DSA: Acute Infectious Diarrhea Flashcards
Acute infectious diarrhea is the of the most infectious causes of death in the world. Most patients die due to ________.
Dehydration
Etiologies of acute infectious diarrhea and Sx
-
Bacterial toxins or bacteria that make enterotoxins
- => small bowel hypersecretion
- Abrupt profuse watery diarrhea and vomitting a few hours after ingestion
- Fever: minimal to none
- => small bowel hypersecretion
-
Entero-adherent pathogens
- More cramping and bloating and less vomitting
- Fever: high
-
Invasive microorganisms that make cytotoxins
- Fever: high
- Abdominal pain
How will a pathogen that affects the small bowel persent?
- Large amounts of watery diarrhea + cramps that can lead to dehydration and malabsorption.
- Cramos occur in mid-abdomen or are diffuse
- No WBC in stool (non-inflammatory)
How will a pathogen that affects the large bowel present?
- Frequent, small amounts of bloody stool (dysentary) due to inflammation + fever and fecal leukocytes.
- Location: lower abdomen or rectum
- Enterotoxins (non- inflammatory) pathogens affect the ____________, causing _____ diarrhea.
- Inflammatory (invasive or cytotoxins) pathogens affect the __________, causing ______ diarrhea.
- Penetrating pathogens affect the __________, causing _________.
- Proximal SB; watery
- Distal SB or colon; dysentary or inflammatory diarrhea
- Distal SB; enteric fever
What do we see in stool findings for these pathogens?
- Non-inflammatory (enterotoxins)
- Inflammatory (invasive or cytotoxin)
- Penetrating
- No fecal leukocytes; mild or NO increase in fecal lactoferrin
- Fecal PNM leukocytes; increase in fecal lactoferrin
- Fecal mononuclear leukocytes
2 Penetrating Pathogens
- Salmonella Typi
- Y. Enterocolitica
High risk groups for acute infectious diarrhea
- Travels
- Immunodeficient people
- Daycare workers/bbs/family
- Instutionalized ppl (nursing home, hospitals)
- Consuming certain foods
Daycare workers/ bbs and families are more susceptible to
- Shigella
- Giardia
- Crytosporidium
- Rotavirus
PE for patients with acute infectious diarrhea
- Fever, hypotension, tachycardia
- Dehydration
- Increased bowel sound
Decreased or absent bowel sounds =>
- Post-op ileus
- Toxic megacolon
Signs of mild, moderate and severe dehydration
Mild:
- Thirst, dry mouth, ↓ sweat / urine output and slight weight loss
Moderate
- Orthostatic fall in blood pressure, skin tenting, sunken eyes (infants = sunken fontanelle)
Severe:
- Lethargy, obtundation, feeble pulse, hypotension, frank shock
Acute Infectious Diarrhea
- ________ transmission and most cases are ________.
- Fecal - oral transmission
- Mild and self-limited, thus, does not need work-up
1st thing to do when a patient presents with acute diarrhea, no matter if mild, moderate or severe is to ___________.
Fluid and electrolyte replacement
In acute Infectious Diarrhea, diarrhea is self-limited and does not need workup. However, what are a few indications for work-ups?
- Profuse diarrhea (6 or more times a day) with dehydration
- Fever above 101 (38.5), hypotension and tachycardia that does not respond to volume repletion
- Dysentary (bloody diarrhea with leukocytes)
- Recent ABX uses (check for c.diff)
- Creatinine is more than 1.5x baseline or peripheral leukocytes is more than 15,000.
What do you perform upon workup of Acute Infectious Diarrhea?
- CBC, electrolytes, BUN/Cr, blood culture
______ is the cornerstone of diagnosing Acute Infectious Diarrhea.
Stool culture
Routine bacterial stool culture tests for
- Salmonella
- Shigella
- E. coli
- Campylobactor (most)
What stool bacterial cultures must be requested?
- Shiga-like toxin detection for 0157:H7 EHEC (enterohemorrhagic e.coli)
- Vibrio
- Yersenia
What other labs may you need to ask for?
- Stool immunoassay PCR/toxin for C.diff
- Ova and parasites
- Stool protzoa antigen (giardia, cyrptosporidium, E. histolytica)
- Stool viral PCR/antigen (rotavirus, Norwalk/norovirus)
- Fecal leukocytes (inflammtory causes)
- Fecal lactoferrin (enzyme in leukocytes => inflammatory)
In Acute Infectious Diarrhea, if stool studies are unrevealing, perform a _________.
Endoscopy
Radiology requests for Acute Infectious Diarrhea
-
Abdominal XR (plain)
- detects free intraperitoneal air and checks for ileus/toxic megacolon
-
Abdominal CT with PO/IV contrast
- More sensitive for free air and IDs colitis
- Suspect food poisening in a patient when:
- Routine testing?
- Multiple illnesses are reproted after sharing food and in the summertime
- Routine testing is NOT done
Consumption of chicken is most associated with
- Salmonella
- Campylobacter
- Shigells
Consumption of undercooked hambuger is most associated with
- Enterohemorrhagic E. coli (O157:H7)
Consumption of fried rice is most associated with
- Bacillus cereus
Consumption of potato salad, mayo, cream pastries is most associated with
- Staph. aureus
Consumption of eggs is most associated with
- Salmonella
Consumption of lunch meats, uncooked foods or soft cheeses is most associated with
- Listeria
Consumption of seafood is most associated with
- Vibrio*, salmonella, acute HepA
- Norwalk and campylobacter
Staph Aureus:
- Micro
- Clinical case
- Treatment
- Micro
- Gram (+) cocci (cluster of grapes) with preformed enterotoxins
- Symptoms
- Rapid onset (within 6 hours) of watery diarrhea and N/V after eating potato salad, mayo, cream pastries or eggs.
- Treatment
- Rapidly goes away (24-48 hours)
Bacillus Cerus
- Micro
- Clinical case
- Treatment
- Micro
- Gram (+) rod with preformed toxins
- Symptoms
- Rapid onset (within 6 hours) with mainly vomitting and may cause watery diarrhea after eating fried rice.
- Treatment
- Rapidly goes away (24-48 hours)
Clostridium Perfringens
- Micro
- Clinical case
- Treatment
- Micro:
- Gram (+) spore-forming rod with preformed enterotoxins
- Heat resistant
- Clinical case
- Rapid onset (8-16) hours of watery diarrhea (no N/V) after eating large amounts of ham, beef, legumes, gravy (heat resistant spores)
- Treatment
- Rapidly goes away (24-28 hours)
Shigella
- Micro
- Clinical case
- Treatment
- Gram (-) rod with enteroxin shiga toxin; non-motile
- Watery diarrhea => intense colitis with fever and dysentary (small bowels with blood + pus) after eating potato/egg salad, lettuce or raw veggies
- Treat: ABX and lasts 7 days
How do we diagnose Shigella toxin?
- (+) fecal leukocytes
- Stool culture makes it hard to distinguish from IBD
Complications of Shigella
-
Reative arthritis (cant see, cant pee, cant climb a tree)
- Conjunctivitis, uretheritis, arthritis
- HUS
Salmonella typhimurium
- Micro
- Clinical case
- Treatment
- Gram (-) rod; motile and non-lactose fermenting that penetrates SI mucosa via M-cells over Peyers patches
- Watery diarrhea => bloody diarrhea + fever, N/V after
- Eating eggs/poultry,
- Expsure to reptiles (turtles), ducks, birds
- Treatment
- Self limited (5-10 days) and DO NOT give ABX
Salmonella typhimurium
Risk factors
Complications
- Risk factors:
- Immunocompromised patients (SICKLE CELL and HIV)
- Complications
- Septic arthritis, osteomyelitis, and abcesses
Salmonella typhi
- Micro
- Clinical case
- Treatment
- Gram (-) rod; aerobic that penetrate the mucosa travese intestinal epithelium through M cells over Peyers patches
- 7-14 days eating ingestion, patients will get Typhoid fever (2 sympomtic phase seperated by asymptomatic phase) after international travel or poor sanitation
- Sustained fever (103-4) +
- Rose colored maculopapular rash +
-
[Pea-soup foul diarrhea] => bloody diarrhea and if lumen is too inflamed, constipation
*
Salmonella typhi
- Othher associated symptoms
- Death most commonly dt:
- Encephalopthy, splenomegaly, bradycardia and dicrotic pulse
- Intestinal hemorrhage
Salmonella typhi
- Dx
- Stool culture to test for salmonella typi
- Blood culture (90% + when febrile)
- Fecal leukocytes (+)
Campylobacter jejuni
- Micro
- Clinical case
- Treatment
- Gram (-) spiral rod; oxidase (+) with flagella that lives in wild birds
- Watery => blood diarrhea + fever + erythema nodusum that occurs after eating undercooked poultry or dairy
- Self limited; no ABX
Camplylobacter jejuni
- Dx
- Complications
- Dx:
- Stool culture (bc hard to culture, need campy blood agar)
- (+) fecal leukocytes
- Complications
- Guillian Barre syndrome
- Reactive arthritis