Assessment of chronic abdominal pain

Chronic abdominal pain is defined as continuous or intermittent abdominal discomfort lasting for at least 6 months. Pain may arise from any system, including the genitourinary, gastrointestinal (GI), and gynaecological tracts. The aetiology of chronic abdominal pain is so wide that only the more common causes can be covered here. A clear relationship with an anatomical structure or underlying process may not always be present.

Classification

Chronic abdominal pain is divided into organic and functional aetiologies. Organic aetiologies have a clear anatomical, physiological, or metabolic cause. Chronic abdominal pain without clear source, in spite of a thorough diagnostic evaluation, is usually termed a functional disorder. Functional abdominal pain is thought to arise from multifactorial visceral hypersensitivity and dysmotility and altered function of the brain-gut axis.[1]Korterink J, Devanarayana NM, Rajindrajith S, et al. Childhood functional abdominal pain: mechanisms and management. Nat Rev Gastroenterol Hepatol. 2015 Mar;12(3):159-71. http://www.ncbi.nlm.nih.gov/pubmed/25666642?tool=bestpractice.com

Chronic abdominal pain is less likely than acute abdominal pain to reveal underlying organic pathology. Acute abdominal pain often indicates a sudden physiological change such as an obstructed or perforated hollow organ, infection, inflammation, or a sudden ischaemic event.

Epidemiology

Chronic abdominal pain is a common complaint in primary care and sub-specialty clinics. The incidence of unspecified abdominal pain is 22.3 per 1000 person-years.[2]Wallander MA, Johansson S, Ruigomez A, et al. Unspecified abdominal pain in primary care: the role of gastrointestinal morbidity. Int J Clin Pract. 2007 Oct;61(10):1663-70. http://www.ncbi.nlm.nih.gov/pubmed/17681003?tool=bestpractice.com Reported prevalence ranges from 8% to 54%.[3]Heading RC. Prevalence of upper gastrointestinal symptoms in the general population: a systematic review. Scand J Gastroenterol Suppl. 1999;231:3-8. http://www.ncbi.nlm.nih.gov/pubmed/10565617?tool=bestpractice.com One cross-sectional survey of US adults reported a prevalence of 21.8% in the general population.[4]Sandler RS, Stewart WF, Liberman JN, et al. Abdominal pain, bloating, and diarrhea in the United States: prevalence and impact. Dig Dis Sci. 2000 Jun;45(6):1166-71. http://www.ncbi.nlm.nih.gov/pubmed/10877233?tool=bestpractice.com Women are more likely than men to report chronic abdominal pain.[4]Sandler RS, Stewart WF, Liberman JN, et al. Abdominal pain, bloating, and diarrhea in the United States: prevalence and impact. Dig Dis Sci. 2000 Jun;45(6):1166-71. http://www.ncbi.nlm.nih.gov/pubmed/10877233?tool=bestpractice.com

The prevalence of paediatric functional abdominal pain is 13.5%.[5]Korterink JJ, Diederen K, Benninga MA, et al. Epidemiology of pediatric functional abdominal pain disorders: a meta-analysis. PLoS One. 2015 May 20;10(5):e0126982. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0126982 http://www.ncbi.nlm.nih.gov/pubmed/25992621?tool=bestpractice.com

Diagnosis and management of patients with chronic abdominal pain is often challenging, and can be a frustrating experience for both physicians and patients. Factors that contribute to this include poor sensitivity of the history and physical examination, a broad differential diagnosis that crosses several specialties, and an often negative diagnostic work-up.

Epidemiological studies suggest that the vast majority of patients with chronic abdominal pain have functional GI disorders such as irritable bowel syndrome or functional dyspepsia.[6]Talley NJ, Weaver AL, Zinsmeister AR, et al. Onset and disappearance of gastrointestinal symptoms and functional gastrointestinal disorders. Am J Epidemiol. 1992 Jul 15;136(2):165-77. http://www.ncbi.nlm.nih.gov/pubmed/1415139?tool=bestpractice.com [7]Ford AC, Marwaha A, Lim A, et al. What is the prevalence of clinically significant endoscopic findings in subjects with dyspepsia? Systematic review and meta-analysis. Clin Gastroenterol Hepatol. 2010 Oct;8(10):830-7.e2. https://www.cghjournal.org/article/S1542-3565(10)00563-X/fulltext http://www.ncbi.nlm.nih.gov/pubmed/20541625?tool=bestpractice.com [8]Keefer L, Drossman DA, Guthrie E, et al. Centrally mediated disorders of gastrointestinal pain. Gastroenterology. 2016 May;150(6):1408-19. http://www.ncbi.nlm.nih.gov/pubmed/27144628?tool=bestpractice.com However, the pain associated with these disorders is non-specific and can resemble or co-exist with organic disorders.