發熱性嗜中性球低下

Buzzwords → Dx

Diagnostic Criteria

• Single oral temperature ≥38.3 °C (101 °F) OR temperature ≥38.0 °C (100.4 °F) sustained ≥1 h.
• AND ANC <500/µL OR expected to drop below 500 within 48 h.
• Profound neutropenia: ANC <100/µL.

Workup

• Vital signs + thorough physical (mucositis, lines, perirectal abscess, skin lesions).
• CBC + diff + CMP + LDH + lactate + cultures (blood ×2 from line + peripheral, urine, sputum, wound, throat, stool if diarrhea).
• CXR + procalcitonin (limited use).
• Influenza / RSV / COVID swab in season.
• Galactomannan + β-D-glucan for prolonged fever / risk.
• CT chest + sinus if respiratory symptoms or persistent fever.
• Marrow biopsy if FN persists >7 d unexplained.
• Reassessment q24h with culture/clinical results.

MASCC Risk Score (≥21 = low-risk → outpatient management)

• Burden of illness no/mild symptoms (5)
• No hypotension (5)
• No COPD (4)
• Solid tumor or no prior fungal infection (4)
• No dehydration requiring IV fluids (3)
• Burden of illness moderate symptoms (3)
• Outpatient status (3)
• Age <60 (2)

Treatment Algorithm

flowchart TD
  A[FN within 1 h of presentation] --> B[Cultures + empiric IV antibiotics]
  B --> C{Risk stratification MASCC + clinical}
  C -- low MASCC ≥21 + clinical reliable --> D[Outpatient: ciprofloxacin + amox-clav<br>q4h check + 24-48 h reassess]
  C -- high-risk / unstable --> E[Inpatient IV: cefepime, pip-tazo, or carbapenem]
  E --> F{MRSA risk? mucositis, line, skin SST, unstable}
  F -- yes --> G[+ Vancomycin]
  F -- no --> H[Continue monotherapy]
  G --> I{Persistent fever >4-7 days?}
  H --> I
  I -- yes --> J[+ Antifungal: voriconazole / posaconazole / echinocandin / liposomal amphotericin<br>+ CT chest, GMN, BDG]
  I -- afebrile + ANC recovery --> K[Stop antibiotics<br>typically when ANC >500 + afebrile 48 h]

Pearls / Pitfalls

• Empiric antibiotics within 1 h of presentation — don't wait for cultures or imaging.
• Cefepime / piperacillin-tazobactam / meropenem monotherapy adequate for most; add vancomycin only with MRSA risk.
• Aminoglycoside addition for hemodynamic instability or extended Gram-negative coverage (synergy + resistant organisms); not routine.
• MASCC outpatient management requires reliable patient + access to medical care + telephone monitoring.
• Typhlitis (neutropenic enterocolitis): severe abdominal pain + fever + cecal wall thickening on CT — antibiotics + bowel rest; surgery if perforation or persistent bleeding.
• Catheter-related infection: peripheral / line cultures (differential time to positivity); remove line if S. aureus, Pseudomonas, Candida, MRSA, persistent bacteremia; salvage attempt with antibiotic lock for less-virulent.
• Antifungal escalation by day 4–7 of persistent fever despite broad-spectrum antibiotics — empirical mold coverage in high-risk (acute leukemia, post-HCT).
• PJP classic in HIV / lymphoma / steroid-treated; bilateral interstitial infiltrates; LDH high; treat with TMP/SMX + steroids if PaO₂ <70.
• G-CSF (filgrastim, pegfilgrastim) is adjunct, NOT replacement for antibiotics; reduces duration of neutropenia in high-risk febrile neutropenia (ASCO 2015 guidelines: yes for high-risk FN with infection-related complications).
• Resolution criteria: afebrile ≥48 h + ANC trending up >500. De-escalate antibiotics as cultures finalize.

Cross-references

• Infection prophylaxis post-chemo
• G-CSF / pegfilgrastim
• AML — high FN risk
• HCT — prolonged FN risk
• Drug Regimens — antibiotics + antifungals

相關題目

• Q-181 — Febrile neutropenia — empirical antibiotics within 1 hour
• Q-182 — FN — antifungal escalation timing
• Q-183 — FN — typhlitis (neutropenic enterocolitis)

Sources