Question

James is a 45 year old man who is brought into the clinic after cutting his right hand with a knife while installing carpet. He has cleaned his hand and wrapped the cut in a bandage which has stopped the bleeding. His physical examination reveals a clean 2 inch laceration (cut) in his right palm which is well-approximated (the edges of the wound align). His vital signs are stable, and he has agreed to surgical repair of his laceration. He states that his pain is a 6/10, and describes it as being a sharp pain, directly in the area of the laceration.

What type of pain is James experiencing? Be specific about the type and subtype, and explain your rationale.

In 3-6 sentences, explain the transmission of James’ pain. Include the transduction, transmission, modulation, and perception of the pain.

Laceration repair involves the use of a needle to draw the suturing material through the healthy tissue. What type of analgesia do you expect to be used to control James’ pain while repairing his laceration? Explain why that type of analgesia would be used, as well as the specific mechanisms by which it will control James’ pain.

Answer 1

There are four major processes: transduction, transmission, modulation, and perception. Transduction refers to the processes by which tissue-damaging stimuli activate nerve endings. Transmission refers to the relay functions by which the message is carried from the site of tissue injury to the brain regions underlying perception. Modulation is a recently discovered neural process that acts specifically to reduce activity in the transmission system. Perception is the subjective awareness produced by sensory signals; it involves the integration of many sensory messages into a coherent and meaningful whole. Perception is a complex function of several processes, including attention, expectation, and interpretation.

Topical local anaesthetics provide effective analgesia for patients undergoing numerous superficial procedures, including repair of dermal lacerations.

Infiltrative or injected anesthesia, such as 1% or 2% lidocaine, has been a commonly used method for pain management during laceration repair. Lidocaine relieves pain by blocking the sodium channels in the local nerve fibres and has proven to be effective, particularly for deeper lacerations.

Mechanism of Action
Topical anesthetics reversibly block nerve conduction near their site of administration by targeting free nerve endings in the dermis or mucosa, thereby producing temporary loss of sensation in a limited area.