Erythromelalgia and Peripheral Nerve Block: A Case Report

Extensive Lumbar Sympathetic Ganglion Block Combined With Epidural Block for Primary Erythromelalgia: A Case Report

A 19-year-old-woman experienced severe burning pain in the lower extremities with erythema and swelling. She was diagnosed with primary erythromelalgia (PE). The pain was unresponsive to medications but relieved by immersing her feet in cold water. We performed a multilevel lumbar sympathetic ganglion block (LSGB) with 5% phenol at second lumbar vertebra (L2) and third lumbar vertebra (L3), and additional fourth lumbar vertebra (L4) levels. An epidural block was intermittently combined. The pain and skin lesions dramatically improved after the procedures, and she no longer needed medications or to soak her feet in cold water. This case demonstrated that extensive LSGB may be a therapeutic option for intractable PE.

Sporadic Erythromelalgia Associated with a Homozygous Carrier of Common Missense Polymorphism in SCN9A Gene Coding for NaV1.7 Voltage-gated Sodium Channel

A 68-year-old female with a history of sporadic type and presumably secondary erythromelalgia with chronic intractable pain presented for foot surgery. The procedure was performed with combined general anesthesia and regional anesthesia consisting of the placement of a popliteal pain catheter for postoperative pain management. Subsequent whole-genome sequencing revealed that the patient was a homozygous carrier of the common missense mutation in the SCN9A gene coding for voltage-gated sodium channel (NaV1.7) - dbSNP rs6746030 (R1150W). The occurrence of this single nucleotide polymorphism (SNP) was previously suggested not to be associated with erythromelalgia but rather thought to be part of quantitative changes in the pain threshold in different cohorts of patients. The placement of the pain catheter, although controversial in patients with erythromelalgia, provided effective postoperative pain relief without any side effects.