[Pain in cancer]

Patients with cancer often experience pain that significantly interferes with their daily life. In this review paper the authors discuss the different aspects of cancer pain by answering different questions regarding cancer pain. Items that are discussed include measurement of pain, medical and interventional pain treatment, side effects, opioid tolerance and addiction and barriers that preclude proper treatment of pain. The conclusion of this review paper is that the treatment of cancer pain is complex and warrants a multidisciplinary team effort with a central role for the patient.

Neuropathic‐like pain symptoms in inflammatory hand osteoarthritis lower quality of life and may not decrease under prednisolone treatment

Background

Pain is common in hand osteoarthritis (OA) and multiple types may occur. We investigated the prevalence, associated patient characteristics, influence on health‐related quality of life (HR‐QoL) and response to anti‐inflammatory treatment of neuropathic‐like pain in inflammatory hand OA.

Methods

Data were analysed from a 6‐week, randomized, double‐blind, placebo‐controlled trial investigating prednisolone treatment in 92 patients with painful inflammatory hand OA. Neuropathic‐like pain was measured with the painDETECT questionnaire. Associations between baseline characteristics and baseline neuropathic‐like pain were analysed with ordinal logistic regression, association of baseline neuropathic‐like pain symptoms with baseline HR‐QoL with linear regression, painDETECT and visual analogue scale (VAS) change from baseline to week 6 and interaction of painDETECT with prednisolone efficacy on VAS pain change from baseline to week 6 with generalized estimating equations (GEE).

Results

Of 91 patients (79% female, mean age 64) with complete painDETECT data at baseline, 53% were unlikely to have neuropathic‐like pain, 31% were indeterminate and 16% were likely to have neuropathic‐like pain. Neuropathic‐like pain was associated with female sex, less radiographic damage and more comorbidities. Patients with neuropathic‐like pain had lower HR‐QoL (PCS‐6.5 [95% CI −10.4 to −2.6]) than those without. Neuropathic‐like pain symptoms remained under prednisolone treatment and no interaction was seen between painDETECT and prednisolone efficacy on VAS pain.

Conclusions

In this study, 16% of inflammatory hand OA patients had neuropathic‐like pain. They were more often female, had more comorbidities and had lower QoL than those without. Neuropathic‐like pain symptoms remained despite prednisolone treatment and did not seem to affect the outcome of prednisolone treatment.

Significance

Pain is the dominant symptom in hand OA, with an unclear aetiology. In this study, we found that neuropathic‐like pain may play a role in hand OA, that it showed associations with female sex, younger age and more comorbidities and that it lowered health‐related quality of life in hand OA. Neuropathic‐like pain in hand OA seems resistant to prednisolone therapy but did not seem to interfere with the treatment of inflammatory pain with prednisolone.

POS0123 NEUROPATHIC PAIN SYMPTOMS IN INFLAMMATORY HAND OSTEOARTHRITIS(OA) LOWERS HEALTH RELATED PHYSICAL QUALITY OF LIFE AND MAY REQUIRE ANOTHER APPROACH THAN ANTI-INFLAMMATORY TREATMENT

Background:

Pain is a common, difficult to manage symptom in hand osteoarthritis (OA). Multiple pain mechanisms may play a role in hand OA.

Objectives:

To investigate presence of neuropathic pain symptoms in patients with inflammatory hand OA, characteristics of those patients, their impact on health related quality of life (HR-QoL), and the influence of anti-inflammatory treatment on neuropathic pain symptoms.

Methods:

Data from a randomised, double-blind, placebo-controlled trial of prednisolone including 92 patients with hand OA fulfilling ACR criteria were used. At baseline patients had signs of synovial inflammation, a VAS finger pain of ≥30 mm and who flared ≥20 mm upon NSAID washout. The primary endpoint was VAS finger pain (0-100) at week 6.

Neuropathic pain symptoms were measured at baseline and week 6 using the validated painDETECT questionnaire, consisting of questions on pain quality, pain intensity over time and radiating pain. Scores range -1 to 38 and patients are classified as having unlikely (<13), indeterminate (13-18) and likely (>18) neuropathic pain. HR-QoL was measured with physical component scale (PCS) of Short-Form 36 (SF36; 0-100), comorbidities with the Self-administered Comorbidities Questionnaire (SCQ; 0-45), radiographic severity with Kellgren-Lawrence (KL) sum score (0-120), and treatment response with OMERACT-OARSI responder criteria.

Association of patient characteristics with neuropathic pain symptoms was analysed with univariate and multivariate ordinal logistic regression, with painDETECT as dependent variable. Association of neuropathic pain symptoms with HR-QoL was analysed with multivariate linear regression, adjusted for age, sex, BMI, VAS finger pain, SCQ score and KL sum score, with PCS as dependent variable. Response of neuropathic pain symptoms and VAS pain to prednisolone was analysed with generalised estimating equations. Association of neuropathic pain symptoms at baseline with response to treatment was analysed using χ2-tests and GEE.

Results:

91 patients had complete painDETECT data at baseline (mean painDETECT score 12.8 [SD 5.9]). Scores were <13 in 53%, 13-18 in 31% and >18 in 16%. Higher painDETECT score categories were associated with less radiographic damage, more comorbidities, female sex and higher VAS finger pain in multivariate analysis. (table 1)

Table 1.

Ordinal logistic regression with painDETECT categories as dependent variable

VariablesMean (SD) N=91 (100%)Odds ratio (95% CI)Age64 (9)0.96 (0.90 to 1.02)Female sex; N (%)72 (79%)3.84 (1.19 to 12.39)*BMI; median (SD)27 (24 to 29)0.97 (0.89 to 1.06)SCQ score; median (SD)2 (1 to 5)1.04 (1.04 to 1.36)*VAS finger pain53.8 (2.1)1.02 (1.00 to 1.04)*KL sum score37 (16)0.96 (0.93 to 1.00)*

*p<0.05. BMI = body mass index. SCQ = Self-administered comorbidities questionnaire. VAS = visual analog scale. KL= Kellgren-Lawrence.

Patients with painDETECT scores >18 had a lower HR-QoL (PCS -6.5 [95%CI -10.4 to -2.6]) than those with painDETECT scores <13.

PainDETECT scores remained unchanged throughout the trial in both prednisolone-treated and placebo-treated patients, and there was no between-group difference at week 6. VAS pain improved more in the prednisolone group than in the placebo group (mean between-group difference -16.5 [95%CI -26.1 to -6.9]) (figure 1). No association between the presence of neuropathic pain symptoms at baseline and OMERACT-OARSI response to treatment was found.

Conclusion:

Patients with inflammatory hand OA and additional neuropathic pain symptoms are more often female and have more comorbidities, and report a lower QoL, than those without. Neuropathic pain symptoms seem unresponsive to anti-inflammatory therapy. Clinicians should be aware of neuropathic pain symptoms in their patients as they might benefit from additional, specific treatment.

Acknowledgements:

The authors thank all patients for their participation in the HOPE study, and participating rheumatologists for inclusion of patients in the HOPE study. We also thank research nurses B.A.M.J. van Schie-Geyer and S. Wongsodihardjo, and technicians J.C. Kwekkeboom and E.I.H. van der Voort, for their contributions.

Disclosure of Interests:

Coen van der Meulen: None declared, Lotte van de Stadt: None declared, Féline Kroon: None declared, Marion Kortekaas: None declared, Annelies Boonen Speakers bureau: Lecture for UCB; paid to department., Consultant of: Yes. Advisory board meetings at Galapagos, Eli Lilly and Abvvie; paid to department., Grant/research support from: Yes. Grants by Celgene and Abbvie; paid to department., Stefan Böhringer: None declared, Marieke Niesters: None declared, Monique Reijnierse: None declared, Frits Rosendaal: None declared, Naghmeh Riyazi: None declared, M. Starmans: None declared, Franktien Turkstra: None declared, Jende van Zeben: None declared, Cornelia Allaart: None declared, Margreet Kloppenburg Consultant of: For Abbvie, Pfizer, Levicept, GlaxoSmithKline, Merck-Serono, Kiniksa, Flexìon, Galapagos, Jansen, CHDR and local investigator of industry-driven trial (Abbvie). All fees were paid to the institution., Grant/research support from: Grant by the Dutch Arthritis Society

[Postoperative opioid overdose due to patient-controlled analgesia by proxy]

Patient-controlled analgesia (PCA) is a popular and efficacious form of postoperative pain relief that, however, is not without complications. Here we describe a 73-year-old Somalian male patient that underwent abdominal surgery and received intravenous morphine PCA for postoperative pain relief. Due to his inability to speak the native language, his son served as interpreter. On the day after surgery, the patient was found unresponsive by the nursing staff with an oxygen saturation of 91%. He was treated with naloxone and transferred to a medium care facility. The son indicated that he had operated the PCA system at regular intervals over the last 12 hours. The dangers of PCA and PCA by proxy in particular are discussed. In this case, the language barrier, and possibly cultural differences and health illiteracy may have contributed to the PCA by proxy.

Safety of sugammadex for reversal of neuromuscular block

Introduction: Sugammadex is a modified cyclodextrin that is able to reverse neuromuscular block induced by aminosteroidal neuromuscular blocking drugs. Compared to reversal with neostigmine, it reverses neuromuscular block quicker and more predictable and without cholinergic side effects. However, there have been concerns about sugammadex ability to bind other drugs and its effects on QT interval and clotting times. In addition, sugammadex might induce hypersensitivity reactions more frequently than initially anticipated. This review summarizes current evidence with regard to these and other safety aspects of sugammadex. Areas covered: This review provides an overview of the efficacy of sugammadex in various patient populations, evaluates potential interactions with other drugs and discusses adverse effects and reactions that have been reported in the literature. Expert opinion: Sugammadex quickly reverses aminosteroid neuromuscular block with less side effects compared to neostigmine. As such, it has the potential to significantly reduce the incidence of residual neuromuscular block and to improve postoperative pulmonary outcome. Current safety concerns mainly focus on hypersensitivity reactions and cardiac arrhythmias. Although the absolute risk for these events is low, ongoing vigilance and research in this area are needed.

[Not Available]

OBJECTIVE To evaluate the effect of an ice-lolly on acute postoperative pain. DESIGN Randomised prospective intervention study. METHOD A total of 100 patients scheduled for an elective laparoscopic cholecystectomy were recruited to participate in the study. Patients were randomised to receive either an ice-lolly or no treatment after arrival at the post-anaesthesia care unit. The analgesic requirements (opioid and non-opioid), pain scores, and the presence of nausea and vomiting were registered on the post- anaesthesia care unit and ward during the first 24 hours after surgery. This study is registered in the Nederlands Trial Register under number NTR5335. RESULTS In the post-anaesthesia care unit, pain scores did not differ between patients who received an ice-lolly and those who did not. The opioid requirements of patients who had consumed an ice-lolly were significantly lower than those of the patients who had not (cumulative piritramide dose: 4.9 (SD 4.2) with ice-lolly vs. 6.6 (SD 4.0) without ice-lolly mg; P = 0.04). Furthermore, patients who did not receive an ice-lolly required more additional pain relief with non-opioid analgesics than patients who had been given an ice- lolly (31% vs. 10%; P = 0.01). Combining all administered opioid and non-opioid analgesics into one analgesic composite score showed that patients who received an ice-lolly required significantly fewer analgesics in the post-anaesthesia care unit than patients who had not been given an ice-lolly (2.2 (SD 1.7) vs. 2.9 (SD 1.8); P = 0.03). No differences between the groups in pain scores or use of analgesics were observed on the ward in the first 24 hours postoperatively. CONCLUSION The postoperative consumption of an ice-lolly reduces postoperative opioid and non-opioid analgesic requirements in the post- anaesthesia care unit. Conflict of interest and financial support: none declared.

A randomized controlled trial and novel mathematical analysis of the analgesic effect of oxycodone versus paracetamol orodispersible tablets

BACKGROUND

For effective treatment of acute pain, a rapid onset of action is important. Here we quantify the antinociceptive profile of an orodispersible oxycodone tablet (OOT) in a randomized, double-blind, active comparator (paracetamol orodispersible tablet, POT), crossover study design in a population of healthy volunteers.

METHODS

Twelve female volunteers were randomized to receive 20 mg OOT and 500 mg POT sublingually on two occasions. The electrical pain threshold (EPTh), electrical pain tolerance (EPTol) and pressure pain threshold (PPT) were obtained at regular intervals for 5 h. Time-response data were analysed with a longitudinal pharmacodynamic model characterized by rate constants for analgesia onset (kON ), offset (kOFF ), potency parameter (EFF) and validated with a bootstrap analysis. Values are the median (95% CI) as derived from the bootstrap analysis.

RESULTS

OOT produced a rapid increase in response values. For electrical pain analgesia onset, t½kON , 44 (25-67) versus analgesia offset, t½kOFF , 156 (63-552) min, p < 0.01. For pressure pain, t½kON equalled t½kOFF : 30 (16-48) min. OOT was most potent on EPTol: EFF 0.95 (0.39-1.71), p < 0.01, with similar potencies on EPTh, 0.43 (0.19-0.87) and PPT, 0.40 (0.21-0.67). Paracetamol displayed 14% of the analgesic efficacy of oxycodone.

CONCLUSIONS

The analgesic effect of orodispersible oxycodone was successfully quantified using a mathematical model of analgesia evolution. This method allows quantification of a variety of responses times from sparse data sets. Response times as defined by a 30% increase in response thresholds varied significantly among end points: EPTol 15 min, PPTh 18 min and EPTh 41 min.

Tapentadol potentiates descending pain inhibition in chronic pain patients with diabetic polyneuropathy

BACKGROUND

Tapentadol is an analgesic agent for treatment of acute and chronic pain that activates the µ-opioid receptor combined with inhibition of neuronal norepinephrine reuptake. Both mechanisms are implicated in activation of descending inhibitory pain pathways. In this study, we investigated the influence of tapentadol on conditioned pain modulation (CPM, an experimental measure of endogenous pain inhibition that gates incoming pain signals as a consequence of a preceding tonic painful stimulus) and offset analgesia (OA, a test in which a disproportionally large amount of analgesia becomes apparent upon a slight decrease in noxious heat stimulation).

METHODS

Twenty-four patients with diabetic polyneuropathy (DPN) were randomized to receive daily treatment with tapentadol sustained-release (SR) [average daily dose 433 (31) mg] or placebo for 4 weeks. CPM and OA were measured before and on the last day of treatment.

RESULTS

Before treatment, none of the patients had significant CPM or OA responses. At week 4 of treatment, CPM was significantly activated by tapentadol SR and coincided with significant analgesic responses. CPM increased from 9.1 (5.4)% (baseline) to 14.3 (7.2)% (placebo) and 24.2 (7.7)% (tapentadol SR, P<0.001 vs placebo); relief of DPN pain was also greater in patients treated with tapentadol than placebo (P=0.028). Neither placebo nor tapentadol SR treatment had an effect on the magnitude of the OA responses (P=0.78).

CONCLUSIONS

Tapentadol's analgesic effect in chronic pain patients with DPN is dependent on activation of descending inhibitory pain pathways as observed by CPM responses.

CLINICAL TRIAL REGISTRATION

The study was registered at trialregister.nl under number NTR2716.

Influence of ketamine and morphine on descending pain modulation in chronic pain patients: a randomized placebo-controlled cross-over proof-of-concept study

BACKGROUND

Descending inhibition of pain, part of the endogenous pain modulation system, is important for normal pain processing. Dysfunction is associated with various chronic pain states. Here, the effect of ketamine and morphine on descending inhibition is examined using the conditioned pain modulation (CPM) paradigm in chronic neuropathic pain patients.

METHODS

CPM responses were obtained in 10 adult neuropathic pain subjects (two men/eight women). All subjects had peripheral neuropathy as defined by abnormal quantitative sensory testing. The effects of S(+)-ketamine (0.57 mg kg(-1) h(-1) for 1 h) and morphine (0.065 mg kg(-1) h(-1) for 1 h) were tested in a randomized, placebo-controlled double-blind study. CPM was measured at baseline and 100 min after the start of treatment and was induced by immersion of the leg into a cold-water bath. The test stimulus was a 30 s static thermal stimulus to the skin of the forearm.

RESULTS

Without treatment, no CPM was detectable. Treatment with ketamine, morphine, and placebo produced CPM responses of 40.2 (10.9)%, 28.5 (7.0)%, and 22.1 (12.0)%, respectively (for all treatments, CPM effect P<0.05), with no statistical difference in the magnitude of CPM among treatments. The magnitude of CPM correlated positively with the magnitude and duration of spontaneous pain relief.

CONCLUSIONS

The observed treatment effects in chronic pain patients suggest a role for CPM engagement in analgesic efficacy of ketamine, morphine, and placebo treatment.

Differences in telomerase expression by the CD1a+ cells in Langerhans cell histiocytosis reflect the diverse clinical presentation of the disease

Langerhans cell histiocytosis (LCH) is a disease characterized by an uncontrolled clonal proliferation of Langerhans cells, whose aetiology is still unclear. The clonal nature of LCH could support the hypothesis that it is a neoplastic disease with unlimited growth potential. One requirement for unlimited proliferation is the maintenance of telomere length. In a group of 70 patients, we set out to investigate whether a telomere maintenance mechanism is indeed active in LCH cells. This work showed that LCH cells from all restricted skin LCH lesions (6/6) expressed telomerase as assessed by human telomere reverse transcriptase (hTERT) immunohistochemistry, whereas LCH cells from the majority of the bone lesions analysed did not express hTERT (26/34). Interestingly, in contrast to the solitary bone lesions, LCH cells from lesions of multi-system patients always expressed telomerase (11/11), regardless of the lesional site. In situ telomeric repeat amplification protocol (TRAP) assays performed on different lesional sites showed that this telomerase was active. In addition, the telomere length of LCH cells from a hTERT-positive skin multi-system lesion was long and homogeneous when compared to that in the LCH cells from hTERT-negative bone single-system LCH lesions, which was heterogeneous in length. No evidence for an alternative lengthening of telomeres mechanism was found in hTERT-negative lesions. The difference in telomerase expression and telomere length at the different lesional sites and in biopsies from patients with solitary versus multi-system disease appears to reflect the diverse clinical presentation and course of this disease. The results from this study have important implications for understanding the nature of this disease.