Chronic abdominal pain (CAP) is pain that persists for more than 3 months either continuously or intermittently. Intermittent pain may be referred to as recurrent abdominal pain (RAP). Acute abdominal pain is discussed elsewhere.
CAP occurs any time after 5 years of age. In a large cohort study, 11% of children reported RAP at ≥ 1 assessment (1). About 2% of adults, predominantly women, have CAP (a much higher percentage of adults have some type of chronic gastrointestinal [GI] symptoms, including nonulcer dyspepsia and various bowel disturbances).
Functional bowel disorders are common causes of chronic abdominal pain. Irritable bowel syndrome (IBS) is a functional bowel disorder that causes recurrent abdominal pain and altered bowel habits. Centrally mediated abdominal pain syndrome, previously known as functional abdominal pain, is a similar but less common disorder that does not cause altered bowel habits. (See the American College of Gastroenterology's 2021 clinical guideline for the management of IBS.)
Nearly all patients with CAP have had a prior medical evaluation that did not yield a diagnosis after history, physical, and basic testing.
General reference
1. Sjölund J, Uusijärvi A, Tornkvist NT, et al. Prevalence and Progression of Recurrent Abdominal Pain, From Early Childhood to Adolescence. Clin Gastroenterol Hepatol. 2021;19(5):930-938.e8. doi:10.1016/j.cgh.2020.04.047
Pathophysiology
Physiologic causes of chronic abdominal pain (see table Physiologic Causes of Chronic Abdominal Pain) result from stimuli of visceral receptors (mechanical, chemical, or both). Pain may be localized or referred, depending on innervation and specific organ involvement.
Irritable bowel syndrome and centrally mediated abdominal pain syndrome cause pain that persists > 6 months without evidence of physiologic disease. The pathophysiology of these disorders is complex and seems to involve altered intestinal motility, increased visceral nociception, and psychological factors. Visceral hyperalgesia refers to hypersensitivity to normal amounts of intraluminal distention and heightened perception of pain in the presence of normal quantities of intestinal gas; it may result from remodeling of neural pathways in the gut-brain axis.
Etiology
Perhaps 10% of patients have an occult physiologic illness (see table Physiologic Causes of Chronic Abdominal Pain); the remainder have a functional process. However, determining whether a particular abnormality (eg, adhesions, ovarian cyst, endometriosis) is the cause of CAP symptoms or an incidental finding can be difficult.
Evaluation
History
History of present illness should elicit pain location, quality, duration, timing and frequency of recurrence, and factors that worsen or relieve pain (particularly eating or moving bowels). A specific inquiry as to whether milk and milk products cause abdominal cramps, bloating, or distention is needed because lactose intolerance is common, especially among people of African, Hispanic, Asian (particularly East Asian countries), and American Indian heritage, with increasing frequency with aging.
Review of systems seeks concomitant GI symptoms such as gastroesophageal reflux, anorexia, bloating or “gas,” nausea, vomiting, jaundice, melena, hematuria, hematemesis, weight loss, and mucus or blood in the stool. Bowel symptoms, such as diarrhea, constipation, and changes in stool consistency, color, or elimination pattern, are particularly important.
Diet history is important. For example, ingestion of large amounts of cola beverages, fruit juices (which may contain significant quantities of fructose and sorbitol), or gas-producing foods (eg, beans, onions, cabbage, cauliflower) can account for otherwise puzzling abdominal pain.
Past medical history should include nature and timing of any abdominal surgery and the results of previous tests that have been done and treatments that have been tried. A medication/drug history should include details concerning prescription and illicit drug use as well as alcohol.
Family history of RAP, fevers, or both should be ascertained, as well as known diagnoses of sickle cell trait or disease, familial Mediterranean fever, and porphyria.
Physical examination
Review of vital signs should particularly note presence of fever or tachycardia.
General examination should seek presence of jaundice, rash, and peripheral edema.
Abdominal examination should note areas of tenderness, presence of peritoneal findings (eg, guarding, rigidity, rebound), and any masses or organomegaly. Evaluation for abdominal wall pain (Carnett sign) can help distinguish between somatic and visceral pain (1).
Rectal examination and (in women) pelvic examination to locate tenderness and masses and stool examination for occult blood are essential.
Red flags
The following findings are of particular concern:
Fever
Anorexia, weight loss
Pain that awakens patient
Blood in vomit, stool, or urine
Severe or frequent vomiting
Jaundice
Edema
Abdominal mass or organomegaly
Interpretation of findings
Clinical examination alone infrequently provides a firm diagnosis.
Determining whether CAP is physiologic or functional can be difficult. Although the presence of red flag findings indicates a high likelihood of a physiologic cause, their absence does not rule it out. With a physiologic cause, pain is usually well localized, especially to areas other than the periumbilical region. Pain that wakes the patient is usually physiologic. Some findings suggestive of specific disorders are listed in table Physiologic Causes of Chronic Abdominal Pain.
Functional CAP may result in pain similar to that of physiologic origin. However, there are no associated red flag findings, and psychosocial features are often prominent. A history of physical or sexual abuse or an unresolved loss (eg, divorce, miscarriage, death of a family member) may be a clue.
The Rome IV criteria are consensus guidelines that provide a framework for diagnosing functional gastrointestinal disorders, including irritable bowel syndrome (2). According to these criteria, irritable bowel syndrome is defined as the presence of abdominal pain for at least 1 day/week in the last 3 months along with at least 2 of the following:
Pain is related to defecation.
Pain is associated with a change in frequency of defecation.
Pain is associated with a change in consistency of stool.
Evaluation references
1. Schneiderman H, Lopetegui-Lia N, Nichols J: The enduring and practical power of physical examination: Carnett sign. Am J Med 133(6):682-684, 2020. doi: 10.1016/j.amjmed.2019.09.027
2. Drossman DA: Functional gastrointestinal disorders: History, pathophysiology, clinical features, and Rome IV. Gastroenterology 150:1262–1279, 2016. doi: 10.1053/j.gastro.2016.02.032
Testing
In general, simple tests (including urinalysis, complete blood count, liver tests, blood urea nitrogen, glucose, and lipase) should be done. Abnormalities in these tests, the presence of red flag findings, or specific clinical findings mandate further testing, even if previous assessments have been negative. Specific tests depend on the findings (see Physiologic Causes of Chronic Abdominal Pain) but typically include ultrasound for ovarian cancer in women > 50 years, CT of the abdomen and pelvis with contrast, upper GI endoscopy (particularly in patients > 60 years old) or colonoscopy, and perhaps small-bowel imaging or stool testing.
The benefits of testing patients with no red flag findings are unclear. Patients > 45 or with risk factors for colon cancer (eg, family history) should undergo colonoscopy if not previously screened; patients ≤ 45 can be observed or have CT of the abdomen and pelvis with contrast if an imaging study is desired. Magnetic resonance cholangiopancreatography (MRCP), endoscopic retrograde cholangiopancreatography (ERCP), and laparoscopy are rarely helpful in the absence of specific indications.
Between the initial evaluation and the follow-up visit, the patient (or family, if the patient is a child) should record any pain, including its nature, intensity, duration, and precipitating factors. Diet, defecation pattern, and any remedies tried (and the results obtained) should also be recorded. This record may reveal inappropriate behavior patterns and exaggerated responses to pain or otherwise suggest a diagnosis.
Treatment
Physiologic conditions are treated.
If the diagnosis of functional CAP is made, frequent examinations and tests should be avoided because they may focus on or magnify the physical complaints or imply that the physician lacks confidence in the diagnosis.
There are no modalities to cure functional CAP; however, many helpful measures are available. These measures rest on a foundation of a trusting, empathic relationship between the physician, patient, and family. Patients should be reassured that they are not in danger; specific concerns should be sought and addressed. The physician should explain the laboratory findings and the nature of the problem and describe how the pain is generated and how the patient perceives it (ie, there may be a tendency to feel pain at times of stress). It is important to avoid perpetuating the negative psychosocial consequences of chronic pain (eg, prolonged absences from school or work, withdrawal from social activities) and to promote independence, social participation, and self-reliance. These strategies help the patient control or tolerate the symptoms while participating fully in everyday activities.
Agents such as antispasmotics, peppermint oil, and tricyclic antidepressants can be effective (1). Opioids should be avoided because of the concern about potential dependency and possibility of narcotic bowel syndrome.
Dietary modification and consumption of high-fiber foods or fiber supplements may help some patients. Evidence supporting the use of probiotics for centrally mediated abdominal pain syndrome is currently limited. (See the American College of Gastroenterology's 2021 clinical guideline for the management of IBS.)
Cognitive methods (eg, cognitive-behavioral therapy, relaxation training, biofeedback, hypnosis) may help by contributing to the patient’s sense of well-being and control (1). Regular follow-up visits should be scheduled weekly, monthly, or bimonthly, depending on the patient’s needs, and should continue until well after the problem has resolved. Psychiatric referral may be required if symptoms persist, especially if the patient is depressed or there are significant psychological stressors at home.
Treatment reference
1. Stemboroski L, Schey R. Treating Chronic Abdominal Pain in Patients with Chronic Abdominal Pain and/or Irritable Bowel Syndrome. Gastroenterol Clin North Am. 2020;49(3):607-621. doi:10.1016/j.gtc.2020.05.001
Key Points
Most cases represent a functional process.
Red flag findings indicate a physiologic cause and need for further assessment.
Testing is guided by clinical features.
Repeated testing after physiologic causes are ruled out is usually counterproductive.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
American College of Gastroenterology: Clinical guideline for the management of IBS (2021)
