Episode Details

In our final stop in our Cytopenias series, we discuss the ins and outs of neutropenia. This is another very commonly seen issue in the clinic and in the hospital so most definitely high yield!

Why is neutropenia dangerous?

Prone to infections, especially gut translocation of bacteria

Definition of neutropenia:

NORMAL: WBC 4400-11000 cells/microL; neutrophils make up 40-70% of that

Neutropenia defined by ANC: WBC (cells/microL) x percent (PMNs  +  bands) ÷ 100 

Breakdown:

Neutropenia: ANC <1500 cells/microL

Mild: ANC ≥1000 and <1500 cells/microL

Moderate: ANC ≥500 and <1000 cells/microL

Severe: ANC <500 cells/microL

Agranulocytosis: ANC <200 cells/microL

Approach to workup: HISTORY IS KEY!

Medications; examples of common culprits-  

Chemotherapy 

Methimazole 

Clozapine 

Infections

Any infections due to bone marrow suppression 

Toxins 

Less common causes: 

Congenital

Severe congenital neutropenia:

Diagnosed in childhood; used to be fatal, but now patients living longer because of G-CSF support

10-30% risk of AML in lifetime

Mutations in neutrophil elastase (ELANE) gene or mitochondrial HAX1 gene 

Cyclic neutropenia:

Self-limiting neutropenia that occurs every 2-5 weeks

Spectrum of symptoms: none or oral ulcers/mild infections

Constitutional/ethnic neutropenia:

Mild neutropenia (ANC >1000)

No history of infections

More common in people of Mediterranean and African descent

Duffy Antigen Receptor Complex (DARC) gene mutations in patients of African origin

Benign Familial:

Mild neutropenia

Not linked to particular ethnic group

Unclear underlying etiology

Autoimmune

Primary autoimmune neutropenia rare in adults

Typically secondary autoimmune neutropenia

Due to underlying autoimmune disorder

Seen with SLE and can worsen with flare of disease

Typically mild, seldom needs treatment unless ANC <500

Felty syndrome:  

Rheumatoid arthritis, splenomegaly, and neutropenia

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