Time Phases of Acute Radiation Syndrome (ARS) - Dose Range 2-4 Gy

• 1 to 2
• 2 to 4
• 4 to 6
• 6 to 8
• Greater than 8
• Caveats and comments

Timeline: 2-4 Gy

ARS time phases and approximate whole body dose from exposure: 2-4 Gy

Predominant Manifest Illness Subsyndromes	Phases
	Prodromal	Latent	Manifest Illness (Critical Phase)	Recovery or Death
	Vomiting Onset: 1-2 hours after exposure Percent of victims who vomit at this dose: 70-90% Diarrhea None in some patients, mild in others at the higher end of the dose range. Headache Mild Level of consciousness Unaffected Body temperature Increased Onset: 1-3 hours after exposure Percent of victims with fever at this dose: 10-80% Medical response Observation in general hospital, especially for those at higher end of this dose range Treatment in specialized hospital as needed and feasible	Duration From end of prodrome through day 18-28 Epilation Moderate hair loss, beginning on day 15 or later Medical response Hospitalization recommended if feasible	Onset 18-28 days after prodrome Duration Weeks to months Possible clinical effects Anorexia Fever Malaise, weakness Bleeding, infection Epilation Diarrhea: none to mild at lower end of dose range; more severe with increased dose from exposure Medical response Appropriate supportive care Lethality Rare in the lower end of this dose range Up to 50% may die at higher end of this dose range at 6-8 weeks. Aggressive supportive care will salvage many patients at the high end of this dose range.	Recovery Depends on GI and bone marrow recovery All victims require surveillance for late effects Psychological support helpful Time to recovery Weeks to months Death Potentially avoidable with appropriate supportive care unless severe complications develop