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Radiation Exposure and Contamination
Diagnosis of Radiation Exposure and Contamination
Symptoms, severity, and symptom latency Serial absolute lymphocyte counts and serum amylase levels Diagnosis is by history of exposure, symptoms and signs, and laboratory testing. The onset, time course, and severity of symptoms can help determine radiation dose and thus also help triage patients relative to their likely consequences. However, some prodromal symptoms (eg, nausea, vomiting, diarrhea, tremors) are nonspecific, and causes other than radiation should be considered. Many patientswithoutsufficient exposure to cause acute radiation syndromes may present with similar, nonspecific symptoms, particularly after a terrorist attack or reactor accident, when anxiety is high. After acute radiation exposure, complete blood count (CBC) with differential and calculation of absolute lymphocyte count is done and repeated 24, 48, and 72 hours after exposure to estimate the initial radiation dose and prognosis (see table Relationship Between Absolute Lymphocyte Count in the Adult at 48 Hours, Radiation Dose*,†, and Prognosis ). The relationship between dose and lymphocyte counts can be altered by physical trauma, which can shift lymphocytes from the interstitial spaces into the vasculature, raising the lymphocyte count ( C-reactive protein (CRP) level: CRP increases with radiation dose; levels show promise to discriminate between minimally and heavily exposed patients. Blood citrulline level: Decreasing citrulline levels indicate gastrointestinal damage. Blood fms-related tyrosine kinase-3 (FLT-3) ligand levels: FLT-3 is a marker for hematopoietic damage. Interleukin-6 (IL-6): This marker of inflammation is increased at higher radiation doses. Quantitative granulocyte colony-stimulating factor (G-CSF) test: Levels are increased at higher radiation doses. Cytogenetic studies with overdispersion index: These studies are used to evaluate for partial body exposure. When contamination is suspected, the entire body should be surveyed with a thin window Geiger-Muller probe attached to a survey meter (Geiger counter) to identify the location and extent of external contamination. Additionally, to detect possible internal contamination, the nares, ears, mouth, and wounds are wiped with moistened swabs that are then tested with the counter. Urine, feces, and emesis should also be tested for radioactivity if internal contamination is suspected. 1.Toft P, Tønnesen E, Helbo-Hansen HS, et al: Redistribution of granulocytes in patients after major surgical stress.APMIS102(1):43-48, 1994. doi: 10.1111/j.1699-0463.1994.tb04843.x 2.DeRijk R, Michelson D, Karp B, et al: Exercise and circadian rhythm-induced variations in plasma cortisol differentially regulate interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor-alpha (TNF alpha) production in humans: high sensitivity of TNF alpha and resistance of IL-6.J Clin Endocrinol Metab82(7):2182-2191, 1997. doi: 10.1210/jcem.82.7.4041 