Module 9.1 - Pain Flashcards
What is acute pain?
- Duration is short- usually < 6 months
- Treatment is definitive due to clear source of injury (i.e. surgery)
- Generally resolves on its own as healing process occurs
What is chronic pain?
- Usually > 6 months duration,
- Rarely resolves on its own
- Examples: RA, OA, post-herpetic neuralgia, diabetic neuropathy, back pain
What is somatic pain?
Pain that arises from bone, muscle, joint, skin, connective tissue; tends to be throbbing or aching in nature and well-localized
What is visceral pain?
Pain that arises from the visceral organs, i.e. GI tract, pancreas or liver; tumor involvement or pain in hollow organ; may be vague and often dull in nature.
What is neuropathic pain?
- Results from abnormal processing by the peripheral and central nervous systems; can be from disease (such as DM) affecting the somatosensory system
- Characterized by unusual burning, tingling sensations, electric shock-like quality to pain and may be triggered by a very light touch
What are the 2 types of neuropathic pain?
- Centrally generated pain: involving the dysregulation of the peripheral, central or autonomic nervous system (phantom limb pain, burning pain below spinal cord lesion)
- Peripherally generated pain: involving pain along the distribution of nerves, or an injury to the peripheral nerves (diabetic neuropathy, post-herpetic neuralgia, trigeminal neuralgia or nerve entrapment)
What are some adverse physiologic and psychological consequences associated with acute pain?
- Reduced tidal volume
- Excessive stress response
- Progression to chronic pain
- Inability to comply with rehabilitation
- Patient suffering and dissatisfaction
- Acute pain is more difficult to manage if permitted to become severe in nature
What are the treatment goals for chronic pain?
- Chronic pain is often debilitating and associated with significant physical, emotional and social issues.
- Treatment should address social and psychological consequences of pain as well as any physical pathology
- Assessment should include the patient’s acceptance of their condition, their motivation to participate in treatment and the ability to follow-through with recommendations; as well as, available time and resources
Main goals:
- Diminished suffering including pain and associated emotional distress
- Restore or increase physical, social and recreational function
- Optimize health and well-being
- Improve coping ability
How do you manage patients with chronic pain?
1. Use a multi-modal therapy approach:
- Medications from different classes (combination drug therapy)
- Rehabilitative therapies: physical therapy, occupational therapy
- Regional anesthesia: nerve blockade
- Interventional pain management: trigger point or steroid injections
2. Medical Management
- Differs from acute pain management in that in chronic pain management there is greater use of adjuvant analgesics
- Chronic pain reflects a greater frequency of neuropathic pain that has a reduced responsiveness to traditional analgesics
- EBP recommendations: Clinical trials support the use of anti-depressants, antiepileptic medications (Gabapentin) and local anesthetics as first line approaches to the treatment of chronic pain.
3. Non-Pharmacological Management
- Reconditioning (physical therapy/occupational therapy) reduces pain and promotes physical and psychological rehabilitation; thereby empowering the patients
- Biofeedback and relaxation can relax muscles and reduce autonomic nervous arousal.
How do you treat patients with chronic arthritis pain? What non-opioids, opioids, or adjuvant analgesics would you use?
Non-opioids:
- Acetaminophen, NSAIDs, Selective COX-2 inhibitors
Opioids:
- Short term mild opioids for flare-ups
Adjuvant Analgesics:
- Corticosteroids (oral for RA, injections for OA and RA); topical capsaicin and diclofenac and lidocaine patches
How do you treat patients with chronic lower back pain? What non-opioids, opioids, or adjuvant analgesics would you use?
Non-opioids:
- Acetaminophen, NSAIDs, Selective COX-2 inhibitors
Opioids:
- Short term opioids for mild to moderate flare-ups
Adjuvant Analgesics:
- Muscle relaxants (short term)
- Topical anesthetics: lidocaine patches, capsaicin
How do you treat patients with chronic fibromyalgia? What non-opioids, opioids, or adjuvant analgesics would you use?
Non-opioids:
- Acetaminophen, NSAIDs, Selective COX-2 inhibitors
- Pregabalin (Lyrica) - works to reduce electrical activity a/w overactive nerve impulses
Opioids:
- Short term opioids for mild to moderate flare-ups
- Tramadol
Adjuvant Analgesics:
- Muscle relaxants (short term)
- Tricyclic antidepressants: amitriptyline and imipramine
- Second generation antidepressants: Duloxetine, fluoxetine, etc.
How do you treat patients with chronic peripheral neuropathy? What non-opioids, opioids, or adjuvant analgesics would you use?
Non-opioids:
- Acetaminophen, NSAIDs
Opioids:
- Short term
Adjuvant Analgesics:
- Anti-epileptics: Gabapentin, pregabalin, tegretol
- Topical anesthetics: Lidocaine patches, capsaicin topically;
- Muscle relaxants: tizanidine
What are some characteristics of NSAIDS?
- Do NOT cross the blood-brain barrier
- 95-99% are bound to albumin
- Act mainly on the periphery, but may have a central effect
- Extensively metabolized by the liver and have a low renal clearance
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Regular NSAIDs inhibit the synthesis of Thromboxane A2 (TXA2) by inhibiting COX-1 & thus inhibits COX-2 (inhibits prostaglandin G/H synthase enzymes, known also as COX; thereby inhibiting the synthesis of prostaglandin E, prostacyclin, and thromboxane. )
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What are some adverse effects associated with NSAIDS?
Since NSAIDs inhibit the production of not only COX-2, but also COX-1 (which synthesizes prostaglandins):
- NSAIDS can affect the kidneys because prostaglandins help to maintain GFR and blood flow.
- Prostaglandins also contribute to the modulation of renin release, excretion of water, and tubular ion transport.
- In patients with normal renal function NSAID-induced renal dysfunction is extremely rare.
- NSAIDS can affect platelets because platelets are very susceptible to COX inhibition, which also inhibits the endogenous pro-coagulant thromboxane. Long-term use of standard NSAIDs produces a consistently prolonged bleeding time, but the prolongation is mild and values tend to remain below the upper limits of normal.
- NSAIDS can cause GI toxicity (ulcer formation)
What are some side effects associated with opioid use?
- Most common opioid prescribed in the U.S. is hydrocodone
- Extremely high doses of morphine and related opioids can produce seizures, presumably by inhibiting the release of GABA (at the synaptic level) - Demerol
- Opioids produce a dose-dependent respiratory depression by acting directly on the respiratory centers of the brainstem
- Therapeutic doses of morphine decrease minute ventilation by decreasing respiratory rate
- Opioids depress the ventilator response to carbon dioxide
- The apneic threshold is decreased and also the increase in ventilatory response to hypoxemia is blunted by opioids
- Naloxone can effectively and fully reverse the respiratory depression from opioids
How do you treat opioid addiction?
- Buprenorphine (Suboxone) is a semisynthetic opioid and is used in out-patient facilities to treat opioid addiction
- It is a sublingual film to take under the tongue.
- Other formulations of Suboxone includes a combination Naloxone/Suboxone sublingual tablet (Zubsolv)
- These medications are usually taken once a day.
- Doses are titrated to response.
- Stopping suboxone may cause withdrawal symptoms, such as hot or cold flushes, restlessness, teary eyes, runny nose, sweating, chills, muscle pain, vomiting or diarrhea.
In what patients and with what combination should benzodiazepines be avoided in?
- Avoid in geriatric patients
- Avoid in combination with opioids
What are some risk factors for NSAID induced renal dysfunction?
- Prolonged and excessive NSAID use
- Older patients
- Chronic renal dysfunction
- Congestive heart failure
- Ascites
- Hypovolemia
- Treatment with nephrotoxic drugs
