Differential Diagnosis for Lower GI Bleeding
The following is a differential diagnosis for lower GI bleeding, categorized into the single most likely diagnosis, other likely diagnoses, do not miss diagnoses, and rare diagnoses.
- Single Most Likely Diagnosis
- Diverticulosis: This is the most common cause of lower GI bleeding in adults, especially those over 40 years old. It is often asymptomatic until bleeding occurs, and the bleeding is usually painless and intermittent.
- Other Likely Diagnoses
- Hemorrhoids: Internal or external hemorrhoids can cause lower GI bleeding, especially with straining during bowel movements. The bleeding is typically bright red and may be associated with pain or discomfort.
- Anal fissures: A tear in the anal mucosa can cause painful bleeding during or after bowel movements.
- Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic inflammation and bleeding in the lower GI tract.
- Angiodysplasia: Abnormal blood vessels in the GI tract can cause bleeding, especially in older adults.
- Do Not Miss Diagnoses
- Gastrointestinal malignancy: Colon cancer or rectal cancer can cause lower GI bleeding, and it is essential to rule out these conditions, especially in patients with risk factors or symptoms like weight loss or changes in bowel habits.
- Ischemic colitis: Reduced blood flow to the colon can cause bleeding, pain, and other symptoms, and it requires prompt treatment to prevent complications.
- Infectious colitis: Infections like Clostridioides difficile (C. diff) or other bacterial, viral, or parasitic infections can cause lower GI bleeding and require specific treatment.
- Rare Diagnoses
- Meckel's diverticulum: A congenital anomaly of the small intestine can cause bleeding, especially in children and young adults.
- Intussusception: A condition where a part of the intestine telescopes into another part, causing bleeding and obstruction, is rare in adults but can occur.
- Arteriovenous malformations (AVMs): Abnormal connections between arteries and veins can cause bleeding in the GI tract, and they are often congenital or associated with other conditions.
- Dieulafoy's lesion: A rare condition where a blood vessel in the GI tract erodes and causes bleeding, often requiring endoscopic or surgical treatment.