What is the initial workup for a patient presenting with hematochezia (passage of fresh blood per rectum)?

From the Guidelines

The initial workup for a patient with hematochezia should begin with a thorough history and physical examination, followed by laboratory tests including complete blood count, coagulation studies, and basic metabolic panel to assess hemodynamic stability and identify anemia, as recommended by the management of lower gastrointestinal bleeding review article 1. The patient's vital signs should be monitored closely, with immediate fluid resuscitation using two large-bore IV lines and crystalloid solutions for unstable patients.

• Digital rectal examination is essential to evaluate for anorectal sources of bleeding.
• Endoscopic evaluation is the cornerstone of diagnosis, with colonoscopy being the preferred initial procedure for most patients, as it has a diagnostic accuracy ranging from 72 to 86% in patients with lower gastrointestinal bleeding 1. For severe, active bleeding, urgent colonoscopy should be performed within 24 hours after adequate bowel preparation.
• If upper GI bleeding is suspected or colonoscopy is inconclusive, upper endoscopy may be warranted, as an upper source will be found in 10–15% of such patients 1. For massive bleeding with hemodynamic instability, angiography or nuclear medicine studies like tagged red blood cell scans may be necessary.
• CT angiography can detect bleeding rates as low as 0.3 mL/min and helps localize the source before intervention, as noted in the review article on the management of lower gastrointestinal bleeding 1. The diagnostic approach should be tailored to the severity of bleeding, with hemodynamically unstable patients requiring more urgent evaluation and intervention compared to those with minor, self-limited bleeding.
• The most common causes of lower gastrointestinal bleeding are diverticulosis, angiodysplasia, haemorrhoids, and ischaemic colitis, as outlined in the review article on the management of lower gastrointestinal bleeding 1.

From the Research

Initial Workup for Hematochezia

The initial workup for a patient presenting with hematochezia involves a step-wise approach to determine the cause and provide appropriate management. This includes:

• Hemodynamic assessment and risk stratification 2
• Focused history and physical examination to identify potential causes of bleeding 2, 3
• Evaluation of clinical factors such as systolic blood pressure, hematocrit level, and BUN/Cr ratio to differentiate between upper and lower gastrointestinal bleeding 3

Diagnostic Considerations

Diagnostic considerations for hematochezia include:

• Endoscopic intervention, such as colonoscopy, to visualize the lower gastrointestinal tract and identify potential sources of bleeding 2, 4, 5
• Evaluation of small bowel bleeding in selected instances 2
• Consideration of other potential causes of hematochezia, such as diverticulosis, angiodysplasia, neoplasm, perianal disorders, and colitis 4, 6

Clinical Factors and Outcomes

Clinical factors such as age, vital signs, and stool color can provide important information about the severity and potential causes of hematochezia. For example:

• Patients with hematochezia due to upper gastrointestinal hemorrhage may have a worse prognosis than those with melena 6
• Patients with substantial lesions, such as adenomas or carcinoma, may be more likely to have a history of blood mixed with stool, more episodes of hematochezia per month, and a shorter duration of bleeding before medical evaluation 5