A patient with alternating constipation and diarrhea, bowel changes, flatulence, and syncope; denies penile discharge or blood in urine. What is the most likely diagnosis?

• A. Diverticulitis
• B. Irritable bowel syndrome
• C. Colorectal cancer
• D. Appendicitis

Answer: (A)

This pattern points to a colonic process where bowel habits swing between constipation and diarrhea, and gas is common. Diverticular disease can cause these intermittent changes in bowel habit and flatulence as the colon’s structure and motility are affected by inflamed diverticula. Some patients may also feel faint or dizzy (syncope) due to dehydration, pain, or the inflammatory response, even if fever isn’t prominent. Although diverticulitis classically presents with localized abdominal pain and fever, many cases don’t show the textbook picture and instead present with nonspecific bowel changes like alternating constipation and diarrhea.

Irritable bowel syndrome is a functional disorder without inflammation, and while it can cause alternating bowel habits and bloating, it usually lacks systemic signs and changes aren’t driven by an inflammatory process. Colorectal cancer tends to produce progressive changes, sometimes blood in stool, and weight loss, rather than fluctuating habits with gas. Appendicitis typically causes acute right-lower-quadrant pain with fever, not intermittent bowel pattern changes.