01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Cytotoxic and targeted treatments disrupt marrow and mucosal barriers. Endogenous gut and oral flora, skin organisms and line pathogens can enter the bloodstream while the inflammatory response is blunted. Risk depends on depth and anticipated duration of neutropenia, mucositis, cancer type, treatment intensity, organ function and previous resistant organisms. A patient may become hypotensive without a high temperature, especially after corticosteroids or antipyretics, so recent anticancer treatment is a triage signal.
The first-hour pathway is deliberately parallel. Assess airway, breathing, circulation and mental state; obtain blood cultures from peripheral and each relevant line lumen, count, kidney and liver function, CRP and lactate; examine mouth, skin, line, lungs, abdomen and perianal region without rectal instrumentation. Start broad intravenous cover immediately. Chest radiography follows respiratory symptoms, but CT may be needed in prolonged fever because neutropenic pulmonary infection can be radiographically subtle.
After stabilisation, refine care. Review previous cultures, prophylaxis and colonisation, then adjust for allergy, renal function and local resistance. Repeat lactate and observations after resuscitation. A validated score such as MASCC can support low-risk classification, but exclusions and local oncology infrastructure matter; outpatient treatment requires reliable oral absorption, support, rapid return and documented review. Persistent fever with anticipated prolonged neutropenia prompts fungal assessment rather than endless antibacterial additions.
Key points
- Any unwell patient receiving or recently receiving systemic anticancer therapy should be assessed for neutropenic sepsis even without fever.
- Profound neutropenia suppresses local inflammatory signs; malaise, rigors, confusion, diarrhoea, mouth pain, line discomfort or hypotension may be the presentation.
- Record ABCDE observations, venous access, lactate, full count, renal and liver function and cultures, but diagnostic sampling must not delay empirical treatment.
- NICE recommends piperacillin with tazobactam as initial intravenous empirical monotherapy unless patient-specific or local microbiological contraindications require another regimen.
- Do not routinely add an aminoglycoside to initial therapy because toxicity outweighs benefit unless a specific microbiological or local indication exists.
- Do not routinely add a glycopeptide solely because a central venous access device is present; add targeted cover for compatible infection or resistant-organism risk.
- Remove or control an infected line, abscess, obstructed urinary tract or other source with the relevant team while antimicrobials continue.
- Use a validated risk tool and experienced clinical assessment after initial treatment, not visual wellness alone, to select inpatient, step-down or outpatient care.
- Persistent or recurrent fever during prolonged profound neutropenia raises invasive fungal disease and requires specialist imaging, biomarkers and mould-active therapy planning.
- Antibiotic review uses cultures, response, neutrophil trajectory, organ function and source; defervescence alone does not answer every duration or discharge question.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Treatment-related marrow suppression
Cytotoxic chemotherapy and some targeted or immune therapies reduce neutrophil production, with a regimen-specific nadir that creates a predictable but individually variable infection window.
Mucosal and device entry
Chemotherapy-damaged oral and gastrointestinal mucosa and central venous devices permit endogenous or skin organisms to cross barriers when neutrophil containment is weak.
Prolonged immune compromise
Acute leukaemia, transplantation, corticosteroids and prior antimicrobials extend risk beyond neutrophils and select invasive fungi and resistant bacteria.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Blunted local response
Low neutrophil recruitment reduces pus, consolidation and erythema, allowing infection to spread before a recognisable anatomical focus appears.
- 2Rapid bloodstream invasion
Barrier breach permits bacterial translocation and line-associated bacteraemia, which can progress from vague malaise to vasodilatory shock over hours.
- 3Selection under antibiotics
Prior prophylaxis and repeated broad-spectrum exposure suppress susceptible flora and increase the probability of resistant Gram-negative, Gram-positive or fungal disease.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Temperature above 38°C with neutrophils at or below 0.5 × 10^9/L after anticancer treatment meets the NICE diagnostic threshold.
Hypotension, confusion, tachypnoea or rigors after treatment remains neutropenic sepsis despite a normal or suppressed temperature.
Tenderness, discharge, tunnel pain or differential culture timing can suggest catheter infection, although the insertion site may look normal.
Raised lactate, mottling, oliguria or falling pressure requires immediate sepsis resuscitation and critical-care escalation.
Persistent fever after broad antibiotics during prolonged neutropenia, pleuritic pain or CT nodules raises invasive mould disease.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Full count with differentialFirst step - Why
- Confirm neutropenia and accompanying marrow suppression.
- Interpretation and limitations
- Treatment must not wait for the result in a clinically suspected case; anticipated duration influences fungal and disposition planning.
- 02
Blood cultures - Why
- Identify bloodstream and line-associated organisms.
- Interpretation and limitations
- Take peripheral and relevant line-lumen cultures before antibiotics if immediately available; never postpone the first dose for difficult sampling.
- 03
Lactate, renal and liver profile - Why
- Assess tissue hypoperfusion and antimicrobial safety.
- Interpretation and limitations
- Repeat elevated lactate after resuscitation and adjust doses to changing organ function without under-treating septic shock.
- 04
Source-specific microbiology - Why
- Sample urine, respiratory, stool, skin or mucosal sites from symptoms.
- Interpretation and limitations
- Avoid routine rectal examination or instrumentation during profound neutropenia; colonisation results require clinical interpretation.
- 05
Chest radiograph or CT - Why
- Investigate respiratory symptoms and occult fungal disease.
- Interpretation and limitations
- Initial radiography may be normal; early CT is more sensitive when prolonged neutropenia and persistent fever raise mould risk.
- 06
Fungal biomarkers - Why
- Support investigation of invasive fungal infection in selected high-risk patients.
- Interpretation and limitations
- Galactomannan or beta-D-glucan performance depends on host, prophylaxis and assay; combine with CT, microbiology and specialist review.
- 07
Validated risk assessment - Why
- Support disposition after immediate empirical treatment.
- Interpretation and limitations
- MASCC or a locally validated tool supplements clinical judgement and cannot make shock, poor support or unreliable review suitable for outpatient care.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Treatment-related fever
Transfusion, growth factor, medicine reaction and cytokine-release syndromes can cause fever, but infection must be treated initially when neutropenia and sepsis remain plausible.
Tumour fever
Malignancy can produce recurrent fever without infection, yet this is a diagnosis reached after urgent empirical cover and structured exclusion in a neutropenic patient.
Viral infection
Respiratory and systemic viruses may be the primary source and influence isolation or antiviral treatment but do not exclude bacterial coinfection.
Thromboembolism
Pulmonary embolism or catheter thrombosis can cause fever, tachycardia and hypoxia and should be evaluated when the clinical pattern remains discordant.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01First hourCulture quickly and treat immediatelyFirst stepRecent anticancer treatment accompanies fever or clinically significant sepsis features.+
- 1Use ABCDE, obtain cultures, lactate, count and organ tests, examine likely portals and begin resuscitation without waiting for a documented neutrophil result.
- 2Give local empirical intravenous antibiotics immediately, using piperacillin with tazobactam monotherapy when NICE criteria and patient microbiology permit.
- 3EscalationEscalate shock, hypoxia, altered consciousness or rising lactate to critical care and pursue source control in parallel with antimicrobial delivery.
02Early reviewRefine cover from risk and sourceInitial antibiotics are given and the first response and results become available.+
- 1Review observations, lactate, cultures, organ function, allergies, previous resistant organisms, prophylaxis and treatment nadir with oncology and microbiology.
- 2Add glycopeptide, aminoglycoside or resistant-organism cover only for a defined clinical or microbiological reason and document the review point.
- 3Use validated risk assessment to select continued admission or a supported low-risk pathway, ensuring reliable review and rapid return access.
03Persistent feverSearch beyond routine bacteriaFever persists or recurs during prolonged profound neutropenia despite appropriate antibacterial treatment.+
- 1Repeat focused examination and cultures and obtain early chest CT and fungal biomarkers according to haematology risk and current prophylaxis.
- 2Discuss mould-active empirical or pre-emptive therapy with infection and haematology specialists, accounting for azole exposure and organ interactions.
- 3Review lines, abscess, drug fever, viral infection and tumour fever rather than layering indefinite antibiotics without a new hypothesis.
Key medicines and prescribing safety3 treatments · regimens, roles and cautions+
Piperacillin with tazobactam
First-line agent: NICE recommends piperacillin with tazobactam as initial empirical intravenous beta-lactam monotherapy unless patient-specific or local microbiological factors contraindicate it. Licensed adult febrile-neutropenia regimen with normal renal function: piperacillin 4 g/tazobactam 0.5 g intravenously every 6 hours. Follow the current local neutropenic-sepsis protocol and adjust dose or interval for renal function and the adopted infusion policy.Review immediate beta-lactam allergy, renal function, sodium load, cytopenia and resistant-organism history; a prior non-severe rash requires precise assessment rather than automatic inferior cover.
Alternative empirical regimen
Microbiology selects a local intravenous beta-lactam or combination regimen immediately for severe allergy, resistant colonisation or a source not covered by standard monotherapy.Avoid routine aminoglycoside or glycopeptide exposure without indication; monitor renal, auditory, marrow, QT and drug-interaction risks of the selected agents.
Mould-active antifungal treatment
Infection and haematology specialists choose product-specific intravenous or oral dosing from CT, biomarkers, prior prophylaxis, organism probability, organ function and interactions.Azoles interact with many anticancer medicines and prolong QT, while amphotericin causes renal and electrolyte toxicity; obtain diagnostic evidence without delaying unstable-patient treatment.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Septic shock
Vasodilation, capillary leak and organ hypoperfusion can develop rapidly with few local signs, requiring immediate fluids, vasopressors and critical-care involvement.
Invasive fungal disease
Persistent prolonged neutropenia permits Aspergillus and other mould invasion of lung, sinus or disseminated sites, sometimes despite a normal initial radiograph.
Organ-toxic treatment
Antimicrobial combinations can cause kidney, liver, marrow, QT and neurological injury, particularly when empirical escalation lacks daily indication review.
Delayed anticancer therapy
Severe infection and prolonged cytopenia interrupt cancer treatment, making prevention, growth-factor strategy and regimen reassessment part of recovery planning.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Repeat early-warning observations and lactate after initial resuscitation, increasing frequency during any haemodynamic or respiratory instability.
- Review cultures at least daily and communicate resistant or line-associated growth immediately for isolation, source-control and antibiotic changes.
- Track neutrophil trajectory, expected nadir, renal and liver function to adjust antimicrobial dose and anticipate duration of risk.
- Inspect mouth, skin, line, lungs and abdomen repeatedly; avoid rectal instrumentation and recognise that new signs may appear during count recovery.
- Assess antimicrobial adverse effects and remove unnecessary duplicate coverage at formal 24- to 48-hour multidisciplinary review.
- Before discharge document risk classification, oral absorption, support, thermometer, emergency number, medicines and the exact return triggers.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
Fever is not required
Corticosteroids, antipyretics and absent neutrophils can blunt temperature, so sepsis physiology after treatment still activates the pathway.
A line is not an indication
Central access alone does not justify routine glycopeptide; clinical infection, culture or resistant risk should drive addition.
Low risk is constructed
A score, stable physiology, reliable support, absorption and rapid oncology access together make outpatient treatment possible.
Persistent fever changes ecology
Prolonged profound neutropenia and antibacterial exposure shift concern toward moulds and resistant organisms requiring a new diagnostic strategy.
11Common pitfallsFrequent interpretation and management errors.
- 01
Waiting for the neutrophil result before antibiotics.
- 02
Excluding sepsis because the temperature is normal.
- 03
Adding aminoglycoside routinely to every regimen.
- 04
Adding glycopeptide solely for a central line.
- 05
Calling a patient low risk from appearance alone.
- 06
Repeating plain radiography while missing fungal CT disease.