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1. A 72-year-old man presents with acute onset of left-sided hemiplegia and confusion. Two weeks earlier had a bout of bloody diarrhea lasting for 2 days, without fever, abdominal cramps. The most likely enteric pathogen is: a. Salmonella b. Norovirus c. Shiga toxin producing E. coli d. Cryptosporidium e. Campylobacter
Answer : c
Brain infarcts, renal infarcts, hemolytic uremic syndrome
(HUS), and thrombotic thrombocytopenic purpura are some of the complications of Shiga toxin producing E. coli. Most of the Shiga toxin producing E. coli belong to serotype
(0157:H7); however, other gram negatives can also produce
Shiga toxin. The toxin is responsible for most of the complications. The sequele could include brain infarcts, chronic kidney disease, or end stage renal disease and death. The other organisms are not typically associated with HUS and TTP.
2. A 69-year-old Asian Indian male presents to your office for fever (102°F), abdominal cramps, urgency, tenesmus, and brownish loose bowel movements. He recently returned from a month vacation in India. WBC 16,000 bands 3%, polys 63% and lymphs 37%, stools demonstrate many polymorphs. The initial empiric therapy is: a. Ciprofloxacin b. Ampicillin c. Sulfa/trimethoprim d. Azithromycin e. Rifaximin
Answer : d
Most enteric pathogens (Salmonella, Campylobacter,
Shigella, etc.) from Asia are resistant to quinolones and therefore ciprofloxacin would not be the empiric drug of choice. Drugs can always be adjusted as soon as the susceptibility pattern for the pathogen becomes available.
Rifaximin is not indicated in patients with signs and symptoms of invasive pathogens, i.e., fever, bloody diarrhea.
Azithromycin or ceftriaxone are the drug of choice for empiric therapy until identity of the organism as well as susceptibility becomes available.
3. An 80-year-old nursing home resident was evaluated for loose bowel movements, with brown stool but no blood; the patient is afebrile. Culture of stools including C. difficile for five speciments were all negative. Examination for ova and parasites was also negative. No improvement was noted after a course of ciprofloxacin and metronidazole.
Your next step would be: a. Start the patient on oral vancomycin b. Start metronidazole plus vancomycin c. Stool for acid fast organisms d. Stool direct fluorescent stain for giardia and cryptosporidium e. Start rifaximin
Answer : d
Chronic diarrhea in an older adult can be due to giardia or cryptosporidium. Routine stool for cultures and ova and parasites does not include testing for cryptosporidium which will be missed unless looked for. The elderly patient is immunocompromised and therefore at risk for pathogens seen in immunocompromised states such as
AIDS, following chemotherapy, etc. In the normal host, cryptosporidium is a self-limiting disease that can cause chronic diarrhea in the elderly. Cryptosporidium will not respond to commonly used drugs for enteric infections.
4. A 76-year-old female being evaluated for fever of unknown origin (FUO) has a temperature of 101.5°F for over 10 days with confusion. Initial tests show Hgb 10.8 g/ dL, WBC 20,000/c.mm, ALT 90 U/L, AST 120 U/L,
Alkaline phosphatase 180 U/L/CT scan of the abdomen
C.S. Pitchumoni and T.S. Dharmarajan (eds.), Geriatric Gastroenterology,
DOI 10.1007/978-1-4419-1623-5_55, © Springer Science+Business Media, LLC 2012
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576 demonstrates an enlarged spleen but is otherwise negative. Two out of two blood cultures grow Streptococcus milleri . The next test in evaluation should be: a. Colonoscopy b. Transthoracic echocardiogram c. MRI of the abdomen d. Total body bone scan
Answer : c
MRI of the abdomen can demonstrate multiple abscesses in the spleen. Unlike liver abscess, splenic abscess develops
D.V. Alcid as a result of hematogenous seeding. The clinical picture of splenic abscess can be subtle frequently lacking peritoneal symptoms, and in the elderly, may present as mental status changes, or FUO. If the blood cultures are negative, intrabdominal abscess should be looked for, as therapy will depend on the source. Liver abscess is frequently secondary to biliary tract disease and sometimes due to diverticulitis, colon cancer, ruptured appendix, whereas splenic abscess is due to hematogenous dissemination, as seen in infective endocarditis. A transthoracic echocardiogram may be a subsequent option to exclude endocarditis.