Chapter 11, Problem 2CCS

Nursing Student with Neuropathic Pain

Tamara Costa broke her right tibia and has undergone two separate surgeries to repair it. Although the bone has healed, she suffers increasing pain around the incision sites. The painful area covers the lateral surface of her right leg. She can't stand wearing anything over it or even having a sheet touch it. Her diagnosis is postsurgical neuropathic pain. Pain medication has not helped.

Tamara is a second-year nursing student and has done some reading to try to understand her problem and perhaps find a solution. She has found an article that says neuropathic pain may be caused by a decreased threshold for action potential generation in pain-detecting neurons. However, she has forgotten some of her physiology and needs some help in understanding what she is reading. She has logged into the “Ask a Nurse" chat line–and she got you!

2. Tamara wants to know how a decrease in threshold in pain-detecting neurons would affect their firing. Draw a graph of an intracellular recording of a neuron showing the response to a below-threshold and an above-threshold stimulus. Then, using this graph, show how decreasing the threshold could lead to additional action potentials.