In a 54‑year‑old woman with a recent normal colonoscopy and a 2.9 cm inferior mesenteric venous (IMV) varix presenting with bright‑red rectal bleeding, what is the appropriate next step in evaluation and management?

Management of Bright-Red Rectal Bleeding with Known IMV Varix

Despite the recent normal colonoscopy, this patient requires urgent ano-proctoscopy or flexible sigmoidoscopy as the first-line diagnostic tool to directly visualize and confirm whether the IMV varix is the source of active bleeding, followed by consideration of upper endoscopy to exclude an upper GI source. 1

Immediate Diagnostic Approach

First-Line Endoscopic Evaluation

• Perform ano-proctoscopy or flexible sigmoidoscopy immediately as the primary diagnostic tool to visualize the varix and assess for active bleeding 1
• The 2.9 cm IMV varix is significantly enlarged (normal IMV diameter is 3-6 mm, mean 3.9 mm), suggesting portal hypertension or venous obstruction 2
• Direct visualization is critical because the distinction between hemorrhoids and anorectal varices can be difficult, especially with active bleeding 1
  • Varices appear as discrete, compressible, serpiginous submucosal veins that cross the dentate line and extend cranially into the rectum
  • Hemorrhoids are confined within the anal canal and do not cross the dentate line 1

Rule Out Upper GI Source

• Perform upper endoscopy within 24 hours because up to 15% of patients with serious hematochezia have an upper GI source, even when a lower source seems obvious 1, 3, 4
• This is particularly important in patients with suspected portal hypertension (given the enlarged IMV), who may have esophageal or gastric varices 1

Advanced Imaging if Initial Endoscopy is Non-Diagnostic

Endoscopic Ultrasound with Color Doppler

• If the bleeding source remains unclear after initial endoscopy, perform EUS with color Doppler as the second-line diagnostic tool 1
• EUS detects deep rectal varices in 85% of cases versus only 45% with standard endoscopy 1
• Color Doppler evaluation shows the anatomy of the entire rectal venous plexus and measures blood flow velocity, which helps identify high-risk varices for rupture 1

CT Angiography

• If both endoscopy and EUS fail to identify the bleeding source, or if EUS is unavailable, perform contrast-enhanced CT scan 1
• CT can visualize large serpiginous veins surrounding the rectum (pararectal varices) and within the rectal wall on portal venous phase images 1
• CT has approximately 15% additional value for detecting vascular lesions compared to colonoscopy alone 1
• Active extravasation is rarely visualized on CT because bleeding from varices is venous rather than arterial in nature 1

Therapeutic Management if Varix is Bleeding Source

Endoscopic Hemostasis

• Use local endoscopic procedures as first-line treatment including endoscopic variceal ligation, endoscopic band ligation, sclerotherapy, or EUS-guided glue injection 1
• Standard hemorrhoidal treatments should NOT be used for variceal bleeding 1
• If local endoscopic therapy is necessary, oversewing of varices rather than attempted excision is the procedure of choice 1

Address Underlying Cause

• Investigate the etiology of the enlarged IMV varix because this size suggests either portal hypertension or mechanical obstruction 2
• Portal hypertension is the most common cause, but external compression (such as from masses or hernias) can cause IMV thrombosis and retrograde flow leading to varix formation 5
• Consider TIPS (transjugular intrahepatic portosystemic shunt) for refractory bleeding if portal hypertension is confirmed and medical management fails 1, 3

Critical Pitfalls to Avoid

• Do not assume the recent normal colonoscopy excludes the varix as the bleeding source – colonoscopy may miss varices that are better visualized with anoscopy or EUS 1
• Do not attribute bleeding to hemorrhoids without direct visualization – this is a common error that delays correct diagnosis 1
• Do not use standard hemorrhoid treatments (such as rubber band ligation or excision) for variceal bleeding, as this can cause catastrophic hemorrhage 1
• Do not forget to evaluate for colorectal cancer – patients with rectal bleeding have a 2.4-11% risk of CRC, and full colonoscopy may be necessary despite the recent normal study if clinical suspicion remains 1