CHAPTER 27

Pain Medicine

Clinical Case 1

1. The correct response is option A: Physical dependence.

   Dependence is a state of adaptation that is manifested by a withdrawal syndrome that can be triggered by abrupt cessation, rapid dose reduction, or decreasing blood level of the drug, or administration of an antagonist. Tolerance is decreased duration of analgesia followed by decreased effectiveness. Addiction is compulsive use of a drug, preoccupation with the drug and its supply, inability to consistently control quantity used, craving of the psychological effects of the drug or urge to use the drug, and continued use despite adverse effects. Abuse may also indicate the habitual use of illegal drugs or the misuse of prescription or over-the-counter drugs with negative consequences that may include problems at work, in school, with interpersonal relationships, or with the law. (pp. 403–404)

2. The correct response is option C: Review the Prescription Drug Monitoring Program (PDMP) database.

   Accessing the PDMP database may indicate whether the patient is obtaining opioids from other physicians or emergency departments. At this point in time, it is not clear whether the patient has truly lost her medication more than once. It would not be prudent to write a prescription for opioids if the patient is consuming more medication than prescribed or misusing or diverting the medication, which may be considered aberrant behaviors. The patient requires counseling on medication safety and usage. It is not clear if the patient is doctor shopping or if she truly lost her medications. Discharging the patient without further investigation is not reasonable. (pp. 401–402)

3. The correct response is option C: Check a urine drug screen.

   The patient is exhibiting signs of acute methamphetamine use, which include pupil dilation, elevated blood pressure, and diaphoresis. Long-term use of methamphetamines may cause hypertension and heart attacks. An electrocardiogram would not address the patient’s current state because she is not having chest pain or shortness of breath. A computed tomography (CT) scan would not be helpful because there is nothing to point toward intracranial pathology, and there are no signs of stroke. A urine drug screen would be helpful in determining which drugs the patient is using and guiding the clinician toward the next step in treatment. The patient is currently not complaining of symptoms suggestive of a myocardial infarction (e.g., fatigue; shortness of breath; chest, jaw, or back pain); therefore, checking cardiac enzymes are not indicated at this time. The patient is not likely experiencing a pulmonary embolism; these symptoms would include shortness of breath, sharp sudden chest pain, rapid heart rate, anxiety, and coughing up pink frothy mucus. (p. 402)

Clinical Case 2

1. The correct response is option B: “I was an alcoholic for 12 years.”

   The acronym AMPS stands for Anxiety, Mood, Psychosis, and Substance abuse (Figure 27–1), and therefore is useful for assessing Ms. Wilson’s alcoholism. The statements about snoring and gasping for air suggest an obstructive process occurring during sleep; this information would be elicited using the STOP-BANG Questionnaire to screen for obstructive sleep apnea (see Figure 27–4 later in this chapter). The rating of pain severity is information obtained from the PQRST tool for the assessment of pain symptoms. PQRST stands for Provoking events, Quality of symptoms, Region and radiation of symptoms, Severity, and Time frame. The statement about running out of opioid medication and asking for early refills shows aberrant behavior. The assessment of opioid management can be determined with the 4 A’s (Analgesia, Activities, Adverse reactions, Aberrancy) (see Figure 27–3 later in this chapter). This aberrant behavior is also represented as the S (substance use) on the AMPS assessment of psychiatric illness, but this tool is geared toward a brief psychiatric and illicit substance use screen. (pp. 394–399, 405)

FIGURE 27–1. AMPS psychiatric assessment.

Source. Adapted from McCarron RM, Xiong GL, Bourgeois J: Lippincott’s Primary Care Psychiatry: For Primary Care Clinicians and Trainees, Medical Specialists, Neurologists, Emergency Medical Professionals, Mental Health Providers, and Trainees. Philadelphia, PA, Lippincott Williams & Wilkins, 2009.

FIGURE 27–2. Three-step analgesic ladder.

NSAID = nonsteroidal anti-inflammatory drug.

Source. Adapted from World Health Organization: Cancer Pain Relief: With a Guide to Opioid Availability, 2nd Edition. Geneva, Switzerland, World Health Organization, 1996.

FIGURE 27–3. Assessment of opioid management with the “4 A’s.”

The 4 A’s is a simple method to monitor outcomes once a patient begins opioid therapy. These factors should be assessed at every office visit to help guide ongoing treatment.

FIGURE 27–4. STOP-BANG Questionnaire: a tool to screen for obstructive sleep apnea (OSA) risk.

Note. High risk of OSA with ≥ 3 answers of “yes.” Additional workup by a sleep specialist or by polysomnography is indicated.

Low risk of OSA with < 3 answers of “yes.”

Source. Adapted from STOP Questionnaire (Chung F, Elsaid H: “Screening for Obstructive Sleep Apnea Before Surgery: Why Is It Important?” Current Opinion in Anesthesiology 22(3):405–411, 2009).

2. The correct response is option E: Try treatment with a topical anesthetic.

   The first step of the three-step analgesic ladder (Figure 27–2), which is for mild to moderate pain rated as 5 or below on the visual analog scale, is to try treatment with nonopioid medications (acetaminophen, NSAIDs, gabapentinoids, antidepressants, anticonvulsants, or topical agents). Before a medication is dismissed as a failure, the patient should take the appropriate dose on a scheduled interval for at least 2 weeks, barring significant side effects. If the nonopioid trial has been unsuccessful and pain persists without functional improvement, movement to the second step is warranted. (p. 404)

3. The correct response is option E: Answers B and D.

   Urine drug screens and PDMP database searches are useful tools if you suspect illicit drug use and to guide in adherence monitoring. Each step of the three-step analgesic ladder should include history and physical examination, 2- to 4-week minimal duration trial of medications, interventional pain procedures if indicated, lifestyle modifications, and a plan to reassess pain and functionality (see Figure 27–2). (p. 404)

4. The correct response is option A: Neck circumference of 36 cm.

   The STOP-BANG Questionnaire is a tool used to assess obstructive sleep apnea risk (see Figure 27–4 later in this chapter). The tool includes eight factors that are used for risk stratification. The presence of three or more of the following categorizes the patient as high risk: loud snoring, daytime tiredness, observed apnea, hypertension, BMI greater than 35, age over 50 years, neck girth above 40 cm for men or above 35 cm for women, and male gender. (p. 398)

Clinical Case 3

1. The correct response is option E: Answers B and D.

   Random urine drug screens and PDMP database searches are used to guide a clinician in adherence monitoring and to look for drug misuse. A CD4 count is a useful test for following the integrity of the immune system and is indicative of the HIV disease stage. Liver function tests are likely not needed at this point. Both tests gather important information but will not change the patient’s immediate state of health and treatment. (pp. 402–403)

2. The correct response is option E: Neuropathic pain.

   Two general classes of pain are neuropathic and nociceptive pain. Neuropathic pain is characteristically described as tingling, numbness, “pins and needles,” shooting, or electric-like and results from ongoing nerve stimulation or abnormal messaging in the peripheral and central nervous system. Nociceptive pain is divided into somatic and visceral pain. Nociceptive pain is caused by primary afferent nerve injury or peripheral inflammation. Somatic pain is described using descriptors such as dull, aching, pressure, and sharp. Visceral pain is usually poorly localized. Referred somatic pain is when pathology in one area causes pain in another area. (pp. 395–396)

3. The correct response is option E: All of the above.

   The patient is taking a large dose of opioids and is at risk for developing tolerance. He has been taking larger doses of opioids over the past 4 years, presumably due to decreased effectiveness or shortened effect. Other common side effects of opioids include sedation, respiratory depression, impaired judgment, impaired coordination, constipation, nausea, accelerated loss of bone mineral density, and opioid-induced hyperalgesia. Hyperalgesia is a syndrome that includes increased sensitivity to painful stimuli, worsening pain despite increasing doses of opioids, and pain that extends beyond the distribution of existing pain. Accidental death is the most serious possible result. The risk of opioid-related accidental death is significantly increased when opioids are used concomitantly with other medications, such as benzodiazepines, that have concomitant side effects of sedation and respiratory impairment. (pp. 403–404)

Clinical Case 4

1. The correct response is option C: Adequate pain relief and increased daily activity.

   The 4 A’s assessment method is used for monitoring outcomes for patients on opioid therapy (Figure 27–3). Although tobacco use is associated with increased pain, it is not assessed using the 4 A’s. The patient drinks alcohol in amounts that are not considered in excess of normal use. If the patient were to use alcohol and opioids at the same time, this would be a demonstration of aberrant behavior. Poor compliance with continuous positive airway pressure (CPAP) is important information and may adversely affect the patient’s health. If the patient continues to fail to use her CPAP machine, the physician may need to have a conversation with the patient regarding continuation of opioid therapy. (p. 405)

2. The correct response is option B: Depression.

   The AMPS psychiatric assessment is used to look for potential psychiatric pain generators (see Figure 27–1). The patient describes sleep disturbances, loss of energy, and loss of interest (anhedonia) in previously enjoyable activities. These are all signs of depression that can make the patient’s pain worse. (pp. 397–398)

3. The correct response is option E: All of the above.

   The clinician should avoid passing judgment when aberrant behavior is demonstrated but should also be vigilant in assessing a patient’s behavior. Respectful scrutiny is warranted because the patient may be taking more of the medication than is prescribed, which can be life threatening (misuse or abuse), or giving the medication to a friend or family member (diversion). Prescription opioids are currently a drug of abuse and have a high street value. It is the prescribing provider’s responsibility to determine how the opioids are being used. Because the PDMP database shows that Ms. Aterman has visited several providers for opioid prescriptions and has made several visits to the emergency department for opioids, she is stratified as being at high risk of opioid use disorder. (pp. 402–403)

4. The correct response is option C: Urine drug screens every 3–6 months.

   Once a patient’s risk is stratified as being low, moderate, or high, adherence monitoring can be determined. Low-risk patients should have urine drug screening every 6–12 months and have the PDMP reviewed at drug initiation and three times per year. High-risk patients should have urine drug screening every 3–6 months and have the PDMP reviewed at drug initiation and four or more times per year. (p. 403)

Clinical Case 5

1. The correct response is option C: Untreated anxiety.

   Posttraumatic stress disorder is a type of anxiety condition primarily marked by a reexperiencing of the traumatic event (e.g., through flashbacks or dreams of the trauma) and by a hyperarousal or hyperstartle response, which may increase muscle tension and subsequently worsen the pain. Poor blood glucose control over time has been shown to cause nonenzymatic glycosylation of peripheral nerves, resulting in neuropathic pain. However, Ms. Davis is not describing neuropathic pain. Poor compliance with medical care can be problematic and make ongoing care difficult. Not following medical directions for medications or recommended adjunct treatment modalities will likely not escalate pain. Alcohol abuse can amplify a patient’s pain level; however, occasional nonexcessive use of alcohol has not been shown to cause escalation of baseline pain levels. (p. 398)

2. The correct response is option A: No further actions.

   In accordance with the World Health Organization’s three-step analgesic ladder, treatment should begin with a nonopioid medication. A medication trial is not a failure until the patient has taken an appropriate dose at a scheduled interval for at least 2 weeks. The first step also includes adding adjuvant treatments, which may include anticonvulsants, antidepressants, topical agents, anxiolytics, antipsychotics, and muscle relaxants. Ms. Davis has been taking an antidepressant and an NSAID for several months, but this treatment has failed. The next step is to start a short-acting opioid with an endpoint in mind. It is not necessary to trial another NSAID prior to the next step because the patient has failed therapy with an NSAID and an antidepressant for an appropriate length of time. (pp. 403–404)

3. The correct response is option C: Tolerance.

   Tolerance is the body’s ability to become adjusted to a substance so that its effects are less strong than previously experienced with the same amount. Dependence is a state of adaptation in which an organism functions normally only in the presence of that substance. Addiction is the compulsive need for and use of a substance characterized by tolerance and by physiological symptoms upon withdrawal of that substance. Abuse is the patterned use of a substance in which the individual uses the substance in amounts that are harmful to themselves or others. Drug diversion involves the use or selling of medications for recreational purposes. (pp. 403–404)

4. The correct response is option D: Accidental death.

   The risk of opioid-related accidental death is significantly increased when opioids are mixed with benzodiazepines. Opioids interfere with the hypothalamic-pituitary-gonadal axis, causing reductions of adrenal androgen production; the addition of benzodiazepines would not contribute to the suppression of the sex steroids. Hyperalgesia is a syndrome of increased sensitivity to painful stimuli, worsening pain despite increasing doses of opioids, and pain that extends beyond the distribution of existing pain. Although Ms. Davis may have hyperalgesia, this syndrome is unrelated to the addition of a benzodiazepine. A patient who has been taking opioids for an extended period of time is at risk for developing tolerance. Ms. Davis has been taking escalating doses of opioids over the past 14 months, presumably because of decreased effectiveness or duration of effect. The addition of benzodiazepines does not affect tolerance. Patients who have been using opioids for a long time are at higher risk of developing bone loss and osteoporosis. The exact mechanism is unknown but appears to be multifactorial. Contributing factors include the development of an endocrinopathy, direct osteoblast inhibition, and the effects of associated comorbidities. (p. 404)

Clinical Case 6

1. The correct response is option B: Thyroid-stimulating hormone test.

   Hypothyroidism can lead to fatigue, whole body aches, weight gain, poor motivation, poor concentration, depression, and generalized myofascial pain. Thyroid irregularities can be easily investigated with blood tests, and Ms. Bradford’s symptoms are most indicative of low thyroid hormone. Poorly controlled blood pressure and blood glucose can worsen headaches and lead to peripheral neuropathy. Pseudotumor cerebri, detected using head and neck CT scan, can occur in obese women and cause headaches, but can also cause neck/shoulder pain, blurred vision, and tinnitus; Ms. Bradford does not exhibit most of these symptoms, making the diagnosis less likely. A complete blood count can detect infection, inflammation, anemia, and a wide variety of disorders. Obesity increases the risk of developing fatty liver disease and other diseases that can elevate liver enzymes. Although elevated liver enzymes can cause headaches, they do not cause the constellation of symptoms described in the case description. (p. 394)

2. The correct response is option E: Answers A, B, and C.

   The STOP-BANG Questionnaire is used to screen for obstructive sleep apnea (Figure 27–4). Patients with three or more “yes” answers have a high risk for sleep apnea and should be evaluated further by a sleep specialist. Ms. Bradford meets several high-risk findings that point toward an obstructive sleep apnea diagnosis: loud snoring (often heard through closed doors), a calculated BMI of 37.8, and daytime tiredness. Being male but not female is considered a positive finding for obstructive sleep apnea on the STOP-BANG Questionnaire. (p. 398)

3. The correct response is option D: Trigger point injections.

   A true trigger point is described as a focal spot within a taught muscle band that causes a radiating referral pattern or motor or autonomic dysfunction. Treatments that have been shown to be beneficial for trigger points include physical therapy, massage, ultrasound, dry needling, and injection with local anesthetic, botulinum toxin, or corticosteroid. Patients with axial back pain that radiates to the posterior thigh can have facet-mediated pain that may benefit from a radiofrequency ablation of the medial branch nerves. Patients with radicular spine pain have nerve root impingement; their pain is frequently described as electrical, burning, or shooting in behavior. These patients may benefit from an epidural steroid injection. Facet-mediated pain in the cervical or lumbar region can be relieved with steroid injections near the joint. The physical examination in Ms. Bradford’s case does not point toward facet-mediated pain. (pp. 405–406)

Clinical Case 7

1. The correct response is option C: Obstructive sleep apnea.

   Obstructive and central types of sleep apnea are common causes of sleep disturbances and should be thoroughly evaluated prior to prescribing an opiate or other potentially sedating medication. Undiagnosed sleep apnea combined with opioids and/or benzodiazepines leads to increased morbidity and mortality. Coronary artery disease, diabetes, and hyperlipidemia are serious medical conditions but do not necessarily need to be ruled out before a patient starts taking an opiate. (pp. 397, 408)

2. The correct response is option B: STOP-BANG.

   The acronym STOP-BANG stands for the eight components of a rapid screen for obstructive sleep apnea (see Figure 27–4). Three or more “yes” responses represent a high risk of obstructive sleep apnea. A-SCAR is a mnemonic that helps in remembering the treatment of obesity among individuals with serious mental illness (Assess, Switch, Change, Add, Refer). VITAMIN D is a mnemonic frequently used to evaluate the etiology for different pathological processes (Vascular, Infectious, Trauma, Autoimmune, Metabolic, Inherited, Neoplastic, Drug). CREATE is a mnemonic that helps providers create cultural competence (Collaborate, Reflect, Empathize, Ancillary, Timing, Educate). (p. 398)

3. The correct response is option C: Referral for a sleep study.

   Mr. Sidel scores 5 on STOP-BANG (tired, pressure, BMI > 35, age > 50, male gender) (see Figure 27–4). Anyone scoring 3 or more is considered to be at high risk for obstructive sleep apnea, and additional workup by a sleep specialist or by polysomnography is indicated. This additional workup should take place before a trial of an opiate medication. Consideration could be given to a retrial of gabapentin at a lower dose; however, workup for obstructive sleep apnea should take priority. Tramadol is an opiate-like medication and carries many of the same risks as traditional opiates, including respiratory depression. (p. 398)

Clinical Case 8

1. The correct response is option A: Anxiety.

   AMPS is an acronym for Anxiety, Mood, Psychosis, and Substance abuse (see Figure 27–1). Mr. Vincent exhibits anxious symptoms and has a clinical presentation that likely meets the criteria for somatic symptom disorder, with predominant pain. The patient may also have a mood disorder, but anxiety is the main psychiatric pain generator. (pp. 398–399)

2. The correct response is option D: Cognitive-behavioral therapy.

   Cognitive-behavioral therapy is the first-line treatment choice to reduce the anxious symptoms associated with this kind of somatic symptom disorder. Pharmacotherapy with a selective serotonin reuptake inhibitor is also efficacious. Physical therapy, acupuncture, and meditation are potential adjunctive treatment modalities. (pp. 394, 405)

3. The correct response is option E: Answers A and B.

   Untreated anxiety can be a tremendous amplifier of any pain condition. Anxiety propagates a vicious cycle of intensified sympathetic response that, if left untreated, will maintain the pain. Anxious rumination can impair sleep, which can in turn impair function and lead to worsened pain. Anxiety is not usually associated with an increase in malingered symptoms. A good doctor-patient relationship can decrease anxiety symptoms. (p. 398)

Clinical Case 9

1. The correct response is option D: Myofascial pain syndrome.

   The patient describes classic trigger points consistent with myofascial pain syndrome. Disc herniation with radicular pain would most likely present with pain radiating down the leg. Patients with facet arthropathy often present with axial lower back pain that may or may not radiate as far distally as the posterior thigh. Fibromyalgia typically consists of widespread musculoskeletal pain and fatigue, with tender points in multiple locations. (pp. 405–406)

2. The correct response is option B: Trigger point injection.

   Myofascial pain syndrome may be treated with trigger point needle injections with local anesthetic, corticosteroid, or botulinum toxin, or with dry needling. Facet arthropathy is treated with radiofrequency ablation of the medial branch nerves innervating arthritic facet joints. Epidural steroid injections are used for radicular spine pain such as that found following lumbar disc herniation. Complex regional pain syndrome can be treated with a sympathetic block. (pp. 405–406)

3. The correct response is option A: Hyperirritable spot with referred symptoms.

   Hyperirritable spots with referred symptoms are called trigger points. Multiple points of tenderness throughout the body are typical for fibromyalgia; these tender points do not have referred symptoms, although palpation of trigger points creates pain in areas other than the location of the trigger point itself. Radicular spine pain is typically not associated with a taut muscle band or hyperirritable spot. The referred symptoms associated with a trigger point can include motor or autonomic dysfunction, but these symptoms are not required for the diagnosis. (pp. 405–406)

Clinical Case 10

1. The correct response is option C: Diabetic peripheral neuropathy.

   Diabetic peripheral neuropathy classically presents with paresthesia in a stocking and glove distribution as described in this case. Spondylolisthesis (displacement of one vertebra over another) can cause bilateral leg pain and paresthesia, but the pain typically presents as radiating pain starting in the back and radiating down one or both legs. Degenerative disc disease can result in lower extremity neuropathic pain if there is encroachment on a spinal nerve; however, this would typically present as radiating back pain down one leg. The pain from fibromyalgia is typically whole body with multiple points of tenderness. (pp. 395, 405–406)

2. The correct response is option A: Duloxetine.

   The first-line treatment of neuropathic pain almost always involves the use of nonopioid medications, such as tricyclic antidepressants, anticonvulsants, and serotonin-norepinephrine reuptake inhibitors (SNRIs). Among the choices, duloxetine, amitriptyline, and gabapentin have shown benefit in treating neuropathic pain, and duloxetine and amitriptyline are indicated for treatment of depression. In a 67-year-old patient, duloxetine would likely be preferred over amitriptyline given its more favorable side-effect profile. (p. 399)

3. The correct response is option C: By increasing appetite.

   Mirtazapine is an efficacious antidepressant for the treatment of major depressive disorder. However, it is associated with increased appetite, which may present a problem for this patient with uncontrolled diabetes and obesity. It is not associated with an increased sensitivity to neuropathic pain, and it typically improves sleep. (pp. 146, 399)

Clinical Case 11

1. The correct response is option B: Lumbar facet arthropathy.

   Patients with lumbar facet arthropathy typically have axial lower back pain; there can be radiation as far distally as the posterior thigh but typically not below the knee. Disc herniation with impingement of a nerve root would classically involve radiating pain down the length of one leg. Spinal stenosis of the lumbar spine often involves numbness, paresthesia, or weakness in both lower extremities worsened by activity. Diabetic neuropathy usually manifests as bilateral paresthesia in a stocking and glove distribution. (pp. 405–406)

2. The correct response is option A: Nonsteroidal anti-inflammatory drug (NSAID).

   NSAIDs are recommended for inflammatory pain such as that found with lumbar facet arthropathy. Anticonvulsants and the SNRIs are recommended for neuropathic pain. Myofascial pain and fibromyalgia may also respond to the SNRIs. Opiates are reserved for those who are unsuccessful with a trial of nonopioid analgesics. (pp. 399, 403)

3. The correct response is option D: Radiofrequency ablation.

   Radiofrequency ablation of the medial branch nerves innervating arthritic facet joints may reduce axial back pain and associated referred pain. Epidural steroid injections may be beneficial for radicular spinal pain. Trigger point injections can be helpful in the treatment of myofascial pain syndrome. Transcutaneous electrical nerve stimulation (TENS) is not an interventional procedure. (pp. 405–406)

Clinical Case 12

1. The correct response is option B: Oxycodone.

   Opioids represent a significant risk in this patient with possible obstructive sleep apnea (she screens positive on the STOP-BANG Questionnaire for tired, hypertension, BMI, and age; see Figure 27–4 earlier in this chapter) and other related side effects including respiratory depression. Undiagnosed sleep apnea combined with opioids leads to increased morbidity and mortality. (pp. 398, 405)

2. The correct response is option A: Weight loss guidance.

   Overweight and obese patients should have nutritional assessment and weight loss guidance as part of their comprehensive pain treatment program. This patient has grade III obesity, and her obesity is likely the main contributor to her pain. It is unlikely that she would be able to participate in yoga. TENS and acupuncture could provide some relief. (p. 405)

3. The correct response is option D: Obstructive sleep apnea and multiple sedating medications.

   Ms. Schulte has four of the eight risk factors for obstructive sleep apnea on the STOP-BANG Questionnaire (see Figure 27–4). Nighttime hypoxia leads to frequent bouts of sleep arousal, which can lead to daytime somnolence. She is also taking multiple sedating medications, including gabapentin, OxyContin, oxycodone, and paroxetine. There is no evidence that the patient’s sleep is interrupted by ruminating thoughts. Her pain is worse with ambulation than while sleeping. (p. 397)