Diarrhea Flashcards
normal function of the colon
- sodium reabsorbed, potassium secreted in exchange
- patients with diarrhea are hypokalemic
normal composition stool water
- volume about 100 ml/day
- Na = 40 mEq/L
- K = 90 mEq/L
- osmolality is close to that of plasma = 280 mOsm/L
features of osmotic diarrhea
- diarrhea stops after fasting
- fecal volume is < 1 L/d
- fecal pH less than 6
- fecal osmolality 280-400
- osmotic gap is above 40-60
features of secretory diarrhea
- diarrhea continues after fasting
- fecal volume is >1 L/day
- fecal pH >7
- fecal osmolality 260-300 mosm/L
- osmotic gap is <20-40 mosm/L
osmotic gap calculation
- stool osmolality - 2(Na+K) = osmotic gap
infectious or inflammatory causes of diarrhea
- enterotoxic organisms
- toxins affect primarily small bowel secretion
- watery diarrhea with cramps, rare fecal PMNs
invasive organisms causing diarrhea
- colon involved- fecal PMNs prominent
- systemic symptoms are unusual
- most common causes are shigella, salmonella, and campylobacter jejuni (#1 cause of infectious bloody diarrhea)
frequent, small volume diarrhea
- usually indicates left sided (rectosigmoid) involement
- tenesmus and urgency are common
- blood and mucous are commonly seen
large volume, less frequent diarrhea
- usually right colonic or small bowel origin
- no tenesmus or urgency
- blood is uncommon
fecal leukocytes in infectious enterocolitis
- present in shigella, C. jejuni, and invasive E. coli
- absent in food poisoning, giardia, virus, ETEC, amoeba, cholera
antibiotic exposure
- C. difficile infection
drinking water from a river
- Giardia
appendicitis like symptoms with diarrhea
- salmonella or yersinia
shigellosis treatment
- dont use antimotility drugs when patient has bloody diarrhea
- do not use amoxicillin
- ampicillin, tetracycline, trimethoprim and cipro work
virus on cruise ship
- Norwallk
- rotavirus in infants and young children
- transmission is fecal oral
giardia
- IgA deficiency
treatment of giardia
- metronidazole
- in pregnancy use paramomycin
treatment of C diff
- vancomycin or metronidazole
hemolytic-uremic syndrome
- usually in children
- hemolysis
- thrombocytopenia
- renal failure
features of ETEC
- has both labile and stable toxins
- usually acquired during traveling
- watery diarrhea
features of EHEC
- verotoxin
- foodborne
- blood diarrhea, and hemolytic-uremic syndrome
mushy stools, increased frequency considerations
- infectious
- IBD
- IBS
mushy, bulky stools considerations
- malabsorption
