankle along the sural nerve, but it is only a 1/10 on the pain scale. The vasculitic lesions have essentially resolved and patient is able to sleep, and resume her normal life style activities.

Bruce Werber DPM, FACFAS
InMotion Foot & Ankle Specialists
Associate Professor Midwestern University
InMotion Foot and Ankle Specialists
10900 N. Scottsdale Road
Suite 604
Scottsdale, AZ 85254
office phone 480 948-2111
inmotionfootandankle@gmail.com
www.inmotionfootandankle.com