Neutropenia

Introduction

Neutropenia is defined as the absolute neutrophil count (ANC) of <1.5 x 109/L, with the exception of neonates within the first week of life and infants where the lower limit of normal is 5.0 x 109/L and 1.0 x 109/L, respectively. 

Neutropenia is categorised as:

• Mild – ANC 1.0-1.5 x 109/L
• Moderate – ANC 0.5-1.0 x 109/L
• Severe – ANC <0.5 x 109/L

The causes of neutropenia are numerous and generally divided into those acquired and congenital. Detailed description of various causes of neutropenia is beyond the scope and purpose of the guideline and is listed below for completeness. 

Acquired

• Post-infectious
• Auto-immune
  • Benign Neutropenia of Infancy and Childhood
  • Systemic (i.e. SLE)
• Nutritional
  • Vitamin B12, Folate, Vitamin D
  • Copper
• Drug induced
• Hypersplenism
• Marrow infiltration
  • Primary disease (i.e. leukaemia)
  • Secondary disease (metastatic neuroblastoma)

Congenital

• Severe congenital neutropenia
• Cyclical neutropenia
• Inherited bone marrow failure syndromes

One of the most common types of neutropenia within the paediatric population is Benign Neutropenia of Infancy and Childhood, most often seen amongst children <3 years of age and usually associated with mild to moderate neutropenia. This transient auto-immune condition is likely to resolve within two to three years of onset. 

Benign familial (ethnic) neutropenia is often mild and asymptomatic and is present in certain ethnic backgrounds such as African and Middle Eastern.  

Pre-referral investigations

Pre-referral investigations should include the following:

• General examination (lymphadenopathy, hepatosplenomegaly)
• Personal and family history
• FBC and blood film – preferably more than one
• ESR, CRP
• ANA
• LFT, UEC
• Vitamin B12, folate, Vitamin D 

Pre-referral management

Neutropenia is associated with an increased risk of potentially serious infections, proportionately increased with lower ANC. Signs and symptoms can be minimal and often limited to raised temperature.

Any child with a fever (defined as T ≥38.5°C, or two isolated T 38.0-38.5°C within 12 hours) and neutropenia should immediately present to the nearest emergency department for evaluation and likely admission for intravenous broad spectrum antibiotics. This is of particular importance in children and adolescents with moderate and severe neutropenia.

When to refer

If there are signs of sepsis, send the child to the nearest Emergency Department immediately.

Any child with isolated moderate or severe neutropenia on more than one occasion should be referred for a specialist assessment. 

Children <3 years of age with mild neutropenia can be considered for a follow up in the community as they are usually asymptomatic and likely to recover. 

Patients with mild presumed familial (ethnic) neutropenia do not require a referral, provided they have not had severe and/or recurrent infections. 

Consultation with the on-call PCH Haematologist (available through PCH Switch on 6456 2222) is recommended, particularly in cases that are borderline and possibly cross specialities such as Haematology, Oncology and Rheumatology. 

How to refer

• Routine non-urgent referrals from a GP or a Consultant should go to the Central Referral Service
• Routine non-urgent referrals from a nurse practitioner, non-medical referrers or private hospitals go to the PCH Referral Office
• Urgent referrals (less than seven days) are made via the PCH Referral Office.

Essential information to include in your referral

Please make sure that you include the following: 

• History leading to presentation with neutropenia
• Detailed description of examination 
• Relevant family history
• Results of required (and any additional relevant) blood tests
• Any other related investigations (i.e. abdominal ultrasound).

Useful resources

• How to approach neutropenia - American Society of Haematology
• Febrile and suspected or confirmed neutropenia - ChAMP Guideline

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