This segment will introduce colony stimulating factors and discuss indications, administration, adverse effects, and special considerations. Afterwards, there is the option to apply what you have learned within a case study.

[Description]

Colony stimulating factors (CSFs) are recombinant glycoprotein cytokines used to treat bone marrow suppression by stimulating the development of granulocytes – in particular, neutrophils. The effect of treatment is to help re-establish and support the body's ability to fight infection and produce white blood cells.

Colony stimulating factors are commonly used for treatment of bone marrow suppression in patients undergoing chemotherapy. It is anticipated that these medications will be recommended for use during a radiation emergency under an Emergency Use Authorization (EUA) from the FDA related to the treatment of acute radiation syndrome. The evidence supporting use of colony stimulating factors to treat acute radiation syndrome is based on animal studies showing survival benefits, and anecdotal experience in human patients treated after significant radiation exposures.

[Availability]

Colony stimulating factors are currently part of federal stockpiles. Hospital pharmacies may have small quantities of colony stimulating factors on hand, though these supplies may be rapidly depleted during a mass-casualty incident. Public health officials will manage and direct federal supplies of colony stimulating factors to maximize their benefit during a radiation emergency.

[Indications]

The decision as to whether a patient can benefit from colony stimulating factors should only be made after a careful assessment of risk by knowledgeable professionals. Ideally, a patient will be evaluated jointly by a healthcare provider and radiation health professional to consider the many variables that would factor into the decision. Criteria for initiating treatment will be based in part on the estimated radiation dose and availability of supplies. In a large-scale radiation emergency there will be a scarcity of resources and personnel to perform evaluations of persons exposed to radiation. Therefore, treatment decisions will likely be made with incomplete information.

As a reflection of radiation dose, individuals presenting with moderate or severe prodromal symptoms of acute radiation syndrome may be candidates for treatment with colony stimulating factors. These symptoms include the rapid onset of nausea, vomiting, diarrhea, and elevated body temperature.

Treatment with CSFs may also be considered for patients who have either:

• Greater than or equal to 2 Gy whole or significant partial body exposure.
• A high probability of prolonged, significant neutropenia.

Early treatment with colony stimulating factors is thought to provide more benefit than delayed treatment after radiation exposure, particularly within the first 72 hours after exposure. However, treatment may be beneficial even if initiated several days after exposure.

The duration of treatment will vary with the amount of exposure a person receives, and higher doses will require longer therapy regimens. In general, treatment should continue until an individual's absolute neutrophil count is consistently above 1000 cells per microliter of blood.

Children and women who are pregnant or breastfeeding can be treated with colony stimulating factors but will require additional precautions and close monitoring. For pregnant women especially, professionals with maternal-fetal expertise are needed to assess and monitor for potential negative health effects in the fetus.

[Dosing and Administration]

Colony stimulating factors are generally administered subcutaneously (SC), but may also be given intravenously (IV). This chart presents doses for different types of colony stimulating factors:

[Monitoring and Follow-up]

Patients receiving colony stimulating factors should have routine monitoring of complete blood counts with differential (especially neutrophil counts). Clinical monitoring should also assess for the presence of thrombocytopenia, and evidence of splenic injury - such as abdominal pain, left upper quadrant pain, and left shoulder pain.

All Individuals who receive colony stimulating factors should be monitored for allergic and other adverse reactions.

[Adverse effects]

Patients taking colony stimulating factors may experience a number of adverse effects, such as muscle or bone pain, allergic reactions, fever, diarrhea, and weakness. Other severe adverse effects associated with use of colony stimulating factors include triggering sickle cell crisis in patients with sickle-cell disease, splenic rupture, acute respiratory distress syndrome, alveolar hemorrhage, and hemoptysis.

[Contraindications]

Clinicians should not administer colony stimulating factors to individuals with a known history of hypersensitivity reactions to CSF medications or to E. coli-derived proteins.

[Special Considerations]

Finally, it is not currently known if CSFs are excreted in breast milk.