The commonest cause of significantly lower gastrointestinal bleed in a middle aged person without any known precipitating factor may be due to: March 2008, September 2010
**Core Concept**
The question is testing the knowledge of a common cause of lower gastrointestinal bleeding (LGB) in a middle-aged person without any known precipitating factor. This requires an understanding of the pathophysiology and clinical presentation of various gastrointestinal disorders.
**Why the Correct Answer is Right**
The correct answer is likely to be angiodysplasia, a condition characterized by the presence of abnormal blood vessels in the gastrointestinal tract. These blood vessels are prone to rupture, leading to significant bleeding. Angiodysplasia is a common cause of LGB in older adults, particularly in the absence of any known precipitating factor. The exact cause of angiodysplasia is not well understood, but it is thought to be related to the aging process and the loss of smooth muscle cells in the blood vessel walls.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is likely to be diverticulosis, a condition characterized by the presence of diverticula (small bulging pouches) in the wall of the colon. While diverticulosis can cause bleeding, it is not the most common cause of significant LGB in a middle-aged person without any known precipitating factor.
* **Option B:** This option is likely to be inflammatory bowel disease (IBD), which includes conditions such as Crohn's disease and ulcerative colitis. IBD can cause bleeding, but it is typically associated with other symptoms such as diarrhea, abdominal pain, and weight loss.
* **Option C:** This option is likely to be colorectal cancer, which can cause bleeding, but it is not the most common cause of significant LGB in a middle-aged person without any known precipitating factor.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that angiodysplasia is a common cause of LGB in older adults, particularly in the absence of any known precipitating factor. This is because the risk of angiodysplasia increases with age, and it can be a challenging diagnosis to make due to its nonspecific symptoms.
**Correct Answer: A. Angiodysplasia**