A 28-year-old woman comes to the office due to pain at a previous surgery site. The patient underwent cesarean delivery a year ago and had no issues with wound healing. However, over the past 2 months, she has had intermittent sharp and burning pain at the incision site. Physical examination reveals a well-healed, low, transverse scar. There is a small knot palpable at the left end of the scar, light touch of which elicits severe pain. Cutaneous sensory nerve injury and abnormal axonal regeneration are suspected. Which of the following ion channels is most likely upregulated within the affected axons?

Question

A 28-year-old woman comes to the office due to pain at a previous surgery site.  The patient underwent cesarean delivery a year ago and had no issues with wound healing.  However, over the past 2 months, she has had intermittent sharp and burning pain at the incision site.  Physical examination reveals a well-healed, low, transverse scar.  There is a small knot palpable at the left end of the scar, light touch of which elicits severe pain.  Cutaneous sensory nerve injury and abnormal axonal regeneration are suspected.  Which of the following ion channels is most likely upregulated within the affected axons?

Quizplus · Accepted Answer

Eductional Objective: A neuroma forms when regenerating axons are unable to find their distal target and create a haphazard mass of axons and supporting cells.  Upregulation of voltage-gated sodium channels, which generate and propagate action potentials, is likely responsible for the increased pain of these lesions.

A 28-Year-Old Woman Comes to the Office Due to Pain