malabsorption

Question 1

what are the clinical manifestations associated with fat malabsorption ?

Answer 1

steatorrhea
greasy foul smelling
stool floats
loss of fat soluble vitamins

Question 2

what are the features of carbohydrate malabsorption ?

Answer 2

watery diarrhea
due to osmotic effect of sugar

Question 3

what must be identified after we see that the diarrhea is watery ?

Answer 3

is it secretory or is it osmotic
secretory - cholera
osmotic - lactose intolerance

Question 4

how can we differentiate between osmotic and secretory diarrhea ?

Answer 4

measure the osmotic gap
if the osmotic gap is large - >50 osmotic diarrhea
if the osmotic gap is low - <50 secretory diarrhea

Question 5

what is celiac sprue ?

Answer 5

autoimmune condition associated with the destruction of the small intestinal villi
triggered by gluten exposure

Question 6

what is the pathogenic component of gluten and what is needed to deaminate it ?

Answer 6

gliadin
that is deaminated by tissue transglutaminase

Question 7

what is the immunological process associated with celiac disease ?

Answer 7

the deamidated gliadin is consumed by APC
presented to T cells
Type 4 hypersensitivity reaction

Question 8

what is the genetic association with celiac disease ?

Answer 8

HLA-DQ2
HLA-DQ8

Question 9

what are the histological features associated with celiac disease ?

Answer 9

blunting of the villi
crypt hyperplasia
lymphocytes in the lamina propria

Question 10

what are the antibodies associated with celiac disease ?

Answer 10

anti gliadin
anti tissue transglutaminase
anti endomysial

Question 11

what are the antibodies measured to detect celiac disease ?

Answer 11

IgA endomysial and tTG

Question 12

what test is used for screening of celiac disease ?

Answer 12

IgA tTg automated

Question 13

what is the order in which the test for the confirmation of celiac disease must be made ?

Answer 13

anti-tTG
IgA level
biopsy

Question 14

which part of the GI tract is mostly affected by celiac disease ?

Answer 14

duodenum

Question 15

what is the presentation of celiac disease ?

Answer 15

flatulence bloating , chronic diarrhea
steatorrhea
in children: failure to thrive
iron deficiency anemia

Question 16

what are the complications associated with celiac disease ?

Answer 16

small bowel cancer - adenocarcinoma
T cell lymphoma (EATL)

Question 17

what is the classic scenario associated with a celiac patient who develops an adenocarcinoma ?

Answer 17

patient adherent to gluten free diet with worsening symptoms

Question 18

what dermatological condition is associated with celiac ?

Answer 18

dermatitis herpetiformis

Question 19

what is the cause of dermatitis herpetiformis ?

Answer 19

IgA deposition in dermal pappillae
resolves with a gluten free diet

Question 20

what is tropical sprue ?

Answer 20

malabsorption due to unknown infectious agents
occurs in the tropics
has bluting of the villi

Question 21

what is the difference between tropical sprue and celiac sprue ?

Answer 21

celiac most commonly affects the duodenum
tropical sprue affects the entire small bowel
and is associated with folate/B12deficiency

Question 22

where is folate and b12 absorbed ?

Answer 22

in the jejunum and the ileum

Question 23

what is the treatment for tropical sprue ?

Answer 23

antibiotics (tetracyclines)
folate supplementation

Question 24

what is whipples disease ?

Answer 24

infection associated with t whippeli
gram positive rod

Question 25

what are the four cardinal features associated with whipples disease ?

Answer 25

diarrhea abdominal pain weight loss joint pains ( migratory arthalgia)

Question 26

what are the other clinical features associated with whipples ?

Answer 26

hyperpigmentation CNS involvement endocarditis - culture negative mesenteric lymphadenopathy

Question 27

how is a diagnosis of whipples made ?

Answer 27

by biopsy -PAS positive foamy macrophages

Question 28

what is the treatment for whipples ?

Answer 28

ceftriaxone

Question 29

what is lactose digested by ?

Answer 29

brush border enzyme lactase

Question 30

what is the pathology associated with lactose intolerance ?

Answer 30

problem with the enzyme lactase usually due to lactase no persitence

Question 31

what are the secondary causes of lactose intolerance ?

Answer 31

mucosal injury bacterial overgrowth , viral infection, giardiasis present as lactose intolerance after GI illness

Question 32

how is a diagnosis of lactose intolerance made ?

Answer 32

often clear from history lactose breath hydrogen test lactose tolerance test

Question 33

what diseases are associated with pancreatic insufficiency ?

Answer 33

cystic fibrosis chronic pancreatitis obstruction

Question 34

how does bacterial overgrowth cause malabsorption ?

Answer 34

small intestine should be sterile if not - present with bloating, flatulence or abdominal discomfort

Question 35

what are the causes of bacterial overgrowth ?

Answer 35

1- altered motility - usually associated with diabetes or scleroderma 2- partial or intermittent obstruction , adhesions from previous surgeries or crohns disease

Question 36

what is the gold standard for the diagnosis of bacterial overgrowth ?

Answer 36

1- jejunal aspirate (gold standard) 2- lactulose test

Question 37

what is a fecal fat test ?

Answer 37

stool is collected over 1-3 days amount fat is measure normal is less than 7 anything more is increased in fat malabsorption

Question 38

what is the d-xylose test ?

Answer 38

tests carbohydrate absorption in the small intestine after fasting, patient ingests D-xylose no enzymes required for this only an intact mucosa

Question 38

when do we see abnormal results in a d xylose test ?

Answer 38

whipples disease celiac disease

Question 39

what test is best to be used in chldren to detect undigested sugars ?

Answer 39

cliniest