B52 Colonic diverticulosis and bowel obstruction

Question 1

What is a diverticulum?

What is the difference between congenital and acquired diverticula?

Answer 1

A blind pouch communicating with the lumen of the GI tract.

Congenital diverticulum:

• The Meckel Diverticulum is fairly common, ~2% of people have it. Resuilting from the remanant of the vitelline duct, off of the ileum near the ileocecal junction.
• Aside from this they are rare, and most diverticula are acquired.

Acquired diverticulum:

• Lack the tunica muscularis or it is very thin.
• They are usually in the Colon.
• In Western countries they are very common in the elderly as high as 50%.
• Due to lack of dietary fiber and difficulty in moving stool through the colon.
• Causes diverticulosis usually with multiple diverticula in the colon.
• It is rare in non-western countries.

Question 2

What are the weak points where acquired diverticula usually form?

Answer 2

In the colon, because its outer longitudinal muscle does not totally surround it but is only in the 3 tenia.

Specifically, they occur at sites where vessels or nerves penetrate the inner circular muscle layer.

Question 3

What causes acquired diverticula?

Answer 3

1. Exaggerated or spastic peristaltic contractions, that aren’t effectively moving the bolus but increasing pressure in the intestine.
2. Focal deficits, like the nerves and vessels penetrating the circular muscle layer.

Question 4

What are the clinical symptoms of colonic diverticulosis?

Answer 4

Asymptomatic

20% of patients have intermittent cramping or lower quadrant pain.

Feelings of being unable to ever completely empty the bowel.

Can become inflamed, causing diverticulitis. Pain and fever, potential for perforation or rupture and peritonitis, sepsis. But most often it resolves spontaneously or is easily treated with antibiotics. Can also be surgically removed.

Question 5

Treatment for diverticulosis?

Answer 5

High fiber diet,. Surgical ablation is possible but rarely necessary.

Question 6

Where does bowel obstruction most commonly occur?

Answer 6

In the Small intestine (it has a smaller lumen)

Question 7

What are the 4 ways bowel obstruction can occur?

Answer 7

Herniation, through the peritoneal cavity. Ubilical, inguinal, femoral, or surgical wound.

Intestinal Adhesions, Due to prior peritonitis from prior infection or from surgery.

Intussusception, Telescoping of a proximal segment into a distal segment. Occur spontaneously in children, In adults it is often due to a luminal tumor. This type specifically causes obstruction of the vessels due to compression, and infarction of the trapped segment.

Volvus, Torsion of the intestine around itself on its mesenteric attachment. Causes venous constriction first, and sometimes arterial constriction. Causes obstruction and infarction.