Pediatric Pearls: Neutropenia May Not Need Subspecialist Interventions

Your patient recently underwent a routine complete blood count (CBC) which showed an absolute neutrophil count of less than 1500/mL. No other abnormalities were present on the CBC.

How would you advise your patient?

(Answer and discussion on next page)

Brittany Perry, DO, is a pediatrician at Nemours/Alfred I. duPont Hospital for Children in Wilmington, Delaware.

A complete blood count (CBC) is a common laboratory test ordered by primary care providers to screen for various conditions in pediatrics. Results may show that a child has isolated neutropenia, defined as an absolute neutrophil count (ANC) of less than 1500/mL, with no other abnormalities on CBC. The etiology of neutropenia may be benign or may indicate a chronic problem. After neutropenia is found on routine CBC, a provider must determine next steps in management with many providers opting to refer patients to a pediatric hematologist and oncologist.

The Research

Nagalapuram and colleagues at the University of Alabama at Birmingham completed a 5.5-year retrospective chart review that examined outcomes of 155 patients following referral to their pediatric hematology and oncology clinic for isolated neutropenia. Neutropenia was characterized as mild (1001-1500/mL), moderate (501-1000/mL), severe (201-500/mL), and very severe (<200/mL).

The Results

In the study, neutropenia resolved in 30% of children by the time of their first hematology and oncology visit. The median time to resolution of neutropenia from the first abnormal CBC was 5.5 months. While 30% of children with mild neutropenia advanced to moderate, none of these children advanced to severe or very severe neutropenia. Of children with mild neutropenia, 75% had resolution, and none of the children required hospitalization or intervention from a hematologist and oncologist during the study period.

Etiologies of neutropenia included viral suppression (16%), autoimmune (14%), and drug induced neutropenia (8%). The most common agents for drug-induced neutropenia were antiepileptics and immunosuppressants. No etiology was found in 54% of patients, and the authors discuss possible explanations for this as lack of viral testing, limitations of antibody testing in autoimmune neutropenia, and benign ethnic neutropenia as a diagnosis of exclusion.

No children referred for isolated neutropenia were diagnosed with malignancy. Four percent of patients received G-CSF during hospitalization for fever, and these were children with moderate to very severe neutropenia at referral. Of the 13 children who were hospitalized for febrile neutropenia, none were found to have bacteremia.

What's the Take Home?

This study highlights the need to ask about offending drugs when isolated neutropenia is identified and to consider viral and autoimmune etiologies. This study also provides reassurance that isolated neutropenia often resolves without intervention. Further research is needed to provide more guidance on CBC monitoring and specialty care referral. 

Reference:

Nagalapuram V, McCall D, Palabindela P, et al. Outcomes of isolated neutropenia referred to pediatric hematology-oncology clinic. Pediatrics. 2020;146(4):e20193637. https://doi.org/10.1542/peds.2019-3637