A 27-year-old woman presents to the Emergency Department with confusion and a high fever. She was at a party earlier in the week and admits to heavy drinking and IV drug use; since then, she has developed fever, chills, fatigue, and shortness of breath. She has no previous medical or surgical history. Her temperature is 39.2°C, blood pressure is 110/74 mmHg, heart rate is 96 beats per minute, respiratory rate is 24 breaths per minute, and oxygen saturation is 97% on room air. On examination, she has elevated jugular venous pressure and a holosystolic murmur heard over the left lower sternal border. A chest x-ray shows several round opacities in bilateral lung fields.
Which of the following represents the correct order in the workup of this patient?
Obtain blood cultures, start vancomycin, then perform a transthoracic echocardiogram. This patient has evidence of acute bacterial endocarditis, which she likely contracted as a result of IV drug use. The holosystolic murmur over the left lower sternal border with an elevated jugular venous pressure is consistent with tricuspid regurgitation. In general, right-sided valvular lesions are more common in IV drug users, and these vegetations can send septic emboli to the lungs and cause pulmonary symptoms. When infective endocarditis is suspected, three blood cultures from three different venipuncture sites should be collected immediately. Only after cultures are drawn should antibiotics be started. The majority of endocarditis in IV drug users is caused by S. aureus, and MRSA is a concern. (E) Patients without acute symptoms can forgo empiric antibiotics and await blood culture results to start definitive antibiotic therapy. However, this patient is symptomatic and therefore empiric antibiotic therapy with vancomycin is warranted. A TTE is typically performed before a TEE, since it is less invasive. However, the sensitivity is much lower than a TEE, and therefore a nondiagnostic result or a negative result should be followed up with a TEE if the clinical suspicion is high. (A) This patient is hemodynamically stable with no history of a prosthetic valve or indicators of a complicated infection, and therefore surgery is not appropriate at this time. (B) Vancomycin, gentamicin, and cefepime is an appropriate antibiotic regimen for the treatment of symptomatic prosthetic valve endocarditis. In addition, antibiotics should be started after blood cultures are collected. (D) Ceftriaxone and gentamicin can be used for empiric treatment of subacute bacterial endocarditis, which presents with a more indolent course than acute bacterial endocarditis.
A 62-year-old man is hospitalized to receive chemotherapy. His treatment course is complicated by neutropenia (serum neutrophil count <500/μL), and he develops a temperature of 38.6°C. On examination, his IV lines are clean without surrounding erythema, his lungs are clear to auscultation, and he has no other obvious sources of infection.
What should be done next in the management of this patient?
Start cefepime. Febrile neutropenia is a medical emergency, and patients are at high risk of developing a wide range of severe and rapidly progressive infections (gram-positive bacteria such as staph and strep, gramnegative bacteria such as Pseudomonas and E. coli, viruses such as HSV and CMV, fungi such as Candida and Aspergillus, etc.). Neutropenic fever is defined by an absolute neutrophil count <500/μL (indicates severe neutropenia) with a single temperature >38.3°C or a temperature >38.0°C for at least 1 hour. Empiric antibiotics should be started immediately after blood cultures are drawn. Because Pseudomonas is a common cause of serious infections in neutropenic patients (though gram-positive bacteria are now the most common cause), the chosen antibiotic(s) should have good Pseudomonas coverage. Cefepime is an appropriate option since it also has good gram-positive coverage.
(A) Blood cultures should be drawn, but empiric antibiotics should also be given right away. (B) Vancomycin for MRSA coverage does not need to be started empirically unless there are specific concerns for MRSA infection. (D) Because febrile neutropenia can progress rapidly and be life-threatening, observation is not appropriate.
A 28-year-old woman presents with fever, sore throat, and lymphadenopathy. A further history reveals that she has had unprotected sex with multiple partners. A screening HIV test is positive, which is confirmed with a Western blot. The woman has no other medical problems, does not use any illicit drugs, and desires to get pregnant. The decision is made to begin treatment with antiretrovirals.
Which of the following is an appropriate regimen for this patient?
Emtricitabine, rilpivirine, and tenofovir. Because there is disagreement about when to start antiretroviral therapy in HIV patients, this topic is less likely to show up on the examination. Although antiretrovirals should be considered for every patient, strong indications include a CD4 count <500/mm3 , pregnancy, an AIDS-defining illness, and the presence of other significant comorbidities. Treatment-naïve HIV patients should generally start treatment with two NRTIs and either an NNRTI, a protease inhibitor (with or without ritonavir), or an integrase inhibitor. The only answer choice that satisfies this rule and takes into account the possibility of future pregnancy is B. (D) This combination is normally a good option for initiating treatment, but efavirenz is teratogenic. (A) This is a combination of two protease inhibitors and an agent that is not approved for treatment-naïve patients (enfuvirtide), and so this is a poor option. (C) The combination of tenofovir and didanosine has a high failure rate.
A 33-year-old woman receives oral antibiotics to treat a mild UTI. She goes on a run, and feels a “pop” above her heel that is associated with severe pain. She has pain and difficulty with plantarflexion of the affected foot.
Which of the following antibiotics is most likely responsible?
Ciprofloxacin. One reported adverse reaction of fluoroquinolone antibiotics is tendinopathy, and the Achilles tendon is most often affected. Fluoroquinolones can also cause GI upset, dizziness, rash, and a prolonged QT interval. (A) Trimethoprim-sulfamethoxazole may cause Stevens– Johnson syndrome, leukopenia, hyperkalemia, hypoglycemia, and hepatitis. The incidence of adverse reactions is much higher in HIV patients. (B) Metronidazole can cause a disulfiram-like reaction with alcohol. (C) Tobramycin and other aminoglycosides may cause renal failure and ototoxicity. (E) Azithromycin and other macrolides can cause a prolonged QT interval and hepatitis.
A 68-year-old woman with a history of hypertension and poorly controlled diabetes presents for further management of her foot ulcer. She has had several weeks of wound care, but the ulcer is not healing. She has had ulcers previously and has been diagnosed with peripheral neuropathy and peripheral arterial disease. On examination, there is a 3-cm ulcer on the left foot with surrounding erythema and purulence. Her laboratory values show an ESR of 102 mm/h. An x-ray is taken of the foot, which is normal.
Which of the following would be most helpful in making the diagnosis?
MRI of the foot. Large diabetic foot ulcers, an ESR >70 mm/h, and failure to respond to wound care after several weeks suggest the possibility of osteomyelitis. Although plain radiographs can be used to make the diagnosis, they are not very sensitive and are often indeterminate or normal. The next step in diagnosis is performing an MRI, which is a much more sensitive test. (A) Most diabetic foot ulcers are colonized with bacteria, and infections are often polymicrobial; thus, wound culture is of limited utility. Common organisms that cause diabetic foot infections include S. aureus (including MRSA), S. epidermidis, S. pyogenes, Pseudomonas, Enterobacteriaceae, and anaerobes. (C) Biopsy and culture of the bone can be helpful in making the diagnosis and guiding treatment; however, MRIs are less invasive and should be performed first. If a plain radiograph is normal, it is best to follow-up with MRI; if the results of MRI are nondiagnostic, and if the patient fails to respond to empiric antibiotics, then a bone biopsy should be performed. (D) Wound care and topical antibiotics are not effective in cases of osteomyelitis. Definitive antibiotic therapy is guided toward culture and sensitivity data when available; however, empiric therapy should be started early and chosen based on the extent of disease. An appropriate regimen would cover gram-positive cocci (including MRSA), aerobic gram-negative bacilli, and anaerobes. An example is clindamycin with ciprofloxacin.
Click to expand