Infectious Diseases
Astra Clinical Library
Infectious diseases
Practical infectious diseases guides for clinical decisions, with cited evidence, testing strategies, and actionable next steps.
38 guides
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Infectious Diseases
Toxic Shock Syndrome
Toxic shock syndrome is a rapidly progressive toxin-mediated shock syndrome from Staphylococcus aureus or group A Streptococcus. Treat suspected disease before surveillance criteria are complete: resuscitate, obtain cultures, remove or debride the source, and provide pathogen-directed antitoxin therapy.Infectious Diseases
Meningitis
Suspected acute meningitis requires parallel stabilization, prompt blood cultures and lumbar puncture when safe, and immediate empiric therapy without diagnostic delay. Cerebrospinal fluid interpretation, targeted molecular testing, host factors, and neuroimaging indications determine etiologic treatment, public-health actions, and surveillance for delayed neurologic sequelae.Infectious Diseases
Acute Pyelonephritis
Acute pyelonephritis requires prompt distinction from uncomplicated lower urinary infection and obstructed upper-tract infection. The supplied results do not contain a pyelonephritis-specific guideline, antimicrobial regimen, imaging pathway, or disposition criteria; treatment decisions require current dedicated guidance and local susceptibility data.Infectious Diseases
Septic Arthritis
A hot, swollen, acutely painful joint requires urgent evaluation for septic arthritis regardless of fever, peripheral blood tests, or initial microbiology. Prompt synovial-fluid sampling, blood cultures, antimicrobial therapy, and early orthopedic source-control assessment are central to preventing irreversible joint injury.Infectious Disease
HIV and AIDS
HIV care hinges on prompt laboratory diagnosis, immediate linkage to antiretroviral therapy, durable viral suppression, and prevention services for patients and partners. This review focuses on diagnostic interpretation, acute infection, transmission prevention, PrEP, and clinically meaningful immune monitoring.Neurology and Infectious Diseases
Herpes Simplex Encephalitis
Herpes simplex encephalitis requires immediate recognition and IV acyclovir while cerebrospinal fluid HSV PCR establishes the diagnosis. Renal-adjusted dosing, hydration, and surveillance for virologic versus autoimmune relapse are the highest-yield management decisions supported by the available evidence.Neonatology and Pediatric Infectious Diseases
Neonatal Meningitis
Neonatal meningitis requires prompt cerebrospinal fluid evaluation and hospital-based empiric antimicrobial therapy because clinical findings are nonspecific, culture sensitivity falls after antibiotics, and delayed recognition risks death and neurodevelopmental disability.Infectious Diseases
Arboviral Encephalitis
Arboviral encephalitis requires early syndromic stabilization, empiric acyclovir while treatable causes are evaluated, and epidemiologically targeted serology coordinated with public health laboratories. Interpretation is complicated by flavivirus antibody cross-reactivity and impaired humoral responses in B-cell-depleted patients.Cardiology and Infectious Diseases
Infective Endocarditis
Manage suspected infective endocarditis by obtaining diagnostic blood cultures before antibiotics, defining valve or device involvement with staged imaging, identifying heart failure or uncontrolled infection requiring urgent surgery, and tailoring antimicrobial therapy to microbiology with documented culture clearance.Cardiology and Infectious Diseases
Prosthetic Valve Endocarditis
Prosthetic valve endocarditis requires early culture-directed evaluation, transesophageal echocardiography, and selective CT or FDG-PET/CT to detect occult paravalvular infection and define urgency for valve surgery.Cardiology and Infectious Diseases
Infective Endocarditis Prophylaxis
Use a two-step decision: identify patients at highest risk of adverse endocarditis outcomes, then determine whether the planned dental procedure manipulates gingiva, periapical tissue, or oral mucosa. Give one preprocedure antibiotic dose only when both conditions are met.Infectious Disease
Latent Tuberculosis
Target testing to patients at increased risk, exclude active tuberculosis before treatment, and preferentially use short-course rifamycin-based regimens after resolving clinically consequential drug interactions and monitoring requirements.Pediatric Infectious Disease
Tuberculosis in Children
A practical approach to pediatric tuberculosis centers on separating exposure, infection, and disease; obtaining microbiologic confirmation whenever feasible; identifying CNS and disseminated disease urgently; and matching treatment to disease severity, susceptibility, age, and the likely source-case resistance pattern.Infectious Diseases
Cellulitis
Manage presumed cellulitis by first excluding a drainable abscess and necrotizing infection, then matching antibiotics to purulence, systemic severity, and MRSA risk. Most uncomplicated nonpurulent cases require streptococcal coverage, source-control assessment, and reassessment within 48 hours.Infectious Diseases
Osteomyelitis
Osteomyelitis management depends on anatomic syndrome, microbiologic confirmation, source control, and a feasible antimicrobial route. In diabetic foot disease, probe-to-bone, radiography, MRI, and bone biopsy guide diagnosis; selected patients can receive medical therapy or conservative bone resection.Infectious Diseases and Preventive Medicine
COVID-19 Vaccine
Use the current-season COVID-19 vaccine to restore protection against circulating SARS-CoV-2, then prioritize a second dose for adults 65 years or older and people with moderate or severe immunocompromise at 6 months, with individualized additional dosing for immunocompromised patients.Pulmonary and Infectious Disease
Community-Acquired Pneumonia
A decision-focused approach to confirming community-acquired pneumonia, selecting site of care, identifying severe disease and resistant-pathogen risk, obtaining targeted microbiology, and reassessing response when initial therapy fails.Infectious Diseases
Pneumocystis jirovecii Pneumonia
Pneumocystis jirovecii pneumonia requires rapid risk-based recognition, respiratory severity assessment, organism-directed testing, and early TMP-SMX. In HIV, hypoxemia determines adjunctive corticosteroid use; in non-HIV immunosuppression, diagnostic uncertainty and the corticosteroid benefit-risk balance require individualized decisions.Infectious Diseases
Sexually Transmitted Infections
Use exposure-site testing, syndrome-directed empiric treatment when indicated, pregnancy-specific screening, partner management, and targeted prevention to interrupt transmission while preventing pelvic inflammatory disease, adverse pregnancy outcomes, and neonatal infection.Infectious Diseases
Influenza
A decision-focused approach to influenza testing, empiric antiviral treatment, agent selection, chemoprophylaxis, and outbreak control, emphasizing patients in whom treatment should not await confirmatory testing and those for whom testing changes management.Infectious Diseases
Clostridioides difficile Infection
Diagnose clinically meaningful infection only in patients with new unexplained diarrhea, rapidly identify fulminant disease, select fidaxomicin or vancomycin by episode and severity, and prevent recurrence with risk-directed adjunctive and microbiota-based strategies.Infectious Diseases
Lyme Disease
Diagnose Lyme disease from syndrome-specific pretest probability, use validated two-tier serology when confirmation changes management, recognize carditis and neurologic emergencies, and select short, manifestation-directed antibiotic courses while avoiding unnecessary prolonged therapy.Pediatrics and Infectious Disease
Hand, Foot, and Mouth Disease
Hand, foot, and mouth disease is usually diagnosed clinically and managed with hydration-focused supportive care. The key physician task is to recognize dehydration, neurologic or cardiopulmonary complications, and mimics requiring lesion PCR, cerebrospinal fluid evaluation, or alternate treatment.Critical Care Medicine and Infectious Diseases
Antibiotic De-escalation in Sepsis
For patients started on empiric broad-spectrum therapy for suspected sepsis, reassess infection likelihood, microbiology, source control, and clinical trajectory at 48–72 hours to stop unnecessary treatment, narrow active therapy, and use serial procalcitonin selectively to shorten exposure.Infectious Diseases and Pulmonary Medicine
MRSA Nasal Screening for Pneumonia
Use MRSA nasal PCR or swab testing to narrow empiric anti-MRSA therapy in pneumonia when pretest risk is meaningful, while obtaining respiratory cultures in severe disease. A negative screen supports early withdrawal of MRSA coverage; a positive screen does not establish MRSA pneumonia.Infectious Diseases
Complicated UTI Antibiotic Selection
Select empiric therapy after obtaining urine culture, triage for systemic illness and obstruction, then narrow to susceptibility-directed treatment. For clinically improving adults receiving effective therapy, 5–7 days of a fluoroquinolone or 7 days of a nonfluoroquinolone is generally preferred over 10–14 days.Emergency Medicine and Infectious Diseases
Pyelonephritis Imaging Indications
Do not image a first, uncomplicated presentation of acute pyelonephritis. Obtain urgent imaging when obstruction, severe illness, high-risk host factors, or failure to improve raises concern for a drainable or gas-forming complication.Infectious Diseases
Cellulitis Antibiotic Selection
Select therapy by first separating nonpurulent cellulitis from abscess-associated infection, then matching route and spectrum to systemic illness, MRSA risk, immune status, source control needs, and clinical response after 48 hours.Infectious Diseases and Orthopedic Surgery
Native Joint Septic Arthritis
Manage suspected native joint septic arthritis as a drainage-and-antibiotic emergency: obtain blood and synovial cultures immediately, start empiric intravenous therapy after sampling unless sepsis mandates earlier treatment, and arrange urgent source control based on joint, purulence, clinical trajectory, and structural damage.Infectious Diseases
Meningitis Empiric Antibiotic Selection
Choose empiric therapy by acquisition setting, age, immune status, and neurosurgical hardware exposure; obtain blood cultures and CSF promptly, but do not delay antibiotics for imaging or lumbar puncture when either will defer treatment.Hematology-Oncology and Infectious Diseases
Neutropenic Fever Antibiotics
Select empiric therapy immediately after cultures by separating unstable or prolonged profound neutropenia from clinically stable low-risk presentations, then individualize coverage for resistant Gram-negative colonization, suspected focus, and indications for anti-MRSA or antifungal escalation.Infectious Diseases
Community-Acquired Pneumonia Antibiotics
Select empiric community-acquired pneumonia therapy by site of care, severity, comorbidity, and validated MRSA or Pseudomonas risk—not by obsolete healthcare-associated pneumonia categories. Obtain targeted microbiology before broad therapy when results can support de-escalation or define treatment duration.Infectious Diseases
Clostridioides difficile Treatment Selection
Select therapy after confirming clinically compatible toxin-mediated disease, classify nonfulminant versus fulminant illness, favor fidaxomicin when feasible, use vancomycin when access or severity dictates, and add recurrence-prevention strategies for patients with prior episodes or high-risk features.Infectious Diseases and Cardiology
Endocarditis Blood Culture Strategy
Obtain adequately collected peripheral blood cultures before antibiotics whenever clinical stability permits, then use pathogen, initial culture burden, clearance, and imaging to determine whether endocarditis evaluation must escalate.Infectious Diseases
Staphylococcus Aureus Bacteremia Workup
Treat every Staphylococcus aureus blood culture as a potential endovascular or metastatic infection: document clearance, identify and control the source, evaluate for endocarditis, and reserve 14-day therapy for patients meeting every uncomplicated-bacteremia criterion.Infectious Diseases
Impetigo
Manage typical impetigo clinically with lesion-directed therapy, reserving culture for atypical, recurrent, or outbreak-associated disease. Use topical treatment for limited disease, oral therapy for numerous lesions or transmission control, and identify ecthyma because it requires systemic treatment.Infectious Diseases