Evidence-Based Medicine Approach to Abdominal Pain

The chief complaint of abdominal pain accounts for 5% to 10% of all presentations in the emergency department. With such broad differential and diagnostic modalities available, this article focuses on a systematic approach to evaluating abdominal pain, essential to providing patients with efficient and accurate care.

Key points

  • A systematic approach to evaluating abdominal pain can provide patients with efficient and accurate care.

  • A thorough history to localize the abdominal pain and associated symptoms can help to create a differential diagnosis.

  • The cough test, inspiration test, and peritonitis test can help to determine if a patient has a concerning abdominal examination.

  • Bedside ultrasound and upright plain radiograph are of utility in an unstable patient to determine the cause of the abdominal pain.

  • Pain medication should not be withheld in a patient presenting with abdominal pain.


The chief complaint of abdominal pain accounts for 5% to 10% of all presentations in the emergency department (ED). With such broad differential and diagnostic modalities available, a systematic approach to evaluating abdominal pain is essential to provide patients with efficient and accurate care. Using evidence-based principles, the approach to abdominal pain can be simplified.


The chief complaint of abdominal pain accounts for 5% to 10% of all presentations in the emergency department (ED). With such broad differential and diagnostic modalities available, a systematic approach to evaluating abdominal pain is essential to provide patients with efficient and accurate care. Using evidence-based principles, the approach to abdominal pain can be simplified.

History of presenting illness

The history of presenting illness is arguably the single most important part in the evaluation of a patient with abdominal pain. History and physical examination alone were able to determine between organic and nonorganic causes of abdominal pain in 79% of patients. Another study demonstrated that a careful history alone can lead to the correct diagnosis in up to 76% of cases. Several key characteristics of a patient’s history can help guide the differential diagnosis.


The timing of patients’ pain can help determine acuity, progression of symptoms, and likelihood of emergent cause. Acute severe pain is more likely to be associated with serious, emergent cause, such as ruptured abdominal aortic aneurysm (AAA), mesenteric ischemia, and bowel perforation. A large retrospective and prospective study demonstrated this when most of the patients with a perforated peptic ulcer presented within 12 hours of symptom onset. More insidious pain correlates with a developing inflammatory or infectious pathologic conditions, such as cholecystitis, appendicitis, or small bowel obstruction (SBO). An example was found in one study demonstrated most patients with appendicitis presenting at 12 to 23 hours of symptoms onset and most patients with diverticulitis presenting after 48 hours.


Location of pain is a key part in determining the affected organs. Understanding the embryologic derivation of the gastrointestinal organs can help the examiner narrow down a differential. Localized pain in the epigastrium is highly specific for diseases of the foregut structures, including the stomach, pancreas, liver, and proximal duodenum. Periumbilical pain is 99% specific for diseases of the midgut region or intestine, including the remaining small bowel, proximal third of the colon, and the appendix. Finally, localized suprapubic pain is associated with the hindgut organs or the remaining two-thirds of the colon, the bladder, and the genitourinary organs. Table 1 demonstrates potential differential diagnosis based on the information obtained from the history of presenting illness.

Table 1

Differential diagnosis based on location of abdominal pain

Location Differential Diagnosis
RUQ Biliary : cholecystitis, cholelithiasis, cholangitis
Hepatic : hepatitis, hepatic abscess
Others : pneumonia, pulmonary embolism, pancreatitis, peptic ulcer disease, retrocecal appendicitis
LUQ Splenic : splenic infarct, splenic laceration
Cardiac : myocardial infarction, pericarditis
Others : pneumonia, pulmonary embolism, pancreatitis, peptic ulcer disease, diaphragmatic hernia
Epigastric Gastric : peptic ulcer disease, gastritis
Pancreatic : pancreatitis
Biliary : cholecystitis, cholelithiasis, cholangitis
RLQ Colonic : appendicitis, cecal diverticulitis, cecal volvulus
Genitourinary : nephrolithiasis, ovarian torsion, PID, ectopic pregnancy, testicular torsion, inguinal hernia
Others : mesenteric adenitis
LLQ Colonic : sigmoid diverticulitis
Genitourinary : nephrolithiasis, ovarian torsion, PID, ectopic pregnancy, testicular torsion, inguinal hernia
Others : abdominal aortic aneurysm

Abbreviations: LLQ, left lower quadrant; LUQ, left upper quadrant; PID, pelvic inflammatory disease; RLQ, right lower quadrant; RUQ, right upper quadrant.

Furthermore, many abdominal pain diagnoses are associated with a typical location of pain. For example, right lower quadrant pain has proven to be highly sensitive for appendicitis, whereas right upper quadrant pain is highly sensitive for cholecystitis. Both right lower quadrant pain and right upper quadrant pain are only moderately specific for appendicitis and cholecystitis, respectively, as there are other processes that can manifest in these areas. Left lower quadrant pain is highly associated with diverticulitis. Finally, a study on bowel obstructions demonstrated that generalized abdominal pain is 93.1% specific for this disease process.


The character of pain can help determine the pathophysiologic process causing patients pain. Visceral nerve fibers, or the fibers that innervate organs, are typically poorly localized. These fibers, when activated, cause an aching or dull pain. Activation of these fibers may occur from stretching, increased peristalsis, or ischemia. The high specificity of colicky abdominal pain for a SBO, for example, demonstrates activation of visceral nerve fibers.

Somatic fibers innervate the peritoneum. When activated or irritated by blood or inflammation, these nerve fibers cause a sharp, well-localized pain. One study designed to identify factors of the history and physical associated with ectopic pregnancies found that when compared with an intrauterine pregnancy, ectopic pregnancies are much more likely to present with sharp abdominal pain.


Inquiring about radiation of pain can further help the clinician deduce the pathophysiologic process causing patients’ abdominal pain. In disease processes, such as those involving the liver, biliary tract, or appendix, radiation or migration of pain can be very pertinent. Gallstone pain, for example, is highly associated with radiation from the right upper quadrant to the upper back. Right subcostal pain is also highly specific for diseases of the liver and biliary tract. Migration of pain from the periumbilical region to the right lower quadrant has proven to be both highly sensitive and specific for appendicitis.

Palliative, Provoking, or Associated Factors

Association of pain with outside factors can provide insight into the differential diagnoses. For example, relief of pain by vomiting and also increased pain with eating is highly specific for SBO. Associated vomiting is a less specific symptom but is seen in 100% of cases of gastroenteritis and 77% of cases of cholecystitis. Furthermore, anorexia is associated with most cases of SBO, appendicitis, and cholecystitis.

Table 2 demonstrates a summary of the clinical features that are associated with each disease process with the associated sensitivity and specificity.

Table 2

Clinical features with sensitivities/specificities based on diagnosis

Diagnosis Clinical Features Sensitivity (%) Specificity (%)
Appendicitis RLQ pain 81 53
Pain before vomiting 100 64
Anorexia 68 36
No pain previously 81 41
Migration of pain 69 84
Nausea and emesis 74 36
Cholecystitis RUQ pain 81 67
Nausea 77 36
Emesis 71 53
Anorexia 65 50
Fever 35 80
Mesenteric ischemia History of atrial fibrillation 7.7–79.0
Hypercoagulable state 2.4–29.0
Acute abdominal pain 60–100
Nausea/vomiting 39–93
Diarrhea 18–48
Rectal bleeding 12–48
SBO Generalized pain at onset 22.9 93.1
Colicky pain 31.2 89.4
Relief of pain by vomiting 27.1 93.7
Increased pain with eating 16.7 94
Previous abdominal surgeries 68.8 74
Vomiting 75.0 65.3
History of constipation 43.8 95

Abbreviations: RLQ, right lower quadrant; RUQ, right upper quadrant.

Past Medical, Surgical, and Social History

Patients’ past medical, surgical, and social history can provide crucial information to further aid in constructing the appropriate differential diagnosis. Recurrence of a similar pain can often be seen in cases of nephrolithiasis, diverticulosis, or gallstone disease, as seen in a study that showed that most patients with cholecystitis reported previous episodes of abdominal pain. This finding is in contrast to new onset of abdominal pain, which is highly sensitive for appendicitis.

Comorbid conditions can help point to a specific diagnosis. For example, patients with type II diabetes have almost a 1.5 times higher risk of acute pancreatitis than nondiabetic patients. Acute abdominal pain in patients with a history of atrial fibrillation has been shown in some studies to be highly sensitive for mesenteric ischemia. Another study showed that half of patients diagnosed with mesenteric ischemia have a history of prior deep vein thrombosis.

Medication use can provide insight into the cause of patients’ pain as well. Nonsteroidal antiinflammatory drug (NSAID) use in elderly patients was associated with a 4-fold increased risk of upper gastrointestinal (GI) bleeding or death from a peptic ulcer from that of nonusers.

A history of multiple abdominal surgeries may raise the diagnostician’s concern for SBO. One study showed that more than three-quarters of patients with a SBO had previous abdominal surgery.

Additionally, a comprehensive social history can shed light on potential leading diagnoses. A smoking history puts patients at a 7.6 times higher risk of developing an AAA when compared with nonsmokers. Illicit drug use is also an important risk factor, as multiple case reports have documented cocaine abuse and its association with acute mesenteric ischemia.

Not to be ignored is the gynecologic history in female patients. History of vaginal bleeding, discharge, prior ectopic pregnancies, and exposure to sexually transmitted infections (STIs) are just a few of the components that can lead to an alternate diagnosis. Ectopic pregnancies have proven to be associated with a prior history of intrauterine device (IUD), history of infertility, and tubal ligation.

Physical examination

Once a thorough history of presenting illness is obtained, the physical examination helps further narrow the differential diagnosis and better localize patients’ abdominal pain to specific areas and/or organ systems. A complete physical examination includes a review of patients’ vital signs and an inspection of other body areas outside of the GI system, particularly the genitourinary system, cardiopulmonary system, and skin.

General Appearance

Patients’ general appearance can be very useful in assessing severity/acuity of their abdominal pain. Patients who are pale, confused, or in severe distress tend to have a higher-acuity illness. However, atypical presentations of abdominal pain can be seen in certain patient populations, such as elderly patients who might not mount an adequate response. The physical examination may demonstrate this, as the slightest movement of abdomen will elicit pain, raising concerns for the presence of peritonitis. Another observation from the general examination can be seen in patients who cannot seem to find a comfortable position while lying on the bed. This pain is suggestive of renal colic. These simple observations on initial evaluation of patients can demonstrate acuity, severity, and characteristics of the abdominal pain.

Vital Signs

Vital sign abnormalities can signify a more serious cause of abdominal pain, but normal vital signs do not exclude emergent diagnoses. Box 1 demonstrates clinical considerations regarding analysis of vital signs.

Box 1

  • 1.

    Fever: It is suggestive of infection or inflammation and may be absent in elderly and immunocompromised patients.

  • 2.

    Blood pressure: Hypotension may indicate sepsis, hemorrhage, and severe dehydration.

  • 3.

    Heart rate: Tachycardia is suggestive of pain, sepsis, hemorrhage, and volume depletion from third spacing and may be absent in patients on beta-blockers.

  • 4.

    Respiratory rate: Tachypnea can indicate metabolic acidosis with respiratory compensation or increased pain. Nonspecific findings are seen in cardiac/pulmonary diseases.

Vital signs clinical considerations

Approach to Unstable Patients with Abdominal Pain

If patients appear ill with unstable vital signs, such as hypotension, volume resuscitation should be started immediately in conjunction with assessing for life-threatening pathologies requiring immediate surgical intervention. Box 2 reviews differential diagnosis considerations in unstable patients with abdominal pain.

Box 2

  • GI bleed

  • Ruptured AAA

  • Massive pulmonary embolism

  • Perforated viscus

  • Ruptured ectopic pregnancy

Differential diagnosis for the unstable patient

Physical Examination Findings

Table 3 demonstrates the classic presentation and considerations for various diagnoses considered in patients with abdominal pain.

Table 3

Classic presentation and clinical consideration based on diagnosis

Differential Diagnosis Classic Presentation Considerations
Appendicitis Periumbilical abdominal pain localizing to RLQ, anorexia, nausea, fever RLQ tenderness is LR+ = 8.0.
Psoas sign is LR+ = 2.38.
Bowel obstruction Abdominal distention, nausea, anorexia, constipation Distention is LR+ = 5.6–16.8.
Cholecystitis Periumbilical abdominal pain localizing to RUQ, anorexia, nausea, fever Murphy sign is a strong positive predictor of cholecystitis: LR+ = 2.8.
Diverticulitis LLQ, fever Localizing tenderness in LLQ is LR+ = 10.4.
EP Abdominal pain, amenorrhea, vaginal bleed Presence of cervical motion tenderness, peritonitis, and lateralizing symptoms all increase the likelihood of EP.
Mesenteric ischemia Abdominal pain out of proportion with examination finding, nausea, anorexia Presence of peritonitis, abdominal distention, or diffuse pain can be suggestive of diagnosis.
Pancreatitis Abdominal pain radiating to back, nausea, vomiting Grey-Turner or Cullen sign can suggest necrotizing pancreatitis.
Perforated viscus Severe generalized abdominal pain, peritoneal sign
Peptic ulcer disease Epigastric pain that is associated with food intake
Ovarian torsion Sudden onset of severe, unilateral lower abdominal pain, nausea A known history of ovarian cyst/mass increases the likelihood of torsion.
Ruptured AAA Abdominal pain and/or back pain + pulsatile abdominal mass Pulsatile abdominal mass LR+ for presence of AAA = 12.0–15.6
Ureterolithiasis Acute onset flank pain radiating to groin, nausea It can mimic ruptured AAA.

Abbreviations: EP, ectopic pregnancy; LLQ, left lower quadrant; LR, likelihood ratio; RLQ, right lower quadrant.

Data from Refs.


Inspection of the abdomen is a fast and easy way to collect useful information. The presence of a surgical scar indicates a history of abdominal surgery, which is a risk factor for certain pathologies, such as bowel obstruction or viscus perforation in the right clinical context. The presence of abdominal distention has a high likelihood ratio (LR) for bowel obstruction (LR+ = 5.6–16.8), though ascites or even intraperitoneal bleed can also present this way. Table 4 demonstrates clinical clues from inspection and differential diagnosis associated with symptoms.

Table 4

Differential diagnosis based on inspection clues

Inspection Clues Diagnosis to Consider
Surgical scar Obstruction
Perforated viscus
Ecchymosis Retroperitoneal bleed
Grey-Turner: bilateral flanks Acute pancreatitis, retroperitoneal hematoma, ruptured ectopic pregnancy
Cullen: umbilicus Ectopic pregnancy, acute Pancreatitis, retroperitoneal hematoma
Fox: inguinal canal Traumatic injury to pancreas, kidneys, aorta, ascending/descending colon
Bryant: scrotal Ruptured AAA
Abdominal distension Obstruction, ascites
Vesicular rash in dermatome distribution Herpes zoster


Auscultation is often done but might be of limited use. Nevertheless, the presence of high-pitched bowel sounds could indicate early SBO, whereas hypoactive bowel sounds could indicate late bowel obstruction, ileus, or many other pathologies, as it is a nonspecific finding.


Percussion can be used to distinguish between distention caused by air (tympanic) and fluid (dull + fluid wave). If in doubt, bedside ultrasound can be used.

Detecting the presence of peritoneal irritation should be the primary goal of any proper abdominal examination as peritonitis is often a sign of more emergent pathologies. Unfortunately, physical examination is not error proof in confirming peritonitis. Rebound tenderness and involuntary guarding are traditionally used, but they are not perfect. Several other examination techniques in our arsenal can help in evaluating peritonitis more reliably. Box 3 demonstrates a differential diagnosis for patients with concerns of peritonitis on bedside physical examination.

Box 3

  • Cholecystitis

  • Perforated appendicitis

  • Boerhaave syndrome

  • Perforated peptic ulcer

  • Perforated viscus

  • Peritonitis

  • Malignancy

  • Mesenteric ischemia

  • Strangulated hernia

  • Spontaneous bacterial peritonitis

  • Tubo-ovarian abscess

  • Volvulus

Differential diagnosis for the acute surgical abdomen


Involuntary guarding (or rigidity) indicates reflex spasm of abdominal muscle due to peritoneal irritation. This guarding is unlike voluntary guarding, which can be due to fear, anxiety, ticklishness, and so forth, and is distractible. True guarding is best exemplified by rigidity and can be characterized by continuous increase in muscle tone throughout respiratory cycle, whereas patients with voluntary guarding would generally show decreased tone during inspiration. Beware relying on involuntary guarding to diagnose elderly patients, as they might not exhibit any guarding or rigidity.

Rebound Tenderness and Alternative Techniques

The rebound tenderness maneuver is done by slow, deep palpation followed by abrupt removal of the examiner’s finger. The test is positive if pain increases with release of the finger as opposed to during compression. However, this test can be falsely positive in one-quarter of patients. Thus, alternative ways have been devised, including cough test, jump test, and heel-strike test. In general, the more tests that are positive in patients, the likelier that the diagnosis is true peritonitis. The cough test has similar sensitivity as traditional rebound testing but with a higher specificity (79% vs 40%–50%). Together with clinical correlation, these techniques can help us in detecting patients with peritoneal irritation and, thus, possible abdominal catastrophe. Box 4 shows a summary of the techniques to elicit if patients have rebound tenderness.

Box 4

  • Maneuvers to elicit signs of peritonitis

  • Cough test : positive when pain is elicited with coughing

  • Inspiration test : positive when pain is exhibited when exhaling and puffing the stomach out

  • Peritoneal irritation : positive when asking patients to jump (especially in children), tapping the heel, or bumping the bed

Evaluation techniques for peritonitis

Data from Bundy DG, Byerley JS, Liles EA, et al. Does this child have appendicitis? JAMA 2007;298(4):438–51; and Bennett DH, Tambeur LJ, Campbell WB. Use of coughing test to diagnosis peritonitis. BMJ 1994;308(6940):1336.

Localized Tenderness

Localized tenderness has a broad differential, but we can narrow this differential based on which quadrant is maximally tender.

Special Examination Techniques to Help with Specific Diagnoses

There are special examination techniques that have been associated with specific diagnosis to help determine the likelihood of this entity. For example, the Murphy sign has an LR of 2.8 for acute cholecystitis with a specificity of 87%. Out of all examination findings studied, the Murphy sign is the strongest positive predictor for acute cholecystitis.

Psoas, obturator, and the Rovsing signs are associated with appendicitis. Although these maneuvers have not been studied extensively, they have been demonstrated to have low sensitivity plus high specificity in several studies, meaning they are more useful if present but do not rule out appendicitis if absent. The psoas sign has an LR of 2.4 for appendicitis. However, various other conditions that cause retroperitoneal inflammation can also elicit this sign, including psoas abscess, pancreatitis, and pyelonephritis. The obturator sign has a similar LR as the psoas sign. It suggests an inflammatory process adjacent to the pelvic wall musculature, including appendicitis. The Rovsing sign is an indirect test for rebound tenderness. Box 5 demonstrates special maneuvers used in diagnosing appendicitis.

Box 5

  • Special examination maneuvers

  • Murphy sign : positive if patients exhibit inspiratory arrest during deep RUQ palpation

  • Psoas sign : positive if pain is elicited with passive hip extension

  • Obturator sign : positive if pain is elicited with passive internal/external rotation of the right hip

  • Rovsing sign : positive if pain is elicited in RLQ when the examiner exerts pressure on the LLQ

Abbreviations: LLQ, left lower quadrant; RLQ, right lower quadrant; RUQ, right upper quadrant.

Special maneuvers based on suspected diagnosis

Data from Refs.

Examination for pulsatile mass is an examination maneuver specific for diagnosis of AAA. This examination finding has a high LR+ of 12.0 to 15.6, depending on AAA size. Palpation of AAA is safe and has not been reported to precipitate rupture. It is the only examination maneuver that has been found to be of any value in detecting AAA, especially ones large enough to warrant intervention.

Rectal Examination

Digital rectal examination has a limited role in the evaluation of undifferentiated abdominal pain or acute appendicitis, and its routine performance in patients with undifferentiated abdominal pain has not been supported by literature. However, in select cases it can yield useful information, as in the case of constipation, anorectal complaints, or GI bleed. Box 6 demonstrates when a rectal examination may be useful.

Box 6

  • Rectal examination may be useful in

  • Acute GI bleed

  • Colon cancer

  • Intussusception

  • Ischemic colitis

  • Perirectal disorder (abscess)

  • Rectal foreign body

  • Stool impaction

Diagnoses whereby rectal examination may have utility

Extra-abdominal Examination

A thorough cardiopulmonary examination should be done, as any intrathoracic disease process can present as abdominal pain.

Pelvic examination should be done to assess for pelvic peritoneal through testing for cervical motion tenderness and to directly visualize cervix for signs of vaginal discharge or bleeding. Although some evidence suggests empiric pelvic examinations performed in the ED on all female patients with abdominal pain might not yield useful data, guidelines still recommend performing a pelvic examination on almost all female patients with lower abdominal pain.

Similarly, male genitourinary examination is important in male patients with abdominal pain to assess for signs of testicular torsions, trauma, strangulated hernias, or infections, including Fournier gangrene and STIs. The flank/back should be tested for the presence of costovertebral angle (CVA) tenderness, which can reflect the presence of pyelonephritis or obstructive uropathy. Box 7 discusses extra-abdominal diagnosis considerations.

Dec 14, 2017 | Posted by in Uncategorized | Comments Off on Evidence-Based Medicine Approach to Abdominal Pain
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