Chapter 11, Problem 4CCS

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!

4. NCLEX-STYLE The article suggests that it might also be possible that Tamara’s pain is due to the lack of the usual inhibition of transmission of pain signals through Tamara's spinal cord. Which of these statements best describes how a postsynaptic neuron is inhibited by a presynaptic neuron?

a. The frequency of action potentials in both the presynaptic and postsynaptic neurons decreases.

b. The presynaptic neuron becomes more negatively charged when it fires instead of becoming more positively charged.

c. The presynaptic neuron stops releasing its neurotransmitter.

d. The neurotransmitter from the presynaptic neuron causes a local hyperpolarization in the postsynaptic neuron, which reduces the likelihood that the postsynaptic neuron fires an action potential.