Congenital defects of GI tract

Question 1

How can the tracheo-oesophageal septum cause congenital defects?

Answer 1

By growing in an abnormal position, not normally between the trachea and oesophagus

Question 2

What congenital defects are caused by abnormalities of the growth of the tracheo-oesophageal septum?

Answer 2

Blind ended oesophagus

Tracheo-oesophageal fistula

Question 3

What is a tracheo-oesophageal fistula?

Answer 3

Abnormal connection between the oesophagus and the trachea

Question 4

How can rotation of the midgut loop cause congenital defects?

Answer 4

Incompletely rotates

Rotates in the opposite direction

Question 5

What congenital defect is caused by incomplete rotation of the midgut loop? Why?

Answer 5

Left-sided colon

because caudal limb enters abdominal cavity first
pushed to left side

Question 6

What congenital defect is caused by the midgut loop rotating in the opposite direction? Why?

Answer 6

Transverse colon is posterior to duodenum

because the caudal limb enters the cranial limb first, without the caudal limb having rotated over the cranial limb as normal

Question 7

What are the complications of congenital defects caused by abnormalities of midgut loop rotation?

Answer 7

Volvulus

Question 8

What is volvulus?

Answer 8

Loop of intestine twists around itself and mesentery

giving bowel obstruction

Question 9

What are the complications of volvulus?

Answer 9

Blood supply to bowel is cut off

gives ischaemia and necrosis of bowel

Question 10

When do complications of congenital defects caused by abnormalities of midgut loop rotation present?

Answer 10

Most present in the neonatal period (first month after birth)

Question 11

How can the vitelline duct cause congenital defects?

Answer 11

Doesn’t close up after physiological herniation

persists

Question 12

What congenital defects are caused by a persisting vitelline duct?

Answer 12

Vitelline cyst

Vitelline fistula

Meckel’s diverticulum

Question 13

What is a vitelline cyst?

Answer 13

Part of intestine contained in vitelline duct

Vitelline duct forms fibrous strands attaching the cyst to the rest of the intestines and the anterior abdominal wall

Question 14

What is a vitelline fistula?

Answer 14

Vitelline duct remains open from intestine to umbilicus

Question 15

What are the consequences of a vitelline fistula?

Answer 15

Intestinal contents can leak out of umbilicus

Question 16

What is Meckel’s diverticulum?

Answer 16

Vitelline duct forms pouch that comes off intestine

Question 17

Where is Meckel’s diverticulum commonly located along the intestines?

Answer 17

2ft before ileo-ceacal valve

Question 18

Is Meckel’s diverticulum more common in males or females?

Answer 18

Twice as common in males

Question 19

What happens to Meckel’s diverticulum during life? Why?

Answer 19

Becomes inflamed

due to secretions from ectopic gastric and pancreatic tissue damaging intestinal wall

Question 20

How can recanalisation cause congenital defects?

Answer 20

Complete failure of recanalisation

Partial failure of recanalisation

Question 21

What congenital defect is caused by complete failure of recanalisation?

Answer 21

Atresia

no lumen

Question 22

What congenital defect is caused by partial failure of recanalsation?

Answer 22

Stenosis

narrowed lumen

Question 23

Where do atresia and stenosis most commonly occur in the GI tract?

Answer 23

Duodenum

Question 24

What is pyloric stenosis?

Answer 24

Narrowing of pyloric region of stomach

Question 25

What causes pyloric stenosis?

Answer 25

Hypertropy of circular layer of smooth muscle in the pyloric region of the stomach

Question 26

What are the consequences of pyloric stenosis? Why?

Answer 26

Stomach distends, due to build of food within it

Projectile vomiting, due to food not being able to leave stomach into duodenum

Question 27

How can the fusion of the anterior abdominal wall cause congenital defects?

Answer 27

Failure of fusion of anterior abdominal wall

Question 28

What congenital defect is caused by failure of fusion of abdominal wall?

Answer 28

Gastroschisis

Question 29

What are the consequences of gastroschisis?

Answer 29

Parts of GI tract are outside of the abdominal cavity

Question 30

How is gastroschisis diagnosed?

Answer 30

Ultrasound scans of foetus

Question 31

When is gastroschisis treated?

Answer 31

After birth

Question 32

How is gastroschisis treated?

Answer 32

Surgery on baby to return GI tract into abdominal cavity and to close up the anterior abdominal wall

Question 33

How can physiological herniation cause congenital defects?

Answer 33

Midgut loop doesn’t return into abdominal cavity

phsyiological herniation persists

Question 34

What congenital defect is caused by persistance of physiological herniation?

Answer 34

Omphalocoele

Question 35

What are the differences between omphalocoele and an umbilical hernia?

Answer 35

Omphalocoele is covered by peritoneum, umbilical covering only
umbilical hernia is covered by skin, subcutaneous tissue

Because umbilical hernia completed physiological herniation, anterior abdominal wall closed up
whereas omphalacoele didn’t

Question 36

Why is important to distuinguish between omphalacoele and umbilical hernias?

Answer 36

Omphalacoele is associated with other congenital defects

whereas umbilical hernias are not

Question 37

What is an umbilical hernia?

Answer 37

Weakness of anterior abdominal wall at umbilicus

allows contents of abdominal cavity to bulge into it

Question 38

How can the development of the hindgut cause congenital defects?

Answer 38

Cloaca isn’t divided completely

Cloacal membrane doesn’t rupture

Anal canal doesn’t develop

Question 39

What congenital defect does incomplete division of the cloaca cause?

Answer 39

Hindgut fistulae

Question 40

What congenital defect does lack of rupture of the cloacal membrane cause?

Answer 40

Imperforate anus

Question 41

What congenital defect does lack of development of the anal canal cause?

Answer 41

Anal agenesis