Febrile neutropenia: antibiotics within 60 minutes.
A single fever plus an ANC under 500 is the whole trigger. The first-60-minute workup, antipseudomonal monotherapy, when vancomycin is actually indicated, and the common sources when the usual signs are blunted.
Reviewed June 2026 · verify against current guidelines
Definition & Risk
Define it fast.
Diagnostic criteria
| Fever | Single oral ≥38.3°C (101°F), or ≥38.0°C (100.4°F) for 1 h |
|---|---|
| Neutropenia | ANC <500, or expected to fall below 500 within 48 h |
| Profound | ANC <100 (highest infection risk) |
Risk stratification
- High risk: prolonged (>7 d) profound neutropenia, instability, comorbidity.
- MASCC ≥21 flags low risk; CISNE refines apparently stable patients.
Febrile neutropenia is an emergency.
ANC absolute neutrophil countMASCC / CISNE febrile-neutropenia risk scores
Why The Source Hides
Few neutrophils, few signs.
Blunted inflammation
Without neutrophils there is little pus, often no infiltrate, and minimal exam findings. Fever may be the only clue, cultures are often negative, and no source is found in roughly half of episodes.
Common sources and organisms
| Bloodstream, line | Coag-negative staph, S. aureus, gram-negatives |
|---|---|
| Mucositis | Viridans group streptococci (can cause shock) |
| Gut, perianal | Enteric gram-negatives, anaerobes |
| Lungs | Bacteria; mold (Aspergillus) if prolonged |
| Prolonged FN | Candida, invasive mold |
Gram-positives are the most common isolates, but gram-negatives like Pseudomonas are the most lethal. That is why empiric therapy must cover Pseudomonas.
FN febrile neutropenia
First 60 Minutes
Cultures, then antibiotics.
Draw before the first dose, but don't delay it
- Two blood culture sets: peripheral plus every central line lumen.
- CBC with differential, CMP, lactate, urinalysis and culture.
- Chest imaging if respiratory signs; culture any symptomatic site.
- Exam skin, catheter site, mouth, perianal. No DRE, no rectal temps.
Antibiotics within 60 minutes of presentation. The clock starts at triage.
DRE digital rectal examCMP comprehensive metabolic panel
Empiric Antibiotics
Antipseudomonal monotherapy.
First-line (high risk, inpatient)
| Monotherapy | Cefepime, piperacillin-tazobactam, or a carbapenem (meropenem, imipenem) |
|---|---|
| Penicillin allergy | Aztreonam + vancomycin, or ciprofloxacin + clindamycin |
| Aminoglycoside | Add if unstable or known resistant gram-negatives |
Add vancomycin only for
- Hemodynamic instability or severe sepsis.
- Suspected catheter or skin/soft-tissue infection.
- Pneumonia, or known MRSA colonization.
- Severe mucositis, or gram-positive blood culture pending.
Vancomycin is not routine. Stop it at 48 h if no gram-positive organism. Tailor all choices to prior cultures and local resistance.
MRSA methicillin-resistant Staphylococcus aureus
Pitfalls & Disposition
Where teams slip.
- Delaying antibiotics for the workup or a risk score.
- Reflexive vancomycin: no survival benefit, drives resistance.
- Missing the source: lines, perianal, mucositis, skin.
- Persistent fever past day 4: add empiric antifungal if high risk.
- Stopping antibiotics before the count recovers.
- Steroids can blunt fever; trust vitals and exam even if afebrile.
Low risk, MASCC ≥21: oral ciprofloxacin plus amoxicillin-clavulanate may allow outpatient care.
Sources
Verify against current guidelines and local protocol before acting.
- Freifeld AG et al. Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the IDSA. Clin Infect Dis 2011;52:e56-e93.
- NCCN Clinical Practice Guidelines in Oncology. Prevention and Treatment of Cancer-Related Infections, Version 1.2025.
- Taplitz RA et al. Outpatient Management of Fever and Neutropenia in Adults Treated for Malignancy: ASCO/IDSA Guideline Update. J Clin Oncol 2018;36:1443-1453.
- Klastersky J et al. The MASCC risk index: identification of low-risk febrile neutropenic patients. J Clin Oncol 2000;18:3038-3051.
- Carmona-Bayonas A et al. CISNE: clinical index of stable febrile neutropenia. J Clin Oncol 2015;33:465-471.
- Wingard JR. Overview of neutropenic fever syndromes. UpToDate; literature review through May 2026, topic updated Apr 2026.
Downloads
Every card for this topic — carousels and tables, print-ready for the wards or for sharing.
