Hemorrhoid
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Basics
Description
- General:
- Normal venous sinusoids of the distal rectum and proximal anal canal
- Normal vascular cushions of anal canal that contribute to anal continence
- Arteriovenous shunt system exists at the level of the internal hemorrhoids that accounts for the bright red blood per rectum
- When the hemorrhoids become symptomatic, hemorrhoid disease develops
- Do not cause pain unless thrombosed or strangulated
- Discrete masses of thick submucosa contain:
- Blood vessels
- Smooth muscle
- Elastic and connective tissue
- Sliding down of part of anal canal lining
- External hemorrhoids:
- Vessels situated below dentate line
- Covered by skin/anoderm
- Drain to internal iliac veins
- Internal hemorrhoids:
- Submucosal vessels above dentate lines
- Drain to portal system
- Usually at left lateral, right posterolateral, and right anterolateral positions
- Grade 1: Painless, bleeding
- Grade 2: Prolapse with bowel movement (BM), spontaneously reduce
- Grade 3: Prolapse with BM, require manual reduction
- Grade 4: Chronically prolapsed, not reducible
Etiology
- Exact cause unknown
- Gravitational forces and abdominal pressure cause distention of the sinusoids
- Associated with straining and irregular bowel habits:
- Hard, bulky stools or diarrhea cause tenesmus/straining
- Push anal cushions out of anal canal
- Weaken submucosal tissue leading to prolapse
- Higher resting anal pressures:
- Erect posture
- Heredity:
- Absence of valves in veins
- Increased intraabdominal pressure:
- Ascites
- Pregnancy
- Portal hypertension
-- To view the remaining sections of this topic, please log in or purchase a subscription --
Basics
Description
- General:
- Normal venous sinusoids of the distal rectum and proximal anal canal
- Normal vascular cushions of anal canal that contribute to anal continence
- Arteriovenous shunt system exists at the level of the internal hemorrhoids that accounts for the bright red blood per rectum
- When the hemorrhoids become symptomatic, hemorrhoid disease develops
- Do not cause pain unless thrombosed or strangulated
- Discrete masses of thick submucosa contain:
- Blood vessels
- Smooth muscle
- Elastic and connective tissue
- Sliding down of part of anal canal lining
- External hemorrhoids:
- Vessels situated below dentate line
- Covered by skin/anoderm
- Drain to internal iliac veins
- Internal hemorrhoids:
- Submucosal vessels above dentate lines
- Drain to portal system
- Usually at left lateral, right posterolateral, and right anterolateral positions
- Grade 1: Painless, bleeding
- Grade 2: Prolapse with bowel movement (BM), spontaneously reduce
- Grade 3: Prolapse with BM, require manual reduction
- Grade 4: Chronically prolapsed, not reducible
Etiology
- Exact cause unknown
- Gravitational forces and abdominal pressure cause distention of the sinusoids
- Associated with straining and irregular bowel habits:
- Hard, bulky stools or diarrhea cause tenesmus/straining
- Push anal cushions out of anal canal
- Weaken submucosal tissue leading to prolapse
- Higher resting anal pressures:
- Erect posture
- Heredity:
- Absence of valves in veins
- Increased intraabdominal pressure:
- Ascites
- Pregnancy
- Portal hypertension
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