Time Phases of Acute Radiation Syndrome (ARS) - Dose Range 4-6 Gy

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

Timeline: 4-6 Gy

ARS time phases and approximate whole body dose from exposure: 4-6 Gy

Predominant Manifest Illness Subsyndromes	Phases
	Prodromal	Latent	Manifest Illness (Critical Phase)	Recovery or Death
	Vomiting Onset: <1 hour after exposure Percent of victims who vomit at this dose: 100% Diarrhea Mild at low end and moderate at high end of dose range Onset: 3-8 hours after exposure Percent of victims with diarrhea: <10% at low end; percentage increases at high end of dose range to ~10% Headache Moderate Onset: 4-24 hours after exposure Percent of victims with headache at this dose: 50% Level of consciousness Unaffected Body temperature Fever Onset: 1-2 hours after exposure Percent of victims with fever at this dose: 80-100% Medical response Treatment in specialized hospital, if feasible	Duration From end of prodrome through day 8-18 Epilation Moderate to complete hair loss Medical response Hospitalization usually necessary	Onset 8-18 days after prodrome Duration Weeks to months Possible clinical effects Anorexia Fever Malaise, weakness Bleeding, infection Epilation: hair is lost by day 11-21 Nausea, vomiting Diarrhea: more severe at higher end of dose range with fluid and electrolyte loss Medical response Aggressive supportive care Lethality Percent of victims who die at this dose: 20-70% beginning at 4-8 weeks	Recovery Recovery will require aggressive supportive care All victims require continued surveillance for late effects Psychological support helpful Time to recovery Months to years