Pain

Authors: Flaherty, Alice W.; Rost, Natalia S.

Title: Massachusetts General Hospital Handbook of Neurology, The, 2nd Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Adult Neurology > Pain

Pain

A. H&P

Location, quality, duration, intensity, aggravating and relieving factors, h/o trauma, disability, litigation, drugs tried, other treatments, imaging work, psychiatric history, strength, range of motion, straight leg raise, pin prick and light touch sensation, skin color and temperature, dystrophic skin changes.

B. Common MD false beliefs about pain

• 1. Masking: Pain meds dangerously mask important sx?

  No you can continue the workup with pt comfortable.

• 2. Physical signs: Pain correlates with VS, ability to sleep?

  No ANS activation varies widely.

• 3. Addiction: Addicts overreport pain because they are addicted?

  No opiate receptor downregulation physiologically worsens pain.

• 4. Dosing: In treating addicts, keep med doses as low as possible?

  No they have opiate tolerance, so need more.

• 5. Emotion: Pain only appears to worsen with stress?

  No it actually worsens it through physiological mechanisms.

• 6. Chief complaint-ism: Treat the true CC, whether pain or emotion?

  No treat both. Treat anxiety even when it is secondary. Conversely, pts. who irrationally fear a brain tumor may not let go of that until you treat their HA.

C. Common pt pain myths

Address these directly and sympathetically.

• 1. Masking: Pain meds dangerously mask my important sx. See above.

• 2. Fear of med dependence: Needing a med physical tolerance addiction. Explain the difference and that <1% of pts. who take meds for pain abuse them. But also ask if relatives have addictions.

• 3. Ignoring mood: Pain is the main cause of my suffering. Describing the physiological effects of stress may help pts. take mood seriously.

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• 4. Stoicism: Pain complaints are for the weak. ( That which does not kill me makes me strong Nietzsche.) Point out that pain saps strength whether you complain or not.

D. Pain rx by comorbidity

• 1. Acute physical injury or surgery: NSAIDS or opiates.

• 2. Depression: Duloxetine; TCAs (beware of TCA SEs).

• 3. Depression and somatization: Duloxetine.

• 4. Epilepsy: Valproate, carbamazepine.

• 5. Mood lability: Valproate, carbamazepine.

• 6. Substance abuse:

  • a. Acute pain: Use opiates as needed, but higher dose (see above).

  • b. Chronic pain: Avoid opiates. If you must, use fentanyl patch (hard to abuse) or methadone much cheaper, easier to titrate.

E. Pain rx in substance abusers

• 1. Sx of prescription substance abuse: Pt requests early refills, gets them from other MDs, relatives (talk to them alone!) report confusion.

F. Pain rx by cause

• 1. Bone pain: NSAIDS (especially aspirin) + acetaminophen are selectively good for bone pain; also steroids, opiates. XRT or strontium-90 for metastases. A corset may help compression fractures.

• 2. Complex regional pain syndrome (includes sympathetically mediated pain or reflex sympathetic dystrophy): Look for altered color or temperature of skin, burning pain, skin hypersensitivity to light touch, trophic changes, stiff joints.

  • a. Lidocaine patch or ointment: May help skin hypersensitivity.

  • b. IV phentolamine test: Can help predict the effect of sympathetic nerve block. Check EKG first.

• 3. Sympathetic nerve block: May help if signs of sympathetically mediated pain (e.g., skin cold, damp).

• 4. Gout: NSAIDS or colchicine; allopurinol (not in acute flare), keep pt hydrated; avoid loop diuretics.

• 5. Organ metastases: Steroids.

• 6. Mouth pain from ulceration: 1:1:1 ratio of diphenhydramine, Xylocaine, and Kaopectate liquids, give 15 cc q3h prn.

• 7. Needles, splinters, etc.: In pain-sensitive children and opiate addicts, lidocaine ointment 30 min before the needle.

• 8. Neuropathic pain:

  • a. Drugs: Duloxetine, nortriptyline, or ACDs.

  • b. Treat accompanying depression: See Table 25, p. 100.

  • c. Surgery: Nerve decompression may help if movement worsens paresthesias.

• 9. Thalamic pain syndrome (D j rine-Roussy syndrome): Hypersensitivity after thalamic stroke. Rx rarely successful.

• 10. Trigeminal neuralgia: Lancinating, often with trigger points. Often associated with MS. Rarely from dental dz or brain tumor. Try carbamazepine 100-400 tid, gabapentin, pregabalin, baclofen, or lamotrigine. Consider surgery or radiofrequency ablation.

• 11. Zoster (shingles):

  • a. Acute: If pt. over 50 or lesions last >72 h, give antiherpetic (e.g., famciclovir). Try lidocaine cream.

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  • b. Postherpetic pain:

    • 1) Early nerve blocks.

    • 2) Constant pain: Try a TCA.

    • 3) Lancinating: Try gabapentin or other ACD.