Diseases of the Small Bowel Flashcards
The longest part of the small intestine is the _____________.
ileum (55%)
The surface area of the small intestines is amplified _______-fold by the plicae circulares, villi, and microvilli.
600
What are the signs/symptoms/sequelae of malabsorption?
Weight loss, diarrhea, steatorrhea, and vitamin deficiencies
There are a lot of causes of malabsorption. List the categories and some examples of each.
Surgery: gastric bypass or small-bowel resection
Bacterial overgrowth
Medications: cholestyramine, phenytoin, folate
Flattened villi: celiac or tropical sprue
Pancreatic insufficiency
Ischemia
Liver disease: failure to produce bile or biliary obstruction
True or false: a normal fecal sample will stain for some fat on Sudan staining.
True. The droplets will be smaller.
True or false: pancreatic insufficiency is an early symptom of pancreas dysfunction.
False. Insufficiency only occurs when 90% of the pancreas is destroyed.
Which nutrient category is the first to be defective in pancreatic insufficiency? The last?
First: fat
Second: protein
Last: carbohydrate (rare, because of the availability of salivary amylase)
Liver disease and bile-duct obstruction can lead to _________.
decreased bile and subsequent inability to form bilious micelles
Gastric-bypass patients should be given _______________.
multivitamins, to avoid deficiencies in B12, C, Ca, and D
The concentration of bacteria generally _____________ as you go down the GI tract.
increases
Small-intestinal bacterial overgrowth (SIBO) is defined as bacteria concentration greater than ______.
10^5/mL
What causes SIBO?
Diverticula Hypomotility Partial obstruction Decreased acid secretion Enterocolonic fistula
Which antibiotic is best for SIBO?
Ciprofloxacin
High folate levels can indicate ____________.
SIBO, because bacteria produce it and then it gets absorbed by the small intestine
Review the fat-soluble vitamins and the symptoms of their deficiencies.
A: night blindness
D: osteomalacia
E: hemolytic anemia
K: clotting disorders
What immunoglobulin will be present in someone with the disorder that results in loss of villi, hyperplasia of the small intestinal crypts, and lymphocyte proliferation?
IgA tissue-transglutaminase (this being celiac)
One slice of bread contains 5 grams of gluten, and those with celiac only need ______ per day to have histologic changes.
50 mg
IgA deposits in the epidermal grooves will appear in which GI disorder?
Celiac (the rash is called dermatitis herpetiformis and is almost pathognomonic for celiac)
Celiac is more common in ____________.
- females (2:1)
- those with autoimmune diseases
- HLA-DQ2 and HLA-DQ8 (100% of those with celiac have one of these, but not everyone with these phenotypes will develop celiac)
- …
Describe the presentation of tropical sprue.
Aerobic coliform bacteria cause flattening of villi (similar to celiac) and subsequent megaloblastic anemia from cobalamin and folate deficiency. It is only found in those who live in or have recently visited the tropics. Treat with long-term folate and cobalamin supplementation.
Whipple’s disease results from ______________.
infection with the Gram-positive actinomycete Tropheryma whippelii; macrophages will stain positive for PAS inclusions
The vasculature of the __________ has redundancies, so multiple vessels or the branching point of lots of vessels must be occluded to develop symptoms.
mesentery
True or false: small-intestine tumors are common.
False. The incidence is roughly 1 / 100,000.
Watery diarrhea indicates _______________.
osmotic or secretory diarrhea
Watery, osmotic diarrhea can result from _____________.
lactose intolerance, excess undigested sorbitol, or fructose consumption (all of which lead to a hypertonic state in the large intestine)
The stool sample test that distinguishes secretory and osmotic diarrhea is ________________.
Stool osmolarity anion gap:
290 - 2(Na + K)
If it is greater than 50 mOsm, then the diarrhea is osmotic. If it is less than 50 mOsm, then it is secretory.
The ____________ is the only site of bile reabsorption.
ileum
The gold-standard diagnostic tool for inflammatory bowel disease is ____________.
endoscopy
The most common cause of pancreatic insufficiency is _____________.
chronic pancreatitis
What antibody, other than IgA-TTG, indicates celiac?
Anti-endomysial antibodies
Transmural necrosis indicates ischemia from what cause?
Thrombosis, whereas chronic presents with mucosal necrosis
Ischemia presents with _____________ pain.
post-prandial
Metastasis of carcinoid tumors to the ___________ causes carcinoid syndrome.
liver
The appendix averages ____ centimeters.
9
Cobblestoning of the small intestine is also called ___________.
scalloping
Celiac causes which kind of cancer?
T-cell lymphoma
What serum test can you run on a patient with selective IgA deficiency if you are suspicious of celiac?
Anti-gliadin IgG
Lactose intolerance leads to ____________ diarrhea.
osmotic
