What are the causes of neutropenia (low neutrophil count)?

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Last updated: May 23, 2025View editorial policy

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From the Guidelines

Patients with low neutrophil counts should be managed based on the severity and cause of neutropenia, with treatment focusing on addressing the underlying cause and preventing infections, rather than routine use of hematopoietic growth factors like G-CSF, unless the risk of febrile neutropenia exceeds 20% or there are special circumstances 1. The management of neutropenia depends on its severity and cause. For mild neutropenia (1,000-1,500 neutrophils/μL), monitoring may be sufficient. For moderate to severe cases (<1,000 neutrophils/μL), treatment of the underlying cause is essential. This might include:

  • Stopping medications causing neutropenia
  • Treating infections
  • Addressing autoimmune conditions In severe cases, medications like granulocyte colony-stimulating factors (G-CSF) such as filgrastim (Neupogen) may be prescribed to stimulate neutrophil production, but their use should be guided by the risk of febrile neutropenia and other complications, as outlined in guidelines 1. While neutropenic, patients should take precautions to prevent infections, including:
  • Practicing good hygiene
  • Avoiding crowds and sick people
  • Cooking food thoroughly
  • Avoiding raw fruits and vegetables if severely neutropenic Neutropenia can result from various causes, including certain medications, chemotherapy, radiation, infections, autoimmune disorders, or bone marrow problems. Understanding the specific cause helps determine the appropriate treatment approach and prognosis. In cases of severe chronic neutropenia, G-CSF therapy may be effective in normalizing neutrophil counts and preventing infections, but the dose should be adjusted to maintain a blood neutrophil level in the normal or low normal range, and patients should be monitored for potential adverse effects and the risk of developing myelodysplasia and leukemia 1.

From the Research

Definition and Classification of Neutropenia

  • Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1,500/mcL or 1.5 × 10(9)/l 2, 3
  • It can be classified as transient or chronic, with chronic neutropenia further described as extrinsic or intrinsic 2

Causes and Risks of Neutropenia

  • Neutropenia can be caused by various factors, including certain medications such as ceftriaxone and meropenem 4
  • Severe neutropenia can lead to severe life-threatening sepsis, shock, and even death 4, 3
  • Patients with neutropenia are at risk of developing bacterial infections, particularly febrile neutropenia 3, 2

Treatment and Management of Neutropenia

  • Treatment of neutropenia typically involves the cessation of offending agents, supportive treatment, and granulocyte-colony stimulating factor (G-CSF) 4, 3
  • G-CSF can facilitate the recovery process and shorten the recovery time 4, 3
  • Patients with febrile neutropenia should undergo treatment with antibiotics 3, 2
  • Pegfilgrastim, a pegylated form of filgrastim, can be used to reduce the risk of neutropenia and its complications in patients receiving myelosuppressive chemotherapy 5, 6

Prophylactic Use of G-CSF

  • Patients at high risk of severe neutropenia (>20% risk) after myelosuppressive chemotherapy should be treated prophylactically with a myeloid growth factor, usually G-CSF 3
  • Prophylactic dosing of filgrastim and pegfilgrastim can be cost-effective and improve clinical outcomes by reducing the length of hospital stays and the need for IV antibiotic administration 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Hematologic Conditions: Leukopenia.

FP essentials, 2019

Research

How I diagnose and treat neutropenia.

Current opinion in hematology, 2016

Research

Neutropenia Induced by Ceftriaxone and Meropenem.

European journal of case reports in internal medicine, 2024

Research

Pegfilgrastim for chemotherapy-induced neutropenia.

Clinical journal of oncology nursing, 2003

Research

Filgrastim and pegfilgrastim use in patients with neutropenia.

Clinical journal of oncology nursing, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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