Pathology of the General Intestinal Tract Flashcards
This GI pathology is caused by the twisting of a loop of the bowel around its mesenteric base of attachment.
Volvulus
What is the most common cause of ischemic colitis?
Arterial obstruction
Acute appendicitis is a surgical emergency with pain in the RLQ. At what point does pain often localize?
McBurney’s Point - 1/3 of the way from the ASIS to the umbilicus
Diverticulosis pain generally arises in what quadrant?
LLQ - descending and sigmoid colon
What are diverticula?
Small outpouchings or sacs in the GI wall through the lamina propria
True/False. Patients with ischemic colitis may present with severe abdominal pain, but a normal abdominal exam.
True - this is called pain out of proportion to exam
This pathology is due to malformed mucosal and submucosal blood vessels, most common in the sixth decade.
Angiodysplasia
Tyeps of ischemic infarcts.
Mucosal and mural infarcts have a better prognosis than transmural that involves more layers.
What is the most common clinical symptoms of angiodysplasia?
Hematochezia - undigested blood in stool
Mesenteric venous thrombosis is classically a result of Virchow’s triad that causes ischemic colitis. What is Virchow’s triad?
Stagnant blood flow, hypercoagulability, vascular injury
Where do direct hernias originate?
Direct hernias are acquired, originate medially to the inferior epigastric artery, and protrude through the inferior peritoneal ring
This type of hernia can be manually reduced back into the abdominal cavity with a finger or by lying supine.
Reproducible hernia
These two factors are responsible for hernia formation.
Weakness of the peritoneal wall and increased abdominal pressure
What areas are most commonly affected by angiodysplasia?
Right colon and cecum
How do the causes of intussusception in children and adults differ?
Most cases occur in children and are idiopathic. In adults, intussusception is often caused by an intraluminal mass.
Watershed areas are the most susceptible to ischemic damage. Where are these areas?
Splenic flexure and rectosigmoid junction
This type of hernia is difficult or impossible to retract due to the enlargement of the hernial sac by obstructed venous flow.
Incarcerated hernia
What is the bloody supply for the distal transverse colon and descending colon?
Inferior mesenteric artery
Blood may appear in the stool in cases of ischemic colitis. Why is this?
Surface epithelium dies due to poor blood flow and ischemia. The dead epithelium sloughs off and carries blood with it in the stool.
Where do cecal volvulus arise?
RLQ - cause collapse of the ascending, transverse, and descending colon
This condition is caused by a lack of blood flow to the bowel, that may be obstructive or non-obstructive.
Ischemic colitis
This type of volvulus arises in the LLQ and is characterized by the coffee bean sign on imaging.
Sigmoid volvulus
How do true and false diverticula differ?
True diverticula involve all layers. False diverticula only involves the mucosal and submucosal layers.
What is the number one cause of small bowel obstructions?
Adhesions
Intestinal obstructions may be caused by one of these GI pathologies.
Hernia, volvulus, adhesion, intussusception
What are GI adhesions?
Fibrous bridges between bowel segments or the abdominal wall due to repeated inflammation that may cause obstruction
What is reperfusion injury?
Causes the most damage during ischemic colitis when blood flow returns due to the release of inflammatory factors, free radicals, neutrophils, etc.
Meckel’s diverticulum is the most common congenital abnormality of the GI tract. What is the cause?
Persistence of the vitelline duct
What is the blood supply for the ascending and proximal transverse colon?
Superior mesenteric artery
This is the most severe type of hernia, considered a surgical emergency due to ischemia and necrosis.
Strangulated hernia
What are the two more common causes of a congenital hernia?
Failure of the inguinal ring to close or process vaginalis to obliterate
Where do indirect hernias originate?
Indirect hernias are congenital, originate laterally to the inferior epigastric artery, and protrude through the deep inguinal ring
What is the most common tumor of the appendix?
Carcinoids (neuroendocrine tumor/NET)
These class of hernias are most common in men, on the right side of the body, and in premature babies.
Congenital hernias
What is intussusception?
Telescoping of a portion of the bowel into the immediate distal portion
What is the most common location of a volvulus?
Sigmoid colon
