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11 Articles in Volume 7, Issue #9
CES in the Treatment of Addictions: A Review and Meta-Analysis
Chronic Cancer Pain Management
Compliant Billing, Coding and Documentation for Interventional Pain Management
Critical Transition from Short-to-Long-Acting Opioid Therapy
Dextrose Prolotherapy and Pain of Chronic TMJ Dysfunction
Dysfunction and Rehabilitation of the Shoulder
Low Level Laser Therapy (LLLT) - Part 2
Placebos in Pain Management
The Good Patient: Responsibilities and Obligations of the Patient-physician Relationship
TMJ Derangement and SUNCT Syndrome Co-morbidity
Ziconotide Combination Intrathecal Therapy

Chronic Cancer Pain Management

Appropriate pain assessment—along with the proper use of opioid analgesics and the management of common opioid side effects—are vital components in an overall treatment and monitoring plan.

Pain is categorized by the International Association for the Study of Pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”1 Accordingly, pain is a complex subjective phenomenon that makes it difficult to qualitatively and quantitatively assess in individuals. Nonetheless, pain is usually described as acute or chronic, and can result from either nonmalignant or malignant causes.

Acute pain is a “wake up” call from nature, signaling us that there is something wrong. It is typically categorized as mild, moderate, or severe. Acute pain is also associated with physiologic changes consistent with sympathetic nervous system activation (e.g., sweating, tachycardia, papillary changes) similar to that seen with acute anxiety. With acute pain, we can expect that the pain will improve when the cause of the acute injury is removed and the healing process proceeds unabated. A classic example would be incisional pain which is characteristically worse during the early postoperative period but steadily improves day by day until complete cessation.

Chronic pain, however, cannot be rationalized as part of the healing process. It has been described as a disease state unto itself and is associated with a significant biopsychosocial component (e.g., depression, sleep disorders, functional impairment). Before a pain disorder can be appropriately treated, the clinician must have an understanding of its causes(s) and its natural history. Likewise, suitable subjective and objective pain assessments must be made that employ appropriate evaluative tools prior to formulating a treatment plan.

The following case study illustrates the use of a problem-based learning (PBL) format2 as it is applied to an individual experiencing chronic cancer pain. The overall objectives include: describing the differences between acute nonmalignant and chronic malignant pain, recognizing the importance of employing the appropriate tool(s) in pain measurement, and developing selected pain management and symptom-control strategies. This approach will allow the reader to apply the principles outlined here to any clinical situation in an effort to resolve patient problems and develop a management plan. There are five basic components to the PBL: identifying the problems, formulating hypotheses for the problems, articulating patient goals, creating solutions for problem resolution, and preparing the management plan.

Case Study3

Chief Complaint and Present Illness

Johnny Hert is a 63-year-old man who presented to a family practice center affiliated with a large tertiary-care academic medical center. His chief complaints were: “I’m having belly pain and my stomach looks like it is getting big. I feel so tired all the time, and I’m having trouble urinating and it hurts whenever I finish.” He was in his usual state of health until approximately one month ago when he developed upper abdominal pain and constipation. He had also lost about 18 pounds during the past two to three months. During a recent visit to his family physician, he was noted to have a tender liver edge on physical examination and elevated liver function tests. He was admitted from the clinic to University Hospital for a diagnostic workup of his abdominal complaints and abnormal laboratory findings.

Medical History

Usual childhood illnesses. No past surgeries. Family History: His father died at age 72 from prostate cancer. His mother died at age 64 from a CVA. One younger brother (age 55) and older sister (age 67) are alive and well. One uncle died at age 80 from rectal cancer. Social History: Retired manual laborer from a local faucet factory. He smoked one and onehalf ppd for 50 years and for the past two years smoked one ppd. He drinks an occasional beer. He is a widower (wife died of breast cancer four years ago). No medications. No known drug allergies but codeine causes nausea.

Pertinent Physical Examination Findings

Appearance, the patient is a cachectic unshaven man
Height, 173cm (5 ft 8”)
Weight, 66 kg (145.2 lbs)
Blood Pressure, 130/76
Pulse, 84
Respiratory Rate, 24
Temperature, 37.1oC (98.8oF)
Head, Eyes, Ears, Nose, Throat (HEENT), Scleral icterus
Neck, 3+ adenopathy
Chest, crackles throughout
Abdomen, Moderately distended, liver edge 3 cm below the right costal margin, liver span 10 cm; (+) fluid wave; no palpable masses;
Lab Results, AST 20 IU/L, ALT 15 IU/L, GGT 1837 IU/L, alkaline phosphatase 952 IU/L, total bilirubin 1.4 mg/dl, direct bilirubin 0.8 mg/dl, PT–12 sec, aPTT–19.5 sec.

Other Findings

Abdominal x-ray, proctoscopy, flexible sigmoidoscopy, and barium enema are nondiagnostic. Liver-spleen scan shows portal vein hypertension. Peritoneal fluid is positive for adenocarcinoma cells. Abdominal CT scan reveals a mass in tail of pancreas, probable metastasis and/or node around head of pancreas with obstruction of biliary tree and portal vein thrombosis, stomach compressed by ascites.

Diagnosis

Inoperable adenocarcinoma of the pancreas.

Clinical Course

The patient was begun on morphine sulfate (2mg SQ Q 4 H PRN) for mild aching stomach and costovertebral angle pain along with temazepam (15mg po Q HS PRN) for sleep. The morphine relieved his discomfort for about four to six hours. Respiratory function was unaffected and the patient remained fully conscious, with no complaints of increased drowsiness. However, the dose of morphine was eventually escalated uneventfully to 3mg SQ Q 4 H PRN over four days for worsening pain.

Discussion

If we follow the PBL format outlined in the case study, the first step is to identify the patient’s pertinent problems and generate a problem list. The patient is a middle-aged retired man who presented to a primary care clinic with complaints of abdominal pain and swelling, constipation, voiding difficulty, weight loss, and lassitude. Additionally, he was noted to have several abnormal laboratory test results. He has a significant smoking history (>75 pack per year history) and occasionally drinks alcohol. He presently takes no medication and he experienced nausea with codeine. Physical examination findings reveal jaundice, head and neck lymphadenopathy, hepatomegaly and ascites. Liver function tests are elevated along with abnormal radiologic tests and peritoneal fluid cytology.

After examining and evaluating all the subjective and objective evidence, we should be able to consolidate these findings into a concise problem list (see Table 1). Next, the clinician should generate hypotheses for each of the major problems identified in the patient. The primary problem is metastatic pancreatic cancer. Likely causative factors include a history of heavy smoking and age.4 Other possible (albeit not proven) links to pancreatic cancer include diet, diabetes, chronic pancreatitis, positive family history of pancreatic cancer, hereditary disorders, occupation, obesity, and H. pylori infections. His abdominal pain resulted from ascites (caused by portal vein thrombosis), tumor infiltration of the abdomen, and abdominal distension. Fatigue and weight loss most likely resulted from decreased oral intake due to pain and loss of appetite. The patient’s urinary complaints of dysuria and voiding difficulty are most likely due to benign prostatic hypertrophy and/or a urinary tract infection. The subjective complaint of nausea from codeine represents a gastrointestinal intolerance to the drug and is not consistent with a Type 1 hypersensitivity reaction.

Table 1. Problem List
  • Metastatic adenocarcinoma of the pancreas
  • Acute abdominal pain
  • Abdominal ascites
  • Fatigue
  • Weight loss
  • Difficulty voiding and dysuria
  • Nausea with codeine
Table 2. Subjective Pain Assessment
PQRST Mnemonic5
P palliative or precipitating factors
Q quality of the pain (e.g., sharp, dull, stabbing,
burning)
R region (of the body) or radiation
S subjective account of the pain
T temporal or time-related character of the pain
Adapted from Rospond RM. Pain assessment. In: Jones RM, Rospond RM. Patient assessment in pharmacy practice. Lippincott Williams and Wilkins. Baltimore. 2003. p 88.

Assessment

As mentioned earlier, pain must be assessed before it can be appropriately treated. Since pain is a subjective experience, its evaluation poses many challenges for the clinician. Additional barriers include patient age and functional status. Cognitive impairment of the patient can also make it difficult to adequately evaluate a painful condition. Subjective and objective assessment strategies should be employed to assist the clinician in this important facet of pain management. The old cliché that “the history is everything” certainly holds true here.

The “PQRST” mnemonic is a useful way to gain valuable insight into the painful condition5 (see Table 2). Along with a good medical history, it’s also important to conduct a thorough drug history. The main components of a drug history should include: prescription and non-prescription medication; drug and food allergies; and the use of tobacco, alcohol, and caffeine.6 Along with these elements of the patient interview, it’s also important to utilize single-dimension pain assessment tools (e.g., visual analog, verbal numeric, verbal rating scales) to assist in “objectifying” the painful experience. These instruments or “pain rulers” typically assess pain using a numeric linear scale (0-10) or a linear scale that measures pain severity or distress using verbal descriptors. Other tools use a continuum of faces (from happy to sad) to measure pain severity.

Unfortunately each of these single-dimension instruments has shortcomings that must be taken into account when choosing a tool or interpreting its results. For example, the elderly may find it difficult to use the standard horizontal pain instrument if they have difficulty with abstract thinking.5 The use of a vertical single-dimension instrument (e.g., pain thermometer) may be preferred for use in the elderly. The faces rating scale may also be useful for the elderly patient.5 These problems reinforce the need to determine the cognitive and sensory function of the elderly before using a particular instrument.

The use of objective pain assessment measures can be complementary to the aforementioned subjective techniques, or they can be used when a patient interview or self-reporting is inappropriate. Observing behavioral or physiologic changes can be used to indirectly assess pain severity or distress. In addition, one should be cognizant of atypical pain presentations, particularly in the elderly. For example, anginal pain may manifest as shortness of breath, and abdominal pain may be a symptom of pneumonia. One should also be aware of the cultural, ethnic, and gender differences in pain expression and the challenges that these pose for the clinician.5

Determining Treatment Goals

Unfortunately, it is not known how our patient’s pain was assessed by the physician(s) in the clinic or hospital. We can only assume that an appropriate single-dimension tool was used along with taking a good history from the patient. The results of the initial pain assessment can be used to aid the clinician in choosing the appropriate analgesic regimen for the patient. We are now at the point in the problem-based learning process where we need to construct and state the overall treatment goals (see Table 3).

Once this task is completed, we can begin to “brainstorm” or generate ideas regarding each of the patient’s active problems. As with most cancers, the hope for a cure rests with the potential benefits of surgery, radiation, and/or chemotherapy. Since most pancreatic cancers have metastasized at the time of diagnosis, surgical resection offers little if any benefit unless the disease is localized. Adjuvant chemotherapy and radiochemotherapy remain the only viable treatment options for metastatic pancreatic cancer. Since a comprehensive evaluation of the chemotherapy of pancreatic cancer is beyond the scope of this discussion, the reader is encouraged to examine published reviews on this subject.7-9 In order to alleviate the patient’s pain and discomfort, a drug exhibiting the appropriate relative analgesic potency should be selected.

Table 3. Overall Treatment Goals
  • Consider curative versus palliative options for pancreatic cancer
  • Alleviate pain and suffering promptly
  • Maintain cognitive function
  • Restore functional status
  • Minimize analgesic related adverse effects
  • Reduce abdominal ascites to improve comfort
  • Restore appetite and nutritional status
  • Improve ease of voiding and urinary symptoms
  • Avoid the use of codeine

“Relative analgesic potency” refers to a drug’s strength or inherent ability to alleviate pain. For example, morphine is a more potent analgesic than aspirin, regardless of the dose of aspirin administered. If a single-dimension assessment tool (e.g., 1-10 visual analog scale) is used to determine pain severity, the results can assist the clinician in choosing an appropriate drug. Simple analgesics such as aspirin or acetaminophen may be useful for numeric ratings from 1-3; opioid combinations (i.e., codeine/codeine congeners with aspirin/acetaminophen, NSAIDs, tramadol, or toradol) may be useful for 4-6 ratings. For ratings above 7, morphine or other strong opioids should be considered to alleviate the pain.

Since ascites may contribute to abdominal pain (due to physical compression of abdominal organs) and compromise respiration (due to impingement on the diaphragm), careful diuresis should be considered along with periodic paracentesis if necessary. Urine output in excess of 2000ml per day should be avoided unless concomitant peripheral edema is also present.10 Vigorous diuresis may result in hypotension and/or reduced urine blood flow. Loop diuretics (e.g., furosemide, torsemide, bumetanide) are preferred over thiazide diuretics due to their increased potency and utility in patients with compromised renal function. The potassium-sparing diuretic spironolactone (a competitive aldosterone antagonist) may also be a useful adjunct to loop diuretics resulting in increased diuresis. Secondary hyperaldosteronism may occur in patients with abdominal ascites as a result of a loss of effective circulating blood volume resulting in activation of the renin-angiotensin-aldosterone system (RAAS) in the kidney. RAAS activation results in the production of aldosterone, which causes the kidney to retain sodium and water and can then exacerbate the abdominal ascites. Spironolactone effectively “shuts off “ the effects of aldosterone in the kidney, thereby decreasing the production of ascitic fluid and increasing renal fluid losses.

This cachectic-appearing patient experienced an 18-pound weight loss during the preceding two to three months. Although a formal nutritional assessment was not initiated, one could speculate that the metastatic pancreatic cancer itself or pain from the tumor and/or ascites contributed to his reduced appetite and resultant weight loss. Regardless of the cause(s), nutritional repletion is paramount for this patient. A formal nutrition consult would be appropriate to assess the patient’s caloric needs, and to determine the proper replacement strategy (enteral vs. parenteral) to ensure weight gain and improve his overall nutritional status and immunocompetency.

Since the patient also had urinary tract complaints, it would be important to evaluate the prostate gland and obtain a clean-catch urine specimen for analysis and culture. Performing a digital prostate exam and obtaining a serum PSA (prostatic specific antigen) could be used to rule out malignancy and/or benign prostatic hypertrophy. Qualitative/quantitative urinalysis and a urine culture can determine whether a urinary tract infection is responsible for the patient’s urinary hesitancy and dysuria.

The patient reported that codeine caused nausea in the past. It should be noted that gastrointestinal complaints are common with opioids and do not represent true allergic reactions. Type 1 hypersensitivity reactions are not common with the opioids, but when they occur, they can be life-threatening. If an allergic reaction occurs with codeine (a naturally occurring opioid), other natural opioids (e.g., morphine) should be avoided. However, semi-synthetic or synthetic opioids (e.g., meperidine, hydromorphone, fentanyl, methadone) could be administered with little likelihood for cross reactivity. For these reasons, it is important for the clinician to thoroughly evaluate a drug “allergy” history to determine its validity. The ramifications of “missing” a true hypersensitivity reaction can be disastrous. Likewise, labeling a reaction as an established “allergy” may keep a patient from receiving an appropriate drug. Since codeine is a relatively weak opioid and there are many other opioid options available, it would be prudent to avoid initiating codeine in this patient who is already experiencing gastrointestinal distress.

Developing a Management Plan

The final step in the problem-based learning process is to prepare the overall management plan. The major components of the plan would include the following:

  1. Initiate a strong analgesic, preferably an opioid for moderate to severe pain. The oral route of administration is typically preferred unless the patient cannot swallow a solid or liquid dosage form or cannot absorb the drug via the gastrointestinal tract.
  2. Initiate a hypnotic (benzodiazepine vs. nonbenzodiazepine) drug for sleep. Importantly, sleep disturbances are often alleviated when the patient experiences adequate pain relief, obviating the need to include a hypnotic as part of the therapeutic regimen.
  3. Initiate an appropriate laxative regimen. Stimulant laxatives (e.g., senna, bisacodyl) are the drugs of choice to prevent opioid-induced constipation. Constipation can be expected in persons taking chronic opioid analgesics. Opioids reduce gastrointestinal secretions, impair forward “propulsive” intestinal peristalsis, augment colonic and rectal sphincter tone, and decrease the normal relaxation reflex to rectal distension. Additionally, the CNS-depressant effects of opioids can cloud a patient’s sensorium, leading to an inability to heed the urge to defecate. The use of psyllium products is discouraged since insufficient water intake may lead to constipation. Also, these products should not be used to manage opioid-induced constipation since bowel obstruction or perforation may result.
  4. Monitor the patient for drug efficacy and adverse effects. It is also important to monitor the functional status of the patient. Every effort should be made to preserve as much of the patient’s functional capacity as possible (e.g., physical and instrumental activities of daily living) without impairing the sensorium with the pain management regimen.

Overcoming Fear of Opioids

Despite our improved understanding of the pathophysiology and management of pain, many healthcare providers remain hesitant to treat it aggressively. Much of this reluctance arises from the fear of using opioids—even when indicated. This “opiophobia” is rooted in such diverse reasons as: a lack of formal education in pain management, fear of inquiry by governmental regulatory agencies, provider “baggage” (i.e., preconceived attitudes and beliefs), and the misguided notion that opioid use would create psychologically dependent patients.11 In fact, in a recent review of medical boards across the United States, the likelihood of a physician receiving disciplinary action for managing patients with legitimate painful disorders with opioids was found to be essentially zero.12

Patient Monitoring and Follow-up

Following admission to the hospital from the clinic, a therapeutic management plan is initiated for the patient (see Table 4). This includes the following recommendations:

  • Maintain constant and careful surveillance
  • Monitor for the development of tolerance
  • Monitor for drug-related adverse effects
  • Transition to oral opioid regimen upon discharge

Maintain Constant and Careful Surveillance

This is necessary to ensure that the patient achieves the optimal benefits from this drug regimen. The therapeutic effectiveness of the drug regimen in addition to potential adverse effects must be assessed. Pain relief can be measured using a standardized assessment tool (e.g., pain ruler, faces rating scale). Ideally, the same observer should assess the patient’s pain to maintain consistency and ensure reliability of the findings. However, adherence to this recommendation is typically unrealistic given contemporary work schedules and staffing patterns in the healthcare setting. Regardless of this fact, pain assessment must be an ongoing part of the patient’s overall care and must be documented in the medical record.

Table 4. Clinical Course
  • JH was begun on morphine sulfate 2mg SQ every 4 hours as needed for abdominal and costovertebral angle tenderness (CVAT)
  • Temazepam 15 mg PO at bedtime as needed for sleep
  • Initial drug regimen was well tolerated
  • Over a 4-day period, the morphine sulfate was increased to 3 mg SQ every 4 hours as needed for pain

Monitor for the Development of Tolerance

Persons receiving opioids for pain must be monitored for the development of tolerance— the apparent cause of this patient’s escalating morphine dose requirements. Tolerance is common in patients receiving chronic opioids and develops in association with physical dependency. It is associated with continued use of the opioid and results in larger doses being required to produce effects similar to lower doses. Tolerance is more likely to occur with short-acting opioids and is less likely with opioid combinations (e.g., oxycodone/ acetaminophen). Tolerance should be suspected if the duration of pain relief from a given opioid begins to decrease. A once-held explanation for tolerance was progression of the underlying disease state. However, it is now known that tolerance results from several neurobiochemical mechanisms, including activation of nociceptive descending pathways in the CNS, neuronal remodeling, and cellular apoptosis.13

Tolerance to opioid adverse effects (including respiratory depression, sedation and euphoria) develops at the same rate as tolerance to the analgesic effects. Significantly, tolerance does not develop to constipation, mandating the continuation of stimulant laxatives indefinitely. Tolerance can be managed in several ways. The dosing interval of the opioid can be decreased or the dose can be increased. Since tolerance is incomplete, another opioid can also be substituted using 50%-75% of the equianalgesic dose.

Monitor for Drug-related Adverse Effects

In addition to monitoring the therapeutic efficacy of the treatment regimen, it is equally important to monitor the patient for drug-related adverse effects. In the case of morphine for this patient, the clinician should routinely watch for sedation, mental status changes, constipation and/or urinary retention, decreased respiratory rate and depth of respiration, nausea and vomiting, gastrointestinal distress or abdominal pain, hypotension, lightheadedness/dizziness, and visual disturbances. In addition, temazepam (a benzodiazepine hypnotic) was prescribed to be given as needed for sleep. Routine monitoring parameters would include sleep latency (time required to fall asleep), sleep duration, morning somnolence, dizziness, confusion, and ataxia.

Transition to Oral Opioid Regimen Upon Discharge

When the decision is made to discharge the patient to home, the patient should be transitioned to an oral opioid regimen if appropriate. The clinician should prescribe an equianalgesic dose of an appropriate drug along with providing a strategy for “rescue” dosing for breakthrough pain. The need for careful monitoring should continue in the ambulatory setting and any medication adjustments made accordingly.

Summary

This case study illustrates the problem-based learning approach to solving complex patient care issues. Subjective and objective patient findings are organized into a working problem list from which an action plan for each of the patient’s acute (and even chronic) problems is eventually formulated. This method can be used by inexperienced as well as seasoned clinicians, regardless of the disease state or management challenges they confront. In addition to illustrating the processes by which management decisions are made in the clinical setting, this case demonstrates basic principles in the management of pain using opioid analgesics. It is hoped that these “clinical pearls” will assist the clinician in avoiding or “filling in” some of the “potholes” encountered when managing patients with painful conditions. n

Acknowledgement

This manuscript originally appeared in The Pain Practitioner [Ponte CD. The Assessment and Management of Opioid-Requiring Chronic Cancer Pain: A Case Study Using a Problem-Based Learning (PBL) Format. Pain Pract. 2005. 15(4); 35-42] and was adapted with permission of the Executive Director of the American Academy of Pain Management (AAPM).

Last updated on: January 24, 2012
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