Time Phases of Acute Radiation Syndrome (ARS) - Dose Range 6-8 Gy

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

Timeline: 6-8 Gy

ARS time phases and approximate whole body dose from exposure: 6-8 Gy

Predominant Manifest Illness Subsyndromes	Phases
	Prodromal	Latent	Manifest Illness (Critical Phase)	Recovery or Death
	Vomiting Onset: <30 minutes after exposure Percent of victims who vomit at this dose: 100% Diarrhea Heavy Onset: 1-3 hours after exposure Percent of victims with diarrhea at this dose: >10% at low end; at high end of dose range ~100% of victims affected Headache Severe Onset: 3-4 hours after exposure Percent of victims with headache at this dose: 80% Level of consciousness May be decreased Body temperature High fever Onset: < 1 hour after exposure Percent of victims with fever at this dose: 100% Medical response Treatment in specialized hospital, if feasible	Duration From end of prodrome through day ≤ 7 Epilation Usually complete hair loss Medical response Hospitalization urgently needed	Onset <7 days after prodrome Duration Months Potential clinical effects Anorexia Fever Malaise, weakness Bleeding, infection Epilation: hair is lost by day 11 Nausea, vomiting Diarrhea: common by day 6-9; more severe with increased dose from exposure Disorientation Hypotension Medical response For those with best prognosis, prolonged, aggressive supportive care, and possible hematopoietic stem cell transplant Supportive care for all others Lethality Percent of victims who die at this dose: >50% beginning at 1-2 weeks	Recovery Recovery will require prolonged, aggressive supportive care. All victims who recover will require continued surveillance for late effects. Psychological support helpful Time to Recovery Months to years Time to Death Days to weeks depending on dose and clinical complications Aggressive supportive care may extend survival and salvage selected patients.