Dr. Karatzios -- Diarrhea Flashcards
Definition of diarrhea (3)
- Stool weight > 200 g/day
- ≥ 3 loose or watery stools per day
- Decreased conmsistency and increased frequency from an individual baseline
3 types of diarrhea and their duration
- Acute: ≤ 14 days duration
- Persistent (subacute): > 14 days duration
- Chronic: > 30 days duration
7 effects of diarrhea
- Dehydration (water loss)
- Salt imbalances (esp Na+ or K+)
- Acidoses (bicarb losses)
- Hemorrhage (if dysentery)
- Chronic anemia (hematochezia)
- Malnutrition
- Sepsis (due to perforation or bacterial translocation into blood)
10 bacterial pathogens causing infectious diarrhea in the developed world
- E. coli**
- *Salmonella *spp.
- *Shigella *spp.
- Yersinia enterocolitica
- Campylobacterer jejuni
- Clostridium difficile
- Clostridium perfringens
- Listeria monocytogenes
- *Vibrio *spp.
- Bacillus cereus
2 types of E. coli causing diarrhea
- Enterohemorrhagic (EHEC)
- O157:H7
- Enterotoxin (ETEC)
2 types of Salmonella spp. causing diarrhea
- Non-typhi
- Typhi
7 viral causes of diarrhea in the developed world
- Calicivirus/Norovirus (Norwalk-like)
- Rotavirus
- Astrovirus
- Coronavirus (SARS)
- Adenovirus
- HIV
- Influenza virus (seen in pandemic 2009 strain)
8 protozoal causes of diarrhea in the developed world
- Giardia lamblia
- Cyclspora cayetansis
- Cryptosporidium **spp.**
- *Microsporidium *spp.
- Isospora belli
- Entamoeba histolytica
- Dientamoeba fragilis
- Blastocystis hominis
5 purely toxin-mediated bacterial pathogens causing diarrhea in the developed world
- Enterotoxigenic E. coli (Traveller’s diarrhea)
- *Staphylococcus aureus *enterotoxin
- *Bacillus cereus *enterotoxin, among others
- *Vibrio *spp
- C. difficile
5 bacterial causes of infectious diarrhea in the **developing **world (or “imported” diarrhea)
- Salmonella **typhi**
- *Shigella *spp.
- Entertoxigenic E. coli
- Vibrio parahaemolyticus
- Vibrio cholerae
4 viral causes of infectious diarrhea in the **developing **world (or “imported” diarrhea)
- Norovirus
- HIV
- Influenza virus (2009 pandemic)
- SARS Coronavirus
4 protozoal causes of infectious diarrhea in the **developing **world (i.e. “imported diarrhea)
- Giardia lamblia
- Entamoeba histolytica
- Microsporidium **spp.**
- Isospora belli
Usual origin of infectious diarrhea in North America
Viral
Visibly bloody stool in **North American **diarrhea is a good predictor for what kind of pathogen?
Bacterial (especially EHEC)
5 bacterial causes of dysentery
SSCYE
- *Shigella *spp.
- *Salmonella *spp.
- Campylobacter jejuni
- Yersinia enterocolitica
- E. coli O157
Viral causes of dysentery
None really, except perhaps adenovirus in immune suppressed patients (i.e. BMT)
Parasitic cause of dysentery
Entamoeba histolytica
EHEC: type of bacteria
Gram negative enteric rods containing a toxin created by a viral plasmis inside the cell
Reservoir of EHEC
Mammalian GIT
Most common cause of acute kidney failure in children
EHEC
Describe the progression of EHEC infection
- Enteritis about 1 - 2 days after infection
- Lasts for about 5 - 10 days
- Usually self-limiting
- 2 - 7% develop Hemolytic Uremic Syndrome (HUS)
3 symptoms of EHEC enteritis
- Severe cramps
- Very bloody diarrhea
- NO fever
Cause of HUS in EHEC
Shigatoxin
7 signs and symptoms of HUS in EHEC
- Renal failure
- Consumptive thrombocytopenia
- Vascular hemolysis (shearing of RBCs called schistocytes/schizocytes)
- Stupor
- Confusion
- Seizures
- Worsens with antibiotic therapy (release of toxin)
Type of bacteria: *Salmonella *spp
Gram negetive enteric rods
Resrvoirs of *Salmonella *spp.
Poultry and reptile GIT
Describe the progression and symptoms of *Salmonella *infection
- Need about 105 bacteria to cause disease
- Diarrhea (usually bloody), abdominal cramps, and fever 2 days after infection
- Lasts about 1 week
Most serious form of *Salmonella *infection
Typhoid fever
Cause of typhoid fever
*Salmonella enterica *serogroup typhi
9 signs and symptoms of typhoid fever
- Dissemination to various organs (i.e. blood, liver, etc)
- High fever
- Stupor
- Cramps
- Bloody diarrhea
- Blood sepsis
- Fleeting rose spots on skin
- Left shift leukopenia
- Bradycardia
What is *Salmonella *infection recurrence linked to?
Presence of biliary stones
*Shigella *spp: Type of bacteria
Gram negative enteric rods
Only reservoir of *Shigella *spp
Primates
Describe the progression of *Shigella *infection
- Need ~10 bacteria to cause disease
- Symptoms 1 - 2 days after infection
- Lasts about 1 week
- Highly contagious
7 signs and symptoms of *Shigella *infection
- High fever
- Stupor
- Cramps
- Dysentery (black currant, jelly-like stools
- Seizures due to shigatoxin
- Sometimes HUS
- Reactive arthritis
Campylobacter jejuni: type of bacteria
Curved gram negative enteric rods
Reservoir of Campylobacter jejuni
Bird GIT
Most common cause of bloody diarrhea in a daycare setting and one of the most common causes of enteritis due to food poisoning
Campylobacter jejuni
Describe the symptoms (3) and progression (4) of *Campylobacter jejuni *infection
- Enteritis starting about 2 days after infection
- Cramps
- Diarrhea may be bloody
- Sometimes HUS
- Usually self-limiting; Lasts for about 1 week
- Guillain-Barre syndrome after about 2 - 3 weeks
- Highly contagious
Yersinia enterocolitica: Type of bacteria
Gram negative enteric rod that loves iron (uses it as a growth factor)
4 Risk factor for *Yersinia enterocolitica *infection
- High iron states
- Eating undercooked meat
- Drinking unpasteurized milk
- Fecal-oral contact
Reservoir of Yersinia enterocolitica
Various mammals (zoonosis)
Describe the general progression of *yersinia enterocolitica *infection (5)
- Starts within a week after infection
- Lasts 1 - 3 weeks
- Sepsis and bacteremia in immune suppressed people
- Different manifestations between young children and older children/adults
- Post infectious arthritis
3 manifestations of *yersinia entercolitis *in young children
- Bloody diarrhea
- Terminal ileitis
- Mesenteric adenitis
Manifestation of *yersinia enterocolitica *infection in older children and adults
Severe abdominal cramps that may mimic appendicitis (pseudoappendicitis)
5 signs and symptoms of *Entamoeba histolytica *infection
- Bloody diarrhea
- Cramps
- Fever
- Abscesses if dissemination to liver, lungs and brain (often in immunosuppressed)
- Amoeboma
Define amoeboma
Large mass in intestine that can be mistaken for a tumor but is really a granuloma due to amoebic infection
Cause of traveller’s diarrhea
ETEC
Describe the symptoms and progression of ETEC infection (traveler’s diarrhea)
- Self-limtied disease
- No fever
- No systemic illness
Describe the progression and symptoms of cholera (vibrio cholerae infection)
- Severe explosive watery diarrhea (liters and liters lost –> deadly)
- Rice water stool
- Highly contagious
When can *Vibrio vulnificus *be acquired?
After eatign shellfish or stepping on a stingray
5 signs and symptoms of *Vibrio vulnificus *infection
- Diarrhea
- Vomiting
- Skin blisters
- Sepsis
- Shock
Describe the progression of *Listeria monocytogenes *infection
Watery diarrhea can progress to disseminated disease in immune suppressed people and pregnant women (CNS disease, bacteremia, still births)
Clostridium difficile: type of bacteria
Gram-positive anaerobic rod that forms resistant spores (need to be WASHED off hands)
Disease caused by C. difficile
C. difficile-associated colitis (CDAD)
4 signs and symptoms of CDAD
Toxin-mediated (toxins A and B)
- Watery diarrhea
- Colitis
- Pseudomembranous colitis
- May progress to toxic megacolon (septic ileus of the colon)
Why don’t babies <6 months get CDAD?
No receptors for C difficile toxins (develpo between 6 months and 1 year), therefore diarrhea in hospitalized children <6 months is NOT C. diff
4 risk factors for CDAD
- Healthcare
- Antibiotic use
- Debilitated conditions (old age comorbidities)
- PPI’s?
2 important viral causes of watery diarrhea
Rotavirus
Norovirus
Most common cause of self-limited gastroenteritis (i.e. 24h stomach flu or “winter gastro”)
Norovirus
Usual type of diarrhea caused by parasites
Protracted and chronic
3 risk factors for parasitic diarrhea
Travel
Fecal-oral contact (i.e. contaminated food)
Immune suppression
Why are the “sporas” (name them) significant causes to remember of parasitic diarrhea
- *Microsporidium *spp
- *Cryptosporidium *spp
- Cyclospora cayetanensis
- Isospora belli
WHY = need special staining to see them
5 points of **initial **management of diarrhea
- Evaluate severity and duration
- Obtain history and physical exam
- Treat dehydration
- Report suspected outbreaks
- Determine whether it is:
- Community-acquired/traveler’s diarrhea
- Nosocomial
- Persistent
3 points of management if diarrha is community-acquired or traveler’s diarrhea
- Consider quinolone for suspected shigellosis in adults (fever, inflammation)
- Macrolide for suspected resistant Campylobacter
- Avoid antimotility or certain antimicrobial drugs if suspected STEC (afebrile, bloody diarrhea)
2 points of management for nosocomial diarrhea
- Discontinue antimicrobial if possible
- Consider metronidazole if illness worsens or persists
Viral, non-bloody diarrhea with vomiting (3 causes)
- Norovirus (esp if 24 - 48 hours)
- Adenovirus
- Astrovirus
Non-bloody viral diarrhea without too much vomiting
Rotavirus
Turnover in lab for stool culture
24 - 48 hours; final ID and sensitivity in 72 hours
4 cases where stool cultures are UNHELPFUL
- ETEC (self-limited traveler’s diarrhea)
- Self-limited *Yersinia enterocolitica *infections
- Self-limtied non-typhoid Salmonellosis
- Diarrhea after 3 days in hospital (think C. diff)
4 cases where stool cultures are HELPFUL
- EHEC (development of HUS)
- Use of antibiotics may worsen renal failure
- Public Health purposes
- Shigella spp
- *Salmonella typhi, Vibrio cholerae, outbreak situation (Campylobacter *spp infections in daycares)
- When treatment will help
- Help in diagnosis of Guillain-Barre syndrome
6 cases where stool culture should be sent as a diagnostic test
- Severe diarrhea (i.e. bloody, extremely large quantity)
- Immunocompromised patients
- HIV, <3 months or >65 years age
- Patients with comorbid conditions (i.e. renal failure)
- Patients with IBD
- Food handlers and health care workers (Public health purposes)
- Patients with Guillain-Barre syndrome
2 diagnostic techniques to detect toxins A and/or B
- Enzyme immunoassay
- PCR
Only viral diagnostic test that is currently widely available and used
Rotavirus test
4 points of diagnostic testing for parasitic causes
- At least 3 stools are required (different bowel movements) since parasites and their eggs are shed intermittently
- Usually iodine-based staining techniques (NOTE: not for the sporas)
- Lab diagnosis based on morphology
- Results depend on how fast lab technician can get to specimens (a few days)
8 situations where antibiotics SHOULD be used to treat diarrhea
- Suspected or confirmed typhoid fever
- Salmonella typhi in stool specimen
- Shigella spp
- Campylobacter spp infection
- Bacteremia with any bacterial pathogen
- Traveler’s diarrhea
- Symptomatic *C. diff *colitis
- Parasitic-related diarrhea
3 cases where Ciprofloxacin po/IV or Ceftriaxone IV are used as treatments
- Suspected or confirmed yphoid fever
- *Salmonella typhi *in stool specimen
- *Shigella *spp
2 treatment options for traveler’s diarrhea
- Ciprofloxacin po
- Azithromycin po
3 treatments for symptomatic *C. difficile *colitis
- Metronidazole (Flagyl) po/IV
- Vancomycin po
- Enema with “healthy” stool
What to treat with the “sporas”
Since available treatments are not very good and they occur primarily in immunosuppressed patients, treat the immune suppression
3 situations where you DO NOT give antibiotics as treatment
- Suspected or proven EHEC infections
- Well-looking and non-bacteremic non-typhi *Salmonella *spp
- Bloody diarrhea and systemically ill patients
Why don’t you give antibiotics in suspected or proven EHEC infection?
May worsen renal failure and HUS
Why don’t you give antiobiotics for well-looking and non-bacteremic non-typhi Salmonellosis?
Risk for prolonged shedding of organisms
Why not give antibiotics for bloody diarrhea and systemically ill patients?
Better to “flush things out” rather than let it fester in the intestines for potential invasion
