Does allopurinol reduce pain of chronic pancreatitis?

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.

Systematic review and meta-analysis: Is there any role for antioxidant therapy for pain in chronic pancreatitis

Chronic pancreatitis (CP) is an irreversible disease with increased oxidative stress. The therapeutic role of antioxidants for pain reduction in CP is debatable. A systematic review of articles in PubMed and Embase until February 2020 was performed. Only randomized controlled trials conducted on humans to evaluate the therapeutic effects of antioxidants for pain in CP were included. Studies of other design, nonhuman studies, and those that did not objectively assess pain were excluded. Twelve articles and four articles were eligible for qualitative and quantitative analysis, respectively. The four included studies had a total of 352 participants. Pain reduction as measured by a visual analog scale was not significantly different in the antioxidant group compared to placebo (standardized mean difference = -0.14 [95% confidence interval [CI] = -0.44 to 0.17]; P = 0.38). Number of pain-free participants was also similar (odds ratio [OR] = 1.59 [0.97-2.59]; P = 0.06). There was no difference in outcome when comparing different etiologies of CP or age group. The reduction in the number of analgesics used did not differ between both groups. Antioxidants were not associated with increased adverse events (OR = 2.59 [CI = 0.77-8.69]; P = 0.12). A qualitative analysis on the effect on quality of life did not suggest any significant improvement with antioxidants. There was no significant pain reduction or change in quality of life in CP patients with use of antioxidants. This makes their routine use in the management of CP questionable. However, further studies may identify a subgroup where they are more useful.

A comprehensive pain assessment tool (COMPAT) for chronic pancreatitis: Development, face validation and pilot evaluation

BACKGROUND/OBJECTIVES

Chronic pancreatitis (CP) pain is challenging to treat. Treatment selection is hampered by there being no validated pain assessment tool that accounts for the complexity of CP pain and its underlying mechanisms. This study aims to develop a comprehensive pain assessment tool (COMPAT) specific for CP, evaluate its face validity with experts and patients and test it with a pilot cohort of patients.

METHODS

COMPAT was developed from existing pain assessment tools and a literature review. Face validity was conducted by pancreatologists and CP patients using an item-content validity index for importance, relevance and clarity. Subsequent revisions were made to COMPAT. A pilot cohort of CP patients tested COMPAT.

RESULTS

COMPAT was developed and covered all important aspects of CP pain. Experts and CP patients reported that 70% of questions were important and relevant to CP pain. Most experts were willing to use COMPAT in clinic, ward/hospital and research settings. The most common location of pain was the epigastrium and food was the most important trigger. Pain Pattern C (constant background pain with pain attacks), had significantly higher frequency of pain attacks, higher opioid use, and affective descriptors of pain than Pattern A (pain attacks with no background pain).

CONCLUSIONS

COMPAT has high face validity and met with high acceptance. CP patients successfully self-reported their pain with COMPAT. The results reveal many differences in the CP pain within the pilot cohort, which may reflect different mechanisms of pain. A larger prospective cohort study is planned to further validate COMPAT.

Pain assessment in chronic pancreatitis: A comparative review of methods

BACKGROUND

Patients with chronic pancreatitis (CP) frequently report chronic abdominal pain that adversely impacts their quality of life. Assessment of pain in CP is required for clinical management and clinical studies. International consensus guidelines recognized a lack of specific and validated pain assessment tools for CP. Therefore, the aim of this systematic review is to identify and compare all clinical studies that assessed pain in the context of a treatment for pain in CP.

METHODS

A systematic literature search was performed in PubMed, Cochrane Library and Ovid MEDLINE. The search identified all intervention studies for pain in CP and the pain assessment tools used based on pre-defined inclusion and exclusion criteria.

RESULTS

Of 341 articles identified, 137 studies were included. Pain assessment tools were both general and CP-specific. The latter were used in only 22 (16%) studies. Despite recommendations the aspects of pain assessed were limited and variable between tools. Validation of these tools in CP patients was limited to quality of life measures. None of the pain assessment tools evaluated duration of pain and postprandial pain.

CONCLUSIONS

There are no published pain assessment tools for CP that includes all relevant aspects of pain. There is the need to develop a comprehensive and validated pain assessment tool for patients with CP to standardised pain assessment, identify likely underlying pain mechanisms, help select appropriate treatments, report outcomes from interventions, improve clinical communication and aid the allocation of patients to clinical trials.

Management of pain in chronic pancreatitis with emphasis on exogenous pancreatic enzymes

One of the most challenging issues arising in patients with chronic pancreatitis is the management of abdominal pain. Many competing theories exist to explain pancreatic pain including ductal hypertension from strictures and stones, increased interstitial pressure from glandular fibrosis, pancreatic neuritis, and ischemia. This clinical problem is superimposed on a background of reduced enzyme secretion and altered feedback mechanisms. Throughout history, investigators have used these theories to devise methods to combat chronic pancreatic pain including: Lifestyle measures, antioxidants, analgesics, administration of exogenous pancreatic enzymes, endoscopic drainage procedures, and surgical drainage and resection procedures. While the value of each modality has been debated over the years, pancreatic enzyme therapy remains a viable option. Enzyme therapy restores active enzymes to the small bowel and targets the altered feedback mechanism that lead to increased pancreatic ductal and tissue pressures, ischemia, and pain. Here, we review the mechanisms and treatments for chronic pancreatic pain with a specific focus on pancreatic enzyme replacement therapy. We also discuss different approaches to overcoming a lack of clinical response update ideas for studies needed to improve the clinical use of pancreatic enzymes to ameliorate pancreatic pain.

Antioxidant therapy in acute, chronic and post-endoscopic retrograde cholangiopancreatography pancreatitis: An updated systematic review and meta-analysis

AIM: To investigate the efficacy and adverse effects of antioxidant therapy in acute pancreatitis (AP), chronic pancreatitis (CP) and post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP).

METHODS: PubMed, Scopus, Google Scholar, Cochrane library database, and Evidence-based medicine/clinical trials published before August 2014 were searched. Clinical and laboratory outcomes of randomized trials of antioxidant therapy in patients with AP, CP and PEP were included. The methodological quality of the trials was assessed by the Jadad score based on the description of randomization, blinding, and dropouts (withdrawals). The results of the studies were pooled and meta-analyzed to provide estimates of the efficacy of antioxidant therapy.

RESULTS: Thirty four trials out of 1069 potentially relevant studies with data for 4898 patients were eligible for inclusion. Antioxidant therapy significantly reduced the length of hospital stay in AP patients {mean difference -2.59 d (95%CI: -4.25-(-0.93)], P = 0.002}. Although, antioxidant therapy had no significant effect on serum C reactive protein (CRP) after 5-7 d in AP patients [mean difference -9.57 (95%CI: -40.61-21.48, P = 0.55], it significantly reduced serum CRP after 10 d {mean difference -45.16 [95%CI: -89.99-(-0.33)], P = 0.048}. In addition, antioxidant therapy had no significant effect on CP-induced pain [mean difference -2.13 (95%CI: -5.87-1.6), P = 0.26]. Antioxidant therapy had no significant effects on the incidence of all types of PEP [mean difference 1.05 (95%CI: 0.74-1.5), P = 0.78], severe PEP [mean difference 0.92 (95%CI: 0.43-1.97), P = 0.83], moderate PEP [mean difference 0.82 (95%CI: 0.54-1.23), P = 0.33], and mild PEP [mean difference 1.33 (95%CI: 0.99-1.78), P = 0.06]. Furthermore, while antioxidant therapy had no significant effect on serum amylase after less than 8 h sampling [mean difference -20.61 (95%CI: -143.61-102.39), P = 0.74], it significantly reduced serum amylase close to 24-h sampling {mean difference -16.13 [95%CI: -22.98-(-9.28)], P < 0.0001}.

CONCLUSION: While there is some evidence to support antioxidant therapy in AP, its effect on CP and PEP is still controversial.

Treatment options for chronic pancreatitis

This Review covers the latest developments in the treatment options for chronic pancreatitis. Pain is the most frequent and dominant symptom in patients with chronic pancreatitis, which ranges from severe disabling continuous pain to mild pain attacks and pain-free periods. Conventional treatment strategies and recent changes in the treatment of pain in patients with chronic pancreatitis are outlined. The different treatment options for pain consist of medical therapy, endoscopy or surgery. Their related merits and drawbacks are discussed. Finally, novel insights in the field of genetics and microbiota are summarized, and future perspectives are discussed.

Antioxidants for pain in chronic pancreatitis

BACKGROUND

Reduced intake and absorption of antioxidants due to pain and malabsorption are probable causes of the lower levels of antioxidants observed in patients with chronic pancreatitis (CP). Improving the status of antioxidants might be effective in slowing the disease process and reducing pain in CP.

OBJECTIVES

To assess the benefits and harms of antioxidants for the treatment of pain in patients with CP.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and the Conference Proceedings Citation Index from inception to October 2012. Two review authors performed the selection of trials independently.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) evaluating antioxidants for treatment of pain in CP. All trials were included irrespective of blinding, numbers of participants randomly assigned and language of the article.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. The risk of bias of included trials was assessed. Study authors were asked for additional information in the case of missing data.

MAIN RESULTS

Twelve RCTs with a total of 585 participants were included. Six trials were double-blinded, placebo-controlled studies, and the other six trials were of less adequate methodology. Most trials were small and had high rates of dropout. Eleven of the 12 included trials described the effects of antioxidants on chronic abdominal pain in chronic pancreatitis. Pain as measured on a visual analogue scale (VAS, scale range 0 to 10) after one to six months was less in the antioxidant group than in the control group (mean difference (MD) -0.33, 95% confidence interval (CI) -0.64 to -0.02, P value 0.04, moderate-quality evidence). The number of pain-free participants was not statistically significantly different (risk ratio (RR) 1.73, 95% CI 0.95 to 3.15, P value 0.07, low-quality evidence). More adverse events were observed in the antioxidant group, both in the parallel trials (RR 4.43, 95% CI 1.60 to 12.29, P value 0.0004, moderate-quality evidence) and in the cross-over trials (RR 5.80, 95% CI 1.56 to 21.53, P value 0.0009, moderate-quality evidence). Adverse events occurred in 16% of participants and were mostly mild (e.g. headache, gastrointestinal complaints), but were sufficient to make participants stop antioxidant use. Other important outcomes such as use of analgesics, exacerbation of pancreatitis and quality of life were rarely reported. One trial from 1991 evaluated the effects of antioxidants on acute pain during exacerbation of chronic pancreatitis and found that a significantly higher proportion of participants in the antioxidant group experienced pain relief. This trial was conducted more than 25 years ago and has not been reproduced since that time. Therefore, additional trials are needed before reliable conclusions can be drawn.

AUTHORS' CONCLUSIONS

Current evidence shows that antioxidants can reduce pain slightly in patients with chronic pancreatitis. The clinical relevance of this small reduction is uncertain, and more evidence is needed. Adverse events in one of six patients may prevent the use of antioxidants. Effects of antioxidants on other outcome measures, such as use of analgesics, exacerbation of pancreatitis and quality of life remain uncertain because reliable data are not available.

Antioxidant therapy for patients with chronic pancreatitis: A systematic review and meta-analysis

BACKGROUND & AIMS

Chronic pancreatitis is a progressive, inflammatory disease of pancreas characterized by significant abdominal pain, malabsorption, and diabetes mellitus. Antioxidant therapy has been proposed as an effective treatment for painful chronic pancreatitis. We performed a meta-analysis of trials in which antioxidant therapy was compared with placebo in chronic pancreatitis.

METHODS

We searched six databases to identify relevant trials. Results are expressed as risk ratio (RR) or standardized mean difference (SMD) with accompanying 95% confidence intervals (CI). The meta-analysis was performed with the fixed-effects model or random-effects model according to heterogeneity.

RESULTS

Eight studies including 573 patients met the inclusion criteria. A meta-analysis of these studies revealed that the intervention of antioxidants was associated with a significant increase in patients with pain relief (RR, 2.15; 95% CI, 1.72-2.69; P < 0.00001), and a significant decrease in patients' need for analgesics (RR, 0.56; 95% CI, 0.40-0.78; P = 0.0006). For pain score, antioxidants improved pain tolerance in chronic pancreatitis patients (SMD: -0.41; 95% CI: -0.83 to -0.10; P = 0.0005). Additionally, antioxidants may cause some adverse reactions (RR, 4.22; 95% CI: 2.17-8.20; P < 0.0001).

CONCLUSIONS

Based on current evidence, oxidative stress may play an important role in the pathophysiology of chronic pancreatitis, and administration of antioxidants to patients with painful chronic pancreatitis is effective in relieving pain. Antioxidant supplements may be advocated as one medical therapy for chronic pancreatitis patients with low antioxidant capacity in their blood.

Treatment options in painful chronic pancreatitis: a systematic review

BACKGROUND

Longlasting and unbearable pain is the most common and striking symptom of chronic pancreatitis. Accordingly, pain relief and improvement in patients' quality of life are the primary goals in the treatment of this disease. This systematic review aims to summarize the available data on treatment options.

METHODS

A systematic search of MEDLINE/PubMed and the Cochrane Library was performed according to the PRISMA statement for reporting systematic reviews and meta-analysis. The search was limited to randomized controlled trials and meta-analyses. Reference lists were then hand-searched for additional relevant titles. The results obtained were examined individually by two independent investigators for further selection and data extraction.

RESULTS

A total of 416 abstracts were reviewed, of which 367 were excluded because they were obviously irrelevant or represented overlapping studies. Consequently, 49 full-text articles were systematically reviewed.

CONCLUSIONS

First-line medical options include the provision of pain medication, adjunctive agents and pancreatic enzymes, and abstinence from alcohol and tobacco. If medical treatment fails, endoscopic treatment offers pain relief in the majority of patients in the short term. However, current data suggest that surgical treatment seems to be superior to endoscopic intervention because it is significantly more effective and, especially, lasts longer.

Pharmacological management of pain in chronic pancreatitis

Introduction:

Chronic pancreatitis is a condition that is rising in incidence in the Western World. It is predominated by severe intractable abdominal pain that presents a significant impact on patients’ quality of life and physical functioning. The pain is persistent in many patients, requiring admission to hospital for the majority at some stage in their illness. There is no current NICE or SIGN guideline with associated grading for the pharmacological management of this symptom. This paper aims to investigate and summarise the current pharmacological therapies for pain control in an attempt to formulate the levels of evidence supporting their use.

Methods:

The online digital archives PubMed, Science Direct, Medscape and the Cochrane Library were searched for the keywords pain and chronic pancreatitis. Hand searches of relevant journals and citations were used to complete the investigation of current literature on the topic. Relevant articles and studies were critically analysed in a standard format with relation to study type, population, number, end point and outcomes. Publications not relevant to the management of pain in chronic pancreatitis were excluded.

Results:

Medical therapies, including oral analgesics and enzyme preparations, were included in the analysis of current modalities for treating pain in chronic pancreatitis.

Conclusions:

A summary of the evidence base for different pharmacological treatments in the context of chronic pancreatitis has shown that large number trials evaluating their efficacy in managing pain are lacking and offer scope for future research on this topic. The use of ‘alternative’ treatments such as antioxidant preparations and enzyme antagonists has shown promise. With regard to opioids, tramadol is as effective as morphine with less neuropsychiatric and gastrointestinal side effects. Oxycodone may derive more benefit than morphine due to an additional Κ-agonist effect.

Cytosolic double-stranded DNA as a damage-associated molecular pattern induces the inflammatory response in rat pancreatic stellate cells: a plausible mechanism for tissue injury-associated pancreatitis

Pancreatitis is an inflammatory disease of unknown causes. There are many triggers causing pancreatitis, such as alcohol, common bile duct stone, virus and congenital or acquired stenosis of main pancreatic duct, which often involve tissue injuries. Pancreatitis often occurs in sterile condition, where the dead/dying pancreatic parenchymal cells and the necrotic tissues derived from self-digested-pancreas were observed. However, the causal relationship between tissue injury and pancreatitis and how tissue injury could induce the inflammation of the pancreas were not elucidated fully until now. This study demonstrates that cytosolic double-stranded DNA increases the expression of several inflammatory genes (cytokines, chemokines, type I interferon, and major histocompatibility complex) in rat pancreatic stellate cells. Furthermore, these increase accompanied the multiple signal molecules genes, such as interferon regulatory factors, nuclear factor-kappa B, low-molecular-weight protein 2, and transporter associated with antigen processing 1. We suggest that this phenomenon is a plausible mechanism that might explain how cell damage of the pancreas or tissue injury triggers acute, chronic, and autoimmune pancreatitis; it is potentially relevant to host immune responses induced during alcohol consumption or other causes.

Antioxidants and chronic pancreatitis: theory of oxidative stress and trials of antioxidant therapy

Chronic pancreatitis (CP) is an inflammatory disease characterized by the progressive destruction of pancreatic tissue and resulting in pancreatic exocrine and endocrine insufficiency. Increased oxidative stress has been implicated as a potential mechanism in its etiology and pathology. A number of studies have demonstrated that CP patients have a compromised antioxidant status, which may be a contributing factor to the enhanced oxidative state associated with the disease. Nutrition is an essential consideration in the treatment of CP, especially since diet is a source of several antioxidants and cofactors required for the production of cellular antioxidant enzymes. Many CP patients have an inadequate intake of macro and micronutrients because of abdominal pain and discomfort, which often increase postprandially and discourage eating. Exocrine insufficiency leads to further complications by preventing adequate digestion and absorption of ingested food, thus causing even greater deficiencies and impairment of antioxidant status. The aims of this article are to review the oxidative stress model of CP and to examine the evidence for nutrition, and, particularly, antioxidants, in the treatment of CP.

Modern treatment of patients with chronic pancreatitis

CP remains a challenging disease. Endoscopic and surgical management, along with antioxidants, have helped in reducing chronic pain. Management of exocrine and endocrine insufficiency forms the cornerstone for improving nutrition in these patients. Newer therapeutic targets that will transcend the management of CP beyond just pain control and enzyme supplementation are required in the future.

Pancreatic nociception--revisiting the physiology and pathophysiology

BACKGROUND

Pain management of many pancreatic diseases remains a major clinical concern. This problem reflects our poor understanding of pain signaling from the pancreas.

OBJECTIVES

This review provides an overview of our current knowledge, with emphasis on current pain management strategies and recent experimental findings.

METHODS

A systematic search of the scientific literature was carried out using EMBASE, PubMed/MEDLINE, and the Cochrane Central Register of Controlled Trials for the years 1965-2011 to obtain access to all publications, especially randomized controlled trials, systematic reviews, and meta-analyses exploring pain and its management in disease states such as acute pancreatitis (AP), chronic pancreatitis (CP) and pancreatic cancer (PC).

RESULTS

Over the last decade, numerous molecular mediators such as nerve growth factor and the transient receptor potential (TRP) cation channel family have been implicated in afferent nerve signaling. More recent animal studies have indicated the location of the receptive fields for the afferent nerves in the pancreas and shown that these are activated by agents including cholecystokinin octapeptide, 5-hydroxytryptamine and bradykinin. Studies with PC specimens have shown that neuro-immune interactions occur and numerous agents including TRP cation channel V1, artemin and fractalkine have been implicated. Experimental studies in the clinical setting have demonstrated impairment of inhibitory pain modulation from supraspinal structures and implicated neuropathic pain mechanisms.

CONCLUSIONS

Our knowledge in this area remains incomplete. Characterization of the mediators and receptors/ion channels on the sensory nerve terminals are required in order to facilitate the development of new pharmaceutical treatments for AP and CP.

26. Pain in chronic pancreatitis

Chronic pancreatitis is defined as a progressive inflammatory response of the pancreas that has lead to irreversible morphological changes of the parenchyma (fibrosis, loss of acini and islets of Langerhans, and formation of pancreatic stones) as well as of the pancreatic duct (stenosis and pancreatic stones). Pain is one of the most important symptoms of chronic pancreatitis. The pathogenesis of this pain can only partly be explained and it is therefore often difficult to treat this symptom. The management of pain induced by chronic pancreatitis starts with lifestyle changes and analgesics. For the pharmacological management, the three-step ladder of the World Health Organization extended with the use of co-analgesics is followed. Interventional pain management may consist of radiofrequency treatment of the nervi splanchnici, spinal cord stimulation, endoscopic stenting or stone extraction possibly in combination with lithotripsy, and surgery. To date, there are no randomized controlled trials supporting the efficacy of radiofrequency and spinal cord stimulation. The large published series reports justify a recommendation to consider these treatment options. Radiofrequency treatment, being less invasive than spinal cord stimulation, could be tested prior to considering spinal cord stimulation. There are several other treatment possibilities such as endoscopic or surgical treatment, pancreatic enzyme supplementation and administration of octreotide and antioxidants. All may have a role in the management of pain induced by chronic pancreatitis.

Use and perceived effectiveness of non-analgesic medical therapies for chronic pancreatitis in the United States

BACKGROUND

Effectiveness of medical therapies in chronic pancreatitis has been described in small studies of selected patients.

AIM

To describe frequency and perceived effectiveness of non-analgesic medical therapies in chronic pancreatitis patients evaluated at US referral centres.

METHODS

Using data on 516 chronic pancreatitis patients enrolled prospectively in the NAPS2 Study, we evaluated how often medical therapies [pancreatic enzyme replacement therapy (PERT), vitamins/antioxidants (AO), octreotide, coeliac plexus block (CPB)] were utilized and considered useful by physicians.

RESULTS

Oral PERT was commonly used (70%), more frequently in the presence of exocrine insufficiency (EI) (88% vs. 61%, P < 0.001) and pain (74% vs. 59%, P < 0.002). On multivariable analyses, predictors of PERT usage were EI (OR 5.14, 95% CI 2.87-9.18), constant (OR 3.42, 95% CI 1.93-6.04) or intermittent pain (OR 1.98, 95% CI 1.14-3.45). Efficacy of PERT was predicted only by EI (OR 2.16, 95% CI 1.36-3.42). AO were tried less often (14%) and were more effective in idiopathic and obstructive vs. alcoholic chronic pancreatitis (25% vs. 4%, P = 0.03). Other therapies were infrequently used (CPB - 5%, octreotide - 7%) with efficacy generally <50%.

CONCLUSIONS

Pancreatic enzyme replacement therapy is commonly utilized, but is considered useful in only subsets of chronic pancreatitis patients. Other medical therapies are used infrequently and have limited efficacy.

Italian consensus guidelines for chronic pancreatitis

This paper gives practical guidelines for diagnosis and treatment of chronic pancreatitis. Statements have been elaborated by working teams of experts, by searching for and analysing the literature, and submitted to a consensus process by using a Delphi modified procedure. The statements report recommendations on clinical and nutritional approach, assessment of pancreatic function, treatment of exocrine pancreatic failure and of secondary diabetes, treatment of pain and prevention of painful relapses. Moreover, the role of endoscopy in approaching pancreatic pain, pancreatic stones, duct narrowing and dilation, and complications was considered. Recommendations for most appropriate use of various imaging techniques and of ultrasound endoscopy are reported. Finally, a group of recommendations are addressed to the surgical treatment, with definition of right indications, timing, most appropriate procedures and techniques in different clinical conditions and targets, and clinical and functional outcomes following surgery.

Antioxidant therapy in the management of acute, chronic and post-ERCP pancreatitis: A systematic review

We systematically reviewed the clinical trials which recruited antioxidants in the therapy of pancreatitis and evaluated whether antioxidants improve the outcome of patients with pancreatitis. Electronic bibliographic databases were searched for any studies which investigated the use of antioxidants in the management of acute pancreatitis (AP) or chronic pancreatitis (CP) and in the prevention of post-endoscopic retrograde cholangio-pancreatography (post-ERCP) pancreatitis (PEP) up to February 2009. Twenty-two randomized, placebo-controlled, clinical trials met our criteria and were included in the review. Except for a cocktail of antioxidants which showed improvement in outcomes in three different clinical trials, the results of the administration of other antioxidants in both AP and CP clinical trials were incongruent and heterogeneous. Furthermore, antioxidant therapy including allopurinol and N-acetylcysteine failed to prevent the onset of PEP in almost all trials. In conclusion, the present data do not support a benefit of antioxidant therapy alone or in combination with conventional therapy in the management of AP, CP or PEP. Further double blind, randomized, placebo-controlled clinical trials with large sample size need to be conducted.

Allopurinol for pain relief: more than just crystal clearance?

Gout and pain are synonymous, and a study in this issue of the BJP reports a novel anti-nociceptive effect of allopurinol, the drug most commonly used to treat gout. Allopurinol works by inhibiting xanthine oxidase (XO), the enzyme responsible for converting hypoxanthine to uric acid which is deposited as crystals in the joints of gout sufferers. Hypoxanthine is a metabolite of, and a possible precursor to, adenosine. Schmidt et al., find that acute inhibition of XO with allopurinol produces a modest adenosine A(1) receptor-mediated anti-nociceptive effect in common tests of chemical and thermal nociception in mice. A concomitant increase in cerebrospinal fluid levels of adenosine supports their hypothesis that inhibiting XO increases adenosine levels via salvage from hypoxanthine. Elevating endogenous adenosine levels by inhibiting metabolism is a well-established strategy for producing anti-nociception in many preclinical models, but inhibiting XO is likely to be particularly beneficial in some chronic pain states because of the pro-nociceptive reactive oxygen species that are produced by XO activity. Thus, allopurinol may have unexpected benefits in pain associated with chronic inflammation, diabetes and vascular dysfunction.

[Treatment of pain in chronic pancreatitis]

Abdominal pain is the most frequent symptom in patients with chronic pancreatitis. Between 70 and 90% of patients experience pain at some point in the course of their disease. In patients with alcoholic pancreatitis, pain is usually experienced at disease onset. Two distinct forms of idiopathic chronic pancreatitis can be distinguished: in early-onset (juvenile) idiopathic chronic pancreatitis, pain occurs initially, while in late-onset (senile) idiopathic chronic pancreatitis, pain is delayed or may even be absent. According to several authors, between 27 and 67% of patients require surgery due to lack of response to medical treatment. Pain may reoccur in more than 30% of patients who have undergone surgery and consequently, reintervention is not uncommon. Several treatment options are currently available: medical, endoscopic and surgical. The most appropriate treatment for each patient should be chosen on an individualized basis.

Management of painful chronic pancreatitis with single-dose radiotherapy

OBJECTIVES

Some patients with chronic pancreatitis present recurrent flare-ups of pancreatitis and/or unrelenting pain. Current management is mostly limited to analgesics and surgery. We reasoned that anti-inflammatory radiotherapy, which has proven useful to alleviate other painful inflammatory painful disorders, might prove valuable for severely symptomatic patients with chronic pancreatitis.

METHODS

We prospectively studied the efficacy of single-dose anti-inflammatory radiotherapy in 15 consecutive patients with chronic pancreatitis who fulfilled the following criteria: either two flare-ups of pancreatitis in the previous 6 months and/or continuous pain for more than 3 months. Treatment consisted of a single radiation dose of 8 Gy to the pancreas. Exocrine function (fecal elastase), endocrine function (c peptide), quality of life (EuroQol questionnaire), and clinical outcome were assessed before and after radiation. Response was defined as no further pain or flare-ups of pancreatitis.

RESULTS

During follow-up (median: 39 months; range: 4-72 months), 12 patients had no further pain or flare-ups. One patient required a second radiation dose 1 year after the initial treatment, but he has remained well ever since (50 months). Two other patients did not respond to radiotherapy. After radiotherapy either exocrine or endocrine pancreatic function, or both, deteriorated in three patients. Patients who responded to treatment (13/15) gained 4-20 kg in body weight during follow-up (median 4 kg) and EuroQol improved significantly from 0.58 to 0.86 (P<0.001).

CONCLUSIONS

Radiotherapy for severe symptomatic chronic pancreatitis appears to be a useful and effective therapeutic choice that could potentially substitute for or delay surgery.

Role of oxidative stress in pancreatic inflammation

Reactive oxygen and reactive nitrogen species (ROS/RNS) have been implicated in the pathogenesis of acute and chronic pancreatitis. Clinical and basic science studies have indicated that ROS/RNS formation processes are intimately linked to the development of the inflammatory disorders. The detrimental effects of highly reactive ROS/RNS are mediated by their direct actions on biomolecules (lipids, proteins, and nucleic acids) and activation of proinflammatory signal cascades, which subsequently lead to activation of immune responses. The present article summarizes the possible sources of ROS/RNS formation and the detailed signaling cascades implicated in the pathogenesis of pancreatic inflammation, as observed in acute and chronic pancreatitis. A therapeutic ROS/RNS-scavenging strategy has been advocated for decades; however, clinical studies examining such approaches have been inconsistent in their results. Emerging evidence indicates that pancreatitis-inducing ROS/RNS generation may be attenuated by targeting ROS/RNS-generating enzymes and upstream mediators.

A randomized controlled trial of antioxidant supplementation for pain relief in patients with chronic pancreatitis

BACKGROUND & AIMS

Oxidative stress has been implicated in the pathophysiology of chronic pancreatitis (CP). We evaluated the effects of antioxidant supplementation on pain relief, oxidative stress, and antioxidant status in patients with CP.

METHODS

In a placebo-controlled double blind trial, consecutive patients with CP were randomized to groups that were given placebo or antioxidants for 6 months. The primary outcome measure was pain relief, and secondary outcome measures were analgesic requirements, hospitalization, and markers of oxidative stress (thiobarbituric acid-reactive substances [TBARS]) and antioxidant status (ferric-reducing ability of plasma [FRAP]).

RESULTS

Patients (age 30.5+/-10.5 years, 86 male, 35 alcoholic, and 92 with idiopathic CP) were assigned to the placebo (n=56) or antioxidant groups (n=71). After 6 months, the reduction in the number of painful days per month was significantly higher in the antioxidant group compared with the placebo group (7.4+/-6.8 vs 3.2+/-4, respectively; P< .001; 95% CI, 2.07, 6.23). The reduction in the number of analgesic tablets per month was also higher in the antioxidant group (10.5+/-11.8 vs 4.4+/-5.8 respectively; P= .001; 95% CI, 2.65, 9.65). Furthermore, 32% and 13% of patients became pain free in the antioxidant and placebo groups, respectively (P= .009). The reduction in the level of TBARS and increase in FRAP were significantly higher in the antioxidant group compared with the placebo group (TBARS: placebo 1.2+/-2.7 vs antioxidant 3.5+/-3.4 nmol/mL; P= .001; 95% CI 0.96, 3.55; FRAP: placebo -5.6+/-154.9 vs antioxidant 97.8+/-134.9 microMFe(+2) liberated, P= .001, 95% CI 44.98, 161.7).

CONCLUSIONS

Antioxidant supplementation was effective in relieving pain and reducing levels of oxidative stress in patients with CP.

Pain management in chronic pancreatitis

Abdominal pain is a major clinical problem in patients with chronic pancreatitis. The cause of pain is usually multifactorial with a complex interplay of factors contributing to a varying degree to the pain in an individual patient and, therefore, a rigid standardized approach for pain control tends to lead to suboptimal results. Pain management usually proceeds in a stepwise approach beginning with general lifestyle recommendations. Low fat diet, alcohol and smoking cessation are encouraged. Analgesics alone are needed in almost all patients. Maneuvers aimed at suppression of pancreatic secretion are routinely tried. Patients with ongoing symptoms may be candidates for more invasive options such as endoscopic therapy, and resective or drainage surgery. The role of pain modifying agents (antidepressants, gabapentin, peregabalin), celiac plexus block, antioxidants, octreotide and total pancreatectomy with islet cell auto transplantation remains to be determined.

Pain in chronic pancreatitis and pancreatic cancer

Chronic, debilitating abdominal pain is arguably the most important component of chronic pancreatitis, leading to significant morbidity and disability. Attempting to treat this pain, which is too often unsuccessful, is a frustrating experience for physician and patient. Multiple studies to improve understanding of the pathophysiology that causes pain in some patients but not in others have been performed since the most recent reviews on this topic. In addition, new treatment modalities have been developed and evaluated in this population. This review discusses new advances in neuroscience and the study of visceral pain mechanisms, as well as genetic factors that may play a role. Updates of established therapies, as well as new techniques used in addressing pain from chronic pancreatitis, are reviewed. Lastly, outcome measures, which have been highly variable in this field over the years, are addressed.

Pathogenesis of pain in chronic pancreatitis: ongoing enigma

The pathogenesis of pain in chronic pancreatitis remains an enigma. The cause of pain is almost certainly multifactorial and may vary at different stages of the disease process. These factors may include the release of excessive oxygen-derived free radicals, tissue hypoxia and acidosis, inflammatory infiltration with influx of pain transmittent substances into damaged nerve ends, and the development of pancreatic ductal and tissue fluid hypertension due to morphological changes of the pancreas. Investigations into the causes of pain have been limited by changes in the dynamics with the progression of the disease process, limitations in studying functional and morphological changes of the pancreas in the clinical setting, and the psychosomatic profile of patients. Many of these patients are addicted to alcohol, and suffer from personality disorders. The difficulty in quantifying pain, which is at best subjective, further compounds the issue, especially when assessing the efficacy of treatment.