Evaluation of the adult with abdominal pain PDF

8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Official reprint from UpToDate® www.uptodate.com © 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Evaluatio...

8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Official reprint from UpToDate® www.uptodate.com © 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Evaluation of the adult with abdominal pain AUTHORS: Robert M Penner, BSc, MD, FRCPC, MSc, Mary B Fishman, MD SECTION EDITORS: Andrew D Auerbach, MD, MPH, Mark D Aronson, MD DEPUTY EDITOR: Jane Givens, MD, MSCE All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Jul 2023. This topic last updated: May 10, 2021. INTRODUCTION Abdominal pain can be a challenging complaint for both primary care and specialist clinicians because it is frequently a benign complaint, but it can also herald serious acute pathology. Clinicians are responsible for trying to determine which patients can be safely observed or treated symptomatically and which require further investigation or specialist referral. This task is complicated by the fact that abdominal pain is often a nonspecific complaint that presents with other symptoms. This topic reviews a diagnostic approach to nontraumatic abdominal pain in adults. The causes of abdominal pain and its pathophysiology, the evaluation of the adult with abdominal pain in the emergency department, and the evaluation of abdominal pain related to trauma is discussed elsewhere. (See "Causes of abdominal pain in adults" and "Evaluation of the adult with abdominal pain in the emergency department" and "Traumatic gastrointestinal injury in the adult patient".) EVALUATION Abdominal pain is a common problem. Most patients have a benign and/or self-limited etiology, and the initial goal of evaluation is to identify those patients with a serious etiology that may require urgent intervention. A history and focused physical examination will lead to a https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 1/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate differential diagnosis of abdominal pain, which will then inform further evaluation with laboratory evaluation and/or imaging. History — The history of a patient with abdominal pain includes determining whether the pain is acute or chronic and a detailed description of the pain and associated symptoms, which should be interpreted with other aspects of the medical history. The overall sensitivity and specificity of the history and physical examination in diagnosing the different causes of abdominal pain is poor , particularly for benign conditions [3,4]. Fortunately, studies of the accuracy of history and physical examination for the more serious causes of abdominal pain (eg, acute appendicitis), alone or in combination with focused investigations, have yielded better results [5-7]. Acute versus chronic — There is no strict time period that will classify the differential diagnosis unfailingly. A clinical judgment must be made that considers whether this is an accelerating process, one that has reached a plateau, or one that is longstanding but intermittent. Patients with chronic abdominal pain may present with an acute exacerbation of a chronic problem or a new and unrelated problem. Pain of less than a few days’ duration that has worsened progressively until the time of presentation is clearly "acute." Pain that has remained unchanged for months or years can be safely classified as chronic. Pain that does not clearly fit either category might be called subacute and requires consideration of a broader differential than acute and chronic pain. Description — Pain should be characterized according to location, chronology, severity, aggravating and alleviating factors, and associated symptoms. It is also important to note if the patient has recurring episodes of similar pain as this may narrow the differential. Location and radiation – The location of abdominal pain helps narrow the differential diagnosis as different pain syndromes typically have characteristic locations ( table 1A-D). For example, pain involving the liver or biliary tree is generally located in the right upper quadrant, but it may radiate to the back or epigastrium. Because hepatic pain only results when the capsule of the liver is "stretched," most pain in the right upper quadrant is related to the biliary tree. Pain radiation is also important: the pain of pancreatitis classically bores to the back, while renal colic radiates to the groin. Temporal elements – The onset, frequency, and duration of the pain are helpful features. The pain of pancreatitis may be gradual and steady, while perforation and resultant peritonitis begins suddenly and is maximal from the onset. https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 2/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Quality – The quality of the pain includes determining whether the pain is burning or gnawing, as is typical of gastroesophageal reflux and peptic ulcer disease, or colicky, as in the cramping pain of gastroenteritis or intestinal obstruction. Severity – The severity of the pain generally is related to the severity of the disorder, especially if acute in onset. For example, the pain of biliary or renal colic or acute mesenteric ischemia is of high intensity, while the pain of gastroenteritis is less marked. Age and general health may affect the patient's clinical presentation. A patient taking corticosteroids may have significant masking of pain, and older adult patients often present with less intense pain. Precipitants or palliation – Determining what precipitates or palliates the pain can help narrow the differential. The pain of chronic mesenteric ischemia usually starts within one hour of eating, while the pain of duodenal ulcers may be relieved by eating and recur several hours after a meal. The pain of pancreatitis is classically relieved by sitting up and leaning forward. Peritonitis often causes patients to lie motionless on their backs because any motion causes pain. Obtaining a history of pain occurring in relationship to eating lactose- or gluten-containing foods may be helpful in identifying sensitivities to these food constituents. Patients with foodborne illness may become ill after eating certain foods ( table 2). Associated symptoms — Symptoms that occur in relation to abdominal pain may give important information. Other gastrointestinal symptoms – We ask about associated nausea, vomiting, diarrhea, constipation, hematochezia, melena, and changes in stool (eg, change in caliber). For patients with right upper quadrant pain or concern for liver disease, we also ask about jaundice and changes in the color of urine and stool. The bowel habit is an important part of the history for chronic abdominal pain. While many organic lesions can result in chronic diarrhea, irritable bowel syndrome (IBS) often presents with swings between diarrhea and constipation, a pattern that is much less likely with organic disease. Genitourinary symptoms – Patients with symptoms such as dysuria, frequency, and hematuria are more likely to have a genitourinary cause for their abdominal pain. Constitutional symptoms – Symptoms such as fevers, chills, fatigue, weight loss, and anorexia would be concerning for infection, malignancy, or systemic illnesses (eg, inflammatory bowel disease [IBD]). https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 3/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Cardiopulmonary symptoms – Symptoms such as cough, shortness of breath, orthopnea, and exertional dyspnea suggest a pulmonary or cardiac etiology. Orthostatic hypotension may indicate early shock or be associated with adrenal insufficiency. Other – Patients with diabetic ketoacidosis will have symptoms of polyuria and thirst. Patients with suspected IBD should be asked about extraintestinal manifestations ( table 3). Other medical history — Other aspects of the history help narrow the differential. Specific questions for females – Females should be screened for sexually transmitted diseases and risks for pelvic inflammatory disease (eg, new or multiple partners). (See "Screening for sexually transmitted infections", section on 'Assessing risk'.) Premenopausal individuals should be asked about their menstrual history (last menstrual period, last normal menstrual period, previous menstrual period, cycle length) and use of contraception. They should also be asked about vaginal discharge or bleeding, dyspareunia or dysmenorrhea, as these symptoms suggest a pelvic pathology. (See "Prenatal care: Initial assessment" and "Acute pelvic pain in nonpregnant adult females: Evaluation" and "Chronic pelvic pain in adult females: Evaluation".) Past medical history – A history of surgeries and procedures should be obtained to assess risk for differing etiologies (eg, a history of abdominal surgery is a risk factor for obstruction). A history of cardiovascular disease (CVD) or multiple risk factors for CVD in a patient with epigastric pain raises concern for a myocardial ischemia. (See "Outpatient evaluation of the adult with chest pain", section on 'Differential Diagnosis'.) Medications – A comprehensive medication list (including over the counter medications and medications that cause constipation ( table 4)) should be elicited as this can inform the differential. For example, patients taking high doses of nonsteroidal antiinflammatory drugs (NSAIDs) are at risk for gastropathy and peptic ulcer disease. Patients with recent antibiotics use or hospitalization are at risk for Clostridioides difficile. Patients on chronic steroids are at risk for adrenal insufficiency and may be immunosuppressed with atypical presentations of abdominal pain. (See "Peptic ulcer disease: Epidemiology, etiology, and pathogenesis", section on 'NSAIDs, including aspirin' and "Peptic ulcer disease: Clinical manifestations and diagnosis", section on 'Evaluate for nonsteroidal anti-inflammatory drug (NSAID) and corticosteroid use' and "Clostridioides difficile infection in adults: Epidemiology, microbiology, and pathophysiology", section on 'Risk factors'.) Other history https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 4/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Alcohol – It is important to ask about alcohol intake to assess for the possibility of liver disease and pancreatitis. Family history – Family history should be asked as appropriate based on other history. For example, patients with history concerning for IBD or cancer should also be asked about family history. (See "Definitions, epidemiology, and risk factors for inflammatory bowel disease".) Travel history – A travel history is important to elicit in patients with symptoms consistent with gastroenteritis or colitis (eg, nausea, vomiting, and diarrhea) to consider infectious etiologies. Sick contacts – Often patients are in contact with someone with gastroenteritis before having similar symptoms. Patients with foodborne illness may also have close contacts with similar illness. Physical examination — All patients should have vital signs and an abdominal examination. Other physical examination will depend on the history. Patients with chronic abdominal pain should have a thorough physical examination. Vital signs – Unstable vital signs are an indication for immediate referral to the emergency department. (See "Evaluation of the adult with abdominal pain in the emergency department".) Vital signs may inform further evaluation. Weight and any changes should be noted for patients seen over multiple visits. Patients with hypoxemia should be evaluated for pulmonary etiologies of abdominal pain. Fever raises suspicion for infectious disease. Orthostatic vital signs may be indicative of dehydration or a sign of adrenal insufficiency. Abdominal examination – The abdominal examination includes inspection, auscultation, percussion, and palpation. In patients with suspected psychogenic abdominal pain, it is important to perform the abdominal examination while the patient is distracted. Inspection – The general appearance and level of comfort or discomfort should be noted. Inspection of the abdomen should include attention to the position assumed by the patient when in pain; strict immobility is typical of a patient with peritonitis, while patients with biliary or renal colic writhe in agony. Patients with peritonitis will have worsening pain when the examiner lightly bumps the stretcher. Auscultation – The abdomen should be auscultated for bowel sounds. Auscultation is a useful physical finding, particularly in detecting ileus [9,10]. Abnormal bowel sounds https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 5/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate are highly predictive of a small bowel obstruction in patients with acute abdominal pain. Abnormally active, high-pitched bowel sounds are a feature of early bowel obstruction, while a friction rub in the appropriate area might be heard in a patient with a splenic infarct. Percussion – We start with gentle percussion (rather than palpation). Patients with peritonitis will have pain with gentle percussion. Percussion is also used to identify ascites and hepatomegaly. Tympany signifies a distended bowel, while dullness may signify a mass. Shifting dullness is a reliable and fairly accurate sign for the detection of ascites. Palpation – Palpation is used to evaluate tenderness of the abdomen and for enlarged organs (eg, hepatomegaly or splenomegaly) or masses. We start by examining the quadrant of the abdomen where the patient is experiencing the least pain. Muscular rigidity or "guarding" is an important and early sign of peritoneal inflammation; it can be unilateral in a patient with a focal inflammatory mass such as a diverticular abscess or diffuse in peritonitis. Guarding is typically absent with deeper sources of pain such as renal colic and pancreatitis. Rebound tenderness may reflect peritonitis. If testing for rebound tenderness is appropriate, we begin with gentle palpation and release. If the patient has no rebound tenderness with gentle palpation, we then proceed to deeper palpation and release. The patient should be examined for signs of nerve and muscle wall injury and hernia. Pain in a dermatomal distribution and hyperesthesia are both signs of nerve involvement as in herpes zoster or nerve root impingement. Abdominal wall pathology may be found by palpation or by noting exacerbation of the pain when using the abdominal wall muscles (eg, sitting up). Rectal examination – Most patients with abdominal pain should have a rectal examination. Fecal impaction might be the explanation for signs and symptoms of obstruction in older adults, while tenderness on rectal examination may be the only abnormal finding in a patient with retrocecal appendicitis. However, some patients with localized upper abdominal pain (eg, right upper quadrant pain) or abdominal pain that is likely from a non-gastrointestinal cause (eg, suspected cystitis) may not require a rectal examination. Pelvic examination – A pelvic examination should be done whenever pelvic pathology is in the differential diagnosis. Unless the patient has another etiology of abdominal pain, all https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 6/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate females with acute lower abdominal pain should have a pelvic examination. (See "The gynecologic history and pelvic examination" and "Causes of abdominal pain in adults", section on 'Females'.) Other – The eyes should be examined for scleral icterus and the skin for jaundice. Patients with pulmonary or cardiac symptoms should have pulmonary and cardiac exams. Patients with history concerning for IBD should be examined for extraintestinal manifestations of IBD ( table 3). (See "Auscultation of cardiac murmurs in adults" and "Auscultation of heart sounds".) Studies — Laboratory studies are determined by the history and physical and will vary depending on the suspected etiology. Pregnancy should be excluded in all females of childbearing age with abdominal pain. (See 'Diagnostic approach to acute abdominal pain' below and 'Diagnostic approach to chronic abdominal pain' below.) Patients with abdominal pain will often have imaging as part of their evaluation. The imaging modality chosen will depend on suspected etiologies. Imaging modalities that may be used to evaluate abdominal pain include ultrasound, computed tomography (CT) scan, magnetic resonance imaging (MRI; including magnetic resonance cholangiopancreatography), endoscopy, and endoscopic retrograde cholangiopancreatography. (See "Overview of upper gastrointestinal endoscopy (esophagogastroduodenoscopy)" and "Overview of endoscopic retrograde cholangiopancreatography (ERCP) in adults".) DIAGNOSTIC APPROACH TO ACUTE ABDOMINAL PAIN The diagnostic approach to acute abdominal pain will depend on whether or not the pain is localized. The location of abdominal pain helps narrow the differential diagnosis as different pain syndromes typically have characteristic locations ( table 1A-C, 1E). Some patients with acute abdominal pain will need urgent or emergency evaluation. Urgent evaluation and/or surgical abdomen — Patients in whom there are concerns for life- threatening causes of abdominal pain should be referred to the emergency department. (See "Evaluation of the adult with abdominal pain in the emergency department".) These include those with: Unstable vital signs Signs of peritonitis on abdominal exam (eg, abdominal rigidity, rebound tenderness, and/or pain that worsens when the examiner lightly bumps the stretcher) https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 7/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Concern that the abdominal pain is from a life-threatening condition (eg, acute bowel obstruction, acute mesenteric ischemia, perforation, acute myocardial infarction, ectopic pregnancy) These patients may require analgesics, which can be administered without compromising their assessment. (See "Evaluation of the adult with abdominal pain in the emergency department".) Patients with concern for infection on initial evaluation (eg, fever, jaundice, and right upper quadrant pain) should also be evaluated promptly, often requiring referral to the emergency department for expedited evaluation. (See "Acute cholangitis: Clinical manifestations, diagnosis, and management".) Patients with less acute illnesses may require consultation or referral for further management following a more detailed history and initial assessment, as described below. Nonurgent evaluation — In patients with localized pain, the differential diagnosis can be considered in terms of "symptom clusters" in order to guide further management and investigation. Patients with diffuse abdominal pain may need a broader evaluation. Right upper quadrant pain — Pain involving the liver or biliary tree is generally located in the right upper quadrant, but it may radiate to the back or epigastrium ( table 1C). Because hepatic pain only results when the capsule of the liver is "stretched," most pain in the right upper quadrant is related to the biliary tree. Patients with right upper quadrant pain should have the following laboratory studies: Complete blood count with differential Electrolytes, blood urea nitrogen (BUN), creatinine, and glucose Aminotransferases, alkaline phosphatase, and bilirubin Lipase and/or amylase Patients should also have an abdominal ultrasound to evaluate for hepatobiliary etiologies. Further evaluation will depend on the results of laboratory studies and ultrasound results. Patients in whom there is concern for hepatobiliary infection, particularly acute cholangitis and acute cholecystitis, should be referred for prompt evaluation. (See "Acute cholangitis: Clinical manifestations, diagnosis, and management" and "Acute calculous cholecystitis: Clinical features and diagnosis".) Epigastric pain — Patients with epigastric pain and cardiac risk factors and/or other symptoms concerning for angina (eg, shortness of breath, exertional symptoms) should have https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 8/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate appropriate cardiac evaluation. (See "Angina pectoris: Chest pain caused by fixed epicardial coronary artery obstruction", section on 'Diagnosis'.) Other patients with epigastric pain should be evaluated for pancreatitis as well as gastric etiologies ( table 1B). Patients should have the following laboratory studies: Complete blood count with differential Electrolytes, BUN, creatinine, and glucose Aminotransferases, alkaline phosphatase, and bilirubin Lipase and/or amylase If there is concern for hepatobiliary pain ( table 1C), patients should have an abdominal ultrasound for evaluation. Patients with concern for other etiologies should have appropriate evaluation (eg, if concern for peptic ulcer disease, endoscopy may be indicated). (See "Peptic ulcer disease: Clinical manifestations and diagnosis", section on 'Upper endoscopy'.) Pain limited to the epigastrium, which may be associated with bloating, abdominal fullness, heartburn, or nausea can be classified as dyspepsia ( table 5). The evaluation of dyspepsia is discussed in detail elsewhere. (See "Approach to the adult with dyspepsia", section on 'Initial evaluation'.) Left upper quadrant pain — Left upper quadrant pain can be caused by splenic etiologies ( table 1A). Patients with left upper quadrant pain should therefore be evaluated for splenomegaly and other disorders of the spleen. Most patients will have imaging with either ultrasound or computed tomography (CT) scan. However, the causes of epigastric abdominal pain are more common than splenic etiologies ( table 1B), and pain from these disorders may atypically present as left upper quadrant pain. The evaluation of patients with splenomegaly is discussed separately. (See "Splenomegaly and other splenic disorders in adults", section on 'Evaluation (splenomegaly)'.) Lower abdominal pain — Pain in the lower abdomen can be associated with the distal intestinal tract, but it may also radiate down from upper abdominal structures or up from the pelvis ( table 1E). Diagnostic evaluation will depend on suspected etiologies based on the history and physical examination. Females of childbearing age should have a pregnancy test. Females with suspected pelvic etiologies ( table 6 and table 7) should have appropriate evaluation, which is discussed elsewhere. (See "Acute pelvic pain in nonpregnant adult females: Evaluation".) https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&sel… 9/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Patients with suspected genitourinary etiologies should have appropriate evaluation (eg, patients with lower abdominal pain and concern for cystitis or pyelonephritis should have a urinalysis and culture). In male patients, scrotal examination is necessary to assess for lower abdominal presentations of testicular torsion. (See "Acute simple cystitis in females", section on 'Diagnostic approach' and "Acute simple cystitis in adult males", section on 'Diagnostic approach' and "Acute complicated urinary tract infection (including pyelonephritis) in adults", section on 'Diagnostic approach'.) Patients thought to have lower abdominal pain from gastrointestinal causes should have a complete blood count with differential. Further diagnostic testing will depend on suspected etiology. As examples: Patients with lower abdominal pain and acute diarrhea may have self-limited presentations and can be managed expectantly depending on severity of illness and other risk factors ( algorithm 1). This is discussed in detail elsewhere. (See "Approach to the adult with acute diarrhea in resource-rich settings".) Subacute right lower quadrant pain with diarrhea is the most characteristic presentation of ileal Crohn disease, although the presentation of inflammatory bowel disease (IBD) can be highly variable. (See "Approach to the adult with chronic diarrhea in resource-abundant settings", section on 'Initial evaluation'.) Acute left lower quadrant pain with fever and elevated white blood cell count is suggestive of diverticulitis. (See "Clinical manifestations and diagnosis of acute colonic diverticulitis in adults", section on 'Diagnosis'.) Patients with anemia should have evaluation for iron deficiency anemia. In older patients, iron deficiency anemia is concerning for colorectal cancer. (See "Causes and diagnosis of iron deficiency and iron deficiency anemia in adults" and "Clinical presentation, diagnosis, and staging of colorectal cancer", section on 'Symptoms from the local tumor'.) In older patients, abdominal pain and a change in bowel habits can be the first sign of colon cancer. Presentations of colonic neoplasia are highly variable, so risk factors for colon cancer (particularly age and family history) should be considered in patients with lower abdominal pain. (See "Clinical presentation, diagnosis, and staging of colorectal cancer".) Diffuse abdominal pain — Patients with diffuse or nonspecific abdominal pain may have pain from etiologies that lead to diffuse abdominal pain ( table 8) or those that tend to be more https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&s… 10/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate localized ( table 1A-C, 1E). Diagnostic evaluation will depend on suspected etiologies based on the history and physical examination. Patients with suspected acute infectious gastroenteritis or toxin-mediated food poisoning may not need further evaluation. The most useful diagnostic tool will often be watchful waiting for spontaneous recovery. Multisystem symptoms, such as upper respiratory tract involvement or myalgias, may suggest a viral etiology. A history of family members or other contacts developing a similar illness is valuable, not only because it points towards a likely diagnosis, but because the patient's illness is likely to mimic the course of their contact's illness. Depending on their degree of systemic illness, patients with self-limited symptoms may need only reassurance or may require significant supportive care. (See "Acute viral gastroenteritis in adults", section on 'Treatment'.) Patients with diffuse upper abdominal pain may have pleural or pulmonary pathology, particularly when the patient also had associated pulmonary symptoms (eg, cough, shortness of breath). Lower lobe pulmonary pathologies (eg, pneumonia, pulmonary embolism) or inflammatory pleural effusions (eg, empyema, pulmonary infarction) can present with what appears to be abdominal pain because they occur at the threshold of the abdomen. In patients with diffuse upper abdominal pain and associated pulmonary symptoms, chest imaging should be done to evaluate for thoracic etiologies. The modality will depend on suspected etiology. For example, patients with suspected pneumonia should have chest radiography, while patients with suspected pulmonary embolism should have a chest CT scan. (See "Clinical evaluation and diagnostic testing for community-acquired pneumonia in adults", section on 'Chest imaging findings' and "Overview of acute pulmonary embolism in adults", section on 'Diagnostic approach to patients with suspected PE'.) In patients with diffuse or nonspecific abdominal pain with unknown etiology, we check the following laboratory studies: Electrolytes, with calculation of an anion gap BUN, creatinine, blood glucose Calcium Complete blood count with differential Lipase and/or amylase Pregnancy test in females of childbearing age In older adult or immunosuppressed patients who may have atypical presentations of biliary tree infection, we also check aminotransferases, alkaline phosphatase, and bilirubin Further evaluation will depend on results from the initial evaluation. As examples: https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&s… 11/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Patients with history concerning for IBD with extraintestinal manifestations ( table 3) and/or family history should be evaluated as appropriate. (See "Clinical manifestations, diagnosis, and prognosis of ulcerative colitis in adults", section on 'Diagnosis' and "Clinical manifestations, diagnosis, and prognosis of Crohn disease in adults", section on 'Diagnostic evaluation'.) The combination of metabolic acidosis and an elevated blood glucose strongly suggests diabetic ketoacidosis (DKA) as the etiology of the symptoms. It is important to keep in mind that an intraabdominal infection could precipitate DKA in a patient with diabetes. (See "Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Clinical features, evaluation, and diagnosis".) Patients with hyponatremia or hyperkalemia and symptoms of fatigue, malaise, nausea and vomiting, and symptoms of hypotension may have adrenal insufficiency. (See "Clinical manifestations of adrenal insufficiency in adults".) Hypercalcemia can cause abdominal pain, either directly or as an etiology for pancreatitis or constipation. (See "Clinical manifestations of hypercalcemia", section on 'Gastrointestinal'.) DIAGNOSTIC APPROACH TO CHRONIC ABDOMINAL PAIN Chronic abdominal pain is a common complaint, and the vast majority of patients will have a functional disorder, most commonly irritable bowel syndrome (IBS) [11,12]. The evaluation of chronic lower abdominal pain (pelvic pain) in females is discussed separately. (See "Clinical manifestations and diagnosis of irritable bowel syndrome in adults", section on 'Chronic abdominal pain' and "Chronic pelvic pain in nonpregnant adult females: Causes".) Initial workup — Initial workup is focused on differentiating benign functional illness from organic pathology. Features that suggest organic illness include weight loss, fever, hypovolemia, electrolyte abnormalities, symptoms or signs of gastrointestinal blood loss, anemia, or signs of malnutrition. Laboratory studies should be normal in patients with functional abdominal pain. The following laboratory measurements should be performed in most patients with chronic abdominal pain: Complete blood count with differential Electrolytes, blood urea nitrogen (BUN), creatinine, and glucose https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&s… 12/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Calcium Aminotransferases, alkaline phosphatase, and bilirubin Lipase and/or amylase Serum iron, total iron binding capacity, and ferritin Anti-tissue transglutaminase Further evaluation with imaging will depend on the differential diagnosis based on the history, physical, and laboratory studies. For example: Laboratory studies suggestive of iron deficiency should raise the suspicion of celiac disease, inflammatory bowel disease (IBD), or malignancy (eg, colorectal cancer). (See "Causes and diagnosis of iron deficiency and iron deficiency anemia in adults" and "Clinical manifestations, diagnosis, and prognosis of Crohn disease in adults", section on 'Clinical features' and "Clinical manifestations, diagnosis, and prognosis of ulcerative colitis in adults", section on 'Clinical manifestations' and "Clinical presentation, diagnosis, and staging of colorectal cancer".) In patients where IBD remains in the differential diagnosis but index of suspicion is low, fecal calprotectin, which is sensitive for detection of intestinal inflammation, may be used to select patients for colonoscopy. (See "Approach to the adult with chronic diarrhea in resource-abundant settings", section on 'General laboratory tests'.) A history of recurrent pancreatitis or excessive alcohol intake should raise suspicion for chronic pancreatitis. (See "Chronic pancreatitis: Clinical manifestations and diagnosis in adults".) Abdominal pain is not a common presentation of hypothyroidism, but when additional symptoms ( table 9) suggest abnormalities of thyroid function, a thyroid-stimulating hormone should be measured. Hypothyroidism can occasionally cause abdominal pain in the setting of constipation and ileus. (See "Diagnosis of and screening for hypothyroidism in nonpregnant adults", section on 'Clinical features'.) While the hallmark of IBS is pain associated with changes in bowel habit, other related functional disorders may present with isolated pain (such as functional abdominal pain syndrome) or with pain mimicking upper gastrointestinal organic pathology (such as functional dyspepsia). (See "Clinical manifestations and diagnosis of irritable bowel syndrome in adults" and "Functional dyspepsia in adults".) Subsequent workup — At the conclusion of the initial workup, young patients with no evidence of organic disease can be treated symptomatically. The use of further invasive testing https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&s… 13/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate should be directed at ruling in or out specific diseases and not as a general screen. However, a diagnosis of new-onset functional illness should be made only with great caution in patients over 50 years of age. These patients, by virtue of their increased risk of malignancy, will likely require abdominal imaging as their symptoms and signs dictate. Some patients have a history of pain that is likely organic, based on historical features or laboratory abnormalities, but may be difficult to definitively diagnose because the symptoms are intermittent. Less common causes of abdominal pain ( table 1D) should be considered in patients with repeated visits for the same complaint without a definite diagnosis, in an ill- appearing patient with minimal or nonspecific findings, in patients with pain out of proportion to clinical findings, and in immunocompromised patients. Examples of such cases include: Right upper quadrant pain after cholecystectomy that mimics biliary colic and could be functional biliary pain; it could also arise from intermittent passage of stones that have formed in the bile ducts, passage of sludge, or sphincter of Oddi dysfunction. Chronic, partial small bowel obstruction may occur in some patients. Patients usually present with chronic postprandial abdominal discomfort and variable nausea. Abdominal distention and tympany may be present, but usually without any fluid or electrolyte derangements. (See "Etiologies, clinical manifestations, and diagnosis of mechanical small bowel obstruction in adults", section on 'Chronic partial obstruction'.) Very rare causes of intermittent acute severe abdominal pain should be considered in the setting of a positive family history (eg, familial Mediterranean fever, hereditary angioedema, acute intermittent porphyria [AIP]); in the case of AIP, the diagnosis may be considered even without a family history of the disease. (See "Clinical manifestations and diagnosis of familial Mediterranean fever" and "Hereditary angioedema: Epidemiology, clinical manifestations, exacerbating factors, and prognosis" and "Porphyrias: An overview", section on 'Acute hepatic porphyrias (AHP)' and "Acute intermittent porphyria: Pathogenesis, clinical features, and diagnosis".) SPECIAL POPULATIONS Pelvic etiologies of abdominal pain ( table 6) should be considered in females. Other populations of patients, including older adults , and patients with human immunodeficiency virus (HIV) may present with unusual causes of abdominal pain or may have unusual presentations of common disorders. https://www.uptodate.com/contents/evaluation-of-the-adult-with-abdominal-pain/print?search=approach to abdominal pain&source=search_result&s… 14/42 8/24/23, 12:16 PM Evaluation of the adult with abdominal pain - UpToDate Females — Lower abdominal pain in females must be considered as a spectrum with causes of pelvic pain ( table 6). The evaluation of pelvic pain in females is discussed separately. (See "Acute pelvic pain in nonpregnant adult females: Evaluation" and "Chronic pelvic pain in adult females: Evaluation".) Acute abdominal pain in pregnant and postpartum individuals may or may not be related to pregnancy. (See "Approach to acute abdominal/pelvic pain in pregnant and postpartum patients".) Older adults — Older adult patients often do not present with the same signs and symptoms of disease characteristic of younger individuals. Older patients may not have fever or abnormal laboratory values with infectious etiologies for abdominal pain. The frequency of misdiagnosis of the acute abdomen in older patients is high and associated with higher mortality rates than in younger patients. A particularly high level of suspicion should be maintained for severe pathology in immunosuppressed patients (including those taking immunosuppressive agents or having comorbidities affecting immune function, such as diabetes or renal failure) and older adults, where classic signs of peritoneal inflammation may be attenuated. Sickle cell — Patients with sickle cell disease may have right upper quadrant pain in the setting of hepatic involvement. The liver can be affected by a number of complications due to the disease itself and its treatment. (See "Hepatic manifestations of sickle cell disease", section on 'Disorders associated with the sickling process' and "Hepatic manifestations of sickle cell disease", section on 'Disorders related to coexisting conditions'.) HIV-infected patients — Diagnostic evaluation of abdominal pain in the HIV-infected patient is similar to that in the general population, but it is also guided by the immunologic function as represented by the CD4 cell count. The differential diagnosis includes common etiologies seen in the general population (eg, appendicitis, diverticulitis) but also opportunistic infections (eg, cytomegalovirus [CMV], Mycobacterium avium complex [MAC], cryptosporidium) and neoplasms (eg, Kaposi sarcoma, lymphoma) if there is evidence of advanced immunodeficiency (CD4 cell count