What’s all the fuss about neutropenia?

• The neutrophil count bottoms out (the "nadir") days 5-10 after last chemotherapy treatment.
• The risk of infection is dependent on the degree and duration of neutropenia
• Important Cutoffs:
• Neutropenia: absolute neutrophil count < 1000/mm3
• Severe Neutropenia: absolute neutrophil count < 500/mm3
• Profound Neutropenia: absolute neutrophil count < 100/mm3

• Signs and symptoms are often minimal due to the diminished inflammatory response
• Mortality rates as high as 5-20%

Where to Start:

• Do not take a rectal temperature in a potentially neutropenic patient
• Check: urinalysis, urine culture, chest xray, blood cultures
• Assess any lines for source of infection and draw blood culture from the site as well
• If a source is found, therapy can be guided
• Treatment is more difficult without a known source
• Be on high alert for new abdominal pain: this may be typhilitis (also known as neutropenic enterocolitis), a potentially catastrophic complication of neutropenia

Treatment:

• Initiate gram negative coverage (typically cefepime 2g IV, aztreonam or meropenem if severe allergy to cephalosporins)
• Evidence supports empiric antibiotics when the patient has severe neutropenia even if a specific organism is not found
• There is little evidence for antibiotics when the patient is not neutropenic
• Vancomycin only required if there is concern for catheter infections (or a history of MRSA in the patient)

References:

1 Lyman. How We Treat Febrile Neutropenia in Patients Receiving Cancer Chemotherapy. J Oncol Pract. 2010 May; 6(3): 149-152.

2 Denshaw-Burke. Neutropenic Fever Empiric Therapy. Medscape. February 11, 2016. https://emedicine.medscape.com/article/2012185-overview

3 Stapczynski, J. Stephan,, and Judith E. Tintinalli. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York, N.Y.: McGraw-Hill Education LLC., 2011.