In Reply: Chronic and Complex Myofascial Pain Syndromes in Chronic Abdominal Wall Pain

Abstract

We appreciate the Letter to the Editor by Comerci and colleagues regarding our manuscript, Chronic Abdominal Wall Pain: A Common Yet Overlooked Etiology of Chronic Abdominal Pain.1Kamboj A.K. Hoversten P. Oxentenko A.S. Chronic abdominal wall pain: a common yet overlooked etiology of chronic abdominal pain.Mayo Clin Proc. 2019; 94: 139-144Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar We believe that this provides us with an opportunity to further discuss the complex topics of chronic abdominal wall pain (CAWP) and myofascial pain. Although our Concise Review on CAWP was expansive, this format did not allow for a detailed discussion on what is known of its pathophysiology. In this review, we discuss CAWP or anterior cutaneous nerve entrapment syndrome.1Kamboj A.K. Hoversten P. Oxentenko A.S. Chronic abdominal wall pain: a common yet overlooked etiology of chronic abdominal pain.Mayo Clin Proc. 2019; 94: 139-144Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar The most common etiology of CAWP is entrapment of the cutaneous branches of sensory nerves that supply the abdominal wall as they pass through the rectus muscle.2Sweetser S. Abdominal wall pain: a common clinical problem.Mayo Clin Proc. 2019; 94: 347-355Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar, 3Shian B. Larson S.T. Abdominal wall pain: clinical evaluation, differential diagnosis, and yreatment.Am Fam Physician. 2018; 98: 429-436PubMed Google Scholar, 4Srinivasan R. Greenbaum D.S. Chronic abdominal wall pain: a frequently overlooked problem. Practical approach to diagnosis and management.Am J Gastroenterol. 2002; 97: 824-830PubMed Google Scholar Myofascial pain refers to a regional pain syndrome characterized by trigger points within muscles.5Yap E.-C. Myofascial pain: an overview.Ann Acad Med Singapore. 2007; 36: 43-48PubMed Google Scholar, 6Skootsky S.A. Jaeger B. Oye R.K. Prevalence of myofascial pain in general internal medicine practice.West J Med. 1989; 151: 157-160PubMed Google Scholar We agree with Comerci et al that myofascial pain is a common cause of chronic pain in the outpatient setting. However, myofascial trigger points, although a common cause of chronic abdominal pain, are a less common cause of CAWP.4Srinivasan R. Greenbaum D.S. Chronic abdominal wall pain: a frequently overlooked problem. Practical approach to diagnosis and management.Am J Gastroenterol. 2002; 97: 824-830PubMed Google Scholar, 7van Assen T. de Jager-Kievit J.W.A.J. Scheltinga M.R. Roumen R.M.H. Chronic abdominal wall pain misdiagnosed as functional abdominal pain.J Am Board Fam Med. 2013; 26: 738-744Crossref PubMed Scopus (45) Google Scholar We also agree with Comerci et al that patients with CAWP and myofascial pain require a multimodal approach, and treatment should be guided by severity of symptoms. For patients with mild symptoms, the mainstay of treatment consists of conservative measures including reassurance, modification of activity, and physical therapy. Although some patients may find chiropractors helpful for myofascial pain, there is no evidence to support their use for CAWP, and we have not routinely sent patients to them in our practice for this indication.8Ernst E. Chiropractic treatment for gastrointestinal problems: a systematic review of clinical trials.Can J Gastroenterol. 2011; 25: 39-40Crossref PubMed Scopus (6) Google Scholar For a patient with moderate to severe symptoms, we recommend a combination of conservation measures and consideration of a trigger-point injection (TPI) using an anesthetic agent with or without a glucocorticoid. Combination therapy with an anesthetic and a glucocorticoid appears to be more effective in sustained relief of pain compared with an anesthetic alone, even for CAWP secondary to myofascial structures.9Niraj G. Pathophysiology and management of abdominal myofascial pain syndrome (AMPS): a three-year prospective audit of a management pathway in 120 patients.Pain Med. 2018; 19: 2256-2266Crossref PubMed Scopus (15) Google Scholar, 10Koop H. Koprdova S. Schürmann C. Chronic abdominal wall pain.Dtsch Arztebl Int. 2016; 113: 51-57PubMed Google Scholar As mentioned by Comerci et al, we emphasize that TPIs are not entirely benign and outline some of the risks associated with this procedure. There is a small risk of injecting into the peritoneal cavity. Although ultrasound may further decrease this risk, physicians should weigh the cost of this additional procedure with the added safety benefit. Obese patients may benefit from ultrasound guidance, given their body habitus. Finally, we discuss bleeding risks with use of antiplatelets and anticoagulation, management of which requires shared assessment and risk stratification. Overall, we agree with Comerci et al that myofascial pain may be the underlying etiology or a contributing factor in certain cases of CAWP. However, distinguishing this from anterior cutaneous nerve entrapment is clinically very challenging, and management strategies, as outlined above, are currently considered standard of care in clinical practice. Chronic Abdominal Wall Pain: A Common Yet Overlooked Etiology of Chronic Abdominal PainMayo Clinic ProceedingsVol. 94Issue 1PreviewChronic abdominal wall pain is a common, yet often overlooked, cause of chronic abdominal pain in both the outpatient and inpatient settings. This disorder most commonly affects middle-aged adults and is more prevalent in women than in men. In chronic abdominal wall pain, the pain occurs due to entrapment of the cutaneous branches of the sensory nerves that supply the abdominal wall. Although the diagnosis of chronic abdominal wall pain can be made using patient history, physical examination, and response to a trigger point injection, patients often undergo extensive and exhaustive laboratory, imaging, and procedural work-up before being diagnosed with this condition, given it is often overlooked. Full-Text PDF Chronic and Complex Myofascial Pain Syndromes in Chronic Abdominal Wall PainMayo Clinic ProceedingsVol. 94Issue 5PreviewWe appreciated reading the recent article by Kamboj and colleagues, entitled Chronic Abdominal Wall Pain: A Common Yet Overlooked Etiology of Chronic Abdominal Pain.1 We were impressed by the emphasis on a careful physician examination and the description of Carnett's sign. Overlooked, however, was a more thorough discussion of the role of myofascial pain as the most common etiology of abdominal wall pain. Our experience has been that myofascial pain involving the rectus abdominis, obliques, and transversus abdominis is a very common cause of previously undiagnosed chronic, distressing abdominal pain, which frequently involved extensive and costly imaging and referrals. Full-Text PDF