title: Primary erythromelalgia in a 12-year-old boy: positive response to sodium channel blockers despite negative SCN9A mutations.
abstract: Erythromelalgia is a rare disorder characterized by recurrent pain attacks, swelling and redness in the distal extremities. The primary forms of the disorder are caused by mutations in voltage-gated sodium channels. Treatment is difficult and controlled therapeutic studies offer little to no guidance. We report on a 12-year-old boy and his first occurrence of primary erythromelalgia. Genetic findings for mutations in the SCN9A gene, which encodes for the α-subunit of sodium channel NaV1.7, were negative. Although initial treatment with sodium nitroprusside was ineffective, subsequent medication with lidocaine and mexiletine, in combination with gabapentin, was successful. Despite negative findings for mutations in the sodium channels, the use of sodium channel blockers should be considered in these patients.
authors.affiliation: Centre for Pediatrics and Adolescent Medicine, General Pediatrics, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Jakob
authors.forename: R
authors.initials: R
authors.lastname: Creutzfeldt
authors.forename: O
authors.initials: O
authors.lastname: Staszewski
authors.forename: A
authors.initials: A
authors.lastname: Winterpacht
authors.forename: R
authors.initials: R
authors.lastname: Berner
authors.forename: M
authors.initials: M
authors.lastname: Hufnagel
mesh_terms: D000284:Administration, Oral; D000588:Amines / Q000009:adverse effects / Q000627:therapeutic use; D000700:Analgesics / Q000009:adverse effects / Q000627:therapeutic use; D002648:Child; D003509:Cyclohexanecarboxylic Acids / Q000009:adverse effects / Q000627:therapeutic use; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D004916:Erythromelalgia / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics*; D000077206:Gabapentin; D006801:Humans; D007262:Infusions, Intravenous; D008012:Lidocaine / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008801:Mexiletine / Q000009:adverse effects / Q000627:therapeutic use; D062556:NAV1.7 Voltage-Gated Sodium Channel / Q000235:genetics*; D009599:Nitroprusside / Q000009:adverse effects / Q000627:therapeutic use; D026941:Sodium Channel Blockers / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000009:adverse effects / Q000627:therapeutic use; D005680:gamma-Aminobutyric Acid / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D062556:NAV1.7 Voltage-Gated Sodium Channel; C486866:SCN9A protein, human; D026941:Sodium Channel Blockers; D014665:Vasodilator Agents; D009599:Nitroprusside; D008801:Mexiletine; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D008012:Lidocaine