Definition and Pronunciation of Hematochezia
Hematochezia is the passage of bright red blood or blood clots per rectum, and it is pronounced "hem-ah-toh-KEE-zee-ah." 1
Clinical Definition
Hematochezia signifies bright red blood per rectum and must be differentiated from melena, which is the passage of darkened, digested blood per rectum that suggests an upper gastrointestinal source. 1
Key Clinical Characteristics:
- Appearance: Bright red blood or clots passed rectally 2
- Source: Typically indicates bleeding from the lower gastrointestinal tract (distal to the ligament of Treitz) 1
- Important caveat: Approximately 10-15% of patients presenting with acute severe hematochezia actually have an upper gastrointestinal source of bleeding identified on upper endoscopy, making this a critical diagnostic pitfall 1
Common Causes
The most common etiologies of hematochezia include 1:
- Diverticulosis (accounts for approximately 30-41% of cases) 1
- Angiodysplasia 1
- Hemorrhoids 1
- Ischemic colitis 1
- Neoplasms and polyps 1
- Inflammatory bowel disease 1
Age-Related Considerations:
- The incidence of lower gastrointestinal bleeding increases dramatically with age, with a >200-fold increase from age 20 to 80 years 1
- This age-related increase is primarily explained by the increasing prevalence of colonic diverticulosis and angiodysplasia with advancing age 1
Clinical Significance
- Mortality: The overall mortality rate for patients with gastrointestinal bleeding remains approximately 10%, but increases to 40% in cases of massive bleeding associated with hemodynamic instability or requiring transfusion of >4 units of blood 1
- Spontaneous resolution: Approximately 75% of episodes of acute lower GI bleeding due to diverticulosis stop spontaneously, especially in patients requiring <4 units of blood transfusion over 24 hours 1