GI infections Flashcards
ACUTE DIARRHEAL ILLNESS
One of the most common problems evaluated by clinicians
> Transmitted via ingestion of contaminated food or beverage
Clinical Manifestations
> In healthy individuals
- A self-limiting illness, lasting only a few days
> Some people experience chronic symptoms
Some may develop more serious symptoms
- Bacteremia
- Dehydration
- Serious sequelae - Malnutrition, severe dehydration, death
EVALUATING GI INFECTIONS
Diarrhea - An alteration in normal bowel movement
characterized by an increase in the water content,
volume, or frequency of stools
more than three bowel movements/day
Clinical History
point to a causative diagnosis
> Most infections are acquired by ingesting the offending microorganism
- An important component is dietary history
> Other important aspects to consider
- Recent travel history
- Recreational activities
- Seasonality
- Daycare attendance
- Living conditions
Clinical History - Key Questions
> What is the duration of symptoms?
> Are there associated symptoms of inflammation?
> Does the patient have a history of previous GI symptoms?
> Does the patient have an underlying illness?
> Is the patient taking any medications?
- A recent history of antibiotic use may also suggest an
infection with Clostridium difficile
CONSIDERATIONS FOR DIAGNOSIS
Chronicity of disease
Possibility of viral, bacterial and parasitic pathogens involvement
Causes of diarrhea
> Preformed toxins
> Numerous noninfectious cause
- laxative use
- tumor-related
- malabsorption
- inflammatory bowel diseaseAnatomic Related Host Defenses
> Stomach acidity (pH of lower than 4)
- Kills more than 99.9% of coliform bacteria within 30 minutes - However some pathogens are resistant
> Small intestine
- Peristalsis movement prevents adhesion of some bacteria to the
intestinal wall ( if there isnt movement bad bacteia can attach )
> Colon
- Normal flora compete with potential pathogens for nutrients and
attachment space
> Immunoglobulin A (IgA) - antibody secretion by colon and small intestine that may have an effect on potential pathogens
risk factors
> Number of ingested organisms
- Median infectious dose (ID50) - Number of organisms required that
must be ingested to cause disease in 50% of exposed individuals
> Achlorhydria - absence of hydrochloric acid in gastric secretion
- Cause inadequate stomach acidity
- More likely to develop illness
> Reduction in normal flora
- Antibiotic exposure alters gut flora and increases the chance of
infection by an enteric pathogen
common normal flora
lots of normal flora
- gram stain wont be helpful in ID of pathogenic bacteria
bacteroides fusobacterium lactobacilli clostridium peptostreptococcus s. aureus enterococcus strep e.coli q
common pathogens
campylobacter salmonella shigella clostridium difficile yersinia enterolictica entamoeba histolytica cryptosporidium gardia lamblia
common pathogen food sources
chicken eggs milk water fried rice
fish
diagosis : patients history
> Traveler’s Diarrhea
- Enterotoxigenic Escherichia coli (ETEC)
- Contaminated food and water consumption
> Parasitic infections - possibly linked to travel
- Giardiasis
- Entamebiasis
> Recent/current Antibiotic treatment - associated with Clostridium difficile infections
> Duration of illness
> Medications
- Can cause GI upset
history of medical condition
IBS , Malabsorption, chemo
laboratory results may assist with diagnosing the GI infection
- Leukocytosis
- Anemia
- Thrombocytopenia
- Electrolyte abnormalities
- Fecal examination (invasive vs toxigenic disease)
- RBCs
- Fecal leukocytes (inflammation)
- Fecal lactoferrin
- Neutrophil marker associated with inflammation
Gram Stain of Direct Fecal Smear
large # of WBC indicates an inflammation
- means an invasive infection/ disease usually NOT enterotoxin
Enterotoxin mediated diarrhea symptoms
- Rapid onset of diarrhea (Less than 12 hours)
- Lack of fever
- Absence of blood or pus
- Large number of watery stools (Sometimes more than 20 per day)
