Ameliorating effect of antioxidants and pregabalin combination in pain recurrence after ductal clearance in chronic pancreatitis: Results of a randomized, double blind, placebo-controlled trial

Progress in treatment of chronic pancreatitis: A review based on the ClinicalTrials.gov database

Chronic pancreatitis (CP) is a chronic progressive fibro-inflammatory disease of the pancreas caused by various etiologies, characterized by recurrent upper abdominal pain and pancreatic exocrine dysfunction. ClinicalTrials.gov is the most commonly used clinical trial database, including information of clinical trials which have been completed or are ongoing, or upcoming. Based on the ClinicalTrials.gov database, we retrieved all clinical studies registered before June 30, 2024, screened out recent clinical studies related to CP, and summarized and integrated highlights and directions of these studies from the perspectives of nutritional support, medication, endoscopy, etc., aiming to provide new ideas for the design of CP clinical studies in the future.

Pain management in chronic pancreatitis

Pain in chronic pancreatitis (CP) is difficult to manage. Many patients suffer from inadequate pain relief, completely incapacitating them in their daily activities. Historically, despite their well-known adverse effects, opioids have been the pillar of treatment regimens in painful CP. The management is now gradually evolving with a better understanding of the underlying pathophysiology of CP-related pain. Clinicians should follow a holistic approach to the management of CP-associated pain, which must involve lifestyle changes that are coupled with analgesic medications and other pain-relieving interventions. Furthermore, there is no easy cure for vanquishing CP-associated pain. Each patient must be evaluated on a case-by-case basis by a multidisciplinary team to decide which treatment option is best suited for that individual.

Management of chronic pancreatitis: recent advances and future prospects

As a progressive fibroinflammatory disease, chronic pancreatitis (CP) often manifests as recurrent bouts of abdominal pain with or without complications, causing a heavy burden of health care. In recent years, some meaningful insights into the management of CP have been obtained from randomized controlled trials, systematic reviews, and meta-analyses, which were of great importance. Based on this research, it is shown that there are various treatments for CP. Therefore, it is of great importance to choose a suitable strategy for patients with CP individually. Relevant evidence on the management of CP was summarized in this review, including nutrition supplements, medication, endoscopy, surgery, exploration of novel therapies as well as evaluation and prediction of treatment response.

Overlap and cumulative effects of pancreatic duct obstruction, abnormal pain processing and psychological distress on patient-reported outcomes in chronic pancreatitis

OBJECTIVE

Several factors have been suggested to mediate pain in patients with chronic pancreatitis. However, it is unknown whether these factors are overlapping and if they have cumulative effects on patient-reported outcomes (PROs).

DESIGN

We performed a multicentre cross-sectional study of 201 prospectively enrolled subjects with definitive chronic pancreatitis. All subjects underwent evaluation for pancreatic duct obstruction, abnormalities in pain processing using quantitative sensory testing, and screening for psychological distress (anxiety, depression and pain catastrophising) based on validated questionnaires. Abnormality was defined by normal reference values. PROs included pain symptom severity (Brief Pain Inventory short form) and quality of life (EORTC-QLQ-C30 questionnaire). Associations between pain-related factors and PROs were investigated by linear trend analyses, multiple regression models and mediation analyses.

RESULTS

Clinical evaluation suggestive of pancreatic duct obstruction was observed in 29%, abnormal pain processing in 23%, anxiety in 47%, depression in 39% and pain catastrophising in 28%; each of these factors was associated with severity of at least one PRO. Two or more factors were present in 51% of subjects. With an increasing number of factors, there was an increase in pain severity scores (p<0.001) and pain interference scores (p<0.001), and a reduction in quality of life (p<0.001). All factors had independent and direct effects on PROs, with the strongest effect size observed for psychological distress.

CONCLUSION

Pain-related factors in chronic pancreatitis are often present in an overlapping manner and have a cumulative detrimental effect on PROs. These findings support a multidisciplinary strategy for pain management.

TRIAL REGISTRATION NUMBER

The study was registered with ClinicalTrials.gov (NCT03434392).

Optimizing nutrition in chronic pancreatitis

PURPOSE OF REVIEW

This review aims to discuss recent developments in the nutritional management in chronic pancreatitis.

RECENT FINDINGS

Nutritional assessment should be comprehensive and include dietary history, anthropometry, and biochemical nutritional parameters. Micronutrients should be evaluated at least yearly and dual-energy X-ray absorptiometry (DEXA) at every 2-yearly intervals. Studies on pancreatic enzyme replacement therapy (PERT) have primarily evaluated coefficient of fat excretion (CFA), coefficient of nitrogen excretion (CNA), and stool weight. Two RCTs, in which patients were treated with PERT for 7 days in a blinded manner and subsequently extended for 6-12 months in an open-label manner, showed improvement in nutritional parameters. However, two subsequent RCTs failed to show any benefit, and the most recent observational study demonstrated persistence of malnutrition even after PERT. The reason for the latter findings were nonadherence to PERT and poor oral intake of calories. Therefore, it is essential to educate the patients on adherence, counsel on taking high-protein, high-calorie diet, and supplement nutrients in those with inadequate oral intake. Other associated manifestations, such as diabetes and related complications, and anxiety/depression could also contribute to malnutrition directly or indirectly, and should, therefore, be adequately managed.

SUMMARY

Nutritional assessment should be performed meticulously. Nutritional therapy should not be restricted to only PERT and nutritional supplementation, but should also include dietary counselling and disease related education.

Efficacy and Predictors of Pain Response to Combined Antioxidants in Children with Chronic Pancreatitis

BACKGROUND

Pain is a major problem in 90% of patients with chronic pancreatitis (CP). Studies evaluating response to antioxidants (AO) are conflicting and no pediatric studies are available.

AIMS

To evaluate markers of oxidative stress (OS), and efficacy and predictors of response to AO in improving pain in children with CP.

METHODS

Antioxidants were given to CP children for 6 months. Subjects were assessed at baseline and post-therapy for pain and markers of OS [serum thiobarbituric acid reactive substances (TBARS), superoxide dismutase (S-SOD)] and antioxidant levels [vitamin C, selenium, total antioxidant capacity-ferric reducing ability of plasma (FRAP)]. Matched healthy controls were assessed for OS and antioxidant levels. Good response was defined as ≥ 50% reduction in number of painful days/month.

RESULTS

48 CP children (25 boys, age 13 years) and 14 controls were enrolled. 38/48 cases completed 6 months of therapy. CP cases had higher OS [TBARS (7.8 vs 5.2 nmol/mL; p < 0.001)] and lower antioxidant levels [FRAP (231 vs. 381.3 µmol/L; p = 0.003), vitamin C (0.646 vs. 0.780 mg/dL; p < 0.001)] than controls. Significant reduction in TBARS and S-SOD and increase in FRAP, vitamin C, and selenium occurred after 6 months. 10.5% cases had minor side effects. 26(68%) cases had a good response, with 9(24%) becoming pain-free. Subjects with severe ductal changes had lower median BMI (- 0.73 vs 0.10; p = 0.04) and responded less often than those with mild changes (17/29 vs 9/9; p = 0.036).

CONCLUSION

CP children have higher OS than healthy controls. Antioxidant therapy is safe. Pain response is seen in 68% cases, less often in patients with severe ductal changes.

Outpatient Pain Management in Children With Chronic Pancreatitis: A Scoping Systematic Review

OBJECTIVES

Although pain management is central to pediatric chronic pancreatitis (CP) care, no evidence-based guidelines exist. In this scoping systematic review, we sought promising strategies for CP pain treatment in children.

METHODS

We systematically reviewed literature on pain management in children and adults with CP, and 2 conditions with similar pain courses: juvenile idiopathic arthritis and sickle cell disease.

RESULTS

Of 8997 studies identified, 287 met inclusion criteria. There are no published studies of analgesic medications, antioxidants, dietary modification, integrative medicine, or regional nerve blocks in children with CP. In adults with CP, studies of nonopioid analgesics, pancreatic enzymes, and dietary interventions have mixed results. Retrospective studies suggest that endoscopic retrograde cholangiopancreatography and surgical procedures, most durably total pancreatectomy with islet autotransplant, improve pain for children with CP. Follow-up was short relative to a child's life. Large studies in adults also suggest benefit from endoscopic therapy and surgery, but lack conclusive evidence about optimal procedure or timing. Studies on other painful pediatric chronic illnesses revealed little generalizable to children with CP.

CONCLUSIONS

No therapy had sufficient high-quality studies to warrant untempered, evidence-based support for use in children with CP. Multicenter studies are needed to identify pain management "best practices."

Evidence-based clinical practice guidelines for chronic pancreatitis 2021

BACKGROUND

Chronic pancreatitis (CP) is defined according to the recently proposed mechanistic definition as a pathological fibro-inflammatory syndrome of the pancreas in individuals with genetic, environmental, and/or other risk factors who develop persistent pathological responses to parenchymal injury or stress.

METHODS

The clinical practice guidelines for CP in Japan were revised in 2021 based on the 2019 Japanese clinical diagnostic criteria for CP, which incorporate the concept of a pathogenic fibro-inflammatory syndrome in the pancreas. In this third edition, clinical questions are reclassified into clinical questions, background questions, and future research questions.

RESULTS

Based on analysis of newly accumulated evidence, the strength of evidence and recommendations for each clinical question is described in terms of treatment selection, lifestyle guidance, pain control, treatment of exocrine and endocrine insufficiency, and treatment of complications. A flowchart outlining indications, treatment selection, and policies for cases in which treatment is ineffective is provided. For pain control, pharmacological treatment and the indications and timing for endoscopic and surgical treatment have been updated in the revised edition.

CONCLUSIONS

These updated guidelines provide clinicians with useful information to assist in the diagnosis and treatment of CP.

Pancreatic QST Differentiates Chronic Pancreatitis Patients into Distinct Pain Phenotypes Independent of Psychiatric Comorbidities

BACKGROUND & AIMS

Quantitative sensory testing (QST) has been previously used to study pain in chronic pancreatitis (CP) but included methods that are not suitable for clinical purposes. The aims of this study were to determine if pancreatic QST (P-QST) can differentiate patients into distinct pain phenotypes and to determine the association of these with their clinical pain and psychiatric comorbidities.

METHODS

A multicenter cross-sectional study was conducted where patients completed validated questionnaires assessing quality of life (QoL), depression and anxiety scores as well as clinical pain symptoms followed by P-QST which included a cold pressor test, repetitive pinprick stimuli and pressure stimulation of the upper abdominal (T10) and control dermatomes. P-QST categorized patients into pain phenotypes based on a previously established nomogram. QoL, clinical pain and psychiatric assessment scores were compared across these groups.

RESULTS

A total of 179 patients were enrolled with a mean age of 54.1±13.6 years among whom 59% were males and 42% had an alcoholic etiology. P-QST showed no hyperalgesia in 91 (51%), segmental hyperalgesia in 50 (28%) and widespread hyperalgesia in 38 (21%) patients. Patients with widespread hyperalgesia had significantly higher pain intensity scores (P = .03) and rates of constant pain (P = .002) as well as decreased QoL (P < .001) and physical functioning (P =.03) in comparison with the other two pain phenotypes. In contrast, psychiatric comorbidities were similar across all groups.

CONCLUSIONS

P-QST may serve as a novel unbiased pain assessment tool in CP as it categorizes patients into distinct pain phenotypes independent of their psychiatric comorbidities.

Efficacy of Pregabalin and Antioxidants Combination in Reducing Pain in Chronic Pancreatitis: A Double Blind Randomized Trial

BACKGROUND

In patients with chronic pancreatitis (CP), pain relief is a dilemma. Antioxidants with pregabalin therapy have been reported to be useful. Hence, this study was carried out to determine the efficacy of the combination of antioxidant and pregabalin therapy in reducing pain in patients with CP.

METHODS

This was a prospective, double blind, superiority, and randomized trial in patients with CP. The treatment group received pregabalin with antioxidants therapy for 8 weeks, and a similar placebo was administered to the controls. Primary outcome was to determine the change in maximum pain intensity assessed by visual analog scale (VAS) and Izbicki pain score. Secondary outcomes were the number of painful days, opioid and non-opioid requirements, improvement in quality of life, number of hospital admission, and overall patient satisfaction.

RESULTS

A total of 90 patients were randomized to 45 in each arm. Demographic profile and baseline pain score were comparable. Patients in treatment group when compared to placebo group had a significant reduction in pain intensity (VAS score 2 ± 0.8 vs. 1.3 ± 0.9; p = 0.007), non-opioid analgesic requirement in days (54.4±2.9 vs. 55.7±1.5; p = 0.014), and number of hospital admissions (0.2 ± 0.5 vs. 0.6 ± 0.7; p = 0.002), respectively. Significant proportion of patients was satisfied in the treatment group compared to placebo group (18% vs. 11%; p = 0.03).

CONCLUSION

The combination of pregabalin and antioxidant significantly reduces the pain, requirement of non-opioid analgesics, and the number of hospital admissions in patients with CP. It also significantly improves the overall patient satisfaction.

CLINICAL TRIALS REGISTER NUMBER

CTRI/2017/05/008492.

Assessment of pain associated with chronic pancreatitis: An international consensus guideline

Pain is the most common symptom in chronic pancreatitis (CP) with a major impact on quality of life. Few validated questionnaires to assess pain in CP exist, and the lack of consensus negatively impacts clinical management, research and meta-analysis. This guideline aims to review generic pain questionnaires for their usability in CP, to outline how pain assessment can be modified by confounding factors and pain types, to assess the value of additional measures such as quality of life, mental health and quantitative sensory testing, and finally to review pain assessment questionnaires used specifically in CP. A systematic review was done to answer 27 questions that followed the PICO (Population; Intervention; Comparator; Outcome) template. Quality of evidence of the statements was judged by Grades of Recommendation, Assessment, Development and Evaluation (GRADE) criteria. The manuscript was sent for review to 36 experts from various disciplines and continents in a multi-stage Delphi process, and finally reviewed by patient representatives. Main findings were that generic pain instruments are valid in most settings, but aspects of pain are specific for CP (including in children), and instruments have to account for the wide phenotypic variability and development of sensitization of the central nervous system. Side effects to treatment and placebo effects shall also be considered. Some multidimensional questionnaires are validated for CP and are recommended together with assessment of quality of life and psychiatric co-morbidities. This guideline will result in more homogeneous and comprehensive pain assessment to potentially improve management of painful CP.

Chronic Pancreatitis: Epidemiology, Diagnosis, and Management Updates

Chronic pancreatitis is a clinical entity that results from the progressive inflammation and irreversible fibrosis of the pancreas resulting from the cumulative injury sustained by the pancreas over time. It is an illness with variable presentations that can severely impact quality of life, while its long-term complications such as exocrine pancreatic insufficiency (EPI), diabetes mellitus, and risk of pancreatic cancer can become life threatening. The diagnosis of chronic pancreatitis can be challenging as despite the recent advancements in imaging technology, the radiographic findings do not become prominent until late stages of disease. Thus, the physicians' clinical acumen in obtaining thorough history taking focusing on risk factors, clinical symptoms, in addition to high-quality imaging, often guide to the accurate diagnosis of chronic pancreatitis. Endoscopy also plays a pivotal role in the diagnosis and management of chronic pancreatitis. Endoscopic ultrasound (EUS) is believed to be the most sensitive modality for diagnosing chronic pancreatitis. Despite efforts, however, natural history studies have demonstrated that 61% of individuals with chronic pancreatitis will require at least one endoscopic intervention, while 31% will require a surgical procedure as part of their management strategy. Recent advancements in genomic studies have furthered our understanding of the genetic polymorphisms that are associated with the pathogenesis of chronic pancreatitis. Genetic testing offers the potential to reveal treatable pancreatitis-related disorders, and can inform decision making with regard to radical therapies for persistent or severe disease such as total pancreatectomy with islet autotransplantation (TPIAT). The management of patients suffering from chronic pancreatitis often requires a multi-disciplinary approach, addressing pertinent symptoms as well as the sequelae of chronic inflammation and fibrosis. Abdominal pain is the prevailing symptom and most common complication of chronic pancreatitis, and impairs quality of life. Although heavily dependent on a wide range of analgesia, endoscopic treatment such as endoscopic retrograde cholangiopancreatography (ERCP) and surgical intervention can offer long-lasting relief of symptoms. For EPI, treatment with pancreatic enzyme supplements offers marginal-to-moderate relief. The most feared complication of chronic pancreatitis-the development of pancreatic cancer-has no known prevention measure to date.

Pain management in chronic pancreatitis incorporating safe opioid practices: Challenge accepted

Patients with chronic pancreatitis often experience severe, unrelenting abdominal pain, which can significantly impact their quality of life. Pain control, therefore, remains central to the overall management of chronic pancreatitis. Most of the strategies aimed at treating the pain of chronic pancreatitis are based on expert opinion and vary from one institution to another, as there are no uniform guidelines to direct a stepwise approach towards achieving this goal. In this editorial, we comment on best practice strategies targeted towards pain control in chronic pancreatitis, specifically highlighting the use of opioid medications in this patient population. We discuss various safe and efficacious prescription monitoring practices in this article.

The antioxidant N-(2-mercaptopropionyl)-glycine (tiopronin) attenuates expression of neuropathic allodynia and hyperalgesia

The current pharmacotherapy of neuropathic pain is inadequate as neuropathic pain involves varied clinical manifestations with multifactorial etiology, modulated by a cascade of physical and molecular events leading to different clinical presentations of pain. There is an accumulating evidence of the involvement of oxidative stress in neuropathy, and antioxidants have shown promise in mitigating neuropathic pain syndromes. To explore the evidence supporting this beneficial proclivity of antioxidants, this study investigated the antinociceptive effectiveness of N-(2-mercaptopropionyl)glycine or tiopronin, a well-recognized aminothiol antioxidant, in a refined chronic constriction injury (CCI) rat model of neuropathic pain. Tiopronin (10, 30, and 90 mg/kg, i.p.) and pregabalin (30 mg/kg, i.p.) were administered daily after CCI surgery. The neuropathic paradigms of mechanical/cold allodynia and mechanical/heat hyperalgesia were assessed on days 3, 7, 14, and 21 post-nerve ligation. At the end of study, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels were estimated in the sciatic nerve, dorsal root ganglion, and spinal cord for assessing the extent of oxidative stress. The expression of neuropathic nociception was attenuated by tiopronin which was observed as a significant attenuation of CCI-induced allodynia and hyperalgesia. Tiopronin reversed the neuronal oxidative stress by significantly reducing MDA, and increasing SOD, CAT, and GSH levels. Pregabalin also showed similar beneficial propensity on CCI-induced neuropathic aberrations. These findings suggest prospective neuropathic pain attenuating efficacy of tiopronin and further corroborated the notion that antioxidants are effective in mitigating the development and expression of neuropathic pain and underlying neuronal oxidative stress.

Conservative Treatment of Chronic Pancreatitis: A Practical Approach

BACKGROUND

Chronic pancreatitis is a long-standing, inflammatory condition of the pancreas that leads to the progressive damage and loss of function of pancreatic parenchyma and to the development of possible locoregional and systemic medical complications.

MATERIALS AND METHODS

In this review, we tried to summarize the current evidence on non-surgical treatment trying to suggest a practical approach to the management of chronic pancreatitis.

RESULTS

Besides the unclear pathophysiological mechanism and a poorly unknown epidemiology, chronic pancreatitis is a complex syndrome that displays different possible challenges for physicians. Despite being traditionally considered as a benign disease, chronic pancreatitis encompasses 10-year mortality rates which are superior to the ones reported for some of the most common cancers.

CONCLUSIONS

Chronic pancreatitis encompasses the management of multiple and complex medical co-morbidities that needs to be understood and addressed in a multidisciplinary specialist context.

Psychiatric Comorbidity in Patients With Chronic Pancreatitis Associates With Pain and Reduced Quality of Life

INTRODUCTION

Abdominal pain, frequent in patients with chronic pancreatitis (CP), has a negative impact on quality of life (QOL). Psychiatric comorbidities including anxiety and depression are associated with pain, but their prevalence and effects on QOL in CP have not been quantified. We studied the prevalence of anxiety and depression in patients with CP and their associated patient and disease characteristics and impact on QOL.

METHODS

This was a cross-sectional, multicenter prospective study. Patients were screened with the Hospital Anxiety and Depression Scale questionnaire. A Hospital Anxiety and Depression Scale score >7 on the respective anxiety or depression subscales indicated the presence of anxiety or depression and was used as a surrogate for the diagnosis of psychiatric comorbidities. Patient demographics, disease characteristics, QOL (EORTC-QLQ-C30), and pain symptoms (Brief Pain Inventory Short Form) were compared between patients with and without psychiatric comorbidities.

RESULTS

One hundred seventy-one patients with CP (mean age 53.8 ± 13.7 years, 60% men) were included. Anxiety and depression were present in 80 (46.8%) and 66 (38.6%) patients, with overlap in 50 (29%). Patients with anxiety or depression reported higher pain prevalence, pain severity, and pain interference scores (all P < 0.001). Psychiatric comorbidities also associated with reduced global health scores and functional subscales (all P < 0.001) and higher symptom burden (P ≤ 0.03). An independent association was noted between global health status and depression (P < 0.001).

DISCUSSION

Psychiatric comorbidities are prevalent in patients with CP and associated with pain and QOL. Where the effect of anxiety on QOL may be mediated via pain, depression is independently related to QOL. These findings warrant consideration in the management of patients with CP.

Chronic pancreatitis: an overview of diagnosis and management

INTRODUCTION

Chronic pancreatitis entails a heavy burden on the healthcare system because of its often protracted evolution, requiring complex diagnostic and therapeutic procedures.

AREAS COVERED

This review focuses on novel imaging and endoscopic diagnostic and therapeutic interventions that have changed the management of patients with chronic pancreatitis. We have conducted an extensive search of original papers and guidelines, in order to provide a comprehensive and up to date review of available evidence in these areas of interest.

EXPERT OPINION

The traditional challenges in managing chronic pancreatitis patients stemmed from the limitations of diagnostic modalities, which could not correctly identify patients in an early stage of the disease, as well as from the scarcity of therapeutic options available. Advances in imaging of CT-scan, MRI, and EUS have opened the way for early diagnosis and staging. This has allowed more aggressive and tailored therapeutic modalities, particularly in endoscopic therapy and minimally invasive surgical interventions. Although high-quality data from large RCTs is still scarce, evidence-based algorithms for diagnosis and therapy are now changing the way we address this chronic disease. In the near future, we can expect a tailored approach based on patient and disease-related predictive factors, relying on a vast armamentarium of endoscopic and surgical solutions.

Combined extracorporeal shock wave lithotripsy and endoscopic treatment for pain in chronic pancreatitis (SCHOKE trial): study protocol for a randomized, sham-controlled trial

Background

Pain is the primary symptom of chronic pancreatitis (CP) and remains a considerable therapeutic challenge. In patients with obstruction of the pancreatic duct, including stones and strictures, endoscopic treatment with or without preceding extracorporeal shock wave lithotripsy (ESWL) has been used for pancreatic duct decompression. The rationale for these procedures is based on the assumption that obstruction of the pancreatic duct leads to ductal hypertension and pain. However, clinical pain symptoms correlate poorly with pancreatic duct morphology, and the evidence for pancreatic duct decompression as an effective treatment for pain is based on case series and comparison between different procedures. No randomized, prospective, sham-controlled trials are currently available. The SCHOKE (Extracorporeal Shock Wave Lithotripsy and Endotherapy for Pain in Chronic Pancreatitis) trial is a randomized, sham-controlled trial designed to determine if pancreatic duct decompression is an effective treatment for pain in patients with CP.

Methods

The SCHOKE trial is a randomized, single-blind, parallel-group, sham-controlled trial designed to evaluate the effect of combined ESWL and endoscopic treatment for pain in patients with CP. In total, 106 adult patients with painful CP and pancreatic duct obstruction will be randomized to combined ESWL and subsequent endoscopic treatment or corresponding sham procedures. The primary outcome is pain relief during the 3-month postrandomization period as documented in a pain diary. Secondary outcomes include quality of life and functional scores, patient global impression of change, change in use of analgesics, frequency of hospitalization, and complications. Standard follow-up is at 3 and 6 months after randomization. In an experimental substudy, quantitative sensory testing obtained before and after intervention will be used to obtain information on central pain processing and to develop models for prediction of treatment outcome.

Discussion

The SCHOKE trial investigates if pancreatic duct decompression, obtained by combined ESWL and endoscopic treatment, is effective for pain treatment in patients with CP.

Trial registration

ClinicalTrials.gov, NCT03966781. Registered on May 25, 2019.

Protocol date and version identifier: March 1, 2020; version 3.0.

Sponsor: Rupjyoti Talukdar, Department of Medical Gastroenterology, Asian Institute of Gastroenterology, Hyderabad, Telangana, India.

A clinically feasible method for the assessment and characterization of pain in patients with chronic pancreatitis

BACKGROUND AND AIMS

Pain is the primary symptom of chronic pancreatitis (CP), but methods for sensory testing and pain characterization have not previously been validated for clinical use. We present a clinically feasible method for the assessment and characterization of pain mechanisms in patients with CP based on quantitative sensory testing (QST).

METHODS

This was a cross-sectional, multicenter study of 122 control subjects without pancreatic disease and another 60 patients with painful CP. All subjects underwent standardized QST assessments including a cold pressor test, a conditioned pain modulation paradigm, repetitive pin-prick stimuli (temporal summation) and pressure stimulation of the upper abdominal (pancreatic) and control dermatomes. The effects of age and gender on QST assessment parameters were investigated and normative reference values based on quartile regression were derived and implemented in algorithms to categorize patients according to their patterns of central pain processing (normal vs. segmental sensitization vs. widespread sensitization).

RESULTS

Absolute pressure thresholds were subject to clinically relevant gender effects (all p < 0.001), while the remainder of QST parameters were unaffected by age and gender. The algorithm with the best discriminatory capacity showed good separation between patients and controls (p < 0.001); 50% of patients had normal central pain processing, 23% had evidence of segmental sensitization and 27% had evidence of widespread sensitization.

CONCLUSION

We show normative reference values for a clinically feasible method for assessment and characterization of pain mechanisms in patients with CP. Application of this method streamlines the evaluation of pancreatic pain and may be used to inform treatment. CLINICALTRIALS.

GOV ID

NCT03434392.

Coenzyme Q10 supplementation alleviates pain in pregabalin-treated fibromyalgia patients via reducing brain activity and mitochondrial dysfunction

Although coenzyme Q10 (CoQ10) supplementation has shown to reduce pain levels in chronic pain, the effects of CoQ10 supplementation on pain, anxiety, brain activity, mitochondrial oxidative stress, antioxidants, and inflammation in pregabalin-treated fibromyalgia (FM) patients have not clearly elucidated. We hypothesised that CoQ10 supplementation reduced pain better than pregabalin alone via reducing brain activity, mitochondrial oxidative stress, inflammation, and increasing antioxidant levels in pregabalin-treated FM patients. A double-blind randomised placebo-controlled trial was conducted. Eleven FM patients were enrolled with 2 weeks wash-out then randomly allocated to 2 treatment groups; pregabalin with CoQ10 or pregabalin with placebo for 40 d. Then, patients in CoQ10 group were switched to placebo, and patients in placebo group were switched to CoQ10 for another 40 d. Pain pressure threshold (PPT), FM questionnaire, anxiety, and pain score were examined. Peripheral blood mononuclear cells (PBMCs) were isolated to investigate mitochondrial oxidative stress and inflammation at day 0, 40, and 80. The level of antioxidants and brain positron emission tomography (PET) scan were also determined at these time points. Pregabalin alone reduced pain and anxiety via decreasing brain activity compared with their baseline. However, it did not affect mitochondrial oxidative stress and inflammation. Supplementation with CoQ10 effectively reduced greater pain, anxiety and brain activity, mitochondrial oxidative stress, and inflammation. CoQ10 also increased a reduced glutathione levels and superoxide dismutase (SOD) levels in FM patients. These findings provide new evidence that CoQ10 supplementation provides further benefit for relieving pain sensation in pregabalin-treated FM patients, possibly via improving mitochondrial function, reducing inflammation, and decreasing brain activity.

Guidelines for the understanding and management of pain in chronic pancreatitis

Abdominal pain is the foremost complication of chronic pancreatitis (CP). Pain can be related to recurrent or chronic inflammation, local complications or neurogenic mechanisms with corresponding changes in the nervous systems. Both pain intensity and the frequency of pain attacks have been shown to reduce quality of life in patients with CP. Assessment of pain follows the guidelines for other types of chronic pain, where the multidimensional nature of symptom presentation is taken into consideration. Quantitative sensory testing may be used to characterize pain, but is currently used in a research setting in advanced laboratories. For pain relief, current guidelines recommend a simple stepwise escalation of analgesic drugs with increasing potency until pain relief is obtained. Abstinence from alcohol and smoking should be strongly advised. Pancreatic enzyme therapy and antioxidants may be helpful as initial treatment. Endoscopic treatment can be used in patients with evidence of ductal obstruction and may be combined with extracorporeal shock wave lithothripsy. The best candidates are those with distal obstruction of the main pancreatic duct and in early stage of disease. Behavioral interventions should be part of the multidisciplinary approach to chronic pain management particularly when psychological impact is experienced. Surgery should be considered early and after a maximum of five endoscopic interventions. The type of surgery depends on morphological changes of the pancreas. Long-term effects are variable, but high success rates have been reported in open studies and when compared with endoscopic treatment. Finally, neurolytical interventions and neuromodulation can be considered in difficult patients.

Medical Management of Pain in Chronic Pancreatitis

The medical management of pain in chronic pancreatitis continues to pose significant challenges for clinicians caring for these patients. There are increasing data, suggesting that pain in chronic pancreatitis is largely due to peripheral and central sensitization that evolves, over time, as a result of nociceptive afferent associated with chronic inflammation and fibrosis of the pancreas. In many instances, patients rapidly progress to requiring opioid analgesics for the adequate treatment of pain despite the unequivocal risks associated with the long-term use of these drugs. Centrally acting drugs, such as gabapentinoids, appear to be effective means of treating pain due to their inhibition of neurotransmitters involved in central sensitization, but side effects limit their use. The present review explores the evidence for various non-pharmacologic and pharmacologic treatments for pain in chronic pancreatitis.