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Question 1

Meckel Diverticulum

most common site?

Etiology?

Answer 1

congenital small bowel diverticulum
Etiology:- It results from failure of involution of the vitelline (omphalomesenteric) duct leaving a persistent blind-ended tubular protrusion as long as 5 to 6 cm

Question 2

Meckel Diverticulum
Characteristics

Answer 2

1-blind-ended tubular protrusion
2– usually in the ileum, about 60cm proximal to the ileocecal valve,
3- about 5 cm in length.
4-composed of all layers of the normal small intestine (True diverticulum).
5 - may contains heterotopic islands: functioning ectopic gastric mucosa Or rarely ectopic pancreatic tissue.

( 2 inches long, 2 feet from ileocecal valve, 2% of population, 2% symptomatic )

Question 3

Meckel Diverticulum
Presentation

Answer 3

Presentation:
- Most are asymptomatic
- If peptic ulceration occurs (in the adjacent ileal mucosa) → present with intestinal bleeding → ± iron deficiency anemia
blood
- Diverticulitis → symptoms resembling acute appendicitis.

Question 4

Congenital Aganglionic Megacolon called

Answer 4

Hirschsprung Disease

Question 5

Hirschsprung Disease
Definition, ethology

Answer 5

Congenital absence of ganglion cells in Meissner submucosal and Auerbach myenteric plexuses causing functional obstruction and progressive distention of the colon proximal to the affected segment.
- Males > females, in a ratio of 4 : 1 imy anyway
- Much more frequent in those with other congenital anomalies as Down syndrome

Question 6

Hirschsprung Disease
Microscopic ,Gross

Answer 6

Gross:
- Involves distal sigmoid and rectum;
- The affected segment is not distended (narrow) but the proximal bowel (properly innervated segment) becomes → massively dilated (megacolon)
- The wall may be thinned by distention and the mucosal lining may show shallow ulcers, so-called stercoral ulcers, produced by impacted, inspissated feces.

Microscopic: - lack of ganglia in the muscle wall and submucosa of the affected constricted segment (aganglionic segment), but may be present
in the dilated portion.

Question 7

Hirschsprung disease
Clinical Features, Diagnosis ,Complication

Answer 7

Clinical Features:
- Alternating periods of obstruction and passage of diarrheal stools.
- Chronic Constipation, abdominal distention/or pain, and vomiting
- may be associated with Down syndrome
- may present early as a delay in the initial passage (doesn’t pass) of meconium (dark green stool ) which is followed by vomiting in 48 to 72 hours

Diagnosis:
- Physical exam reveals absent stool on the examining finger,
Rectal biopsy: → absence of ganglion cells in the nondistended bowel segment (surest way to confirm the diagnosis)
Complication:
- Superimposed enterocolitis of dilated bowel with fluid and electrolyte disturbances.
- Rarely, the distended colon may perforates

Question 8

Acquired Megacolon: may result from:

Answer 8

1) Chagas disease: in which the trypanosomes directly invade the bowel wall to destroy the ganglia in the plexuses,
2) Organic obstruction of the bowel by a neoplasm or
inflammatory stricture,
3) Toxic megacolon complicating ulcerative colitis or Crohn disease,

Question 9

Trypanosoma cruzi cause

Answer 9

dilated cardiomyopathy, heart rhythm abnormalities → sudden death. About 1/3 → digestive system damage → dilation of the digestive tract (megacolon and megaesophagus), confusion, chronic encephalopathy and sensory and motor deficits

Question 10

Intestinal Diverticula
Type

Answer 10

Congenital diverticula:
have all three layers of the bowel wall (mucosa, submucosa, and most notably the muscularis propria) uncommon e.g. Meckel diverticulum
Acquired diverticula:
- either lack or have an attenuated muscularis propria. may occur anywhere in the alimentary tract, but by far the most common location is the colon, giving rise to diverticular disease of the colon (Colonic diverticulosis.

Question 11

Colonic Diverticulosis Risk factor:

Answer 11

Consumption of a refined, low-fiber diet

Question 12

Pathogenesis of Colonic Diverticulosis

Answer 12

Two factors are important in the genesis of diverticular protrusions:
1- Consumption of a refined, low-fiber diet with increased constipation → resulting in reduced stool bulk → exaggerated peristaltic contractions
→ abnormal elevation of intraluminal pressure →
2- Diverticular protrusions through the focal defects

Question 13

Morphology, Site Colonic Diverticulosis

Answer 13

small, spherical outpouchings, usually 0.5 to 1 cm in diameter
- Site: 95% are located in the sigmoid colon,
sometimes the entire colon are affected
Most diverticula penetrate between the bundles of circular muscle fibers and protrude lateral to taeniae coli at sites of penetrating blood vessels.

Question 14

clinical features, diagnosis of Colonic Diverticulosis

Answer 14

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