Is an internal hemorrhoid visible on physical exam and can it protrude out?

Internal Hemorrhoids: Visibility and Prolapse

Internal hemorrhoids are not visible on external physical examination but can protrude outside the anus (prolapse) depending on their severity grade. 1

Anatomy and Classification of Hemorrhoids

Internal hemorrhoids are located above the dentate line and are covered by rectal mucosa. They require anoscopy for proper visualization during physical examination 1, 2. The American Society of Colon and Rectal Surgeons endorses a classification system for internal hemorrhoids:

• First-degree: Bleeding without prolapse
• Second-degree: Prolapse during defecation with spontaneous reduction
• Third-degree: Prolapse requiring manual reduction
• Fourth-degree: Irreducible prolapse

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In contrast, external hemorrhoids are located below the dentate line, covered by anoderm and perianal skin, and are visible during external examination 1.

Diagnostic Approach

Physical Examination Findings

• External inspection: Internal hemorrhoids are not visible on external inspection unless they have prolapsed (grades II-IV) 1, 3
• Digital rectal examination: Cannot reliably detect internal hemorrhoids
• Anoscopy: Essential for proper visualization and diagnosis of internal hemorrhoids 2, 1

The World Journal of Emergency Surgery guidelines recommend performing anoscopy as part of the physical examination for hemorrhoids whenever feasible and well tolerated 2.

Prolapsed Internal Hemorrhoids

Internal hemorrhoids can indeed protrude outside the anal canal based on their grade:

• Grade II: Prolapse during defecation but spontaneously reduce
• Grade III: Prolapse and require manual reduction
• Grade IV: Prolapsed and cannot be reduced (irreducible) 1, 3

When prolapsed, internal hemorrhoids may be confused with external hemorrhoids or other anorectal conditions. Prolapsed hemorrhoids can present as an anorectal mass, similar to condylomas, abscesses, polyps, anorectal prolapse, or anorectal cancer 2.

Clinical Pearls and Pitfalls

Important Distinctions

• Internal hemorrhoids: Usually painless due to visceral innervation above the dentate line, but can cause bleeding and discomfort 3
• External hemorrhoids: Can be painful due to somatic innervation below the dentate line 1
• Mixed hemorrhoids: Concurrent internal and external hemorrhoidal disease 3

Common Pitfalls

1. Misattribution of symptoms: Never blindly attribute rectal bleeding to hemorrhoids without proper examination, as it may indicate other serious conditions like colorectal cancer 2, 1

2. Inadequate examination: Failure to perform anoscopy can lead to missed diagnosis of internal hemorrhoids 2, 1

3. Overlooking complications: Thrombosed or strangulated hemorrhoids require different management approaches 2

4. Missing other pathology: Patients with rectal bleeding who have negative findings on initial examination should have colonoscopy as the next diagnostic step 1

Evaluation Algorithm

1. External inspection: Check for visible prolapsed tissue or external hemorrhoids
2. Digital rectal examination: Assess for masses, tenderness
3. Anoscopy: Essential for visualizing internal hemorrhoids 2, 1
4. Further endoscopic evaluation: Consider colonoscopy if:
   • Atypical bleeding pattern
   • Risk factors for colorectal cancer present
   • Concern for inflammatory bowel disease
   • Age over 50 years 2, 1

Remember that anoscopy may be difficult or impossible in patients with thrombosed or strangulated hemorrhoids due to severe pain, and may require proper sedation in these cases 2.