Snapshot A 40-year-old man presents to a local emergency room. He is currently on a medical mission in India. He reports sudden-onset nausea, vomiting, and copious amounts of watery diarrhea. His blood pressure is 93/65 mmHg and pulse is 114/min. On physical exam, he has sunken eyes, decreased skin turgor, and dry mucous membranes. He is given intravenous rehydration with the goal of rapid rehydration. Introduction Classification Vibrio cholerae a comma-shaped, flagellated, and gram(-) rod oxidase + and produces cholera toxin transmission fecal-oral via water or uncooked food Epidemiology incidence rare in the United States demographics endemic in developing countries most severe in children risk factors raw seafood contaminated water travel Pathogenesis acid-labile enterotoxin activates Gs and overactivates adenylate cyclase, causing ↑ cAMP requires large inoculum or decreased acidity in the host’s stomach causes ↑ chloride secretion, resulting in secretory diarrhea and water efflux this results in loss of potassium and bicarbonate Prevention live-attenuated oral cholera vaccine indication adults traveling to endemic areas > 10 days prior to travel Prognosis if untreated, mortality is > 50% if treated, mortality is < 1% Presentation Symptoms may be asymptomatic acute onset painless rice-water secretory diarrhea nausea vomiting Physical exam dehydration sunken eyes dry mucous membranes decreased skin turgor Studies Labs stool culture in alkaline media definitive diagnosis but not always necessary no white blood cells in stool electrolyte abnormalities hypokalemia hyponatremia metabolic acidosis Making the diagnosis most cases are clinically diagnosed Differential Norovirus diarrhea distinguishing factors often associated with cruise ships, child care centers, or other crowded condition typically self-limited no association with geographic endemic locations Campylobacter jejuni-associated diarrhea distinguishing factors bloody diarrhea comma-shaped, but does not grow in alkaline media white blood cells in stool Treatment Management approach management is centered around rapid rehydration Conservative oral rehydration indication all patients intravenous hydration indication severe dehyration Medical antibiotics indication severe dehydration drugs doxycycline tetracycline ciprofloxacin Complications Rapid dehydration Hypovolemic shock Death
QUESTIONS 1 of 2 1 2 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.MC.14.1) A stool sample was taken from a 19-year-old male who presented with profuse watery diarrhea. He recently returned from a trip to Central America. A microbiologist identified the causative agent as a gram-negative, oxidase-positive, comma-shaped bacteria that is able to grow well in a pH > 8. Which of the following is a mechanism of action of the toxin produced by this bacteria? Tested Concept QID: 106331 Type & Select Correct Answer 1 Degradation of cell membranes by hydrolysis of the phosphilpids 0% (0/32) 2 Overactivation of adenylate cyclase by activation of Gs subunit by ADP-ribosylation 81% (26/32) 3 Overactivation of adenylate cyclase by inhibition of Gi subunit by ADP-ribosylation 12% (4/32) 4 Inactivation of the 60S ribosomal subunit by cleaving an adenine from the 28S rRNA 0% (0/32) 5 Overactivation of guanylate cyclase 6% (2/32) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review tested concept