A 26-year-old man presents to the emergency room with fevers and headache for the last 2 days. His temperature is 39.1°C, heart rate 123 beats/min, blood pressure 88/54 mm Hg, and respiratory rate 28 breaths/min. He appears diaphoretic and pale on examination but has no rash and no other abnormal physical findings. His white blood cell count is 3.9 × 10 9 /L, hemoglobin 5.6 g/dL, platelet count 112,000/µL, and creatinine 2.7 mg/dL. He is oliguric. He is a medical student and returned from Uganda 6 days ago, where he has been conducting research for the last year. He reports no sexual contacts within the last six months.
Which of the following is the MOST likely cause of his acute illness?
Correct Answer: C
Malaria is the most common infection among returned travelers, and P. falciparum is the malaria species causing the vast majority of malaria infections in travelers to sub-Saharan Africa. Diagnosis is traditionally made using thick and thin peripheral blood smears but requires an experienced microscopist. Rapid diagnostic tests using immunochromatography to detect malaria antigens are also commonly used for diagnosis. Because malaria is the most common infection among returned travelers, this is the most likely cause of this patient’s illness. The illness described is less likely to be Strongyloides hyperinfection syndrome (Answer A), which usually presents in an immune-suppressed patient, often with a high white blood cell count and signs of meningitis. Zika virus infection (Answer B) is often mild or asymptomatic and does not fit well with the scenario of extremis presented here. Brucellosis (Answer D) is usually an indolent infection presenting as fever of unknown origin with malaise and mylagias.
Which of the following statements are TRUE about empiric antibiotic selection for patients in septic shock?
Correct Answer: A
Empiric antibiotic selection for sepsis and septic shock should be tailored to the individual. Clinicians should take into account each patient’s medical history and comorbidities, immune deficits, prior microbiologic history including known antimicrobial-resistant infections, recent hospitalization or facility contact, suspected site of infection, presence of invasive or indwelling devices, and local infection prevalence and antimicrobial resistance patterns. Most patients with septic shock should receive at least two antibiotics from two different classes (combination therapy), especially if a gram-negative pathogen is suspected. If severe P. aeruginosa infection is suspected, one or two antibiotics can be used empirically, but if two antibiotics are used, they should be from different classes. The broadest-spectrum antibiotic combination available is not always appropriate, as broad-spectrum antimicrobial use has the potential to drive antimicrobial resistance, confer additional toxicities, and may not benefit the patient.
A 19-year-old woman is admitted to the intensive care unit for massive hemoptysis. Computed tomography (CT) of the chest reveals a large, cavitated lesion in the right middle lobe. The patient has no known past medical history, lives with her family, and recently immigrated from China.
What is the MOST appropriate management strategy?
Mycobacterium tuberculosis infection can present as primary disease or reactivation of latent disease. Hemoptysis in a patient with epidemiologic risk factors for tuberculosis should raise the specter of active pulmonary tuberculosis, which is a public health concern. Management principles include admission to a negative-pressure isolation (airborne infection isolation) room. Positive-pressure or “reverse” isolation rooms are used to protect patients with systemic immune defects against airborne infections and are not used for management of tuberculosis. Healthcare workers caring for patients with suspected tuberculosis should wear N95 respirator masks or powered air-purifying respirators when entering the patient’s room. Empiric tuberculosis therapy would be reasonable in this patient with signs, symptoms, and epidemiologic risk factors compatible with active pulmonary tuberculosis. Discontinuation of negative-pressure isolation in patients suspected of tuberculosis requires a determination that (1) infectious tuberculosis is unlikely, and one or more of the following: (2a) an alternative diagnosis has been established, (2b) three or more consecutive sputum samples are smear-negative for acid-fast bacteria, or (2c) two or more sputum samples are negative for M. tuberculosis DNA using the Xpert MTB/RIF assay. Note that these are not the same requirements for discontinuing negative-pressure isolation in patients diagnosed with active tuberculosis.
You admit a 61-year-old man to the intensive care unit after a witnessed generalized tonic-clonic seizure at home. He has a history of sarcoidosis and has been treated with prednisone 10 to 60 mg for the last year. Before admission, he had no cough or sputum production and had felt well. CT of the head, chest, abdomen, and pelvis reveals a 2.5 cm pulmonary nodule in the right upper lobe and 3 cm parenchymal brain lesion.
What is the MOST likely diagnosis?
Correct Answer: D
This case presentation is most consistent with nocardiosis, a classic “brain and lung” infectious syndrome (Answer D). Although nocardiosis typically presents in immune-compromised patients, up to one-third are immunocompetent. Infections caused by aerobic actinomycetes in the genus Nocardia are characterized by their ability to spread to any organ (especially the central nervous system) and a tendency to relapse or progress despite appropriate therapy. Glucocorticoids depress the phagocytic function of alveolar macrophages and neutrophils and alter antigen presentation and lymphocyte activation, increasing risk of bacterial and fungal infections. Virtually every chronic illness that requires prolonged glucocorticoid therapy has been associated with nocardiosis. P. jirovecii (formerly carinii) (Answer A) and sarcoidosis (Answer B) are not associated with parenchymal mass–like brain lesions. Although tuberculosis (Answer C) can present with masslike lesions in the brain parenchyma (tuberculomas), it is very uncommon to have simultaneously pulmonary and central nervous system tuberculomas/nodules. Furthermore, most patients with pulmonary tuberculosis present with cough.
A 71-year-old man with diabetes, obesity, hypertension, and benign prostatic hypertrophy is admitted to the intensive care unit with abrupt-onset groin pain, fever, and a rapidly spreading erythematous groin and lower abdominal rash with ill-defined margins. The rash is exquisitely tender and firm to palpation. He develops hypotension with mean arterial pressure measured at 52 mm Hg, refractory to intravenous fluid resuscitation.
What is the MOST appropriate sequence of events to manage his disease?
This scenario describes the clinical presentation of necrotizing fasciitis, specifically Fournier gangrene, a necrotizing soft tissue infection of the perineum. The microbiology of this disease comprises facultative organisms (Escherichia coli, Enterococcus spp.) and anaerobes (anaerobic or microaerophilic streptococci, Bacteroides, Clostridium, Fusobacterium). Thus, antimicrobial therapy should target this spectrum of bacterial pathogens and should also include clindamycin, for its antitoxin properties against toxin-producing streptococci and staphylococci. Meropenem or piperacillin-tazobactam is an appropriate component of first-line regimens, which should also include clindamycin. Patients with risk factors for methicillin-resistant S. aureus should also be given vancomycin or daptomycin. Hemodynamic instability is common with necrotizing soft tissue infections and requires aggressive supportive care with intravenous fluids and vasopressors. Vasopressor therapy should not be delayed until a central line can be placed, and hypotensive shock should be addressed before or simultaneously as blood cultures are drawn and antibiotics are started, and not delayed. Surgical consult should not be delayed by obtaining CT, MRI, or other imaging looking for soft tissue gas collections to support a diagnosis of necrotizing soft tissue infection. Surgical exploration is the only way to truly establish the diagnosis and obtain source control. Early surgical debridement has also been shown to improve outcomes.
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