Chronic Pain Flashcards
A chronic pain patient has been taking scheduled fluoxetine, clonazepam, and hydrocodone-acetaminophen for three years. The patient developed upper respiratory viral symptoms one week ago and has been taking an over-the-counter cold medicine every four hours. She arrives in the emergency department with new onset of severe nausea and vomiting. No specific findings are found on physical exam. Of the following, which is the MOST likely?
Acetaminophen toxicity occurs when a large dose of acetaminophen is ingested. It is often a result of the patient not knowing acetaminophen is contained in so many medications, particularly over-the-counter medications. Acetaminophen itself is not toxic; instead it results in enzyme induction that overwhelms the hepatic systems. Rapid diagnosis and appropriate treatment with N-acetylcysteine helps to decrease the risk of permanent injury significantly.
Regarding presynaptic nociceptor terminals (such as the transient receptor potential vanilloid 1), which neurotransmitter is most likely to mediates the inhibition of central nociceptor terminals, thus reducing excitatory transmitter release ?
Chemical stimuli that mediate the activation of peripheral nociceptors include prostaglandins, substance P, calcitonin gene-related peptide, glutamate, bradykinin, protons, adenosine triphosphate, and proinflammatory cytokines, whereas spinal cord inhibition is mediated by opioids, γ-aminobutyric acid, and/or glycine.
You have been consulted for an 8-year-old patient who is postoperative day one following exploratory laparotomy and tumor resection for neuroblastoma. The patient has had a very difficult year with chronic pain issues following multiple abdominal surgeries. She was previously on methadone to control this pain. The patient is now complaining of severe pain and lack of sleep despite every 2-hour morphine administration from the nurse. Which of the following is the most appropriate next step?
Patient-controlled analgesia is an excellent modality for managing acute pain control. Adding a basal infusion ensures a constant infusion of medication and more constant plasma levels of opioid. The disadvantage is there is a higher risk for respiratory depression thus proper monitoring is vital.
Which of the following opioids would be the BEST choice for the treatment of chronic neuropathic pain?
Opioid use for treating chronic pain is controversial. Methadone, however, is effective for chronic pain since in addition to its opioid analgesic effects, it has NMDA and serotonin reuptake antagonistic properties. The NMDA receptor antagonism also makes methadone effective for neuropathic pain.
Low dose ketamine exerts its analgesic properties primarily through which of the following receptor types?
The analgesic properties of ketamine are primarily NMDA receptor-mediated at low ketamine doses with proportionally more opioid receptor-mediated effects at higher doses.
Which of the following is MOST likely to occur in patients taking chronic opioid therapy for the treatment of chronic nonterminal pain?
Chronic opioid therapy has a profound effect on the adrenal and gonadal axes leading to increased prolactin levels, and decreased testosterone, estrogen, cortisol, LH, and FSH. Immunosuppression is observed in patients on chronic opioid therapy and during withdrawal from opioid treatment.
