Approach to Abdominal Pain
Author: Luz Silverio, MD, Santa Clara Valley Medical Center
Editor: Jared Strote, MD, University of Washington
Last Updated: September, 2019
Case Study: A 43 year-old female with a past medical history of cesarean section presents with four hours of abdominal pain. Pain is located in the right upper quadrant with radiation to the epigastrium and associated with 2 episodes of nonbloody, nonbilious emesis. She ate a cheeseburger with fries and had two beers shortly before the onset of pain. She has had pain like this in the past but this is the first time it has persisted despite acetaminophen. She has no family history, drinks 8-9 alcoholic beverages per week, and is sexually active with her husband. On examination, her vitals are within normal limits and stable and she has tenderness to palpation to the right upper quadrant (positive Murphy’s) without rebound or peritoneal signs. She has no CVA tenderness or lower abdominal tenderness. The remainder of her examination is normal.
By the end of this module, the student will be able to:
- Recognize physical exam findings requiring emergent resuscitation in the patient presenting with abdominal pain
- Create a broad differential for abdominal pain, including extra-abdominal causes
- Recognize the critical diagnoses for abdominal pain
- Discuss the advantages and limitations of different radiologic modalities used in the evaluation of abdominal pain
- Discuss the treatment and disposition for the critical diagnoses for abdominal pain
Abdominal pain is the most common emergency department (ED) chief complaint in adult patients. In the US, abdominal pain is responsible for more than 7 million ED visits per year. Despite this frequency, it remains a challenging complaint due to the large number of possible etiologies and widely variable clinical presentations. While a specific diagnosis is frequently difficult to make in the ED (approximately 25% of presenting patients are ultimately diagnosed with ‘nonspecific abdominal pain’), it is imperative that the emergency physician exclude time-dependent disease processes that if left undiagnosed could lead to morbidity or mortality.
Initial Actions and Primary Survey
A primary assessment and evaluation of ABCs must be completed on any patient presenting to the emergency department with abdominal pain. While airway compromise and respiratory insufficiency can develop in a patient suffering from an abdominal catastrophe, the circulatory system most commonly needs the attention of the clinician in the setting of abdominal pain.
Abdominal pain in conjunction with hemodynamic instability should alert the physician to the possibility of hemorrhage, sepsis, perforated viscus, or necrotic bowel. Tachycardia or orthostatic vital signs are often the first sign of hemodynamic instability; it requires blood loss of 30-40% of normal blood volume to cause a significant drop in systolic blood pressure. In patients with established hemodynamic instability, immediate fluid resuscitation should begin by establishing 2 large bore IVs and rapidly infusing isotonic crystalloid. Supplemental oxygen should be administered, and patients should be placed on a monitor.
The primary survey of patients with abdominal pain should include a brief history evaluating for symptoms of infection, bleeding diathesis, and the possibility of pregnancy; an abdominal examination should be performed for the presence of peritonitis, as this indicates a patient requiring more immediate surgical intervention.
In the unstable patient with abdominal pain in whom hemorrhage is diagnosed or highly suspected, typed and crossed blood should be immediately ordered. The transfusion of type O blood can be performed in critical situations where there is not enough time to wait for cross matched blood.
Women of childbearing age who present with abdominal pain require urgent pregnancy testing to rule out ectopic pregnancy. When such a patient is unstable, rapidly obtain either urine serum for qualitative beta-HCG testing. If the patient is pregnant, blood should also be sent for a quantitative beta-HCG level.
Patients with abdominal pain have a wide range of potential presentations. A thorough history will catch potentially challenging diagnoses in otherwise unrevealing presentations. A clear description of the pain itself is often quite helpful in narrowing down the cause of abdominal pain. Elicit:
- provocative, palliative factors
- symptoms associated with the pain
- progression and migration
For example, pain that is constant, originally located in the periumbilical area but now migrated to the right lower quadrant, and palliated by staying still is quite different than a pain that is located in the epigastrium with radiation to the right upper quadrant, worsened with oral intake, and associated with fever and vomiting.
In addition to evaluation of the pain, a brief evaluation of the patient’s previous medical, surgical history, and risk factors may increase your suspicion for particular pathologies. A medical history of diabetes or HIV may result in an atypical presentation of a common complaint. A history of abdominal surgeries or hernias increases the likelihood of bowel obstruction. The social history of a patient with abdominal pain can also be similarly illustrative. Sexual activity puts the patient at risk for sexually transmitted infections and, in the case of the female patient, ectopic pregnancy. A recent diet of highly acidic food, food with significant fats, or alcohol can increase the patient’s risk of gastritis, cholecystitis, or pancreatitis respectively. Ask your patient about similar episodes and associated diagnostics and treatments.
A thorough abdominal examination includes inspection, auscultation, and palpation. Inspect the patient for surgical scars and evidence of distension. Auscultate for bowel sounds is not considered to be diagnostic and can be unreliable. Palpation should focus on the presence or absence of rigidity and the location of primary tenderness, as this will help guide the differential diagnosis. The presence of a Murphy’s sign in the right upper quadrant may suggest gallbladder pathology. Tenderness at McBurney’s point in the right lower quadrant may suggest appendicitis.
In addition to palpation of the abdomen, the costovertebral angles should be percussed for evaluation of the kidneys. In the setting of lower abdominal pain, an evaluation of the genitalia should be completed. In males, this is relevant for referred pain secondary to testicular torsion, infection, or incarcerated hernia. In females, ovarian torsion, pelvic inflammatory disease, and ectopic pregnancy will often present as abdominal pain.
The most common approach to the diagnosis of abdominal pain focuses on the location of the pain, with a separate grouping for causes of diffuse abdominal pain. Two other factors that need to be considered up front with abdominal pain include sex and age. Although these lists are useful as an initial approach, it is important to remember that it is common to see diagnoses present with pain and tenderness where it isn’t expected. It is important to begin your differential diagnoses with the potential life-threatening or critical diagnoses in order to rule them out. These diagnoses are highlighted in the tables below and link to their chapters within the site.
|Table 1: Differential Diagnosis of abdominal pain by location|
|Right Upper Quadrant||Left Upper Quadrant|
|Right Lower Quadrant||Left Lower Quadrant|
Table 2: Differential Diagnosis for diffuse abdominal pain
Diagnostic testing should be guided by the patient’s history and physical examination findings which can be used to initially narrow the differential diagnosis. Standard “abdominal labs” are listed below, but should be tailored to the patient’s presentation. Refer to the Common Laboratory Studies chapter for further information about each test.
- Complete blood count
- Liver function tests
- Urine analysis
- Beta- HCG (females only)
In addition to these labs, further labs that can be helpful in particular presentations of abdominal pain include: troponin, coagulation studies including prothrombin time and partial thromboplastin time, lactate, C reactive protein, and gonococcal/chlamydia testing.
Portable x-ray and ultrasound can serve as immediate diagnostic tools that can be performed at the bedside when there is concern for pneumoperitoneum or hemoperitoneum, respectively. An upright chest x-ray or lateral decubitus abdominal film has been demonstrated to reveal free air in 80% of cases with perforated viscus.
Ultrasound is an excellent tool for the evaluation of many urgent causes of abdominal pain. Bedside ultrasound can be used to search for abdominal free fluid suggestive of hemoperitoneum along with possible etiologies such as a ruptured abdominal aortic aneurysm (AAA) or ruptured ectopic pregnancy. Bedside and radiology-performed ultrasound can also be diagnostic of nephrolithiasis, abdominal aneurysms, and in slender patients, appendicitis. An ultrasound verifying intrauterine pregnancy can help to rule out ectopic pregnancy in the case of the pregnant female. It may not entirely rule out ectopic or heterotopic pregnancy. Ultrasound is the diagnostic modality of choice for patients with suspected biliary pathology and ovarian and testicular torsion.
For patients presenting with concerning findings in whom ultrasound is unlikely to be diagnostic, CT should be considered. The use of CT scans can improve diagnosis and treatment of acute abdominal pain and decrease return visits by up to 30%. On the other hand, computed tomography carries significant radiation exposure and cost, can lead to false positives, and does not completely rule out all serious life-threatening illnesses causing abdominal pain.
Antibiotics: The abdomen is a frequent site of infection in the development of sepsis. Patients with abdominal pain who are found to be septic should receive early administration of antibiotics as part of their initial resuscitation. Antibiotics should also be given promptly to patients with peritonitis or a perforated viscus.
Antiemetics: Abdominal pain is frequently associated with nausea and vomiting. Two commonly used drugs for nausea and vomiting in the emergency department are ondansetron and metoclopramide and they have been demonstrated to be roughly equivalent in efficacy. Ondansetron is given 4-8 milligrams orally or intravenously every 4 hours; metoclopramide is given 10 milligrams intravenously, sometimes with the addition of diphenhydramine to prevent extrapyramidal side effects.
Analgesia: Patients presenting in significant abdominal discomfort and a history and physical suggesting a concerning diagnosis should be provided with immediate pain relief. Narcotic medication should not be withheld out of concern that the abdominal exam may become unreliable and the diagnosis therefore obscured. Fentanyl provides a nice option if a shorter acting agent is desired or if the blood pressure is tenuous.
Specialty Consultation: Immediate surgical consultation should be obtained in patients whose presentation of abdominal pain involves hemodynamic instability and/or a rigid abdomen. It is important to consider which specialty to consult based on the likely diagnosis. For instance, a ruptured AAA will be managed by vascular surgery, a perforated viscus by general surgery, testicular torsion by urology, and a ruptured ectopic pregnancy by OB/GYN. Nonsurgical consultation such as gastroenterology for a GI bleed or the medical ICU for diabetic ketoacidosis may also be necessary.
Outpatient Follow-up: Approximately 25% of patients presenting to the emergency department with abdominal pain ultimately receive the diagnosis of “nonspecific abdominal pain,” and follow-up is an essential part of their disposition plan. Of these patients, 30-hour follow-up can yield a difference in diagnosis or treatment in up to 20%. In addition to expedited outpatient follow-up, many patients presenting with nonspecific abdominal pain may benefit from outpatient specialty follow-up for further, non-emergent testing.
Pearls and Pitfalls
- Monitor vital signs for impending hemodynamic collapse
- Patients with a peritoneal examination warrant early surgical consult.
- Elderly patients may present with very atypical symptoms but have high morbidity and mortality associated with the complaint of abdominal pain. CT is diagnostic of an urgent intra-abdominal condition in 50% of these patients.
- Every female of childbearing age with abdominal pain must receive a pregnancy test.
- Diffuse or upper abdominal pain should warrant thorough cardiac and pulmonary evaluation; diaphragmatic irritation can present as abdominal discomfort.
- The most frequent causes of emergency department missed CT diagnoses are right upper quadrant pathology (only 15-20% of gallstones are radiopaque) and urinary tract infections.
- Patients with significant intra-abdominal conditions tend to have exams that evolve over time. Frequent re-examinations will help with both diagnosis and early treatment.
- Manage and treat pain when appropriate.
- When in doubt, arrange close follow-up.
Case Resolution: The patient is given morphine and ondansetron with good resolution in her symptoms. Her EKG is normal. A bedside ultrasound demonstrates gallstones with a normal-appearing gallbladder without wall thickening, pericholecystic fluid, or dilated common bile duct. Her liver function tests, white blood cell count, and lipase are normal. Her urine pregnancy test and urine analysis are similarly normal. After an hour of observation she tolerates food without significant pain and her abdominal examination is benign. She is discharged home with strict return precautions and an outpatient referral to general surgery to discuss elective cholecystectomy for symptomatic cholelithiasis.
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