Differential Diagnosis for Acute on Chronic Rectal Pain

Single Most Likely Diagnosis

• Internal hemorrhoids: This is the most likely diagnosis given the presentation of acute on chronic rectal pain, as internal hemorrhoids can cause intermittent pain, especially during bowel movements, and can lead to chronic discomfort if not properly managed.

Other Likely Diagnoses

• Anal fissure: This condition can cause severe, sharp pain during and after bowel movements, which may be superimposed on a background of chronic discomfort.
• Proctitis: Inflammation of the rectum can cause pain, discomfort, and difficulty with bowel movements, which could be acute or chronic.
• Rectal prolapse: A condition where the rectum loses its normal attachments inside the body, allowing it to protrude out, which can cause chronic discomfort and acute pain during episodes of prolapse.

Do Not Miss Diagnoses

• Rectal cancer: Although less common, rectal cancer can present with chronic rectal pain and changes in bowel habits, making it crucial not to miss this diagnosis due to its severe implications.
• Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic pain, diarrhea, and other symptoms, and their diagnosis is critical for appropriate management.
• Ischemic proctitis: Reduced blood flow to the rectum can cause severe pain and is a medical emergency requiring prompt intervention.

Rare Diagnoses

• Solitary rectal ulcer syndrome: A condition characterized by the presence of one or more ulcers in the rectum, which can cause chronic pain, difficulty with bowel movements, and rectal bleeding.
• Levator ani syndrome: A condition involving the muscles of the pelvic floor, leading to chronic pain and discomfort in the rectal area.
• Coccygodynia: Pain in the coccyx (tailbone) area, which can be chronic and is often associated with falls onto the buttocks or difficult childbirth.