Abdominal Pain, Chronic

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[edit] Abdominal Pain, Chronic

Leonor Fernandez

Chronic abdominal pain is defined as intermittent or continuous abdominal pain or discomfort for longer than 3 to 6 months. It is a difficult disorder to manage; its persistence often leaves the patient and physician unsure of how much diagnostic certainty to pursue. This quandary reflects concern about missing a treatable disorder and diagnosing a functional gastrointestinal (GI) disorder. The functional disorders, by definition, lack any clear physiologic or structural markers, although recent studies about increased nociception are challenging traditional notions of organic vs. functional illnesses (see Chapter 50 ). Many patients with chronic abdominal pain undergo repeated surgery and its accompanying risks because other gynecologic and surgical problems were wrongly attributed to functional disorders. Given the high prevalence of these functional disorders, an emerging consensus is that physicians should seek a positive diagnosis rather than rely only on a diagnosis of exclusion. This approach can help avoid the cascade of tests and procedures that otherwise may occur, with associated financial and medical costs.^[1] Data are limited, however, to guide the primary care physician to the most helpful tests. This chapter outlines a general diagnostic approach to patients with chronic abdominal pain; further studies are needed to evaluate diagnostic tests in the primary care setting.

[edit] History.

The differential diagnosis for chronic abdominal pain includes chronic pancreatitis, intestinal angina, inflammatory bowel disease, pancreatic cancer, porphyria, Addison's disease, abdominal adhesions, small and large bowel cancer, and peritoneal metastases (see Chapter 107 ). It also includes several functional GI disorders, such as functional abdominal pain syndrome, functional abdominal bloating, and irritable bowel syndrome (IBS) (see Chapter 110 ). The physician should routinely inquire about the chronology, severity, pattern and location of pain, exacerbating and alleviating factors, change in stool quality or caliber, hematochezia, weight loss, family history, medication and drug use, and travel history. A psychosocial history is very important, since prior trauma or sexual abuse may predispose to chronic pain.

When patients describe chronic intermittent pain with complete lack of pain between episodes, the physician should assess for features of biliary colic, intermittent intestinal obstruction, metabolic disorders (e.g., porphyria, lead intoxication), endometriosis, intestinal angina, and IBS.

Continuous pain may suggest functional syndromes, metastases, pelvic inflammatory disease (PID), colon or small bowel cancer, pancreatic pathology, or adrenal insufficiency. A prior history of hematochezia, excess alcohol use, or the triad of diabetes, steatorrhea, and weight loss may suggest pancreatitis as a cause of abdominal pain (although the triad is not a sensitive indicator).

The pain of chronic pancreatitis may differ from typical acute pancreatitis and may be in the right or left upper quadrants or in the back. It is often deep, persistent, and unresponsive to antacids. A family history of episodic abdominal pain, especially if accompanied by neurologic symptoms, suggests porphyria. Women with lower abdominal and pelvic pain should be evaluated for possible PID, endometriosis, and other gynecologic disorders (see Chapter 37 ). Dull or cramping abdominal pain 15 to 30 minutes after a meal and lasting for several hours may suggest chronic mesenteric insufficiency or intestinal angina, particularly in patients with risk factors for atherosclerosis.

Many patients with chronic abdominal pain have IBS, especially of the bloating type. From 10% to 20% of the U.S. adult population reports symptoms compatible with IBS, although only 15% to 50% of those affected seek medical attention.^[2][3] The pain is often described as crampy, variable in intensity, and generally on the left side, although location may vary. Emotional stress and eating may exacerbate the pain, and defecation typically relieves it. A longer duration of symptoms generally favors IBS over “organic” disease. Most patients with IBS develop symptoms in early adulthood or even younger; therefore the new onset of IBS in a patient over 50 should prompt a more rigorous evaluation (colonoscopy, computed tomography [CT] scan). Many women (48% to 79%) with chronic pelvic pain, dyspareunia, and dysmenorrhea also have symptoms that meet the criteria for IBS.^[2]

[edit] Physical Examination.

After being weighed, the patient is assessed for location of tenderness and presence of any organ enlargement, masses, jaundice, or ascites. Many patients have abdominal scars because of the predisposition to undergo abdominal surgery. The usefulness of a stool guaiac test is controversial,^[3] especially if obtained by digital rectal examination. Patients over age 50 or with risks for colon cancer should probably undergo a structural colon examination (colonoscopy, sigmoidoscopy, or barium enema) even with a negative guaiac test. Patients with IBS will often have tenderness over the sigmoid colon. Patients with functional abdominal pain syndrome usually have a pattern of diffuse tenderness with no clear localization. A complete pelvic and bimanual examination is important in the evaluation of women. Carnett's test involves palpating the supine patient's abdomen to elicit the area of tenderness. The examiner keeps the palpating fingers over the tender spot while the patient lifts the head, contracting the abdominal wall muscles. When the source of the pain is in the abdominal wall, the pain is as severe or increased; when the source is intraabdominal, the tensed muscles protect the viscera, and pain should decrease.^[4]

[edit] Medications.

Chronic narcotic use may result in a narcotic constipation syndrome with abdominal pain. Several medications (e.g., exogenous gonadal steroids, barbiturates, sulfonamide antibiotics, anticonvulsants) can trigger abdominal pain in porphyria. Chronic steroid use may predispose to secondary adrenal insufficiency, leading to abdominal pain.

[edit] Alarm Symptoms.

Anorexia, weight loss, or malnutrition should prompt further workup. These are not features of IBS and may be caused by psychiatric comorbidity (e.g., depression). Pancreatic cancer may also present with depression. New onset of IBS in an older patient is unusual (see A). Anemia and unexplained low albumin should be evaluated further. Hematochezia and hematemesis also require further workup, although rectal bleeding from hemorrhoids is common.^[5] Fever requires further evaluation for infectious, neoplastic, or other etiologies (e.g., abscess, lymphoma, familial Mediterranean fever, rheumatologic conditions). Pain that awakens the patient at night also suggests a more serious pathology, although it may be difficult to distinguish between pain-induced awakening and poor sleep for other reasons (e.g., depression).^[6]

[edit] Dietary Factors.

Lactose, fructose, and sorbitol intake may aggravate diarrhea-predominant IBS. A trial of dietary exclusion of dairy products may be considered when lactose intolerance is suspected. Given the high efficacy of any intervention in patients with IBS, dairy products should probably be reintroduced eventually even if the trial is successful. Indeed, self-reported lactose intolerance and actual lactose malabsorption seem to be poorly correlated. In one study, one third of patients who reported severe lactose intolerance absorbed lactose normally.^[7]

[edit] Psychosocial History.

This should be elicited in the initial evaluation and then again over time as the patient's trust in the physician increases. Depression, generalized anxiety disorder, and a history of sexual abuse are more common in patients with functional GI disease. Their identification may enable treatment, and their mere acknowledgment may strengthen the physician-patient relationship. Understanding the symptom's meaning and cultural context is important.

[edit] Laboratory And Other Studies.

Few data are available on the cost-effectiveness of studies on patients presenting to a primary care physician (vs. the more selected population presenting to a gastroenterologist). Most agree that a limited laboratory and structural evaluation is sufficient for many patients. The patient's age, predominant symptom, and its duration and severity may help physicians to select tests. A complete blood count (CBC) should be done to check for anemia and leukocytosis. Some authors suggest blood chemistry, including liver function tests (LFTs) and amylase, erythrocyte sedimentation rate (ESR), and thyroid-stimulating hormone (TSH). In patients with typical IBS symptoms, more blood tests may not be helpful. Stool ova and parasites may be considered, especially in patients with predominant diarrhea, and in those with a relevant travel history or possible exposure to Giardia organisms or in immunosuppressed patients.

The presence of alarm symptoms should indicate imaging studies such as a CT scan and colonoscopy. A flexible sigmoidoscopy or colonoscopy is reasonable for many patients with chronic abdominal pain and is essential in those over age 50 or with risk factors for colon cancer. In a young patient with typical IBS symptoms, however, the structural examination has a low yield. If diarrhea predominates as a symptom, it may be necessary to rule out inflammatory bowel disease. A rectal biopsy (e.g., to rule out collagenous proctitis) is not routinely necessary, especially in patients who fulfilled symptom criteria for IBS.^[3] A CT scan may be helpful with suspected pancreatic pathology, with alarm symptoms and an unrevealing colon evaluation, or with a suspected hernia not obvious on examination. The role for laparoscopy is controversial; often it is suggested to rule out adhesions in patients with prior surgery. One study found a high prevalence of asymptomatic adhesions in an autopsy study of women (50% in women with no prior history of surgery, 69% in those with prior surgery).^[8] This may suggest that adhesions are common and nonspecific. Endoscopic retrograde cholangiopancreatography (ERCP) is used to investigate biliary tract pathology; some authors question its utility in the absence of structural abnormalities.

[edit] Management.

Alarm symptoms should prompt a referral and further investigations, as described. If no alarm symptoms are present and the diagnostic criteria for a functional disorder are met, the patient can be managed with a drug regimen targeting the specific symptom (see Chapter 110 ). An exacerbation of symptoms without an alarm symptom does not require reinvestigation with multiple tests.

These patients often benefit from a multidisciplinary approach, with the input of gynecologists, gastroenterologists, pain specialists, and social workers working with the primary care physician. This approach may help avoid fragmentation of care (e.g., through emergency room use) and unnecessary tests and surgeries. As with other chronic illnesses, setting realistic goals, providing reassurance, and involving patients in their care reduces the burden of the disorder^[6](see Chapter 142 ).

[edit] REFERENCES