What is the initial step in evaluating a 70-year-old patient presenting with sudden abdominal tenderness, normal abdominal ultrasound (U/S) and physical examination, and low hemoglobin (HB) percentage?

From the Guidelines

For a 70-year-old patient presenting with sudden abdominal tenderness, normal abdominal ultrasound and examination, but low hemoglobin, the initial approach should be abdominal CT (option C). This recommendation is based on the need to rapidly identify potentially life-threatening causes of acute abdominal pain with associated blood loss, such as aortic aneurysm, mesenteric ischemia, or intra-abdominal hemorrhage that may not be visible on ultrasound 1. The guidelines from the World Society of Emergency Surgery emphasize the importance of early diagnosis and intervention in acute mesenteric ischemia, and computed tomography angiography (CTA) is recommended as the diagnostic study of choice 1.

Key Considerations

• The patient's presentation with sudden abdominal tenderness and low hemoglobin suggests a possible acute surgical emergency that requires immediate evaluation.
• Abdominal CT can visualize the entire abdomen, retroperitoneum, and vascular structures, making it superior to ultrasound for detecting subtle abnormalities.
• The combination of sudden abdominal pain with unexplained anemia suggests possible active bleeding that requires immediate identification.
• While endoscopy/colonoscopy and stool testing are valuable for evaluating gastrointestinal bleeding, they are more appropriate as second-line investigations after ruling out acute surgical emergencies in an elderly patient with this presentation.

Diagnostic Approach

• Computed tomography angiography (CTA) should be performed as soon as possible for any patient with suspicion for acute mesenteric ischemia (AMI) 1.
• CTA can help identify potentially life-threatening causes of acute abdominal pain with associated blood loss, such as aortic aneurysm, mesenteric ischemia, or intra-abdominal hemorrhage.
• The guidelines recommend a comprehensive biphasic CTA, including pre-contrast scans, arterial and venous phases, and multi-planar reconstructions (MPR) to assess the origin of the mesenteric arteries 1.

Management

• The initial approach should prioritize identifying and managing any life-threatening conditions, such as acute surgical emergencies or active bleeding.
• Abdominal CT can guide subsequent management decisions and help determine if endoscopic evaluation is needed urgently or if other interventions are required first.
• The patient's hemodynamic stability and clinical presentation should be closely monitored, and further diagnostic investigations or interventions should be tailored to their individual needs.

From the Research

Initial Assessment and Diagnostic Steps

The patient presents with sudden abdominal tenderness, low hemoglobin levels, and normal abdominal ultrasound and examination results. Given these symptoms, the initial steps should focus on identifying the cause of the abdominal tenderness and the low hemoglobin levels.

Diagnostic Considerations

• The patient's low hemoglobin levels could indicate bleeding in the gastrointestinal tract, which may be related to colorectal cancer (CRC) or other conditions 2.
• The use of fecal immunochemical tests (FIT) can help detect occult blood in the stool, which is a common screening method for CRC 3, 4, 5.
• A study found that lowering the cut-off value for an abnormal FIT result to 10 μg hemoglobin/g feces can increase the detection of advanced neoplasia, but may also increase the number of patients requiring diagnostic colonoscopy 3.

Recommended Initial Steps

• Occult stool testing by FIT with a cut-off value of 10 μg Hb/g faeces to rule out CRC is a reasonable initial step, as it is a non-invasive and cost-effective method 4.
• If the FIT result is positive, further diagnostic testing, such as colonoscopy, may be necessary to confirm the presence of CRC or other conditions 3, 4.
• Abdominal CT scan may also be considered as a diagnostic tool, but it is not the initial recommended step in this case.

Considerations for Anemia

• The patient's low hemoglobin levels may indicate anemia, which can be a symptom of CRC or other underlying conditions 2.
• Further evaluation and management of the patient's anemia should be considered, including potential referral for colonoscopy or other diagnostic tests.