From the Guidelines
Hematochezia, or gastrointestinal bleeding, is most commonly caused by diverticulosis, angiodysplasia, hemorrhoids, and ischemic colitis.
Causes of Lower Gastrointestinal Bleeding
- Diverticulosis: accounting for 30% of cases 1
- Neoplasms
- Stress ulcers
- Surgical anastomoses
- Vascular lesions such as angiodysplasia
- Inflammatory bowel disease
- Portal hypertension can cause lower GIB as a result of clinically obvious anorectal varices or obscure ectopic varices in the small or large bowel 1
Clinical Presentation
- Hematochezia signifies bright red blood per rectum and needs to be differentiated clinically from melena, the passage of darkened, digested blood per rectum, which suggests an upper gastrointestinal source 1
- Approximately 10–15% of patients presenting with acute severe hematochezia have an upper gastrointestinal source of bleeding identified on upper endoscopy 1
Diagnostic Approach
- Diagnostic colonoscopy is the diagnostic procedure of choice in the setting of acute lower gastrointestinal haemorrhage 1
- The diagnostic accuracy of colonoscopy ranges from 72 to 86% in patients with lower gastrointestinal bleeding 1
- Radionuclide imaging, such as [99Tcm] pertechnetate-labelled red blood cells, can be used to detect intermittent bleeding, but has highly variable accuracy rates for localizing bleeding, ranging from 24 to 91% 1
From the Research
Causes of Hematochezia
The causes of hematochezia, also known as gastrointestinal bleeding, can be varied and complex. According to the studies, the possible causes of hematochezia include:
- Diverticulosis 2
- Angiodysplasia 2
- Neoplasm 2
- Perianal disorders 2
- Meckel's diverticulum 2
- Colitis (infectious and non-infectious) 2
- Intussusception 2
- Duodenal ulcer 3
- Gastric ulcer 3
- Rectal ulcer 4
- Upper gastrointestinal hemorrhage (UGIH) 3, 5
- Lower gastrointestinal bleeding (LGIB) 2, 4, 5
Clinical Characteristics
The clinical characteristics of patients with hematochezia can vary depending on the underlying cause of the bleeding. For example:
- Patients with UGIH and hematochezia tend to be older and have a worse prognosis than those with melena 3
- Patients with comorbid illnesses and acute lower gastrointestinal bleeding tend to have longer hospital stays, more severe anemic conditions, and more transfusion requirements 4
- Clinical factors such as systolic blood pressure, hematocrit level, and BUN/Cr ratio can be used to differentiate between UGIB and LGIB causes in patients with hematochezia 5
Diagnosis and Treatment
The diagnosis and treatment of hematochezia can be challenging due to the various possible causes and clinical characteristics. According to the studies, the use of colonoscopy and arteriography can assist in clinical practice 2, and urgent colonoscopy can be used to evaluate patients with acute lower gastrointestinal bleeding 4. Additionally, clinical factors can be used as a guide for further investigation in patients who present with hematochezia 5.