What is the primary cause of large bowel obstructions?

The primary cause of large bowel obstructions is indeed tumors. Tumors, both benign and malignant, can lead to obstruction of the bowel by physically obstructing the lumen of the intestine as they grow. Colorectal cancer, for instance, is a common cause of obstruction in older adults, and as it progresses, it can result in significant narrowing or blockage of the colon.

While other factors like adhesions, inflammation, and diverticulitis are also relevant in the context of bowel obstructions, they are not as predominant as tumors in leading to large bowel obstructions. Adhesions are typically more associated with previous abdominal surgeries and can lead to small bowel obstructions more commonly than large bowel. Inflammation, while it can cause swelling in conditions like inflammatory bowel disease, is usually part of a more complex scenario rather than being the direct primary cause. Diverticulitis can lead to strictures over time, but it is not the leading cause when we consider the overall incidence of bowel obstructions.

Understanding that tumors are the main culprit helps in prioritizing diagnostic and treatment strategies in patients presenting with signs of large bowel obstruction.