Measurement of radiation: Grays (1 Gy = 100 rad)

must be ionizing radiation at large dose (> 70 rad) affecting significant portion of the body exposed over a short period of time

Acute radiation syndrome progresses over 4 stages:

• Prodromal Phase: nausea, vomiting; the faster the onset of GI symptoms, the worse the prognosis
• Latent Phase: relative recovery (hours to weeks depending on dose)
• Manifest Illness Stage: 
• clinical syndromes of hematopoietic, GI, CNS, cardiovascular 
• Hematopoietic:
• lymphocytes deplete first
• hemorrhage, pancytopenia, infection
• if 48-hour lymphocyte count > 1200: likley insignifcant radiation dose, good prognosis
• if 48-hour lymphocyte count < 500, significant radiation dose, poor prognosis
• GI: nausea, vomiting, abdominal pain, diarrhea, bleeding, fluid loss/ shock
• CNS: altered mental status, ataxia, seizure, cerebral edema
• Cardiovascular: damage to blood vessels, shock unresponsive to treatment
• Recoveryr or Death: typically determined by dose of radiation received; lethal dose 350-450 rad

Management:

• supportive
• decontamination
• treat injuries/ burns
• serial CBC, Chem7

References:

Tintinalli, Judith, et al. “Radiation Injuries.” Tintinalli’s Emergency Medicine, 8th ed., McGrath-Hill, 2016, pp 51 – 57.