Differential Diagnosis for BRBPR and Trouble Passing Stool

Single Most Likely Diagnosis

• Anal Fissure: This condition is characterized by a tear in the lining of the anus, which can cause severe pain during and after bowel movements, as well as bleeding. The symptoms of bright red blood per rectum (BRBPR) and difficulty passing stool are classic for anal fissure, making it the most likely diagnosis.

Other Likely Diagnoses

• Hemorrhoids: Hemorrhoids can cause BRBPR, especially if they are thrombosed or prolapsed. They can also cause discomfort and difficulty with bowel movements, although the pain is typically less severe than with anal fissures.
• Proctitis: Inflammation of the rectum can cause pain, bleeding, and difficulty with bowel movements. It can be due to infectious or inflammatory causes.

Do Not Miss Diagnoses

• Colorectal Cancer: Although less common in younger individuals, colorectal cancer can present with BRBPR and changes in bowel habits. It is crucial to rule out this diagnosis, especially in individuals with risk factors or those over 50 years old.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause rectal bleeding, pain, and changes in bowel habits. Missing these diagnoses can lead to significant morbidity.
• Rectal Ulcer: A solitary rectal ulcer can cause bleeding and pain, similar to an anal fissure or hemorrhoids, but its presence requires specific management.

Rare Diagnoses

• Rectal Prolapse: Although more common in older adults or those with significant pelvic floor weakness, rectal prolapse can cause difficulty with bowel movements and bleeding.
• Solitary Rectal Polyp: While usually asymptomatic, a large polyp can cause bleeding and difficulty with stool passage.
• Angiodysplasia: Vascular malformations in the rectum can cause bleeding, but they are less common and typically seen in older adults.

Each of these diagnoses has distinct management strategies, ranging from conservative treatments for anal fissures and hemorrhoids to more invasive procedures for conditions like colorectal cancer. A thorough evaluation, including history, physical examination, and possibly endoscopic procedures, is necessary to determine the correct diagnosis and appropriate treatment.