Professional and Linguistic Assessments Board (PLAB) Practice Exam

Toxic megacolon is most commonly associated with which condition?

1. Crohn's disease

2. Ulcerative colitis

3. Diverticulitis

4. Colorectal cancer

The correct answer is: Ulcerative colitis

Toxic megacolon is most commonly associated with ulcerative colitis, which is an inflammatory bowel disease characterized by chronic inflammation of the colonic mucosa. In ulcerative colitis, the inflammation can lead to a rapid and severe dilation of the colon, resulting in toxic megacolon. This condition is a serious complication that can occur when the colonic muscle becomes paralyzed and unable to function properly, often in the presence of severe inflammation or infection. The risk of developing toxic megacolon increases in cases of extensive disease, particularly when there is a significant inflammatory burden. Patients with this condition may exhibit symptoms such as abdominal distension, fever, tachycardia, and electrolyte disturbances, necessitating immediate medical intervention. In contrast, while Crohn's disease can lead to complications, it is less frequently associated with toxic megacolon. Diverticulitis and colorectal cancer, while also serious, do not typically lead to this specific complication. Understanding these associations is crucial for recognizing and managing potential life-threatening complications in patients with inflammatory bowel diseases.