Neutropenic Fever (Febrile Neutropenia)

Sepsis & Nonfocal

Patient + scenario modifiers

Patient

Clinical scenario / source

Annotations only — chart still shows the full chemistry of each drug.

1. Clinical Syndrome

Fever in a neutropenic host: single temp ≥38.3°C OR ≥38.0°C sustained ≥1 h, AND ANC <500/mm³ (or <1000 with predicted decline to <500 within 48 h). Even one fever in this setting is a medical emergency — gut/skin barrier failure + functional immune defect → rapid gram-negative or staphylococcal bacteremia → shock within hours.

Risk-stratify with MASCC:

High-risk (MASCC <21, or any of: anticipated ANC <100 for >7 d, significant comorbidity, hemodynamic instability, oral intolerance, line infection, pneumonia, hepatic/renal dysfunction): IV antibiotics + admission.
Low-risk (MASCC ≥21, expected neutropenia <7 d, no comorbidities, hemodynamic stable, reliable 24/7 outpatient access): oral antibiotics may be considered.

Distinct from sepsis (unknown source): empiric anti-pseudomonal coverage is mandatory from minute one, regardless of source.

2. Pathogens

Consider the patient: Underlying malignancy (heme vs. solid), regimen (high-dose chemo → deep neutropenia; allo-HSCT → prolonged neutropenia + GVHD + steroids → mold risk), prophylaxis on board (fluoroquinolone, fluconazole, posaconazole, TMP-SMX for PCP, acyclovir for HSV), prior MDRO (ESBL, VRE, MRSA, Pseudomonas), known colonization, indwelling lines, mucositis severity, recent corticosteroids.

Consider the case: Source-suggestive findings — catheter-site erythema, perirectal pain (DO NOT do DRE — bacteremia risk; inspect externally), abdominal pain → typhlitis / neutropenic enterocolitis, sinus pain → mold, focal pulmonary findings → aspergillus / nocardia / PJP. Most episodes are clinically undocumented; blood cultures positive in only ~30%. Coagulase-negative staphylococci (CoNS) and viridans group streptococci (mucositis → bacteremia → shock + ARDS) are major line/mucositis pathogens but not seeded here — track via blood-culture results.

Common

- Escherichia coli
  Gut translocation — most common gram-negative.
- Klebsiella pneumoniae
  Gut translocation; check for ESBL if prior FQ prophylaxis or known colonization.
- Pseudomonas aeruginosa
  Empiric coverage mandatory — high mortality with delayed therapy.
- Staphylococcus aureus (MSSA)
  Line, skin breakdown, mucositis.
- Staphylococcus aureus (MRSA)
  Add empiric vancomycin only for specific triggers — see below.

Less common

- Enterococcus faecalis
  Gut translocation, particularly under cephalosporin pressure.
Fungal
- Candida albicans
  Persistent fever >4 d on broad-spectrum → empiric antifungal.
- Candida glabrata (Nakaseomyces glabratus)
  Breakthrough on fluconazole prophylaxis — use echinocandin.
- Aspergillus fumigatus
  Prolonged neutropenia (>10 d), HSCT, GVHD on steroids → mold-active azole.

3. Empiric Therapy

Tier	First choice	Alternatives	Duration	Comments
Outpatient	750 mg · BID · PO 875 mg · BID · PO	750 mg · BID · PO + clindamycin 600 mg q8h PO if true PCN allergy.	Until afebrile ≥48 h AND ANC >500 trending up	MASCC ≥21 ONLY. Patient must have reliable transport, 24/7 phone, caregiver, no oral intolerance, and rapid IV escalation pathway. NOT for prior FQ prophylaxis (FQ resistance), prior pseudomonas, or any hemodynamic concern.
Admitted to ward	2 g · q8h · IV	4.5 g · q6h (or q8h extended infusion) · IV Equivalent monotherapy; also covers anaerobes (mucositis, perirectal). Watch AKI signal vs vanc. 1 g · q8h · IV Reserve for prior ESBL, critically ill, or β-lactam failure.	Reassess at 72 h; continue until afebrile ≥48 h AND ANC >500 with recovery trajectory.	Standard high-risk monotherapy. Do NOT routinely add vancomycin — Cochrane meta-analysis: no mortality benefit, more nephrotoxicity. Add vanc only per triggers below.
Admitted to ICU	4.5 g · q6h · IV 25–30 mg/kg load, then AUC dosing · q8–12h · IV	1 g · q8h · IV + vancomycin. Substitute pip-tazo if prior ESBL, septic shock, or recent broad-spectrum exposure. 5–7 mg/kg · q24h · IV ADD for double GN coverage if septic shock + prior pseudomonas / MDRO history. Amikacin preferred in oncology centers — substitute when seeded. Monitor levels + audiometry.	Reassess at 72 h with cultures; narrow as data return.	Hemodynamic instability, septic shock, suspected line infection, pneumonia, severe mucositis, or known MRSA colonization. Send galactomannan + β-D-glucan early and consider empiric antifungal if persistent fever expected (see triggers).

Add coverage if:

MRSA coverage

Hemodynamic instability / septic shock
Clinically suspected catheter-related infection
Skin or soft-tissue infection
Pneumonia
Severe mucositis (high-dose ara-C, conditioning regimens)
Known MRSA colonization or prior MRSA infection
Gram-positive cocci in clusters on blood culture pending speciation

Add:

25–30 mg/kg load, then AUC dosing · q8–12h · IV

Reassess at 48 h — discontinue if cultures negative for resistant gram-positives. Linezolid 600 mg q12h IV/PO or daptomycin 6–8 mg/kg q24h IV are alternatives if vanc-intolerant or VRE concern. Daptomycin NOT for pneumonia (surfactant inactivation).

Anaerobe coverage

Severe necrotizing mucositis
Perirectal cellulitis / abscess
Suspected intra-abdominal source (typhlitis / neutropenic enterocolitis)

Add:

500 mg · q8h · IV
Already covered by pip-tazo or meropenem. Add ONLY if using cefepime or aztreonam monotherapy.

Pip-tazo and carbapenems cover anaerobes — no metronidazole needed. Typhlitis: bowel rest, IV fluids, broad-spectrum + anaerobic coverage; surgery rarely required unless perforation.

4. Directed Therapy

Pivot to source-specific therapy as data return:

Gram-negative bacteremia: narrow to susceptibilities (ceftriaxone, cefepime, or carbapenem for ESBL); 7–14 days typical, longer if endovascular
MSSA bacteremia: cefazolin or nafcillin; rule out endocarditis (TTE/TEE), durable focus → ≥14 d
MRSA bacteremia: vancomycin or daptomycin (NOT pneumonia); ≥14 d, longer with metastatic focus
Viridans strep / α-strep bacteremia (mucositis): add vancomycin urgently — can cause shock + ARDS in neutropenic patients
Candidemia: echinocandin (micafungin 100 mg IV q24h) until speciation; line removal within 24–72 h; ophtho exam for chorioretinitis; treat ≥14 d after first negative blood culture
Aspergillus / invasive mold: voriconazole (load 6 mg/kg q12h × 2, then 4 mg/kg q12h IV) — isavuconazole or liposomal ampho B alternatives. Tissue / BAL galactomannan when possible.
Culture-negative + clinical improvement: continue broad-spectrum until afebrile ≥48 h AND ANC >500 with recovery trajectory. Do NOT routinely escalate or change drugs purely for persistent fever in a clinically improving patient.

5. Monitoring

Daily: vital signs, fever curve, ANC + CBC, focused exam (line site, perirectum (inspect — no DRE), oropharynx, lungs, abdomen), repeat blood cultures if persistent fever or positive cultures at 48 h.

Persistent fever >4 days on broad-spectrum + expected prolonged neutropenia: send galactomannan (serum, BAL if intubated), β-D-glucan, fungal blood cultures; HRCT chest (halo / reversed halo / nodules), sinus imaging if facial pain; consider empiric antifungal (micafungin OR voriconazole — mold-active if prolonged neutropenia / HSCT / steroids).

Toxicity: vancomycin AUC + daily Cr; aminoglycoside trough + audiometry; cefepime mental status (especially renal impairment — NCSE on EEG); voriconazole levels + LFTs + visual disturbance check; QTc on fluoroquinolones.

Stop antibiotics: afebrile ≥48 h + ANC >500/mm³ trending up + cultures negative + no identified source (or source-directed course completed). Some centers stop based on clinical recovery alone before ANC recovery (IDSA 2018 update — supported but controversial).

Pearls

One fever = full work-up. Even an asymptomatic-feeling patient with ANC <500 + temp 38.3°C needs blood cultures (peripheral + each lumen) + lactate + broad-spectrum abx within 1 hour. Empiric anti-pseudomonal coverage is non-negotiable.

MASCC score ≥21 = low risk — some centers send home on oral cipro + amox-clav; most still admit. Outpatient management requires strict adherence + 24/7 reliable contact.

Don't routinely add vanc in stable patient — Cochrane: no mortality benefit, more AKI. Reserve vanc for specific triggers.

Catheter management: keep tunneled line + treat through UNLESS tunnel infection, port pocket infection, septic emboli, persistent bacteremia >72 h on appropriate abx, OR specific pathogens: S. aureus, P. aeruginosa, Candida, atypical mycobacteria, B. cereus. Then remove.

Don't do a DRE in profound neutropenia — bacteremia risk. Inspect externally instead.

G-CSF doesn't shorten the febrile episode but speeds ANC recovery; ASCO supports it as primary prophylaxis for regimens with >20% expected FN rate.

Beware viridans strep / α-strep bacteremia in severe mucositis — empiric vanc until cleared; can cause shock + ARDS.

Step 3 association: know MASCC, know that monotherapy = standard, know which pathogens / findings trigger line removal, know when to escalate to mold-active antifungal.