L5: Infectious Diarrhea Flashcards
Def of Diarrhea
- Having three or more loose or liquid stools per day, or as having more stools than is normal for that person
Mechanisms of Diarrhea
Defect in Secretory Diarrhea
Characters of Stool in Secretory Diarrhea
Examples of Secretory Diarrhea
Defect in Osmotic Diarrhea
Characters of stool in Osmotic Diarrhea
Examples of Osmotic Diarrhea
Defect in Increased motility Diarrhea
Characters of Stool in Increased motility Diarrhea
Examples of Increased motility Diarrhea
defect in Decreased motility Diarrhea
Characters of Stool in Decreased motility Diarrhea
Examples of Decreased motility Diarrhea
Defect in Decreased surface area Diarrhea
Characters of stool in Decreased surface area Diarrhea
Examples of Decreased surface area Diarrhea
Defect in Inflammatory mucosal invasion Diarrhea
Stool Characters in Inflammatory mucosal invasion Diarrhea
Examples of Inflammatory mucosal invasion Diarrhea
Diagram of causes of diarrhea
Compare between Non-Inflammatory Diarrhea & Inflammatory Diarrhea
- Symptoms
- Stool
- Site
- Mechanism
- Common Pathogens
Def of Dysentery
Causes of Diarrhea
Common Viral Causes
- Rotavirus
Common Bacterial Causes
- E-Coli
- Cholera
- Shigella
- Salmonella
- Colstridium
- Staph
Common Protozoal Causes
- Amebiasis
- Giardia
- Cryptosporidium
Agde of Rota Virus
It causes severe diarrhea among infants and young children
MOI by Rota Virus
faecal-oral transmission.
IP of Rota Virus
2 days
CP of Rota Virus
Disease presented by vomiting, watery diarrhea, low grade feve
Hallmark of TTT in Rota Virus
maintenance of hydration
Prevention of Rota Virus
Two vaccines are safe and effective in children.
Both are taken orally and contain attenuated live virus
Most E. coli strains are harmless, but some serotypes are pathogenic and can cause serious food poisoning in humans
..
MOI by E-Coli
faecal-oral transmission
Enterotoxigenic E. coli (ETEC)
Traveler’s diarrhea
Enteropathogenic E.coli (EPEC)
Rarely causes disease in adults.
Enteroinvasive E. coli (EIEC)
Dysentery
Enterohemorrhagic E. coli (EHEC)
Bloody diarrhea
Severe hemorrhagic colitis
Hemolytic uremic syndrome in 6-8% of cases
Cattle are predominant reservoir of infection.
What is the most common illness in travelers?
Traveler’s diarrhea
Def of Traveler’s diarrhea
Three or more unformed stools in 24 hours passed by a traveler, commonly accompanied by abdominal cramps, nausea, and bloating
Causative agent of Traveler’s diarrhea
Enterotoxigenic E.coli is the most commonly isolated pathogen.
TTT of Traveler’s diarrhea
- Antibiotics are typically given for three to five days, but single doses of azithromycin or levofloxacin have been used.
TTT of Traveler’s diarrhea if it persists despite antibiotics
If diarrhea persists despite therapy, travelers should be evaluated for possible viral or parasitic infections, bacterial or amoebic dysentery, Giardia, helminths, or cholera
IP of Cholera
1 - 5 days
MOI by Cholera
- fecal-oral route, especially contaminated water
CP of Cholera
- Sudden profuse, painless diarrhea and vomiting of clear fluid.
- “rice water” in nature and may have a fishy odor
Investigations in Cholera
1) A rapid dip-stick test is available
2) Stool and swab samples collected and cultivated using Enrichment media
TTT of Cholera
Prevention of Cholera
vaccination of Cholera
Another Names of Shigellosis
Bacillary dysentery or Marlow Syndrome
IP of Shigellosis
12 - 96 h
MOI by Shigellosis
- Feco-oral route especially contaminated water
- Less than 100 bacterial cells can be enough to cause an infection
Investigations for Shigellosis
1) Stool smear revealed red and white blood cells.
2) Culture
CP of Shigellosis
Range from mild abdominal discomfort to severe dysentery
TTT of Shigellosis
What not to use as TTT in Shigellosis?
Antidiarrheal drugs (loperamide) may prolong the infection and should not be used in shigellosis
Another Names of Enteritis Salmonellosis
food poisoning Salmonell “Non typhoidal”
IP of Enteritis Salmonellosis
12 - 72 h
MOI by Enteritis Salmonellosis
1) Poultry, pork, and beef, if the meat is prepared incorrectly or is infected with the bacteria after preparation.
2) Infected eggs, egg products, and milk.
CP of Enteritis Salmonellosis
- Nausea, vomiting, abdominal cramps, and bloody diarrhea with mucus.
- Headache, fatigue, and rose spots may present.
- Can be severe, especially in young children and the elderly.
Investigations for Enteritis Salmonellosis
- Stool smear revealed red and white blood cells.
- Culture (from stool or vomitus) is positive in 10-15%.
TTT of Enteritis Salmonellosis
- Immunocompromised and patients with evidence of Bacteremia
⇒ Antibiotics, such as norfloxacin, ciprofloxacin or third generation cephalosporin may be given
Def of C. difficile
- C. difficile is a commensal bacterium of the human
intestine in 2-5% of the population
Method of Infection by C. difficile
Antibiotics (clindamycin) (antibiotic associated colitis)
CP of C. difficile
- the most common cause of pseudomembranous colitis, and in rare cases this can progress to toxic megacolon, which can be life-threatening
Investigations for C. difficile
Isolation of toxin in stool
Culture of organism
TTT of C. difficile
Stop offending agent
metronidazole + vancomycin
MOT of Staph-Induced Diarrhea
ingestion of contaminated food Containing preformed staph (cake, salad, ham) with heat stable
CP of Staph-Induced Diarrhea
- Nausea, vomiting, abdominal pain followed by diarrhea
- Fever is rare
INVx for Staph-Induced Diarrhea
- Definite diagnosis is by culturing the organism from
contaminated food, stool or vomitus
TTT of Staph-Induced Diarrhea
- Supportive.
- No role for antibiotics bacterial toxins.
Common Protozoal Causes of Diarrhea
- Amebiasis
- Giardiasis
- Cryptosporidium
MOT by Amebiasis
Ingestion of cyst (Feco-oral)
CP of Amebiasis
1) Asymptomatic
2) Amoebic dysentery.
3) Amoebic liver abscess
stool samples ELISA or RIA can also be used
TTT of Amebiasis
- Metronidazole for the invasive trophozoites
- A luminal amoebicide for cysts paromomycin or
diloxanide furoate (Furamide).
MOT by Giardiasis
Ingestion of cyst
CP of Giardiasis
- Steatorrhea.
- Multiple stool examinations
TTT of Giardiasis
- Metronidazole (7 days)
- Tinidazole (single dose)
- Nitazoxanide (3 days)
Def of Cryptosporidium
an acute, short-term infection, but can become severe and non-resolving in
- Children
- Immuno compromised individuals (HIV)
Nature of CP of Cryptosporidium in Children & Immu ocomprimised
can become severe and non-resolving in:
- Children
- Immuno compromised individuals (HIV)
CP of Cryptosporidium
- Usually suspected and isolated in HIV patients presenting by diarrhea
TTT of Cryptosporidium
- Treatment is symptomatic, with fluid rehydration, electrolyte correction
Diarrhea is a defense mechanism
…
Diarrhea may function as an evolved expulsion defense mechanism
- As a result, if it is stopped, there might be a delay in recovery
…
Managment of Acute Diarrhea
- Rehydration
- Role of Antibiotics
- Other drugs
Managment of Acute Diarrhea
- Rehydration
The primary treatment of gastroenteritis in both children and adults is …..
Rehydration
This is preferably achieved by ……, although intravenous delivery may be required if a there is a decreased level of consciousness or if dehydration is severe.
oral rehydration therapy
Managment of Acute Diarrhea
- Role of Antibiotics
Antibiotics are not usually used for gastroenteritis, although they are sometimes recommended if:
1) Symptoms are particularly severe
2) If a susceptible bacterial or protozoal cause is isolated or suspected.
3) A macrolide (such as azithromycin) is preferred over a fluoroquinolone in traveler diarrhea due to higher rates of resistance.
Bacteria and protozoans that are amenable to treatment include ……
(Shigella, Salmonella typhi and, Giardia. Species)
Antibiotics are specific to …..
- Giardia species / Entamoeba histolytica.
⇒ Tinidazole treatment is recommended and superior to metronidazole
Antibiotics are useless in …….
Viral gastroenteritis
Antibiotics are harmful in cases of …..
- The Pseudomembranous colitis usually caused by antibiotic
- TTT: stop offending agent + metronidazole + vancomycin
Other Drugs used in Diarrhea
- Antimotility drugs
- Physical adsorbents
- Role of micronutrients
- Role of probiotics
Other Drugs used in Diarrhea
- Antimotility Drugs
Should be avoided.
Other Drugs used in Diarrhea
- Physical Adsorbents
Compounds as Bismuth, kaolin, charcoal are postulated to act by adsorbing toxins.
Other Drugs used in Diarrhea
- Role of Micronutrients
- Trials of zinc supplementation in India demonstrated clinically important decrease in severity and duration of diarrhea.
Other Drugs used in Diarrhea
- Role of Probiotics
- Recommended in diarrhea after use of antibiotics
The following types of diarrhea may indicate further investigation