EXAM #1: SMALL BOWEL PATHOLOGY II Flashcards
What is diverticulosis?
Outpouching of the intestinal wall (mucosa and submucosa through the muscularis propria)
What is diverticulitis?
Inflammation of an outpouching of the intestinal wall
Which is more associated with bleeding, diverticulosis or diverticulitis?
Diverticulosis
Describe the pathogenesis diverticular disease.
- Focal weakness in colonic wall caused by:
1) Increased luminal pressure
2) Low fiber diet - Focal weakness where vasa recta enter muscularis propria
What intestinal wall layer is absent that leads to development of diverticula?
Muscularis propria
Where are most diverticula located?
Sigmoid colon
How do multiple diverticula appear on a barium enema?
“Sawtooth”
What are the complications of diverticular disease?
1) Inflammation i.e diverticulitis
2) Perforation
3) Abscess formation
4) Rupture
5) Fistula tract formation
What are the symptoms of diverticular disease?
- Abdominal cramping
- Lower abdominal pain
- Sensation of not being able to empty rectum
What part of the bowel is most commonly affected by intestinal obstruction?
Small bowel
What are the symptoms of intestinal obstruction?
- Pain
- Distention
- Vomiting
- Constipation
- Failure to pass gas
What causes most of the cases of intestinal obstruction?
1) Hernia
2) Adhesions
3) Intussusception*
4) Volvulus*
*These are medical emergencies
What is a hernia?
Outpouching of the peritoneum through a defect in the abdominal wall
What are the major complications of hernias?
1) Strangulation
2) Incarceration
This is a medical emergency when it occurs
What is an inguinal hernia?
Portion of the small intestine enters the inguinal hernia
What is a direct inguinal hernia?
Medial to the inferior epigastric artery
What is an indirect inguinal hernia?
Lateral to the inferior epigastric artery
- Through inguinal canal
- In testes
What are “adhesions?”
Fibrous bridges between bowel segments or abdominal wall
What are adhesions associated with?
1) Inflammation i.e. peritonitis
2) Surgery
3) Infection
4) Endometriosis
What is the major complication of adhesions?
Bowel slips between fibrous bridges resulting in:
- Obstruction
- Infarction
Note this is called an internal hernia*
What is Intussusception?
Telescoping of one segment of bowel into an immediately distal segment
What causes intussusception in kids?
1) Secondary lymphoid hyperplasia
2) Rotavirus
What causes intussusception in adults?
1) Mass
2) Tumor
What are the major complications of Intussusception?
- Obstruction
- Infarction (mesenteric vessels become trapped)
What is volvulus?
Complete twisting of a loop of bowel
What are secondary causes of bowel obstruction?
1) Foreign body (drug mule)
2) Carcinoma
How does malabsorption present in kids?
- Diarrhea
- Failure to thrive
What type of stool change is typical of malabsorption?
Steatorrhea
What are the three phases of nutrient absorption?
1) Intraluminal digestion (saliva, gastric enzymes, pancreatic enzymes…etc.)
2) Terminal digestion (hydrolysis at the brush border)
3) Transepithelial transport
What are the three most common malabsorptive disorders in the US?
1) Celiac sprue
2) Chronic pancreatitis
3) Crohn’s Disease
What is Celiac spure?
Gluten sensitive enteropathy
What is the component of gluten that causes an inflammatory reaction?
Gliadin
What cells mediate the inflammation seen in Celiac Sprue?
T-cells
What is the hallmark characteristic of a mucosal biopsy in Celiac Sprue?
Proximal villous atrophy
- Preceeded by villous blunting
What are patients with Celiac Spure at risk of?
Malignancy
What is Tropical Sprue?
Tropical disease–bacterial infection
In Tropical Spure, what is one major complication related to the fact that the entire small bowel is affected?
- Folate/B12 deficiency
- Megaloblastic changes
How is Tropical Sprue treated?
Broad spectrum antibiotics
What is Whipple Disease?
Rare systemic infectious disease caused by the bacterium Tropheryma whipplei
What is the hallmark of Whipple Disease?
Macrophages stuffed with PAS+ granules in multiple organ systems
What are the clinical features of Whipple Disease?
Fat malabsorption and steatorrhea
- Macrophages compress lacteals (lymphatic vessels of the small intestine that absorb digested fats)
- Chylomicrons cannot be transferred from enterocytes to lymphatics
**Note that Whipple Disease also involves the cardiac valves, lymph nodes, and CNS.
How is Whipple Disease treated?
Antibiotics
