Management of Severe Infection

Initial Assessment and Diagnostic Approach

The American Society of Clinical Oncology recommends obtaining at least two sets of blood cultures from different anatomic sites immediately for patients with suspected severe infection and elevated immature granulocytes (IGs) 1, 2
For patients with suspected severe infection, measure procalcitonin or C-reactive protein if the probability of bacterial infection is low-to-intermediate; if high probability, proceed directly to empiric therapy without waiting for biomarkers 2

The Infectious Diseases Society of America suggests initiating combination therapy with anti-pseudomonal β-lactam plus aminoglycoside for suspected gram-negative bacteremia in severely granulocytopenic or septic patients 1, 3, 4
Add vancomycin immediately for septic-appearing patients or when gram-positive pathogens are suspected; if blood cultures remain negative, discontinue after 48-72 hours to reduce cost and toxicity 1, 3, 4

For fever persisting beyond 4-7 days despite broad-spectrum antibiotics, consider empiric amphotericin B for fungal coverage, especially if clinical focus of infection is present or no oral antifungal prophylaxis was given 1, 4, 5
Continue broad-spectrum antibiotics; discontinuation may be associated with fatal bacteremia in febrile neutropenic patients 1, 5, 6, 7

The American College of Physicians recommends a total of 7 days of treatment for patients responding to empiric therapy without microbiological documentation; aminoglycoside can be discontinued earlier in most cases 5, 6, 7
Avoid prolonged antimicrobial treatment without clear indication, as this significantly increases the risk of superinfections, particularly fungemia 1, 5, 7
Repeat complete blood count (CBC) with differential in 2-4 weeks to monitor trends in asymptomatic patients with elevated IGs but no other abnormalities 1