lecture 4 Flashcards
What are some distinguishing factors of enteric (Intestinal) infections?
- They’re usually due to water and food contamination with Fecal mater/
- GI symptoms, pain, Nausea and vomitting and diahherea
- Usually leads to sepsis and fever and shock
What are the two mechanisms of injury for enteric infections? examples
- Enterotoxic (Noninvasive): cholera and sataph
- Enteroinvasive: Salmonella
What are the three types of diarrhoea?
- Acute 0-13 days
- persistant 13-29
- Chronic 30+
Whats the most important test for enteric infections?
-Stool samples and rarely biopsy. (CMV and adenovirus are biopsies)
What are the distinguishing features of ecoli and the ecoli infection?
- Gram negative bacilli
- Normally found in GI tract (Normal microflora)
- Hundreds of different pathogenic and none pathogenic serotypes
- Usually, symptoms are diahhrea, and usually come from contaminated individuals or water
- Pathogenic serotypes are based on what type of antigen they have present, O or K or H
What are the two emphasised E coli infections in lecture? What are the syndroms associated with them?
- ETEC– watery and known as travellers diarrhea. 70% of travellers diarrhea.
- EHEC (STEC) and that associated with Hemorrhagic Colitis
What are the serotypes of STEC? wjat is the cause of the infection and how are the symptoms and complications?
- The two serotypes are O157 and None O157 serotypes.
- Defined by finidn the shiga toxins
- Symptoms are bloody diarrhea, abdominal pain and NA
- Serious complications could lead to renal failure and hemolytic anemia and thrombocyopenia).
- Labratory diagnosiss is mconkeey aga culture and NAAT for shiga toxins gene
- HAVE PSEUDOMEMBRANES
What are the distinguishing features of cholera?
- Its watery and usually afebrile and painless (RICE WATER stool)
- Usually associated with gram- vibrio cholera
- Enterotxic none invasive
- Stool culture and use of thiosulfate-citrate bile salts (SPECIAL MEDIA FOR CHOLERA)
- Mechanism increases cAMP which leads to water secretion and electrolyte imbalance
What are the distinguishing features of STaph food poisoning
-Rapid onset, afebrile and general N/V stomach cramps.
Quick resolution withing 24-48 hours/
-Unrefrigerated food usually the cause
What are the distinguishing features of Shigella enteritis?
- Gram - rod that can survive stomach acidity and low infection dose
- Small volume bloody stool with cramps
- Disease is self limited and not systemic
- Can cause pseudomembranes
- Stool sample will have WBCs and RBCs
- Fastidous organismsand have to be handled well to be cultured
What are the complications of shigella? (4)
- Proctitis
- Toxic megacolon
- intestinal obstruction
- colonic perforation
- Punctuate hemorrhages which are teeny tiny ulcer (picture)
- Pseudomembrane will differentiate it from acute collitis
What are the distinguishing features of salmonella and what is it responsible for? What are some pre requisits for sallmonella to infect?
- Gram - Rod. Sallmonella typhi responsible for typhod fever. Humans are the only reservior and happens in endemic areas of the world.
- Decrease acid production and proton antagonists increase the likelyhood of salmonella thats why it affects older people
- People who had a gastrectomy(Stomach reduction) will be in more trouble
What is the pathogneisis of sallmonella?
Infiltaret the epithelium of small bowel, infect the peyers patches and causers hypertropju. NAAT or stool culture
-Salmonella can cause errosion of the blood vessles in peyers patches that leads to hemmorage and hepatosplenomegaly
What is typhoid fever? What are the causes and clinical features.?
Ulceration in the peyers patches due to Salmonella typhi, infection. Granulomatous and typhoid nodules look like fat blobs in histo
What are the distinguishing features of campelobacter enteritis?
- Gram -
- Mostly poutlery and meat that is contaminated during the slaughtering process.
- Food borne or uncooked meat most common form of diarrhea in the statse.
- May mimic acute appendicities, no may have melena or no melena in stool
