Bleeding from the bottom (rectal bleeding)

Hematochezia

Introduction

Rectal bleeding refers to passage of fresh or altered blood from the anus, either visible in stool, on toilet paper, or dripping into the toilet.

• Bright red blood → usually from the lower bowel (anal canal, rectum, sigmoid colon).

• Dark or mixed blood → suggests bleeding higher up in the colon or small bowel.

• Tarry black stools (melena) → bleeding from stomach or duodenum.

Rectal bleeding is common, especially in adults over 40. While often benign, it must always be evaluated to exclude serious conditions like colorectal cancer.

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Pathophysiology

• Bleeding occurs due to damage, inflammation, or abnormal blood vessels in the gastrointestinal tract.

• Amount and color of blood depend on site, cause, and rate of bleeding.

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Causes of Rectal Bleeding

1. Anorectal Causes (Most Common, Benign)

• Hemorrhoids (piles): swollen rectal veins → bright red blood after defecation.

• Anal fissure: painful tear in anal lining → blood streaks on stool or tissue.

• Anal fistula/abscess.

2. Colonic Causes

• Diverticular disease: outpouchings in colon wall, can rupture → sudden painless bleeding.

• Angiodysplasia: fragile abnormal blood vessels, common in elderly.

• Polyps: benign growths that can bleed, some precancerous.

• Colorectal cancer: bleeding may be occult or visible.

3. Inflammatory Causes

• Ulcerative colitis.

• Crohn’s disease.

• Infective colitis (e.g., Shigella, Salmonella, Campylobacter, Clostridium difficile).

4. Upper GI Causes (less common in rectal bleeding but possible)

• Peptic ulcer disease, gastritis → usually melena (black stool).

5. Systemic / Other Causes

• Bleeding disorders (hemophilia, thrombocytopenia).

• Anticoagulant therapy (warfarin, DOACs, heparin).

• Radiation proctitis (after pelvic radiotherapy).

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Clinical Features

• Blood characteristics:

  • Bright red: hemorrhoids, fissures, distal colon bleeding.

  • Dark red/clots: proximal colon or small bowel.

  • Mixed with stool: colitis, polyps, cancer.

• Associated symptoms:

  • Anal pain, itching → fissure, hemorrhoids.

  • Abdominal pain, diarrhea, fever → colitis, IBD, infection.

  • Weight loss, fatigue, anemia → colorectal cancer.

  • Sudden large-volume painless bleeding → diverticular disease.

• Systemic signs: pallor, tachycardia, hypotension (if severe blood loss).

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Diagnostic Approach

1. History

• Onset, duration, frequency of bleeding.

• Color, quantity, relation to stool.

• Associated symptoms (pain, diarrhea, weight loss).

• Medication history (NSAIDs, anticoagulants).

• Family history of colorectal cancer, polyps, IBD.

2. Examination

• General: anemia, weight loss.

• Abdominal: tenderness, masses.

• Perianal exam: fissures, hemorrhoids, abscess.

• Digital rectal exam (DRE): masses, blood, tenderness.

3. Investigations

• Blood tests: CBC (anemia), coagulation profile, renal/liver function.

• Stool tests: occult blood, stool culture if infection suspected.

• Endoscopy (gold standard):

  • Colonoscopy: full colon evaluation, biopsy, polyp removal.

  • Flexible sigmoidoscopy: rectum and sigmoid evaluation.

• Imaging: CT angiography (if massive bleeding).

• Capsule endoscopy / enteroscopy: small bowel bleeding.

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Management and Treatment

Treatment depends on the cause and severity of bleeding.

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A. General Emergency Care (if severe bleeding)

• IV fluids, blood transfusion if needed.

• Monitor vital signs.

• Correct coagulopathy (Vitamin K, fresh frozen plasma).

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B. Specific Treatments

1. Hemorrhoids

• Conservative: high-fiber diet, stool softeners, sitz baths.

• Topical treatments: Hydrocortisone 1% cream rectally twice daily × 7 days.

• Procedures: rubber band ligation, sclerotherapy, hemorrhoidectomy.

2. Anal Fissure

• Stool softeners, sitz baths, topical anesthetics.

• Topical glyceryl trinitrate 0.2–0.4% ointment applied twice daily (relaxes sphincter).

• Diltiazem 2% cream twice daily.

• Resistant cases: lateral sphincterotomy.

3. Diverticular Bleeding

• Usually self-limiting.

• Endoscopic cauterization or clipping if persistent.

• Surgery if recurrent/severe.

4. Angiodysplasia

• Endoscopic cauterization with argon plasma coagulation.

• Hormonal therapy sometimes used (rare).

5. Colorectal Cancer / Polyps

• Surgical resection (segmental colectomy).

• Chemotherapy (5-Fluorouracil, Capecitabine).

• Targeted therapy depending on tumor profile.

6. Inflammatory Bowel Disease (IBD)

• Ulcerative colitis / Crohn’s disease:

  • Mesalazine 2–4 g orally daily (5-ASA).

  • Prednisone 40 mg orally daily, taper over weeks (for flares).

  • Immunosuppressants: Azathioprine 1.5–2.5 mg/kg/day.

  • Biologics: Infliximab, Adalimumab.

7. Infective Colitis

• Supportive: hydration, rest.

• Antibiotics if bacterial:

  • Ciprofloxacin 500 mg orally twice daily × 5–7 days.

  • Metronidazole 400 mg orally three times daily × 7 days (for C. difficile: Vancomycin 125 mg orally 4× daily × 10 days).

8. Anticoagulant-Related Bleeding

• Adjust or stop anticoagulant.

• Reversal agents:

  • Vitamin K 5–10 mg IV (for warfarin).

  • Idarucizumab (for dabigatran).

  • Andexanet alfa (for apixaban, rivaroxaban).

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Complications

• Anemia and fatigue.

• Hypovolemic shock (if severe bleeding).

• Missed colorectal cancer.

• Recurrence (diverticular disease, hemorrhoids, IBD).

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Prognosis

• Hemorrhoids/fissures: Excellent with treatment.

• Diverticular bleeding: Usually self-limited; recurrence possible.

• IBD: Chronic but manageable.

• Colorectal cancer: Prognosis depends on stage; early detection improves survival.

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Patient Education

• Rectal bleeding is not always serious, but should never be ignored.

• Maintain high-fiber diet and hydration to prevent constipation.

• Limit alcohol, processed food, and smoking (risk for colorectal cancer).

• Report persistent, painless, or recurrent bleeding, especially if over 40 or with family history of bowel cancer.

• Screening colonoscopy after age 45–50 as per guidelines.