Diarrhea

Question 1

Secretory diarrhea and fasting

Answer 1

A 24-;48 hour fast does not stop secretory diarrhea, except in fatty acid-and bile acid-related diarrheas

Question 2

osmotic gap in osmotic diarrhea

Answer 2

> 50

Question 3

If an osmotic diarrhea persists despite a 24-hour fast

Answer 3

suspect surreptitious ingestion of a Mg-containing antacid. Most laxatives, including castor oil, cause an osmotic diarrhea

Question 4

Stool osmolality that is greater than serum osmolality

Answer 4

indicates an improper stool collection procedure

Question 5

AB in invasive diarrhea

Answer 5

TMP/SMX

Quinolones

Question 6

AB for Campylobacter

Answer 6

erythromycin

Question 7

AB for amebiasis

Answer 7

metronidazole

Question 8

AB for E. coli O157:H7 infection (EHEC).

Answer 8

is treated only symptomatically. Antibiotics are contraindicated

Question 9

If you suspect E coli O157:H7

Answer 9

specifically ask for MacConkey-sorbitol agar for the stool culture media. If you suspect Clostridium difficile, also add C. difficile toxin assay.

Question 10

Treat travelers’ diarrhea with antibiotics if

Answer 10

Treat travelers’ diarrhea with antibiotics if the patient is febrile (TMP/SMX, ciprofloxacin, doxycycline, bismuth subsalicylate); otherwise, usually treat by replacing fluid and with antimotility drugs (e.g., diphenoxylate + atropine [Lomotil)

Question 11

the most common cause of invasive diarrhea

Answer 11

Campylobacter

Question 12

suspect this bacteria especially in patients with sickle cell or achlorhydria

Answer 12

Salmonella

Question 13

usually ingested from undercooked/raw poultry or unpasteurized milk, but may also be obtained from drinking water from mountain streams, foreign travel, or contact with infected dogs and cats.

Answer 13

Campvlobacter jejuni

Question 14

Symptoms of Campylobacter

Answer 14

Symptoms of Campylobacter enteritis include abdominal cramping and diarrhea that is often bloody. Symptoms last 5-7 days, but may be shortened by taking erythromycin

Question 15

What is the first and most critical laboratory test to do in an acute diarrhea workup?

Answer 15

fecal WBC

Question 16

A stool culture in a patient with common “travelers’ diarrhea” will usually show what?

Answer 16

normal flora

Question 17

Which diarrheal organism is Guillain Barre most commonly linked to?

Answer 17

Campylobacter

Question 18

especially associated with ingestion of raw eggs or contaminated icc cream

Answer 18

Salmonella

The larger the dose of Salmonella, the worse the disease.

Question 19

Salmonellosis consists of

Answer 19

fever, abdominal cramps. and diarrhea-often bloody,

Question 20

do we treat salmonella diarrhea with AB?

Answer 20

most of the time you do not treat Salmonella diarrhea with antibiotics

Question 21

a major reservoir for EHEC

Answer 21

Dairy cattle

and the disease is linked to eating undercooked beef and unpasteurized milk or apple juice.

Question 22

These patients more commonly experience nausea and vomiting, compared to other bacterial colitides

Answer 22

EHEC

Question 23

which diarrhea organism can cause HUS

Answer 23

EHEC

Question 24

HUS associated with E coli O157:H7 (EHEC)presents with what triad of symptoms?

Answer 24

HUS classically has the triad of kidney failure, thrombocytopenia with purpura, and hemolytic anemia

Question 25

correlation between pseudomembranous diarrhea and AB

Answer 25

This usually presents in about a week after starting antibiotics.
but it may start up to 6-8 weeks after antibiotics are stopped!

Question 26

the best test for Clostridium difficile:

Answer 26

Because the organism is carried in 20% of healthy persons, the best test for disease is finding the toxin in the feces using the
C. difficile toxin assay

Question 27

when to consider C.difficile

Answer 27

Consider C. difficile anytime diarrhea occurs > 6 days after initiation of antibiotics.
Also suspect C. difficile infection in patients on antibiotics in whom unexplained leukocytosis (WBC > 15,000) develops.

Question 28

Diagnosis of C. difficile:

Answer 28

First, do a fecal leukocyte (very sensitive). If fecal leukocyte is positive, do an EIA (best) or toxin assay (good, just a long wait).

Question 29

If the patient with AIDS has diarrhea and weight loss without fever. suspect

Answer 29

Cryptosporidia (usual cause), E. histolytica, Giardia, Isospora, Strongyloides, and AIDS enteropathy

Question 30

If the patient with AIDS has diarrhea and weight loss with fever. suspect

Answer 30

Mycobacterium, Campylobacter, Salmonella, Crvptococcus, Histoplasma, and CMV .

Question 31

A CD4 count < 200. especially if accompanied by weight loss, points to which etiology of diarrhea in AIDS?

Answer 31

points to an infectious etiology rather than AIDS enteropathy

Question 32

Diabetic diarrhea may be caused by:

Answer 32

• use of dietetic foods rich in sorbitol (erroneously labeled “sugarless”)
• visceral autonomic neuropathy (especially suspect this in the incontinent diabetic patient),
• malabsorption (less common) due to sprue (present in 5% of diabetics), pancreatic insufficiency, or bacterial overgrowth (treat with metronidazoleor arnoxicillin-clavulanate)

Question 33

where most of the secretory carsinoids are located?

Answer 33

About 75% of the secreting, symptomatic carcinoids are in the ileum,

Question 34

Diagnosis of carsinoids(secretory)

Answer 34

Diagnosis: check 24-hour urine for 5-hydroxyindoleacetic acid (5-HIAA)-a breakdown product of 5-hydroxytryptamine. Normal is < 10 mg/24 hr; with carcinoid, patient has > 25 mg/24 hr.

Question 35

What is the best way to diagnose giardial infection?

Answer 35

II is best diagnosed with an enzyme-linked immunosorbent assay for Giardia antigen. This is both sensitive (92%) and specific (99%), and becomes negative after successful therapy (i.e., this is an antigen test, not an antibody test). The classic series of 3 stool specimens is only 60-80% sensitive

Question 36

What are the symptoms of a secreting carcinoid?

Answer 36

The symptornatic carcinoids [Know] secrete various vasoactive mediators, including 5..hydroxytryptophan, 5-hydroxytryptamine. and histamine, which cause paroxysmal flushing; crampy, explosive diarrhea; and sometimes tachycardia and hypotension. The flushing is often bright red with well defined borders and can be on the whole body-including hands and soles.

Question 37

What are the 3 stages used in the workup of chronic diarrhea?

Answer 37

Stage I: Stool O&P & fecal leukocytes x 3.
Stage 2.:Imrnunoabsorbent assay for giardiasis.
Stage 3: EGD and colonoscopy.