From the Guidelines
For a patient with abdominal pain and a negative ultrasound, the next steps should include further diagnostic evaluation with a CT scan, as it has been shown to change the diagnosis, improve diagnostic certainty, and affect potential patient management decisions in 49% of patients 1. A thorough history and physical examination should be repeated, focusing on the character, location, and timing of pain, along with associated symptoms. Additional imaging studies such as MRI may be warranted to detect conditions not visible on ultrasound or CT, particularly in patients where CT is contraindicated or inconclusive. Laboratory tests including complete blood count, comprehensive metabolic panel, lipase, and urinalysis should be considered to help narrow down the differential diagnosis. Some key points to consider in the diagnostic workup include:
- The importance of clinical suspicion in guiding the choice of imaging modality, with CT being highly valuable in the setting of acute abdominal pain 1.
- The potential for CT to detect conditions such as intestinal ischemia, intramural or portal gas, and lack of bowel wall enhancement, which may require urgent medical or surgical attention 1.
- The role of MRI as a problem-solving modality, particularly in pregnant patients or those where CT is contraindicated, with a high accuracy in diagnosing diseases ranging from acute bowel inflammation to pancreaticobiliary diseases 1. If symptoms persist, endoscopic procedures like upper endoscopy or colonoscopy might be appropriate depending on the suspected diagnosis. Empiric treatment with acid suppressants (such as omeprazole 20mg daily) may be initiated for suspected gastroesophageal reflux or peptic ulcer disease. For suspected irritable bowel syndrome, antispasmodics like dicyclomine 10-20mg three times daily might be beneficial. Pain management should be addressed with acetaminophen or NSAIDs if not contraindicated. These steps are necessary because ultrasound has limitations in visualizing certain abdominal conditions, particularly those affecting hollow organs, retroperitoneal structures, or those causing functional rather than structural abnormalities. It is also important to consider the patient's overall clinical presentation, including the presence of fever, which can increase the suspicion of an intra-abdominal infection or other serious condition requiring prompt attention 1.
From the Research
Next Steps for Abdominal Pain with Negative Ultrasound
- If the ultrasound is negative, the next steps may include:
- Computed Tomography (CT) scan, as it leads to the highest sensitivity and specificity in patients with acute abdominal pain 2
- Clinical evaluation to differentiate between urgent and non-urgent causes, as the diagnostic accuracy of clinical assessment is insufficient to identify the correct diagnosis but can discriminate between urgent and non-urgent causes 2
- Re-evaluation the next day for patients suspected of non-urgent diagnoses 2
- In some cases, an abdominal radiography (X-ray) may be considered, especially if there is a suspicion of appendicitis, as it has a positive predictive value of 90% for appendicitis 3
- The use of pelvic ultrasound following negative abdominal/pelvic CT in the emergency room may not yield additional diagnostic information and does not alter acute care 4
- Evaluation and management of acute abdominal pain in the emergency department should consider multiple diagnoses, especially life-threatening conditions that require timely intervention to limit morbidity and mortality 5
- Contrast-enhanced CT scanning can result in superior diagnostic precision in patients with acute abdominal pain and can be included early in the routine diagnostic process 6