What are the appropriate laboratory tests and orders for a 69-year-old female presenting to the emergency department (ED) with hematochezia (bright red blood per rectum) and diffuse abdominal pain?

From the Guidelines

For a 69-year-old female presenting with bright red blood per rectum and diffuse abdominal pain, immediate laboratory tests and orders should include a complete blood count, comprehensive metabolic panel, coagulation studies, type and cross, and blood cultures if infection is suspected, as well as a CT scan of the abdomen and pelvis with contrast to identify the source of bleeding, as recommended by the most recent guidelines 1.

Initial Assessment and Management

The patient's presentation with bright red blood per rectum and diffuse abdominal pain suggests lower gastrointestinal bleeding, which can be caused by various conditions such as diverticulosis, angiodysplasia, ischemic colitis, or colorectal cancer.

• Laboratory tests:
  • Complete blood count to assess for anemia and signs of infection
  • Comprehensive metabolic panel to evaluate organ function
  • Coagulation studies (PT/INR, PTT) to rule out bleeding disorders
  • Type and cross for potential blood transfusion
  • Blood cultures if infection is suspected
• Imaging studies:
  • CT scan of the abdomen and pelvis with contrast to identify the source of bleeding, as recommended by the American College of Radiology 1
  • Abdominal X-ray to check for obstruction or perforation

Further Management

• Urgent gastroenterology consultation for possible colonoscopy or flexible sigmoidoscopy should be arranged, as recommended by the British Society of Gastroenterology 1
• Additional orders should include:
  • Two large-bore IV lines for fluid resuscitation
  • Continuous vital sign monitoring
  • Cardiac monitoring
  • Supplemental oxygen if needed
  • NPO status
• Medications may include:
  • IV fluid resuscitation with normal saline or lactated Ringer's solution
  • Antiemetics for nausea
  • Pain management with titrated opioids

Considerations

• The patient's hemodynamic stability should be closely monitored, and if unstable, CT angiography or transcatheter arteriography/embolization may be considered, as recommended by the American College of Radiology 1
• If the patient is clinically stable but may need red blood cell transfusion, restrictive RBC thresholds should be used, as recommended by the British Society of Gastroenterology 1

From the Research

Initial Assessment and Laboratory Markers

The initial assessment of the patient should include:

• A history of co-morbidities and medications that promote bleeding
• Hemodynamic parameters
• Physical examination (including digital rectal examination)
• Laboratory markers 2

Risk Score and Discharge Criteria

A risk score, such as the Oakland score, can be used to aid in clinician judgment, but should not replace it. An Oakland score of ≤ 8 points can be used to guide the decision to discharge the patient for outpatient investigation in cases of self-limited bleed and no adverse clinical features 2

Transfusion Strategy

In hemodynamically stable patients with acute lower gastrointestinal bleeding:

• A restrictive red blood cell transfusion strategy is recommended, with a hemoglobin threshold of ≤ 7 g/dL prompting red blood cell transfusion, and a post-transfusion target hemoglobin concentration of 7-9 g/dL in patients with no history of cardiovascular disease 2
• A more liberal red blood cell transfusion strategy is recommended, with a hemoglobin threshold of ≤ 8 g/dL prompting red blood cell transfusion, and a post-transfusion target hemoglobin concentration of ≥ 10 g/dL in patients with a history of acute or chronic cardiovascular disease 2

Diagnostic Modalities

The following diagnostic modalities can be used to evaluate patients with acute gastrointestinal bleeding:

• Colonoscopy: should be performed sometime during the hospital stay in patients with major acute lower gastrointestinal bleeding 2
• Computed tomography (CT) angiography: can aid in identifying the location and cause of bleeding, and is an important complementary tool to endoscopy, nuclear medicine, and angiography in evaluating patients with GI bleeding 3, 4
• CT enterography: can be used to evaluate patients with GI bleeding, especially in cases of obscure GI bleeding 3

Management of Anticoagulants and Antiplatelets

• Vitamin K antagonists should be withheld in patients with major lower gastrointestinal bleeding, and coagulopathy should be corrected according to the severity of bleeding and thrombotic risk 2
• Direct oral anticoagulants should be temporarily withheld at presentation in patients with major lower gastrointestinal bleeding 2
• Aspirin should not be withheld in patients taking low-dose aspirin for secondary cardiovascular prevention, but can be resumed within 5 days or earlier if hemostasis is achieved or there is no further evidence of bleeding 2
• Dual antiplatelet therapy (low-dose aspirin and a P2Y12 receptor antagonist) should not be routinely discontinued before cardiology consultation, but can be continued or temporarily interrupted according to the severity of bleeding and ischemic risk 2