Darrow Malabsorption and Diarrhea (CIS)

Question 1

chronic diarrhea lasts how long?

Answer 1

at least 4 weeks

Question 2

secretory diarrhea

osm gap?

Answer 2

from bile acids***

osmotic gap <50

-interrupts sleep!!***

also:
-neuroendocrine tumors (carcinoid, VIP)

increased motility (postvagotomy, DM, meds, IBS)

villous adenoma

microscopic colitis

infections

Question 3

osmotic diarrhea

Answer 3

from carbohydrates (sugar)! these create osmolality

-lactase deficiency
sorbitol ingestion
poorly absorbed salts

osmotic gap >100,

relieved by fasting

Question 4

Fatty diarrhea

2 types

Answer 4

Malabsorption (celiac, tropical sprue, short bowel, lymphatic obstruction, mesenteric ischemia, Tropheryma whipplei)
-don’t absorb fats

Maldigestion (pancreatic insufficiency, bile acid deficiency** or deconjugation/bacterial overgrowth***)

• bile acids can be deficient b/c of obstruction or b/c the bile acids are being digested by bacteria in the small intestine
• can’t breakdown the fat/FA’s to form chylomicrons

Bulky, floating stool = steatorrhea

Question 5

blood and pus inflammatory diarrhea

Answer 5

positive hemoccult and fecal leukocytes

painful, and may be febrile:

From infections (CMV, Herpes including Kaposi’s, E. histolytica, Balantidium coli (pigs)***, C. diff, Campylobacter, Aeromonas, Plesimonas, Mycobacteria, Shistosoma (eosinophilia), IBD, ischemic and radiation colitis, colon cancer, and lymphoma.

Question 6

niacin deficiency (

Answer 6

diarrhea
dermatitis
dementia

delayed diagnosis
death

Question 7

carcinoid syndrome

Answer 7

find via urine diagnosis–> 5-hydroxy acetic acid

tryptophan is shunted to serotonin and is not available for niacin production.

present with niacin deficiency

Question 8

stool osmolality calculation

Answer 8

2x (NA + K)

Question 9

Less than ___ cm of ileal involvement or resection – liver able to keep
up with bile acid synthesis, so enough bile acid for fat absorption.
The bile lost to the colon produces a secretory diarrhea, so it needs to
be bound to control the diarrhea.

Answer 9

100 cm

Question 10

Greater than ___ cm of ileal involvement – not enough micelle
formation (steatorrhea), so need low fat diet, vitamin replacement,
and medium-chained triglycerides.

Answer 10

100 cm

horrendous bile acid malabsorption

Question 11

A 45 y/o male presents with a new onset right kidney stone with evidence of gall stones on CT scanning. He has a long history of episodic hemoglobinuria, hemosiderinuria and LDH elevation. He also has a history of iron deficiency anemia, and prior DVT of the left arm. He had a bowel resection two months ago related to a “blood clot” of the small intestine…

What is the cause of the hemoglobinuria?
Why has the patient had venous and arterial blood clots?
What will flow cytometry reveal?

Answer 11

He has hemosiderinuria b/c of intravascular hemolysis

LDH elevation b/c of hemolysis

Iron deficiency anemia (hemoglobinuria)

Arterial and venous thrombosis (complement actived thrombosis)

He has paroxsymal nocturnal hemoglobinuria- where complement is attacking his RBCs
you can end up with malabsorption

Flow cytometry reveals deficiency of CD 59 and CD 55 (due to lack of glycosylphoshatidylinositol (GPI) anchor for complement – regulating proteins)

Question 12

with short bowel syndrome, what type of diarrhea will occur?

what is the effect on bile salts and B12 with terminal ileal resection?

Answer 12

you get fatty chronic diarreah- steathorrea

malabsorption type- short bowel syndrome

with terminal ileal resection you get malabsorption of bile salts and B12

without bile salts, he can’t solubilize cholesterol so you get cholesterol gallstones

unabsorbed FA’s bind calcium, decreased absorption of calcium occurs along with increased absorption of oxalate so oxalate kidney stones form

Question 13

what type of diarrhea do you get with irritable bowel disease?

Answer 13

inflammatory diarrhea

due to
Increased fecal serine 
protease activity, probably 
from an altered fecal flora!”
You have 3 pounds of bacteria in your gut with 30,000 species
and multiplying!

Question 14

when diarrhea is post-prandial (after eating) consider what?

Answer 14

Celiac and Crohn’s

then proceed to Sudan III and fecal elastase-1.

If the latter is below (or even above) 100 ug/g stool, then try pancreolipase.

A bile acid binder should also be tried and even an alpha glucosidase might be worth a try. If this fails give a trial of an antibiotic for bacterial overgrowth and as a last resort consider an endocrine tumor. When all these options are exhausted, rest you laurels on IBS.

Question 15

skin biopsy shows granular deposits of IgA in the tips of the dermal papillae (on extensor surfaces)

Answer 15

rash is dermatitis herpetiformis

celiac disease

Question 16

what type of diarrhea do you get with celiac

Answer 16

malabsorption fatty diarrhea

Question 17

Extraintestional manifestations: elevated liver and pancreatic
enzymes; infertility or spontaneous miscarriages; iron deficiency
anemia; peripheral neuropathy; diabetes type 1, Addisons,
osteopenia

Answer 17

Celiacs

do a mucosal biopsy villous atrophy and crypt hypertrophy with lymphocyte and plasma cell infiltration.

Question 18

what if a pt has celiacs and they start to develop overactive diarrhea despite being gluten free?

Answer 18

suspect they developed a B cell lymphoma

 HLA-DQ2(MHC class II molecules)
 present antigen peptides to CD4 
(TH0) cells resulting in production 
of IgA against EMA and tTG
 (tissue transglutaminase)

TH2 cells activate b cells –> overactivation can lead to lymphoma

Question 19

a stool pH of <5 indicates what?

Answer 19

presence of FFAs consisting of butyrates, acetates, and proprionates which are all organic anions produced when colonic bacteria carry out fermentation on fecal CHOs. Thus, a stool pH of 3.5 would point to excess CHOs (carbohydrates) and an osmotic diarrhea.

Question 20

what are the causes of nonerosive atrophic gastritis

Answer 20

pernicious anemia

h. pylori

Question 21

why would a pt with pernicious anemia get bacterial overgrowth and get two different kinds of diarrhea?

Answer 21

with pernicious anemia you have loss of parietal cells so loss of acid–> no acid is getting to the small intestine so you get bacterial overgrowth

the patient has watery diarrhea b/c of the osmotic load of unabsorbed CHO’s

( proteases from the bugs destroy the brush border disaccharidases) arriving in the colon. The colonic bacteria carry out fermentation on these CHOs with the additional production of FFAs consisting of butyrates, acetates, and proprionates which are all organic anions that lower the pH of the stool content to less than pH 5. The bacteria also consume B12 and other nutrients.

In addition, the bacteria deconjugate bile acids. This results in malabsorption of fat with resultant steatorrhea* from lack of micelle formation, and the subsequent parade of these deconjugated bile acids to the colon where they further irritate and produce a secretory diarrhea, in this case accounting for the increased stool volume.

Question 22

how do you prove that the problem of diarrhea is bacterial overgrowth

Answer 22

d-(14C)xylose breath test - when you take this in, the gut bacteria metabolize to CO2
CO2 is measured in the expired air at 30 minutes

Hydrogen breath test: Give 50 gm of lactose and measure
breath hydrogen. In 90 minutes will have > 20 ppm of hydrogen from bacterial metabolism in the colon. An earlier peak (30 minutes) will be seen in bacterial overgrowth.

Question 23

fever of undetermined origin

Answer 23

3 weeks duration
Temp over 38.3 (101) on several occasions
No diagnosis after 3 office visits or 3 days of hospitalization or one week of evaluation.

Question 24

multisystem involvement

fever, lymphadenopathy, arthralgias, weight loss, malabsorption , chronic diarrhea

PAS positive macrophages

heart murmurs

positive stool leukocytes

Answer 24

whipple disease

causes edema b/c of loss of protein

malabsorption type fatty diarrhea

Question 25

how do you differentiate whipple disease due to tropheryma whippelii from MAC

Answer 25

perform an acid fast test