Acute radiation syndrome occurs when a person is exposed to a high dose of external penetrating radiation within a short time period.

Acute radiation syndrome (also called acute radiation sickness) occurs when a person is exposed to radiation of more than 1 Gy in a very short time period. It occurs when the whole body or nearly the whole body is exposed to radiation. External contamination occurs due to fallout of radioactive particles that could land on the body or clothes of a person. Internal contamination occurs when a person breathes in contaminated air or eats or drinks contaminated food or water. It could also occur when the radioactive particles are absorbed through skin and open wounds. Most cases of acute radiation syndrome have occurred when the contamination was external.

Acute Radiation Syndrome

An exposure of less than 1 Gy usually does not cause any symptoms. It may produce a decrease in white blood cells, which usually recovers on its own.

Radiation usually affects the dividing cells of the body. These include sperms, blood cells and the cells lining the digestive system. Children and elderly are more susceptible to radiation injury. At lower doses, the bone marrow is usually affected. At higher doses, the digestive system is also involved. Very high dose exposure could be fatal with the patient, besides suffering from the above features, also suffers from very low blood pressure, seizures, confusion and death.

The patient goes through various phases following exposure. These include the prodromal phase where the patient suffers from symptoms like nausea, vomiting and diarrhea, a latent phase where the patient shows apparent recovery, a manifest illness phase where most of the symptoms appear, and a fourth phase of either recovery or death.

Exposed patients are treated according to the dose of exposure and severity of symptoms. Patients should initially undergo decontamination. Low blood counts may be treated with growth factors and transfusion of packed cells. Stem cell transplantation may be tried out in some cases. Infections should be prevented and treated with antibiotics. Medications should be administered to treat symptoms like vomiting, diarrhea, pain and burns. Fluids, electrolytes and nutrition should be maintained. Psychological support should also be offered to these patients. Patients who develop multiorgan failure after several days, may require critical care.

Very severely exposed patients usually do not survive and are administered only supportive treatment.


  1. Harrison’s Principles of Internal Medicine 17th edition
  2. Waselenko JK et al. Medical Management of the Acute Radiation Syndrome
  3. Recommendations of the Strategic National Stockpile Radiation Working Group. Ann Intern Med. 2004;140:1037-1051.

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