Thrombosed Hemorrhoid
A thrombosed hemorrhoid is a painful condition that occurs when a blood clot forms within a hemorrhoid, typically presenting as an acutely painful perianal lump with sudden onset of symptoms. 1
Definition and Classification
Thrombosed hemorrhoids can be classified as either external or internal, depending on their location relative to the dentate line:
External thrombosed hemorrhoids: These are more common and occur beneath the skin around the anus. They present with:
- Acute onset of anal pain
- A palpable, tender perianal lump
- Occasional bleeding if local pressure causes erosion through the overlying skin 1
Internal thrombosed hemorrhoids: These are less common and occur above the dentate line. They typically present with:
- Pain
- Pressure
- Bleeding
- Mucus production
- Inability to reduce spontaneously prolapsing tissue 1
Clinical Presentation
The hallmark symptom of a thrombosed hemorrhoid is acute pain, which distinguishes it from non-thrombosed hemorrhoids. While regular hemorrhoids may cause bleeding, itching, or discomfort, they typically don't cause significant pain unless thrombosis has occurred 1.
Key clinical features include:
- Sudden onset of severe anal pain
- Firm, tender lump near the anal opening (for external thrombosed hemorrhoids)
- Bluish-purple discoloration of the affected area
- Pain that worsens with sitting, standing, or defecation 2, 3
Pathophysiology
Thrombosed hemorrhoids develop when:
- Blood stagnates within the hemorrhoidal vessels
- Trauma occurs to the anal vessels due to strain
- Excessive pressure leads to clot formation within the hemorrhoid 2
Common precipitating factors include:
- Constipation and straining during defecation
- Prolonged sitting
- Heavy lifting
- Pregnancy 2
Diagnosis
Diagnosis is primarily clinical and based on:
- Focused medical history
- Complete physical examination including digital rectal examination
- External visual inspection revealing a painful, swollen, bluish lump (for external thrombosed hemorrhoids) 1
Laboratory tests are generally not required specifically for thrombosed hemorrhoids but may be performed to rule out other causes of anal pain or to assess the severity of bleeding if present 1.
Management
Treatment options depend on timing, severity, and patient factors:
Early Presentation (within 72 hours)
- Surgical excision is the most effective treatment if diagnosed early. This involves:
Later Presentation (after 72 hours)
- Conservative management is appropriate as symptoms typically resolve in 7-10 days:
- Adequate fiber and water intake
- Sitz baths
- Topical analgesics
- Stool softeners 1
Special Considerations
- Pregnancy: Treatment should focus on conservative measures when possible
- Immunocompromised patients: Higher risk for infection, particularly after invasive procedures
- Patients on antithrombotic agents: Require careful management of bleeding risk 4
Complications
If left untreated, potential complications include:
- Persistent pain
- Recurrence
- Skin tags after resolution of thrombosis
- Rarely, infection or abscess formation 5
Prevention
Preventive measures focus on avoiding precipitating factors:
- Maintaining adequate fiber and water intake
- Avoiding prolonged straining during defecation
- Regular physical activity
- Avoiding prolonged sitting 1, 2
Key Pitfalls to Avoid
Misdiagnosis: Anal pain may be due to other conditions such as anal fissures (present in up to 20% of patients with hemorrhoids) or anorectal abscesses 1
Delayed treatment: Surgical excision is most effective within the first 72 hours of symptom onset 3
Inappropriate surgical technique: Cutting too deeply and injuring the sphincter muscle during excision 3
Attributing all rectal bleeding to hemorrhoids: All patients with rectal bleeding should undergo appropriate evaluation to rule out other causes 1