Infectious Disease Flashcards
Patients undergoing cardiothoracic or orthopedic surgery should be screened for
nasal carriage of Staphylococcus aureus and, if positive, should have preoperative decolonization
Immune reconstitution inflammatory syndrome is the return of a robust immune response resulting from treatment of HIV that may “unmask” a pre-existing infection; when this occurs,
the underlying infection should be treated while antiretroviral therapy is continued.
In endemic areas such as California, as many as one third of cases of community-acquired pneumonia are caused by
Coccidioides species
Guideline-based recommendations for empiric therapy of community-acquired pneumonia requiring ICU admission include
a β-lactam (ampicillin-sulbactam, cefotaxime, ceftriaxone, or ceftaroline) to treat Streptococcus pneumoniae, gram-negative bacilli, or Haemophilus influenzae plus an agent active against Legionella, such as a macrolide or quinolone.
Initial studies for fever of unknown origin in most patients typically include a complete blood count with differential, complete metabolic profile with kidney and liver studies, at least three blood culture sets and cultures of other bodily fluids (such as urine or from other sources based on clinical suspicion), an erythrocyte sedimentation rate, tuberculosis testing, and serology for HIV; it is reasonable to perform
chest imaging (radiography or CT) &CT ABDOMEN & PELVIS as initial diagnostic imaging.
Risk factors for invasive or disseminated aspergillosis include profound and prolonged neutropenia and stem cell and solid organ transplantation; patients have fever, cough, chest pain, and hemoptysis at presentation, and pulmonary infiltrates, nodules, or wedge-shaped densities may be seen on chest radiographs. The most efficient way to establish a definitive diagnosis (and then initiate antifungal therapy) is with?
Serum galactomannan testing in patients with suspected invasive pulmonary aspergillosis. Bronchoalveolar lavage and biopsy, if necessary, are recommended if the serum galactomannan result is negative but strong risk factors are present. (Added March 2020)
Usually develops weeks after exposure, during the second phase of illness, and can present with uveitis, rash, conjunctival suffusion, sepsis, lymphadenopathy, kidney injury, and hepatosplenomegaly.
Leptospiral meningitis
Fulminant Clostridium difficile infections require
oral vancomycin plus intravenous metronidazole; vancomycin enemas may also be added if ileus is present.
A poorly understood sequela of Lyme disease thought to be due to a disordered immunologic response to the preceding infection; most patients slowly improve over a 6-month course, and treatment is directed toward symptom amelioration.
Post–Lyme disease syndrome
Rapidly growing, non-tuberculous mycobacteria, such as _______________, can produce chronic, non-healing wounds that do not respond to conventional antimicrobial therapy.
Mycobacterium fortuitum
In patients with a high likelihood of pelvic inflammatory disease without indications for hospitalization, empiric therapy with?
A single dose of IM Ceftriaxone, 500 mg, should be given (for persons ≥150 kg, the dose should be 1 g) along with oral doxycycline and metronidazole for 14 days without waiting for microbiologic testing results. (Updated by CDC in 07/2021)
Screening for and possibly treating asymptomatic bacteriuria is supported by only two indications:
pregnancy and medical clearance before an invasive urologic procedure
Preferred HIV postexposure prophylaxis regimens include
tenofovir disoproxil fumarate, emtricitabine, and either dolutegravir or raltegravir and are appropriate whether the exposure was occupational or nonoccupational
Acute, uncomplicated pyelonephritis can usually be managed with oral outpatient antimicrobial therapy, with
fluoroquinolones ciprofloxacin and levofloxacin being the preferred, first-line agents. 5-7 day course
Patients with selective IgA deficiency are susceptible to ________________ infection, manifesting as abdominal cramping, bloating, and chronic diarrhea.
Giardia lamblia
In patients with potential Zika virus exposure more than 2 weeks previously, testing for
Zika virus IgM antibodies is necessary.
is a cause of Ramsay Hunt syndrome, which usually presents with ear pain, a vesicular rash in the external ear (although the rash may be absent), and ipsilateral peripheral facial palsy.
Varicella-zoster virus
Many zoonotic organisms have the potential to cause pulmonary infection (i.e Q fever pneumonia), but they can be differentiated based on the severity of illness and animal reservoir; relatively mild infection coupled with exposure to livestock indicates likely
Coxiella burnetii infection
Coagulase-negative Staphylococcus is less virulent than S. aureus and is less likely to cause metastatic infection or endocarditis in patients without prosthetic devices or endovascular hardware in place (such as prosthetic heart valves) and may be treated with
simple removal of the intravenous catheter
____________________________ should be considered when possible, and patients should be monitored for their ability to void spontaneously after catheter removal.
Early removal of urinary catheters
Cat bite–associated wound infections comprise a mix of anaerobic and aerobic organisms, including Pasteurella species, which require treatment with
antibiotic agents such as piperacillin-tazobactam, ampicillin-sulbactam, imipenem, and meropenem; coverage for methicillin-resistant Staphylococcus aureus must be included in select patients who have risk factors for this infection.
characterized by a nonfocal febrile illness associated with leukopenia, thrombocytopenia, elevated hepatic enzyme levels, and a rapid response to tetracycline.
Human monocytic ehrlichiosis infection
In patients with health care–associated ventriculitis or meningitis
device removal, if present, should accompany empiric antimicrobial therapy.
First-line treatment for primary pneumonic plague is
streptomycin or gentamicin
Treatment of choice for disseminated histoplasmosis
Liposomal amphotericin B
In patients with pneumonia unresponsive to appropriate antibiotic therapy,
a noninfectious cause mimicking pneumonia, antibiotic-resistant bacterial infection, infection with a nonbacterial organism, or loculated infection such as an empyema may be the cause.
___________________________ should be suspected if the patient traveled to Africa, symptoms begin soon after return from an endemic area, and the peripheral blood smear shows a high level of parasitemia.
Plasmodium falciparum malaria
Patients with spinal epidural abscess who also have neurologic compromise should immediately
begin broad-spectrum antimicrobial therapy and undergo surgical drainage.
Fever is the major manifestation & is often associated with a relative bradycardia; additional symptoms may include a brief period of diarrhea followed by constipation, abdominal discomfort, nonproductive cough, mild confusion, and transient small blanching skin lesions (rose spots)
Typhoid (enteric) fever
Is recommended immediately after a diagnosis of HIV infection to guide the selection of active agents for the antiretroviral regimen or after virologic failure of a regimen to guide adjustment of antiretroviral therapy?
Genotypic viral resistance testing
Can cause acute aseptic meningitis year round and is the most common cause of recurrent viral meningitis?
Herpes simplex virus type 2
Indications for influenza, tetanus-diphtheria-pertussis, hepatitis A virus, and human papillomavirus vaccines are the same for patients with HIV infection as for the general population.
HPV vaccine can be given up to age 26 & beyond age 26 as indicated
In a patient with Lyme disease and possible central nervous system involvement, positive findings on ______________ can support the diagnosis of Neuroborreliosis, which necessitates parenteral therapy with ceftriaxone, cefotaxime, or penicillin.
Lumbar puncture
Note: New guidelines published in 2020 on the prevention, diagnosis, and treatment of Lyme disease allow for the choice of either intravenous (ceftriaxone, cefotaxime, penicillin G) or oral (doxycycline) antibiotics in patients with peripheral and/or central nervous system involvement without brain parenchymal involvement. Lumbar puncture is no longer necessary in these patients.
Patients with no known direct exposure to anthrax
Do not require treatment or separation from those who may be infected.
Preventing HIV acquisition?
The combination of tenofovir disoproxil fumarate (or tenofovir alafenamide, except in women engaging in receptive vaginal intercourse) plus emtricitabine taken once daily is more than 90% effective, if taken consistently
Osteomyelitis in a patient with a diabetic foot infection and no evidence of skin or soft tissue infection or sepsis requires
A bone biopsy before antibiotics are administered
In patients with previously treated syphilis,
treponemal serology results will remain positive, but nontreponemal tests will be negative; these patients require no further testing or treatment.
A screening HIV test result that is positive on the initial antigen/antibody combination immunoassay but negative on the antibody differentiation immunoassay and nucleic acid amplification testing for HIV RNA represents
a false-positive result
Is the most common cause of swimming pool–related outbreaks of diarrhea; diagnosis is made by microscopic examination of the stool or by stool antigen testing?
The protozoan Cryptosporidium
Persons with chronic inflammatory bowel disease or who are immunocompromised are most susceptible to severe travelers’ diarrhea or complications, should be given:
Guidelines were updated regarding the prevention and treatment of travelers’ diarrhea. Ciprofloxacin is no longer recommended for prophylaxis.
Central venous catheters should be
assessed daily for continued necessity and removed promptly when they are no longer needed.
Cyclospora protozoan infections are typically acquired after consumption of fecal-contaminated food or water, particularly in countries where the parasite is endemic, such as Peru, Guatemala, Haiti, and Nepal. How do you treat?
Bactrim (trimethoprim-sulfamethoxazole)
Antiretroviral therapy during pregnancy is crucial and significantly decreases the risk of perinatal transmission of HIV to the baby.
Tenofovir disoproxil fumarate (TDF), & emtricitabine, and efavirenz
OR
Zidovudine, lamivudine & ritonavir-boosted lopinavir is a valid alternative, it was previously a preferred regimen in pregnancy