Pathology of the General Intestinal Tract Flashcards
What are the 4 common causes of intestinal obstruction?
- hernias
- adhesions
- volvulus
- intussusception
What is a hernia?
- a protrusion of something through another area. WEAKNESS in the wall of the peritoneal cavity can cause a serosa lined pouch of peritoneum called a hernia sac. The sac may protrude externally, which can result in obstruction of venous outflow and enlargement of the hernia sac, making it difficult to reduce.
To what can an externally protruded sac (hernia) lead?
ENTRAPMENT (INCARCERATION), which in turn can cause arterial and venous compromise (STRANGULATION) which can cause infarction.
What are adhesions?
Acute peritoneal inflammation can lead to the formation of fibrous bridges (adhesions) between bowel segments, the abdominal wall, and operative sites. Portions of the bowel may become entrapped, leading to infarction. AKA leading to luminal or vascular compromise.
What are the 2 common t types of hernias?
- umbilical
2. inguinal
What is volvulus?
complete twisting of a loop of bowel around its mesenteric base of attachment. This can cause vascular and luminal obstruction.
** What is the most common site for volvulus to occur? (BOARD QUESTION)
- SIGMOID colon, followed by the cecum, small bowel, and stomach.
What is Intussusception?
- portion of the intestine, which is moved by a wave of peristalsis, telescopes into the immediately distal portion of bowel. PERISTALSIS propels the portion of bowel and mesentery. This may also result in vascular obstruction and subsequent infarction.
What tends to cause intussusception in children?
- anatomic defects and may be associated with ROTAVIRUS infection.
What tends to cause intussusception in older children and adults?
an intraluminal mass
What may be a good treatment for children with intussusception?
barium enema
What treatment is often needed for adults with intussusception?
surgery
With what vascular supply must we be concerned in ischemic bowel disease?
celiac, superior mesenteric, and inferior mesenteric arteries. Acute obstruction of one of these arteries can lead to infarction of several meters of intestine.
What are some causes of acute obstruction?
atherosclerosis, aortic aneurysms, hypercoagulable states, oral contraceptives, embolization of cardiac vegetations and aortic atheromas, shock, dehydration, or vasoconstrictive drugs
What is the intestinal response to hypoxia?
- hypoxic injury at onset of vascular compromise, minimal damage may occur if the hypoxia is TRANSIENT.
- the most damage occurs when the blood supply is restored and the bowel undergoes REPERFUSION INJURY.