Shared Flashcard Set

Details

Malabsorption
Malabsorption
30
Accounting
Pre-School
02/08/2011

Additional Accounting Flashcards

 


 

Cards

Term
Describe the journey of triglycerides and how does it differ from that of proteins/carbs
Definition
Triglycerides are digested in the pancreas to FAs/monoglycerides, become part of the mixed micelle with bile acids in the liver, go to the brush border of the jejunal mucosa to partake in triglyceride synthesis/chylomicron formation and are transported to the lymphatics as chylomicrons and then to blood

Proteins and Carbs digestion starts from the pancreas and => the jejunal mucosa as AAs and monosaccharides.
Term
T/F: the body is very efficient at absorbing 100% of nutrients at the small bowel
Definition
False:

Nutrients
Fat 93-95% of triglyceride
Starch 80-95% depending on type
Disaccharides 96-98%
Protein 95-99%
Minerals
Iron 6-20% depending on body iron status
Term
What happens to leftover carbs in the colon?
Definition
Colon scavenges malabsorbed carbohydrates as short chain fatty acids, products of bacterial fermentation
Term
T/F: diarrhea and malabsorption go hand in hand
Definition
False - malabs is only a small part of diarrhea
Bowel disease may => diarrhea if 1. Enough osmotically active molecules reach the colon
2. Malabsorbed molecules stimulate colon/SB ion secretion (long-chain fatty acids, bile acids)
Term
Signs of vitamin/mineral deficiencies:
Definition
glossitis, cheilosis (iron/B vitamins)
acrodermatitis (zinc)
dry skin and hair (essential fatty acids)
anemia microcytic - iron deficiency
macrocytic - folate/B-12 deficiency
osteopenia/osteoporosis Vit D/calcium
night blindness Vitamin A
easy bruising Vitamin K
Term
Clues to nutrient malabsorption:
Definition
Weight loss, fatigue, “out of gas”
Intake of excess calories without weight gain
Diarrhea: bulky, oily stools (fat)
liquid stools (carbohydrates)
Flatus
Term
Acrodermatitis what is it due to?
Definition
Zn deficiency: Loss of hair, skin rash and diarrhea due to zinc deficiency
Term
A patient with pancreatitis presents with?
Definition
Luminal maldigestion (fat) => steatorrhea due to no pancreatic lipases and lack of conjugated bile acids (salts) from the liver

No small intestinal back-up available
Term
What's the etiology of chronic pancreatitis, and how can we see the damage?
Definition
Often due to long-standing alcohol use
Marked destruction of ducts/acini
Reduced secretion of digestive enzymes, fluid, bicarbonate
Lipases most affected
Anatomic damage assessed by ERCP or endoscopic ultrasound (EUS) or pancreatic calcifications on x-rays
Term
Why would you get edema/hypoproteinemia with chronic panc?
Definition
Due to malnutrition with decreased hepatic synthesis of albumin/serum proteins
Term
3 Mechanisms of pancreatic insufficiency:
Definition
1) Bile salt deficiency: Loss of terminal ileum loss of bile salts in stool, insufficient bile salts
Bacterial overgrowth: Deconjugation and loss of bile acids
Gastric hypersecretion: Acid inactivation of pancreatic enzymes
Term
Mucosal maldigestion - example?
Definition
lactase deficiency
Lactase: enterocyte brush-border disaccharidase found in nursing mammals.

Lactase splits lactose in milk to the monosaccharides glucose and galactose for absorption.

Normally little of the enzyme is made by villus enterocytes after weaning
exceptions are groups of humans who exhibit unusual persistance of lactase throughout adulthood
northern Europeans and other "dairying" cultures

Symptoms occur upon ingestion of lactose by lactase-deficient individuals.
Term
Why is it that you get flatus with lactase deficiency?
Definition
If you have enough you abs >80%, but if you don't you abs <50% of lactose and that goes into the colon where most of the bacteria live => 6-20g of malabs lactose => FLATUS! >20g => flatus + diarrhea
Term
Mucosal maldigestion/malabsorption examples:
Definition
celiac sprue, bacterial overgrowth
Term
Define Celiac sprue
Definition
It's a patchy disease in the proximal bowel, Immune-mediated destruction of enterocytes in response to ingestion of the protein gluten found in wheat and certain other grains. A fraction termed gliadin contains the immunogenic material
Villi are destroyed but you still have CRYPTS
Small intestinal villi are damaged or destroyed - "flat gut" appearance.

Mature digesting and transporting enterocytes are virtually absent.
Term
Dx of CS
Definition
Characteristic antibodies used in diagnosis: IgA antibodies to tissue transglutaminase or gliadin.
Term
What's responsible for the destruction in CS?
Definition
T-cells, not the antibody
Term
Histologic finding in CS
Definition
no villi but you find massively enlarged crypts
Term
CS Clinical manifestations
Definition
Weight loss, often with increased appetite
Bulky, oily stools – steatorrhea - fat malabsorption
Flatus/frothy stools – carbohydrate malabsorption
Microcytic Anemia – deficiencies of iron b/c you KNOCK OUT THE DUODENUM!, folate
Osteopenic bone disease – Vitamin D and calcium malabsorption
Edema/hypoproteinemia – protein deficiency and malnutrition
Cheilosis and glossitis – B vitamin deficiencies
Term
What causes bacterial overgrowth and what as a result is lost?
Definition
anatomic or motility factors.

Clinical consequences:
Deconjugation of bile acids by bacterial enzymes
Loss of deconjugated bile acids in stool
Decreased bile acid pool - not enough for lipid digestion/absorption
Damage to enterocytes by bacteria
Term
Clinical consequences of bacterial overgrowth?
Definition
Intraluminal consumption of nutrients by bacteria (competition)
Carbohydrates, amino acids
Vitamin B-12, iron
Damage to small bowel enterocytes causing a sprue-like histologic appearance
Mild to severe generalized malabsorption
Term
Cheap diagnostic tests for malabsorption?
Definition
Screening tests – simple, cheap, fast
Stool smear with fat stain
CBC for evidence of anemia
Cholesterol/carotene blood levels
Stool osmotic gap for carbohydrates
Weight loss/clinical clues
Term
What does a Sudan stain show in pancreatitis?
Definition
Big fat globules triglycerides…if they’re eating normally then you have probably fat malabs
Term
Quantitative tests for malabs?
Definition
Quantitate nutrient malabsorption: messy, take time, accurate and quantitative
72-hour fecal fat
D-xylose excretion (monosaccharide)
Schilling’s test for B-12 absorption (no longer available)
Breath hydrogen test (carbohydrate)
Term
What is the D-xylose test?
Definition
monosacch not require splitting. Can measure in blood/urine and has been standardized. So this is good for seeing if px is malabs sugar.
Term
Schilling's Test
Definition
Give labeled B12 – load up body stores and you see excretion in urine!
requires good renal fxn
Term
H2 breath test
Definition
Principle:
malabsorbed sugar passes into colon
bacteria produce hydrogen gas
H2 diffuses into blood and is excreted by lungs
Practice:
Administer 25-50 grams of glucose or other sugar orally
Measure hydrogen in exhaled breath at 2-4 hours
Term
How can a patient have both fat and B12 malabs?
Definition
Luminal maldigestion due to
(have to involve terminal ileum) ileal loss of bile salts and bile salt deficiency
Bacterial overgrowth:
deconjugation of bile acids
and bacterial uptake of B-12
Term
Fat and d-xylose malabsorption
Definition
due to Mucosal malabsorption: CS, Bacterial overgrowth, Severe Crohn’s disease, Whipple’s disease
Term
Evaluating malabs...which tools?
Definition
Radiographs of the small bowel to delineate anatomy
Endoscopic retrograde cholangiopancreatography (ERCP) to define the anatomy of biliary and pancreatic ducts
Pancreatic secretory function tests
Small bowel biopsy and/or antibody tests for celiac sprue
Quantative small bowel bacterial culture, bile acid or glucose breath tests for bacterial overgrowth
Supporting users have an ad free experience!