-Acute lower gastrointestinal (GI) bleeding refers to blood loss of recent onset originating from the colon.

-Upper GI bleeding presents with melena or hematemesis, whereas lower GI bleeding produces passage of bright red or maroon stools

Common causes: Diverticulosis, malignancy, polyps, colitis, hemorrhoids, anal fissures

Less common: angiodysplasia, ulcers,malignancy

Physical examination: Look for signs of hypovolemia (hypotension, tachycardia)

Laboratory tests: complete blood count, serum chemistries, liver tests, and coagulation studies

Diagnosis: Anoscopy, sigmoidoscopy, colonoscopy, radionuclide imagine, CT angiography,

Treatment: Fluid resuscitation, blood transfusions, therapeutic colonoscopy, intra-arterial embolization, surgery.

Q: What is the most common cause of major lower tract bleeding? Diverticulosis

Q: What is the initial examination of choice for the diagnosis and treatment of acute lower GI bleeding? Colonoscopy