Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ INTRODUCTION ++Table Graphic Jump LocationTABLE 8.11An Approach to Diagnosing and Treating Infectious DiseasesView Table||Download (.pdf) TABLE 8.11 An Approach to Diagnosing and Treating Infectious Diseases Phase of Clinical Decision-making Approach Define the illness Host: Different individuals, depending on their age, exposure history, prior infections, and immune status, are at risk for different types of infections. An understanding of the host allows us to better understand the organisms to which they are most susceptible. Tempo: Different pathogens cause different tempos of illness. Labeling the illness tempo will help us determine with more precision which infections are more or less likely. Generally, we can label the time course as acute (from hours/days to 1 week), subacute (weeks to months), and chronic (months to years). Clinical syndrome: Define the clinical syndrome (e.g., pneumonia or cholangitis). Putting it together: The first step in a suspected infection is to frame the patient based on these three features, for example: - An individual with HIV and a CD4 112 cells/μL presents with subacute onset of fever and cough. - An elderly person with hypertension presents with acute onset fever and cough. While these two individuals have a similar clinical syndrome, the potential organisms that cause this syndrome vary based on the host (individual with HIV vs. elderly immunocompetent person) and tempo (weeks vs. days). Select an empiric therapy Many infections have a high morbidity and mortality early in the course of illness when there is still diagnostic ambiguity. Therefore, we often start antimicrobial therapy prior to identifying the definitive pathogen(s). Most suspected infections that require hospitalization warrant empiric antibiotic therapy. Based on the host, tempo, and clinical syndrome, generate a list of possible and probable pathogens, which guides empiric antibiotic therapy. See Table 8.12 for empiric antibiotic regimens for commonly encountered infections. Finalize the management plan Targeted antibiotics and duration of therapy: Targeted antibiotics depend on the antimicrobial susceptibilities of the identified organism(s) The duration of therapy depends on the type of infection Source control: Source control is a key step in controlling any infection. Niduses for ongoing infection include: Indwelling catheters Infected fluid pockets (e.g., an abscess or effusion) Obstructed organs (e.g., pyelonephritis with an obstructing stone or cholangitis) ++Table Graphic Jump LocationTABLE 8.12*Empiric Antibiotic Regimens for Hospitalized Immunocompetent PatientsView Table||Download (.pdf) TABLE 8.12 Empiric Antibiotic Regimens for Hospitalized Immunocompetent Patients Clinical Syndrome Common Pathogen(s) Possible Empiric Antibiotic Regimen* (all are required unless indicated with OR or +/–) Comments Meningitis (community onset, age <50 yr and no immunocompromising condition) Bacteria: Streptococcus pneumoniae Neisseria meningitidis Group B Streptococcus Hemophilus influenzae Viruses: HSV1 VZV vancomycin ceftriaxone (2 g IV q12hr) +/– acyclovir (if HSV encephalitis is suspected) +/– adjunctive corticosteroids (dexamethasone 0.15 mg/kg q6hr) Perform a lumbar puncture (LP) to confirm the diagnosis Do not delay empiric antibiotics if the LP is delayed Immunocompromising conditions include HIV, solid organ or bone marrow ... Your Access profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free a profile for additional features.