Neutropenia and neutrophil disorders: SAQ

This child has febrile severe neutropenia complicating chemotherapy, and he is already showing mottling, so he must be treated as presumed bacteraemic and managed as an emergency in the first hour. The absolute neutrophil count of 0.18 times ten to the ninth per litre sits in the profound-severe band, and his fever of 39.0 degrees Celsius meets the febrile-neutropenia definition. The plan is resuscitation, cultures, and empiric anti-pseudomonal beta-lactam within the first hour, with escalation for his early shock. ^[1]

Question 1 (10 marks)

Outline your immediate management of this child in the first hour, define the severity of his neutropenia, and explain the mechanism-based classification that frames the broader topic. ^[1]

The immediate management is the febrile-neutropenia bundle. Assess airway, breathing and circulation; he is mottled, so recognise early shock, remembering that the signs of sepsis are blunted when the neutrophil count is near zero. Take blood cultures from every lumen of the central line and peripherally, send a urinalysis, and obtain a chest radiograph. Start empiric intravenous anti-pseudomonal monotherapy within the first hour: ceftazidime, piperacillin-tazobactam, cefepime or meropenem, weight-dosed by the local oncology protocol, with vancomycin added for suspected line or soft-tissue infection or haemodynamic instability. Resuscitate shock with isotonic crystalloid boluses of 10 mL per kilogram titrated to perfusion, and escalate to vasoactive support and paediatric intensive care if he does not respond. Maintain oral and perianal hygiene and avoid rectal instrumentation. ^[1]

His neutropenia is severe by definition. Neutropenia is graded by the absolute neutrophil count in three bands: mild 1.0 to 1.5, moderate 0.5 to 1.0, and severe under 0.5, all times ten to the ninth per litre, with infection risk climbing sharply in the severe band and counts under 0.1 considered profound. The absolute neutrophil count is the white cell count multiplied by the percentage of segmented neutrophils plus bands divided by 100. The mechanism-based classification localises the problem to one of four sites: production failure in the marrow (severe congenital neutropenia, marrow infiltration, chemotherapy), peripheral destruction (autoimmune and alloimmune), retention in the marrow (WHIM myelokathexis), or splenic sequestration. This child's mechanism is production failure from chemotherapy. ^[1]