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34 Cards in this Set
- Front
- Back
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What is the differential diagnosis for a patient presenting with esophagitis?
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- Candida albicans
- Herpes simplex virus - CMV |
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What is the differential diagnosis for a patient who has consumed a toxin?
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- S. aureus
- B. cereus - C. perfringens - C. botulinum |
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What is the differential diagnosis for a patient presenting with inflammatory diarrhea (dysentery)?
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- Shigella spp.
- E. coli - Salmonella - Campylobacteriosis - Pseudomembranous colitis - Amoebiasis (E. histolytica) |
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What is the differential diagnosis for a patient presenting with enteric fever?
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- Typhoid fever: Salmonella typhi
- Yersiniosis: Yersinia enterocolitica and Yersinia pseudotubercuolosis |
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What is the differential diagnosis for a patient presenting with peptic ulcers?
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- Heliobacter pylori
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What is the differential diagnosis for a patient presenting with hepatitis?
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- Yellow fever virus
- Leptospira interrogans - Hepatitis A, B, C, D, E, G Virus |
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What is the differential diagnosis for a patient presenting with intestinal blockage from a cestode (tapeworm)?
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- Diphyllobothriasis
- Echinococcosis - Taenisasis - Cysticercosis |
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What is the differential diagnosis for a patient presenting with intestinal blockage from a trematode (flukes)?
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- Schistosomiasis
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What is the differential diagnosis for a patient presenting with intestinal blockage from a nematode (roundworm)?
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- Enterobiasis
- Trichuriaisis - Hoockworm - Trichinellosis - Toxocariasis |
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What are the symptoms of esophagitis?
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- Pain and difficulty swallowing
- Heart burn - Acid regurgitation |
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Candida albicans esophagitis
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- Risk factors: HIV, diabetes, broad spectrum antibiotics
- Clincal presentation: Yellow-white mucosal plaques, ulceration, and luminal narrowing. - Complications: Performation - Treatment: Fluconazole |
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Herpes Simplex Virus esophagitis
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- Risk factors: Hematologic malignancies, chemotherapy, or immunosupppressive therapy.
- Clinical presentation: Small ulcers on the distal third of the esophagus. Pseudomembranes or volcano ulcers may occur with progression. - Treatment: Acyclovir. |
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CMV esophagitis
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- Risk factors: AIDS and immunosupression.
- Clinical presentation: "Punch-out" ulcers (well circumscribed) in mid to distal esophagus. - Treatment: Ganciclovir. |
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What are the signs and symptoms of GI infections?
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- Fever
- Loss of apetite - Nausea - Vomiting - Weight loss - Dehydration - Mucus or blood in stool |
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Staph aureus intoxication
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- Risk factors: Many strains have enterotoxins (exotoxins) that infect custards, creamy dishes, mayonaise, salad dressing, and meat.
- Clinical presentation: Vomiting, diarrhea, and headache. - Virulence factors: Produces toxins lettered A through E. - Rapid onset. - Treatment: Symptoms pass within 24-48 hours so antibiotic therpay is not needed. |
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Staphlococcal enterotoxins
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- A: Most commonly associated with food poisoning.
- B: Associated with enterocolitis - C: Rare - D: Second most common alone or assciated with toxin A. Associated with milk products. - E: Rare |
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Mechanism of action of Staphlocoocal enterotoxins?
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- Stimulate the vagal nerve endings in the stomach that control the vomiting response.
- Act as superantigens in the blood stream to cause T-cell proliferation, which causes malaise. - Different amounts are produced among strains due to differing promoter strengths. |
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Bacilus cereus emetic syndrome
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- Intoxication: From preformed, heat stable toxin ingestion.
- Duration: After 1-6 hour incubation period, symptoms prosist for 24 hours. - Virulence factors: Cereulide, a circular peptide - Clinical presentation: Profuse vomiting, nausea, and abdominal cramps are present, but fever and diarrhea are absent. - Diagnosis: Retreive 10^5 orgaisms from the infected food. |
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Bacilus cereus diarrheal syndrome
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- Infection: Caused by ingestion of organisms with subsequent production of toxin.
- Duration: Slow onset and symptoms last for 24 hours. - Virulence factors: Diarrheal enterotoxin and hemolysins - Risk factors: Meat, stew, gravy, vanilla sauce, vegetable, puddings, and milk. - Clinical presentation: Watery diarrhea, nausea, and abdominal cramps, but vomiting is absent. - Diagnosis: Recovery of the organism in stools, oucherterlony assay for toxin. |
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Bacilus cereus characterisitics
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- Gram positive rod
- Grows aerobically or anaerobically - Beta hemolytic - Motile - Heat resistant, radiation, dessication, and disinfectants - Spores survive cooking and grow in the refrigerator. |
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Clostridium botulism general characterisitics
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- Gram positive bacili
- Virulence factors: produces eight distinc toxins, four of which cause disease in humans. - Diagnosis: Eggyolk agar or anti-Ig mouse antibodies. - Treatment: Trivalent botulinum antiboxin (ABE), and BabyBIG for the infantile form (AB). - Prevention: Adequate cooking and maintaining acid pH. |
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Botulism toxin
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- Botulism toxin is an A-B type toxin (A is the toxin and B attatches).
- The B chain is called the heavy chain and the A chain is called the light chain. - Targets cholinergic nerves and inhibits the release of acetyl choline causing flacid paralysis. |
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Botulism toxin serotypes
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- A and E: Target SNAP-25 previnting neurtransmitter release.
- B, D, and F: Target synaptobrevin - C cleaves syntaxin on the membrane. |
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Clostridium botulism intoxication
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- Duration: Incubation period is 12-72 hours with symptoms lasting days to months.
- Risk factors: Home canned food, herb infused oils, cheese sauce, bottled garlic. - Clinical presentation: Nausea, vomiting, blurred vision, dilated pupils, bilateral descending parlysis, respitory involvement. |
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Infantile infection of clostridium botulism
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- Duration: 3 to 30 days of incubation.
- Infection: Spores infect the gut of infants because they do not have normal flora to fight the infection. - Clinical presentation: "Floppy baby syndrome" - Assocaited with bottled honey. |
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What are the symptoms associated with non-inflammatory diarrhea?
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- Mucousal hypersecretion or hypoabsorption without inflammation changes to the wall of the intestine.
- Typically involve the small intestine. - Less severe than the inflammatory diseases. |
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General characteristics of Clostridium perfingins
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- Risk factors: Meats (pork)
- Infection: Food poisoning because of ingestion of the toxin. - Duration: 8-16 hours. - Clinical presentation: Abdominal cramps, watery diarrhea, and nausea. - Complication: Rarely a cause of necrotic enteritis (most often from the C sub-strain). - Diagnosis: Toxin is detected in feces. - Prevention: Reheating to denature the toxin. |
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General characterisitics of family Enterobacteridae.
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- Gram negative bacilli
- Ferment glucose - Part of the normal intestinal flora. - Cause a wide range of diseases. - Biotyping is required for the final diagnosis. - Virulence factors: Lipid A compoent of LPS, capsule, Type III secretion systems, Iron chelating. |
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E. coli general characteristics
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- Produces adhesins CFA, Bfp, and AAF.
- Causes septicemia, UTIs, and neonatal meningitis. - Colonizes the small intestine and causes traveler's diarrhea (ETEC). |
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Travelers diarrhea
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- Duration: 1-3 days incubation with a week of symptoms.
- Clinical presentation: Toxins cause the hypersecretion of fluids. - Virulence factors: CFA, LT, STa, STb, and heat liable toxin. - HL is a A-B type toxin with an ADP-ribosylating toxin that causes cAMP to accumulate, which alters sodium and choloride transporteres. - There is also heat stable toxin that causes cGMP to accumulate. |
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Infantile diarrhea (EAEC)
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- Virulence factors: Produces ST-like toxin (EAST 1).
- E. coli colonization causes the bacteria to become lodged in the growing mucous. - Causes a shortening of the microvilli. |
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Infantile Diarrhea (EPEC)
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- More common is less developed countries.
- Causes the intestine to take on a patchy appearance. - No toxin is produced, but destruction of the microvilli leads to malabsorption. |
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E. coli attatchment (EPEC)
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- E. coli lodge to the intestinal mucous membrane and secrete TIR into the epithelial cells via a type III secretion system.
- TIR insertes into the membrane and binds to E.coli via EPEC. - A cascade of signaling events lead to cytoskeleton rearrangement, pedistle formation, and loss of the microvilli. |
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Diagnosising E. coli infections.
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- MacConkey agar: Bile and crystal violet inhibiit gram poisitive growth. Lactose fermenters will appear as pink colonies and others will be clear.
- Eosine methyline blue: Eosin will inhibit gram positive growth and lactose inhibitors turn pink purple. E. coli has a greenish sheen. |
