Differential Diagnosis for a 69-year-old Male with Bloating and Altered Bowel Habits

Single Most Likely Diagnosis

• Constipation: Given the patient's symptoms of bloating and no bowel movement for 4 days, constipation is a highly plausible diagnosis. The single episode of diarrhea could have been an initial response to a gastrointestinal issue that then led to constipation.

Other Likely Diagnoses

• Gastroenteritis: Although the patient has not had diarrhea since the initial episode, gastroenteritis could still be a cause, especially if the infection has led to a temporary cessation of bowel movements.
• Diverticulitis: This condition, characterized by inflammation of the diverticula in the wall of the colon, can cause bloating, changes in bowel habits, and potentially an absence of bowel movements due to pain or obstruction.
• Partial Bowel Obstruction: This could explain the bloating and the cessation of bowel movements. It might be due to various causes such as adhesions, hernias, or tumors.

Do Not Miss Diagnoses

• Mesenteric Ischemia: Although less common, this condition is critical and can present with abdominal bloating, pain, and changes in bowel habits. It requires immediate attention due to its high mortality rate if not promptly treated.
• Colorectal Cancer: While less likely to present acutely, colorectal cancer can cause obstructive symptoms leading to bloating and changes in bowel habits. Given the patient's age, this is a diagnosis that should not be missed.
• Intestinal Volvulus: A condition where the intestine twists around itself and the tissue that holds it in place, potentially cutting off blood flow. It's an emergency that requires immediate surgical intervention.

Rare Diagnoses

• Intussusception: A condition where a part of the intestine slides into an adjacent part, potentially causing bowel obstruction. It's rare in adults but can occur, especially in the context of a lead point such as a tumor.
• Ogilvie's Syndrome (Acute Colonic Pseudo-obstruction): Characterized by significant colonic dilatation in the absence of a mechanical obstruction, often occurring in hospitalized or debilitated patients. It can present with bloating and cessation of bowel movements.