Prevalence of and factors associated with psychiatric morbidity in chronic pain patients.

OBJECTIVE: The reported prevalence of psychiatric morbidity in chronic pain patients (CCPs) was high, although it varied tremendously since structured diagnostic instruments were seldom used for diagnosis in previous studies. Study in this area after the launching of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) was scarce. This study serves to estimate the prevalence of psychiatric morbidity in patients attending a chronic pain clinic by using the Structured Clinical Interview for DSM-IV (SCID) Axis I disorders and to identify factors highly associated with psychiatric disorders, particularly depression, which is treatable. METHOD: Consecutive patients attending a chronic pain clinic were recruited during a 6-month period. Psychiatric diagnoses were made by using the SCID. Logistic regression was used to identify factors predicting overall psychiatric morbidity and depression. RESULTS: Prevalence of psychiatric disorders in this 89-patient sample was 62.9%. Current major depressive disorder was present in 31.5% and somatoform disorders in 33.7%. Anxiety disorders and current substance use disorders each constituted 18. "Younger age of onset of pain" (odds ratio [OR]=0.956, P<.05) and "higher pain intensity" (OR=1.544, P<.001) were independently associated with presence of psychiatric disorders. "Higher pain intensity" (OR=13.7, P<.05), "negative pain cognition" (OR=0.967, P<.05) and "problems with social and leisure activities" (OR=38.5, P<.05) were associated with depression. CONCLUSION: Prevalence of psychiatric disorders in this Chinese chronic pain clinic sample with reference to the DSM-IV was similar to that reported in previous studies. Specific factors were identified to alert pain physicians to underlying psychiatric disorders.

Opioids in chronic non-cancer pain.

INTRODUCTION: The use of chronic opioid therapy for chronic non-cancer pain is growing and is now accepted as an effective treatment modality. AREAS COVERED: Although there are guidelines and reviews for chronic opioid therapy for chronic non-cancer pain patients, physicians may still have concerns and be reluctant to prescribe strong opioids for chronic non-cancer pain. Common issues and concerns when prescribing opioid for chronic pain management are reviewed and discussed. The literature search was done using Medline with key words 'chronic non-cancer pain', 'chronic opioid therapy', 'effectiveness', 'opioid tolerance', 'opioid-induced hyperalgesia', 'adverse effect', 'opioid dependency', 'addiction', 'monitoring', 'opioid contract' and various combinations with these key words. Studies from 1990 - 2010 have been included. This article helps readers to update, clarify and understand the common concerns when using opioid for chronic non-cancer pain. Clinical effectiveness and adverse effects with chronic opioid therapy, opioid tolerance and opioid-induced hyperalgesia, opioid dependency and addiction, monitoring during chronic opioid use, and opioid contact are discussed in detailed. EXPERT OPINION: Not much strongly positive data supports the long-term use of opioids for pain relief, and the evidence for an improvement in functional activity is inconclusive. With careful selection of patients, meticulous prescription and monitoring protocol, chronic non-cancer pain patients who are likely to benefit from potent opioids should not be prevented from obtaining this treatment.

An audit of postoperative intravenous patient-controlled analgesia with morphine: evolution over the last decade.

The development and refinement of an acute pain service based on the increased availability of clinical evidence would be expected to improve the quality of postoperative pain control. This report reviews the application of postoperative patient-controlled analgesia (PCA) using intravenous morphine in a single institution between 2002 and 2005. More than 5000 patients were evaluated and the results were compared with a similar study performed 10 years ago. Prescription of PCA had increased by more than threefold. Morphine consumption from post-operative day 1 to day 3 (19.1 vs. 26.1, 8.6 vs. 18.1 and 4.5 vs. 19.0 microg/kg/h, respectively), demand-to-delivery ratio (1.35-1.76 vs. 2.4-2.8) and the incidence of respiratory depression (0.06% vs. 2%) were significantly reduced (p<0.001), but there was no improvement in pain relief. A substantial proportion of patients still experienced postoperative nausea (47%) and vomiting (18.5%) despite a reduction in morphine consumption. Most patients ranked PCA as good and only 0.3% were dissatisfied. We conclude that, in our institution over the last decade, PCA has become more popular for postoperative pain management but with no attendant improvement in pain relief or reduction in side effects. Using PCA alone may result in poorer quality postoperative analgesia. Our findings add to the growing body of evidence that postoperative pain management has not substantially improved despite increased adoption of acute pain services.

Acute intraoperative hemolysis and hemoglobinuria during radiofrequency ablation of hepatocellular carcinoma.

Radiofrequency ablation is a safe and effective treatment for small primary or secondary liver tumors. Development of new probes has allowed the use of radiofrequency ablation for ablation of tumors > 5 cm in the liver. We present a case of acute intravascular hemolysis and hemoglobinuria during radiofrequency ablation of a large 8-cm hepatocellular carcinoma via laparotomy. The hemolysis was recognized during the operation by change of urine color, and prompt management was initiated to prevent acute renal failure. Literature search revealed that radiofrequency ablation can induce hemolysis in experimental setting, but this is the first clinical report of acute hemolysis during radiofrequency ablation for liver tumors.

Prevalence of common chronic pain in Hong Kong adults.

OBJECTIVE: Chronic pain is prevalent in many Western countries. Its prevalence in a non-Caucasian population is not known. The authors performed this study to measure the prevalence of chronic pain in the Hong Kong Chinese adult population, as well as the pattern of pain and the demographic characteristics, the impact on social and work function, and the help-seeking behavior of those with pain. DESIGN: Cross-sectional survey using telephone interview with a structured questionnaire. Chronic pain was defined as pain persisting for more than 3 months. SUBJECTS: A random sample of over 1,000 persons out of the entire Chinese adult population of Hong Kong. RESULTS: One thousand fifty-one adults were interviewed. One hundred thirteen (10.8% [95% C.I.: 8.9%-12.7%]) had chronic pain. The median number of pains was two. Of those with chronic pain, 38.3% reported their work was affected, and 19.8% had taken a median of 5 days' sick leave in the past year; 70.8% said the pain had interfered with their daily life, 88.5% had tried self-treatment, and 74.3% had sought medical advice. Only 35.7% considered the treatment definitely helpful. Two risk factors were identified: the female gender (O.R. 1.5, 95% C.I. 1.0-2.3) and age greater than 60 (O.R. 2.2, 95% C.I. 1.3-3.6). CONCLUSIONS: The study showed that the prevalence of chronic pain in Hong Kong adults was approximately 10.8%. Work and daily life are significantly affected and there is considerable demand on the health care system. Despite the ethnic difference, the prevalence, pattern, and demographic characteristics of chronic pain in Hong Kong are very similar to those seen in Western countries.

Unidimensional pain rating scales: a multidimensional affect and pain survey (MAPS) analysis of what they really measure.

Pain is now regarded as 'the fifth vital sign' and patients are frequently asked to score the intensity of their pain on a numerical pain rating scale (NPRS). However, the use of a unidimensional scale is questionable in view of the belief, overwhelmingly supported by clinical experience as well as by empirical evidence from multidimensional scaling and other sources, that pain has at least two dimensions: somatosensory qualities and affect. We used a Chinese translation of the 101 descriptor multidimensional affect and pain survey (MAPS) questionnaire to determine the relative contributions of various dimensions of postoperative pain to a patient's score on a unidimensional NPRS. MAPS and NPRS were administered postoperatively to 69 patients with descending colon carcinoma who were recovering from left hemi-colectomy. Multiple linear regression revealed that the emotional pain qualities supercluster (P=0.0005) and four of its eight subclusters, anxiety, depressed mood, fear and anger, significantly (P=0.001-0.007) predicted a patient's score on the unidimensional NPRS. Notably, none of the 17 subclusters in the somatosensory pain qualities supercluster predicted NPRS scores. It may be concluded that patient scores on unidimensional pain intensity scales reflect the emotional qualities of pain much more than its sensory intensity or other qualities. Accordingly such scales are poor indicators of analgesic requirement. The results also suggest that patients' postoperative anxiety and depression are inadequately treated. Based on our findings we present six unidimensional scales that should yield a more accurate assessment of the sources of a patient's pain.