Febrile Neutropaenia

Kajanan Nithiyananthan -

High-Yield Tips

  • Patients have (usually) had chemotherapy within past 7-14 days → important to elucidate this information on history.
  • Start tazocin + gentamicin in all patients with ?febrile neutropaenia w/i 1 hour of presentation (ASAP) after obtaining blood cultures.
  • If patient has been given GCSF, it can mask neutropaenia. Similarly, paracetamol can mask fever.
  • Never perform a DRE in a ?FN patient.
  • Giving GCSF in acute setting doesn’t improve mortality but can ↓ duration of hospital stay and ↓ duration of neutropaenia.

Definition

  • Febrile = temperature > 38.3 ℃ (single occasion) OR temperature > 38 ℃ (2 occasions, 1 hour apart).
  • Neutropaenia = absolute neutrophilic count (ANC) < 1.5 cells/litre
  • Note: severe neutropaenia if ANC < 0.5 cells/litre or predicted to drop below this in next 2 hours
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If patient reports a subjective fever at home but there are no recorded fevers in healthcare setting, still proceed through management pathway.
  • TRIAGE 2 MEDICAL EMERGENCY (same as stroke or chest pain)

Aetiology

  • Source of infection identified in only 20-40% of cases

Common sources include:

  • Gastrointestinal, genitourinary, lines (e.g. PICC lines, Portacath), skin, oral ulcers, respiratory tract

Common bacteria include:

  • Pseudomonas, Staphyloccoccus, Streptococcus, E. coli, Klebsiella

Atypical:

  • Atypical bacteria e.g. mycoplasma, legionella
  • Viral/fungal
  • Collection (abscess) e.g. intra-abdominal, spinal
  • Cardiac vegetations → echo

Epidemiology

  • Affects patients 7-14 days post-chemotherapy (this is the nadir i.e. the lowest point of the neutrophil count)
  • Not all chemotherapeutics are equal. Some (e.g. alkylating agents, taxanes) are more likely to kill bone marrow and cause neutropaenia.

Clinical Presentation

History

  • Recent chemo
  • Fever
  • Non-specific symptoms e.g. lethargy, malaise
  • Infective symptoms (respiratory, urinary, GI, cutaneous, intracranial, oral)
  • Vascular devices in-situ

GCSF given post-chemo:

  • Usually given 24h post-chemo in chemotherapy regimens with ↑ likelihood of causing neutropaenia
  • Can mask neutropaenia
  • Pegfilgrastim = long-acting GCSF; filgrastim = short-acting GCSF

Examination

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Pus may not be present as neutrophils are what’re responsible for pus generation.
  • Vitals
  • Source - skin, oral mucosa, vascular devices ENT, eye, further systematic examination
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Never perform DRE in ?FN as it may → ↑ bleeding or can promote bacterial shower into bloodstream.

Management

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Initiate septic pathway.

Investigations

  1. ≥ 2 sets of blood cultures at separate sites (or one from vascular device and one elsewhere) BEFORE Abx
  2. FBC, UEC, CMP, LFT, coags, lactate, procalcitonin, CRP
  3. Urine MCS, stool culture
  4. CXR
  5. Sometimes: skin swab, echo, MRI spine

Empiric antibiotics

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Start Abx within 1 hour of presentation to reduce mortality rates.
  1. In HNELHD:
    • w/o penicillin allergy → tazocin (piperacillin + tazobactam) 4.5g IV + gentamicin 5-7 mg/kg IV
    • w/ mild penicillin allergy → ceftazidime + gentamicin
    • w/ severe penicillin allergy (anaphylaxis) → meropenem + gentamicin
    • In any of the above, consider adding vancomycin if suspected line sepsis (i.e. the source is an indwelling line e.g. PICC line, Portacath)
    • Note: check eTG or HealthPathways prior to prescribing antibiotics until you feel comfortable with the specific medications
  2. Fluid resuscitation.
  3. Target Abx after culture results return.
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Don’t chart regular paracetamol (can mask fever) just use PRN.

Ongoing Management

  1. If fever persists > 24h → repeat septic screen (look for source)
  2. If fever persists > 48-72h → broaden Abx coverage and repeat septic screen (include imaging to detect abscesses)
  3. If fever persists > 72h, consider discussion with Infectious Diseases.