Acute radiation syndrome

Acute radiation syndrome
Other names	Radiation poisoning, radiation sickness, radiation toxicity
Radiation causes cellular degradation by autophagy.
Specialty	Critical care medicine
Symptoms	Early: Nausea, vomiting, skin burns, loss of appetite[1] Later: Infections, bleeding, dehydration, confusion[1]
Complications	Cancer[2]
Usual onset	Within days[1]
Types	Bone marrow syndrome, gastrointestinal syndrome, neurovascular syndrome[1][3]
Causes	Large amounts of ionizing radiation over a short period of time[1]
Diagnostic method	Based on history of exposure and symptoms[4]
Treatment	Supportive care (blood transfusions, antibiotics, colony stimulating factors, stem cell transplant)[3]
Prognosis	Depends on the exposure dose[4]
Frequency	Rare[3]

Acute radiation syndrome (ARS), also known as radiation sickness or radiation poisoning, is a collection of health effects that are caused by being exposed to high amounts of ionizing radiation in a short period of time.^[1] Symptoms can start within an hour of exposure, and can last for several months.^[1][3][5] Early symptoms are usually nausea, vomiting and loss of appetite.^[1] In the following hours or weeks, initial symptoms may appear to improve, before the development of additional symptoms, after which either recovery or death follow.^[1]

ARS involves a total dose of greater than 0.7 Gy (70 rad), that generally occurs from a source outside the body, delivered within a few minutes.^[1] Sources of such radiation can occur accidentally or intentionally.^[6] They may involve nuclear reactors, cyclotrons, certain devices used in cancer therapy, nuclear weapons, or radiological weapons.^[4] It is generally divided into three types: bone marrow, gastrointestinal, and neurovascular syndrome, with bone marrow syndrome occurring at 0.7 to 10 Gy, and neurovascular syndrome occurring at doses that exceed 50 Gy.^[1][3] The cells that are most affected are generally those that are rapidly dividing.^[3] At high doses, this causes DNA damage that may be irreparable.^[4] Diagnosis is based on a history of exposure and symptoms.^[4] Repeated complete blood counts (CBCs) can indicate the severity of exposure.^[1]

Treatment of ARS is generally supportive care. This may include blood transfusions, antibiotics, colony-stimulating factors, or stem cell transplant.^[3] Radioactive material remaining on the skin or in the stomach should be removed. If radioiodine was inhaled or ingested, potassium iodide is recommended. Complications such as leukemia and other cancers among those who survive are managed as usual. Short term outcomes depend on the dose exposure.^[4]

ARS is generally rare.^[3] A single event can affect a large number of people,^[7] as happened in the atomic bombings of Hiroshima and Nagasaki and the Chernobyl nuclear power plant disaster.^[1] ARS differs from chronic radiation syndrome, which occurs following prolonged exposures to relatively low doses of radiation.^[8][9]