Adult Pain Management (Week 4--Pham and Melega)

Question 1

Nociceptive local neck pain

Answer 1

Paraspinal muscles and soft tissues within spinal canal and/or neural canal are inflamed (posterior longitudinal ligament, peripheral anulus fibrosis fibers, epidural blood vessels, dura mater, periosteum)

The sinuvertebral (recurrent meningeal) nerve relays localized pain information

Question 2

NSAIDs classified by chemical structure

Answer 2

Salicylates: aspirin; diflunisal, 5-aminosalicylate, sodium salicylate, magnesium salicylate, sulfasalazine, olasalzine

Acetic acids: indomethacin, diclofenac, sulindac, etodolac, ketorolac, tolmetin

Propionic acids: ibuprofen, naproxen, fenoprofen, ketoprofen, flurbiprofen, oxaprozin

Fenamic acids: meclofenamate, mefenamate

Enolic acids (oxicam class): piroxicam

Ketones: nabumetone (converted to 6-naphthylacetic acid in liver)

Question 3

Antiepileptic adjuvants

Answer 3

Gabapentin: minimal side effects; FDA approved for seizures but widely used for neuropathic pain; takes time to titrate to higher dose

Pregabalin: FDA approved for neuropathic pain; similar to gabapentin but with fewer side effects; more expensive

Topiramate: weight loss side effects

Question 4

Antidepressant adjuvants

Answer 4

Amitriptiline: widely studied for neuropathic pain, highly sedating (useful as sleep aid)

Nortriptiline: fewer anticholinergic side effects

Question 5

What type of therapy can be done for acute neck pain?

Answer 5

Protection: cervical pillow, posture training, work place modification; avoid extension

Modalities: heat, ice

Exercises: gentle ROM and stretching

Bracing: soft collar for 1-2 days (longer wear will cause atrophy and weakness of cervical paraspinal muscles)

Question 6

What can be done after initial flare-up of neck pain?

Answer 6

Gentle ROM

Gentle traction if spine is stable

Continue ice/heat

Consider ultrasound for muscle spasm

Isometric strengthening exercises

Question 7

Epidural injection intervention

Answer 7

Helps reduce pain in limbs due to radiculopathy

Pain relief is temporary

Risk involves cord (nerve) injury, anesthetic toxicity, vascular injury, seizures, death

Various approaches: transforaminal (risk vessel damage), translaminar (risk spinal cord injury)

Solution contains: corticosteroids +/- lidocaine

Question 8

Do glucocorticoids act based upon how much there is in circulation?

Answer 8

No, it’s been suggested that duration of action of GC is NOT determined by presence in circulation (thus plasma half life)

Effects of GCs continue to act within cell after GCs have disappeared from circulation (note differences in plasma vs. biologic half life!); due to acetylation/deacetylation of histones which affects transcription of genes involved in inflammation (phospholipase A2, COX2, iNOS, etc)

Question 9

Glucocorticoid toxicity

Answer 9

Endocrine: hyperglycemia, hypokalemia, growth suppression, truncal obesity, hirsuitism, impotence, menstrual irregularities

Cardiovascular: HTN, CHF

MSK: fatigue, weakness, myopathy, osteoporosis, avascular necrosis

Immunologic: immunosuppression

Ophthalmic: cataracts, glaucoma

GI: PUD, pancreatitis

Neuropsychiatric: pseudotumor cerebri, alterations in mood, psychosis

Dermatologic: fragile skin, ecchymoses, impaired wound healing, acne

Question 10

Steroid withdrawal

Answer 10

Patients on long term steroids may need slow, low reductions back to baseline (taper) to minimize symptoms of withdrawal (joint and muscle pain, nausea, lethargy, weight loss, fever)

Question 11

What kind of steroids are patients with acute nerve compression given?

Answer 11

Steroid taper over 7-20 days so withdrawal is not usually an issue (start high dose then go down)

If steroid is injected locally, systemic absorption minimal and withdrawal is not an issue

Question 12

How much medication post-op do you give a patient who is already on opioids?

Answer 12

Convert current requirement to IV dosing in an opioid-user post-op

(opioid naive patient gets low dose IV morphine at 10-60mg/day)

Question 13

Equianalgesia

Answer 13

The need to change from one opioid to another, or from one route to another

Question 14

When switching to a new opioid, what percent of equianalgesia do you give and why?

Answer 14

Give 50% of calculated equianalgesic dose because there is incomplete cross-tolerance between different opioids

Question 15

What do you do if one class of NSAIDs does not work?

Answer 15

Try another class of NSAID

Also, for noncompliant patients can put them on an NSAID that you can take fewer times per day

Question 16

If an opioid isn’t working well, should you switch the medication?

Answer 16

Not right away

First you want to maximize the dose to get maximal effect before switching the medication

But also people will eventually develop tolerance…that will happen after the opioid has already worked for a long time..and in that case you WOULD change opioids (long acting?) or slow taper for drug holiday and then start on lower dose (painful for patient!)

Question 17

Do you always need to taper off opioids?

Answer 17

No!

If patient has only been taking opioids for a few weeks, don’t need to taper

(if been taking opioids for a year, then taper)

Question 18

Calculation for switching from oral to IV morphine

Answer 18

Calculate current 24 hour dose: 90mg q h 12 = 180mg every 24 h

Look up equianalgesic ratio: 30 mg po = 10 mg iv

Calculate new dose: 180 po x (10/30) = 60 mg iv every 24 h, or 2.5 mg/hour infusion