The accidental or hostile exposure of individuals to ionizing irradiation is of great public and military concern. Radiation sickness (acute radiation syndrome, or ARS) occurs when the body is exposed to a high dose of penetrating radiation within a short period of time. Systemic infection is one of the serious consequences of ARS. There is a direct relation between the magnitude of radiation exposure and the risk of developing infection. The risk of systemic infection is higher whenever there is a combined injury such as burn or trauma. Ionizing radiation enhances infection by allowing translocation of oral and gastrointestinal flora, and reducing the threshold of sepsis due to endogenous and exogenous microorganisms. The potential for concomitant accidental or terrorism-related exposure to bio-terrorism agents such as anthrax and radiation also exists.

This site is made of a home page that presents new developments and updates on the management of acute radiation syndrome including concomitant exposure to radiation and anthrax. Separate pages are dedicated to the treatment modalities.

Wednesday, May 29, 2013

The ASCO clinical practice guideline for antimicrobial prophylaxis and outpatient management of fever and neutropenia; Use in those exposed to ionized iradiation

The American Society of Clinical Oncology published their clinical practice guideline for antimicrobial prophylaxis and outpatient management of fever and neutropenia in adults treated for malignancy. The guidelines were based on 43 studies.

These were the recommendations: Antibacterial and antifungal prophylaxis are only recommended for patients expected to have < 100 neutrophils/μL for > 7 days, unless other factors increase risks for complications or mortality to similar levels. Inpatient treatment is standard to manage febrile neutropenic episodes, although carefully selected patients may be managed as outpatients after systematic assessment beginning with a validated risk index (eg, Multinational Association for Supportive Care in Cancer [MASCC] score or Talcott's rules). Patients with MASCC scores ≥ 21 or in Talcott group 4, and without other risk factors, can be managed safely as outpatients. Febrile neutropenic patients should receive initial doses of empirical antibacterial therapy within an hour of triage and should either be monitored for at least 4 hours to determine suitability for outpatient management or be admitted to the hospital. An oral fluoroquinolone plus amoxicillin/clavulanate (or plus clindamycin if penicillin allergic) is recommended as empiric therapy, unless fluoroquinolone prophylaxis was used before fever developed.

Even though the principles behind these guidelines are similar to the ones used for the treatment of individuals who developed neutropenia after exposure to ionized radiation, caution should be used in implementing these guidelines for those who were irradiated. There is a risk in using antimicrobials effective against anaerobic bacteria (amoxicillin/clavulanate or clindamycin) in individuals exposed to ionizing radiation as studies in rodents illustrated the developmentof early sepsis in those treated with such agents. 


Neutropenia

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