B2.051 Big Case Diarrhea and Abdominal Pain

Question 1

classify diarrhea

Answer 1

3 or more loose/watery stools per day
change from normal bowel habits
usually >200 /day

Question 2

dysentery

Answer 2

diarrhea with blood

Question 3

gastroenteritis

Answer 3

infection of the GA tract by bacteria, viruses, parasites

Question 4

what accounts for improvement in mortality from diarrhea

Answer 4

better sanitation and food safety
improved case management (rehydration)
rotavirus vaccine

Question 5

what are some adverse outcomes of recurrent diarrhea?

Answer 5

malnutrition
micronutrient deficiencies
developmental delays

Question 6

what is the distinction between chronic/acute diarrhea?

Answer 6

more or less than 2 weeks

Question 7

what are the 4 mechanisms of diarrhea?

Answer 7

secretory
osmotic
malabsorptive
exudative/inflammatory

Question 8

outline the mechanisms of absorption in the intestines

Answer 8

sodium coupled solute transporter takes things like glucose, galactose, AAs, etc. through the mucosa against concentration gradients while water moves into enterocytes along gradient
Na+/H+ exchangers allow for electrolyte absorption without other solutes
paracellular transport allows for passive solute transport across enterocyte membrane

Question 9

outline the mechanisms for intestinal secretion

Answer 9

chloride channels in small bowels allow Na+ and water to follow Cl- into the lumen
Cl-/HCO3- and Na+/H+ exchangers in colon

Question 10

what are the 4 characteristics of secretory diarrhea

Answer 10

1. increased water secretion by activation of Cl- channels
2. decreased Na+ and water absorption
3. severe fluid and electrolyte losses
4. isotonic, low stool osmotic gap, persists during fasting

Question 11

what are the 3 characteristics of osmotic diarrhea

Answer 11

1. increased osmotic pressure due to non-absorbed solutes
2. water pulled into lumen
3. high stool osmotic gap, abates during fasting

Question 12

what are 2 characteristics of malabsorptive diarrhea

Answer 12

1. failure of nutrient absorption

2. steatorrhea (fat in diarrhea)

Question 13

what are 2 characteristics of inflammatory/exudative diarrhea

Answer 13

1. multifactorial

2. fecal leukocytes, persists during fasting

Question 14

what do you look for in a physical exam of a patient w diarrhea?

Answer 14

degree of dehydration
growth chart
pallor, icterus, petechiae, rash
abdominal distention, tenderness
rectal exam
extraintestinal manifestations

Question 15

characterize <5% dehydration state

Answer 15

well, alert
normal eyes
drinks normally
skin recoils

Question 16

characterize 5-10% dehydration state

Answer 16

restless, irritable
sunken eyes
thirsty
skin recoils slowly

Question 17

characterize >10% dehydration

Answer 17

lethargic, unconscious
sunken eyes
drinks poorly/unable to drink
skin recoils very slowly

Question 18

what are the two major classes of acute diarrhea?

Answer 18

infectious (viral, bacterial, parasitic)
non infectious (drugs, food allergies, extraintestinal infections, surgical conditions)

Question 19

what is intussusception?

Answer 19

telescoping of the intestines caused by the inhibiting of periscopic movements by a tumor/neoplasia/etc
diminishes blood supply to part of the intestine resulting in necrosis/inflammation/diarrhea

Question 20

what are some causes of chronic diarrhea?

Answer 20

malabsorption
inflammation
congenital disorders
intestinal failure
infectious
drug induced
neurohormonal
fecal impaction 
IBS

Question 21

what blood tests would you do in a case of acute diarrhea?

Answer 21

electrolytes
CBC with differential
peripheral smear

Question 22

what stool tests would you do in a case of acute diarrhea?

Answer 22

culture
ova and parasites
extend for immunocompromised patients

Question 23

what additional blood tests would you get for chronic diarrhea?

Answer 23

other organ function measures
TSH
celiac disease
vitamins

Question 24

what additional stool tests would you get for chronic diarrhea?

Answer 24

pH
electrolytes
osmotic gap
fecal leukocytes and fat

Question 25

what tests other than blood/stool would you look into for chronic diarrhea?

Answer 25

sweat chloride radiology endoscopy

Question 26

characterize norovirus

Answer 26

ssRNA virus of Caliciviridae family | most common cause of acute gastroenteritis in US

Question 27

transmission/incubation norovirus

Answer 27

contaminated food/water person to person short incubation

Question 28

symptoms norovirus

Answer 28

nausea, vomiting, watery diarrhea, abdominal pain mild mucosal abnormalities self limited in immunocompetent host

Question 29

characterize rotavirus

Answer 29

dsRNA virus, encapsulated common cause of diarrheal mortality in children worldwide protection by maternal antibodies in first 6 months vaccine available

Question 30

transmission/incubation rotavirus

Answer 30

contaminated food/water person to person small infection inoculum short incubation period

Question 31

symptoms rotavirus

Answer 31

nausea, vomiting, watery diarrhea, abdominal pain | destruction of mature enterocytes w loss of absorptive surface

Question 32

characterize salmonella

Answer 32

gram negative bacilli in Enterobacteriacea family 2 types: typhoid and non typhoid non typhoid >1 mil in US per year

Question 33

transmission salmonellosis (non typhoid)

Answer 33

contaminated food, particularly poultry, eggs | very small inoculum

Question 34

mechanisms of salmonellosis

Answer 34

virulence genes and toxins type 3 secretion system- endocytosis of bacteria in mucosal cells flagellin activates TLR5 and causes inflamm lipopolysaccharide actiates TLR4 and causes inflamm

Question 35

symptoms salmonellosis

Answer 35

watery diarrhea or dysentery, may have fever usually self limited antibiotic treatment not recommended can be severe in immunocompromised patients

Question 36

transmission s.typhi

Answer 36

contaminated food/water person to person resistant to gastic acid

Question 37

mechanism of s.typhi

Answer 37

invade mucosal cells and disseminate via mononuclear cells throughout the body

Question 38

symptoms s.typhi

Answer 38

anorexia, nausea, vomiting, ab pain, dysentery followed by flu like phase with fever and bacteremia positive blood cultures extraintestinal manifestations antibiotic treatment

Question 39

characterize campylobacter

Answer 39

common in adults/travelers contaminated food/water small inoculum

Question 40

mechanism of campylobacter

Answer 40

mucosal colonization and adherence virulence toxins- cytotoxins, cholera-like enterotoxins invasion uncommon

Question 41

symptoms campylobacter

Answer 41

watery diarrhea, dysentery (uncommon) usually self limited extraintestinal complications- arthritis and Guillain-Barre syndrome

Question 42

what are the 4 types of E.coli?

Answer 42

``` enterotoxigenic (ETEC) enteropathogenic (EPEC) enterohemorrhagic (EHEC) enteroinvasive (EIEC) enteroaggregative (EAEC) ```

Question 43

what are 3 parasites that can cause diarrhea?

Answer 43

giardia cryptosporidium- spreads in pools (resistant to chlorine) entamoeba

Question 44

what are some life threatening conditions to look for in a patient with diarrhea/ ab pain?

Answer 44

``` HUS pseudomembranous colitis (C.diff) appendicitis, intussusception, obstruction toxic megacolon poisoning severe dehydration ```

Question 45

what is HUS?

Answer 45

hemolytic uremic syndrome

Question 46

what are 3 features of HUS?

Answer 46

microangiopathic hemolytic anemia thrombocytopenia (decreased platelets) renal injury

Question 47

what is HUS usually associated with?

Answer 47

prodromal diarrheal illness gastroenteritis due to shiga toxin producing E.coli (EHEC) or other organism -5-15% of cases develop HUS

Question 48

clinical features of HUS

Answer 48

``` diarrhea bloody stools weakness, lethargy, oliguria/anuria (small or no pee) pallor petechial (pinpoint bleeds) ```

Question 49

lab findings of HUS

Answer 49

anemia with schistocytes thrombocytopenia increased LDH (cellular contents released in RBC breakdown) decreased haptoglobin increased indirect bilirubin (metabolized hemoglobin) increased creatinine, hematuria,proteinuria shiga toxin +

Question 50

how do you manage HUC?

Answer 50

renal support, hydration, RBC transfusions AVOID platelet transfusion AVOID antibiotics and anti-diarrheals

Question 51

histo finding of HUS

Answer 51

see sheared RBC's due to formation of platelet clots RBCs collide with clots and break