Acute radiation syndrome

(Redirected from Acute Radiation Syndrome)


  • Also called radiation poisoning, radiation toxicity, or radiation sickness.
  • Acute illness caused by exposure to high doses (at least 1 Gy)[1] of ionizing radiation over a short period of time.
    • 1 Gray (Gy) = 100 rads
  • Generally requires exposure of whole body (or most of the body)
  • Fast-replicating cell lines most affected - GI, lymphohematopoietic, spermatocytes
  • Healthcare providers should use isolation precautions and decontamination procedures
    • Geiger counters may be useful in identifying contamination

Clinical Features

Clinical Syndromes[1][2]

Bone Marrow Syndrome

  • Clinical syndrome seen at doses >100-200 rad (1-2 Gy)
  • Lymphocytes depleted first, then granulocytes, platelets, and RBCs
    • Lymphocyte depletion is predictable based on dose
  • Death usually secondary to infection or hemorrhage and poor healing
    • Doses >350 rad fatal within several months if untreated

Gastrointestinal (GI) Syndrome

Cardiovascular (CV)/Central Nervous System (CNS) Syndrome

Clinical Course[1][2]

  • Each ARS syndrome typically progresses through 4 stages of disease

Prodromal Stage

  • Characterized by nausea and vomiting
    • Other symptoms include: malaise, fever, conjunctivitis
    • Doses over 1000 rad (10 Gy), vomiting is not seen in early symptoms
  • Occurs within 48h-6d of exposure (at higher doses, can begin within minutes)
  • Lasts up to 2 days

Latent Stage

  • Short period of symptom improvement
  • Lasts several days to 1 month

Manifest Illness Stage

  • Manifestation of symptoms of clinical syndromes
  • Severity based on, among other things:
    • Overall dose
    • Irradiated body volume
    • Comorbidities and overall health status
    • Age
  • Characterized by significant immunosuppression
  • Lasts for days to months

Recovery or Death

  • If patient survives manifest illness stage, recovery is slow (weeks to years)
  • If lethal dose received, death can occur within days (very high, rapid doses) or may be delayed up to several months
  • Doses over 1000 rad (10 Gy) are uniformly fatal

Differential Diagnosis

Mass casualty incident

Nausea and vomiting





  • Clinical diagnosis, based on history and physical
  • Absolute lymphocyte count is the best prognosticator at 48hrs post-exposure[3] (<1500 is abnormal and indicates a significant exposure)


  • Typically risk of contamination to clinicians is minimal, therefore immediate treatment of life-threatening conditions takes precedence[4]
  • Aggressive supportive care is hallmark of ED management
  • Potassium iodide as thyroid protectant, at 130mg QD for adults, until radiation exposure ceases[5]


  • Admit

See Also

External Links


  1. 1.0 1.1 1.2 Waselenko JK, MacVittie TJ, Blakely WF, et al. Medical management of the acute radiation syndrome: recommendations of the Strategic National Stockpile Radiation Working Group. Ann Intern Med. 2004 Jun 15;140(12):1037-51.
  2. 2.0 2.1 Donnelly EH1, Nemhauser JB, Smith JM, et al. Acute radiation syndrome: assessment and management. South Med J. 2010 Jun;103(6):541-6.
  3. Colwell CB: Radiation injuries, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2013, (Ch) 146: pp 1945-1951.
  4. Hryhorczuk D, Theobald JL: Radiation injuries, in Walls RM, Hockberger RS, Gausche-Hill M, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 9. Philadelphia, Elsevier 2018, (Ch) 138:p 1805-1812
  5. New York State Potassium Iodide (KI) and Radiation Emergencies: Fact Sheet.