SFP: developmental anomalies, vascular disorders, obstruction, diverticulosis Flashcards
Describe malrotation of the large intestine
Incorrect rotation of the GI tract can result in the cecum in the upper quadrant instead of the lower quadrant. This can result in fibrous band formation that may cause obstruction.
Describe annular pancreas
A failure of clockwise rotation of the ventral pancreas results in the pancreas encircling the upper duodenum.
Describe duodenal atresia
A failure to recanalize causes a double bubble looking structure of the duodenum, due to a fibrous band-like structure with no lumen.
What are symptoms of duodenal atresia?
Abdominal distention, vomiting, no passage of meconium.
When do symptoms of duodenal atresia begin?
Immediately after birth.
Describe jejunal, ileal, and colonic atresia
Less common form of atresia caused by inadequate supply of blood to the intestines during development.
Describe Meckel’s diverticulum
Incomplete obliteration of the vitelline duct (connection between small bowel and umbilicus).
Describe the location/structure of the lesion in Meckel’s diverticulum
It is about 2 ft from the ileocecal valve, 2 inches in length.
When does Meckel’s diverticulum begin to show symptoms?
2 years after birth - Later in life.
Describe histology of Meckel’s diverticulum
Two mucosae: gastric and pancreatic. The increased acidity from these mucosal types may cause signs of inflammation.
Describe an omphalocele
Persistence of herniation of abdominal content into the umbilical cord and sealed by peritoneum.
What causes an omphalocele?
Incorrect rotation of the bowel when it returns to the abdomen.
What genetic issues are associated with an omphalocele?
Trisomy 13, 18, 21.
What is gastroschisis?
Abdominal content extrusion lateral to umbilicus and not covered by peritoneum.
Describe Hirschsprung’s disease
A congenital megacolon (dilated with thin wall) due to an absence of ganglion cells distal to the dilated segment.
What is seen histologically in Hirschsprung’s disease?
Neural hyperplasia, nerve hypertrophy, no ganglion cells in the stroma.
Describe an ischemic small bowel
A dark red infarcted small intestine due to blood supply being cut off; this could lead to necrosis.
What might cause small bowel ischemia?
Shock, emboli, atherosclerosis, obstruction, trauma.
What is seen histologically in ischemic small intestine?
Atrophic crypts, hemorrhage, fibrin, necroinflammatory debris.
Describe angiodysplasia
Tortuous, dilated vessels in the submucosa that lead to hemorrhage and bleeding.
What are hemorrhoids?
Swollen and dilated veins in the anorectal region caused by straining and constipation; may be internal or external.
What are diverticuli?
Outpouching of the mucosa and submucosa through the muscularis.
What are the most common sites of diverticuli?
Sigmoid colon/left colon.
What are possible outcomes of diverticuli?
Fecal matter can get stuck in the outpouchings and lead to inflammation or possibly perforation.
What are the major causes of obstruction?
Herniation, adhesion, intussusception, volvulus.
What is an inguinal hernia?
Protrusion of abdominal contents through the inguinal canal.
Compare indirect and direct inguinal hernia
Indirect hernias go through the deep and superficial rings and are lateral to the inferior epigastric vessels. Direct hernias protrude through a weakened area of fascia directly behind the superficial ring and are medial to inferior epigastric vessels. These also rarely enter the scrotum, whereas indirect hernias can.
Describe adhesions
Irregular bands of scar tissue that may be due to previous surgery, infection, trauma, or radiation. These bands connect various bowel segments that can cause obstruction.
What is intussusception?
Small bowel found within the colon.
What is volvulus?
A twisting of the small or large intestine. The blood supply also gets twisted, which may cut off supply to the area and lead to complete necrosis.
Where does inflammation begin in acute appendicitis?
The mucosa.
What is seen grossly in acute appendicitis?
Swollen appendix with white exudates on the surface, necrosis in the lumen, inflammation in the mucosa.
What is seen histologically in acute appendicitis?
Necroinflammatory debris, transmural inflammation, neutrophils.
What is paralytic ileus?
Nerve or muscle issues lead to slowed or stopped contractions of the intestine. The movement of food and fluid is impacted without the presence of mechanical obstruction.
What is meconium ileus?
In a newborn, meconium (greenish material) gets stuck in the distal small intestine, leading to obstruction, distention, and possibly perforation.
What is a main cause of meconium ileus?
CF.
What are diagnostic markers of meconium ileus?
Soap bubble appearance on x-ray and empty rectum.
What is rectal prolapse?
Rectum protrudes through the anal canal.
What causes rectal prolapse?
Diverticular disease, straining, colonic spastic contractions.
What are outcomes of rectal prolapse?
Ulceration of mucosa, ischemia or necrosis from impacted blood supply, damage to the sphincter muscle.
What is seen histologically in rectal prolapse?
Hypertrophic smooth muscle in the stroma, erosion/inflammation of mucosa, hyperplastic and serrated changes.
