A 70-year-old nursing home resident had been admitted to the hospital for pneumonia and treated for 10 days with levofloxacin. She improved but developed diarrhea 1 week after discharge, with low-grade fever, mild abdominal pain, and 2 to 3 watery, nonbloody stools per day. A cell culture cytotoxicity test for Clostridium dif icile–associated disease was positive. The patient was treated with oral metronidazole, but did not improve after 10 days. Diarrhea has increased and fever and abdominal pain continue. What is the best next step in the management of this patient?
The diagnosis is very consistent with C difficile disease. The patient is elderly, has been in both a nursing home and hospital setting and received more than a week of a fluoroquinolone antibiotic. Mild fever, abdominal pain, and watery diarrhea are all consistent with the diagnosis, and the cell culture cytotoxicity test is the most specific of diagnostic tests. Failure on metronidazole is increasingly reported, with at least a 25% failure rate. Switching to oral vancomycin is recommended. The patient does not have fulminant disease which usually presents as an acute abdomen, sepsis, or toxic megacolon; so hospitalization is not necessary. Synthetic fecal bacterial enema is one potential treatment being studied for recurrent C difficile disease but is not standard treatment.
A college wrestler develops cellulitis after abrading his skin during a match. He is afebrile and appears well, but the lateral aspect of his arm is red and swollen with a draining pustule. Gram stain of the pus shows gram-positive cocci in clusters. Which of the following statements is correct?
Community onset skin infection is often caused by community-acquired methicillin-resistant S aureus (CA-MRSA). Over 63% of S aureus isolates from the community were methicillin-resistant in one study. However, these isolates are different from the methicillin-resistant S aureus seen in the hospital setting. CA-MRSA isolates are sensitive to linezolid and trimethoprim-sulfamethoxazole and to a lesser degree to clindamycin and tetracyclines. They are resistant to beta lactams and erythromycin. In healthy individuals such as the wrestler described, hospitalization and treatment with vancomycin would not be necessary. Telavancin, ceftaroline, and daptomycin are alternatives to vancomycin in some circumstances for the management of community-acquired or hospital-acquired methicillin-resistant S aureus. Streptococci usually cause a rapidly spreading cellulitis without pustule formation.
A 27-year-old man has fever, macular rash, and lymphadenopathy. He had unprotected sex with a male partner 2 weeks before the onset of these symptoms and has just learned that the partner is infected with HIV. The patient’s rapid HIV test is negative. What is the best test to evaluate this patient for HIV infection?
HIV infection is usually diagnosed by the detection of HIV-specific antibodies using rapid HIV test or a conventional enzyme-linked immunoabsorbent assay (ELISA), which are highly sensitive tests, and confirmed by Western blot or indirect immunofluorescence assay, which are highly specific tests. Antibodies appear in few weeks after infection, sometimes after the development of acute HIV infection (acute retroviral syndrome). Clinicians should maintain a high level of suspicion for acute HIV infection in all patients who have a compatible clinical syndrome and who report recent high-risk behavior. When acute retroviral syndrome is a possibility, a plasma RNA polymerase chain reaction (PCR) should be used in conjunction with an HIV antibody test to diagnose acute HIV infection. Although HIV DNA testing is available, it offers no added advantages over the more readily available and FDA-approved HIV RNA testing. The patient’s HIV serology (antibody testing) is negative, so repeating the serology testing by ELISA or ordering Western blot is not indicated at this point. It is appropriate to repeat the serology testing in 4 to 6 weeks.
A businessman traveling around the world asks about prevention of malaria. He will travel to India and the Middle East and plans to visit several small towns. What is the most appropriate advice for the traveler?
Whether or not to use drugs such as atovaquone-proguanil, mefloquine, or primaquine for resistant P falciparum will depend on knowledge of specific local patterns of drug sensitivity of plasmodia. Specific information can be obtained from the CDC malaria hotline or the CDC emergency operation center. The common sense measures described are extremely important and part of the overall worldwide plan to contain the spread of malaria. Prophylaxis should begin 2 days to 2 weeks before departure in order to have adequate levels of drug on arrival and to identify potential side effects before leaving. Chemoprophylaxis is not entirely reliable, and malaria should always be in the differential diagnosis of a febrile illness in a traveler to endemic regions, even if the drug regimen has been faithfully followed. Mosquito peak feeding periods are dawn and dusk.
A 36-year-old man with history of acute myelogenous leukemia is admitted to the ICU with neutropenic fever and low blood pressure that requires norepinephrine drip. The patient finished his first cycle of chemotherapy 10 days ago. He denies respiratory, gastrointestinal, or urinary symptoms. CBC reveals mild thrombocytopenia and an absolute neutrophil count of 100/µL. Urinalysis is within normal limits and chest x-ray does not show any infiltrate. Awaiting culture results, which of the following antibiotic regimens is most appropriate?
Neutropenic fever is a medical emergency. Infections, most commonly gram-negative bacteria such as P aeruginosa, are responsible for most cases. Prompt empiric antibiotic therapy with two antibiotics from two different antibiotic classes (double coverage) that have anti-pseudomonal activity is most appropriate. Adding an antibiotic with anti–methicillin-resistant Staphylococcus aureus (MRSA) activity to the initial antibiotic regimen is indicated if the patient was on antibiotic prophylaxis before the onset of the neutropenic fever or if he has any of the following conditions: skin infection, moderate to severe mucositis, central venous catheter, or shock (as in this vignette). Imipenem alone is not enough because it lacks anti-MRSA activity. Vancomycin does not provide gram-negative coverage and should never be used alone in the treatment of neutropenic fever. Awaiting culture results without initiating empirical antibiotic coverage is inappropriate because it increases the patient’s mortality risk. Antifungal therapy is often added in the subsequent days if the patient fails to respond to broad-spectrum antibiotics.
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