Radiation Sickness (Acute Radiation Syndrome) (ARS)

Radiation Sickness (Acute Radiation Syndrome) (ARS)

Dr. Kennedy
Radiation sickness comes from damage to organs due to excessive exposure to ionizing radiation. The term is generally used to refer to acute problems caused by a large dosage of radiation in a short period, such as occurred at Chernoble. The clinical name for “radiation sickness” is acute radiation syndrome (ARS). A chronic radiation syndrome does exist but is very uncommon. It has been observed among workers in early radium source production sites and in the early days of the Soviet nuclear program. Short exposure can result in acute radiation syndrome; chronic radiation syndrome requires a prolonged high level of exposure. Radiation exposure can also increase the probability of contracting some other diseases, mainly cancer, tumors, and genetic disorders. These are referred to as the stochastic effects of radiation, and are not included in the term radiation sickness.


The severity of symptoms of radiation sickness depends on the amount of radiation is absorbed which in turn depends on the strength of the radiated energy and the distance between you and the source of radiation. The absorbed dose of radiation is measured in a unit called a gray (Gy). A conventional dental X-ray, which results in an absorbed dose to the jaw of about 0.0025 Gy is an example of a safe dose. A typical whole-body computerized tomography (CT) scan results in an average whole-body dose of about 0.012 or about five times the dose of a dental x-ray. Signs and symptoms of radiation sickness usually appear with absorbed doses to the whole body of at least 1 Gy, that is to say about 83 times the dose of a CT scan. Doses greater than 8 Gy are generally not treated successfully and usually result in death within two days to three weeks depending on the duration of the exposure.

The initial symptoms of treatable radiation sickness are usually nausea and vomiting. The amount of time between exposure and the onset of these symptoms is a relatively reliable indicator of how much radiation a person has absorbed. After the initial onset of symptoms, a person with radiation sickness then experiences a brief period of a few days with no apparent illness, and then the hammer falls. Mild radiation sickness may include:

  • Nausea and vomiting within 24 to 48 hours
  • Fatigue
  • Headache
  • Weakness

Moderate radiation sickness can be fatal to those most sensitive to radiation exposure and comes from an acute absorbed dose of 2 to 3.5 Gy. The symptoms which can present are:

  • Nausea and vomiting within 12 to 24 hours
  • Fever
  • Hair loss
  • Vomiting blood
  • Bloody stool
  • Poor wound healing
  • Infections
  • Any signs and symptoms associated with a lower absorbed dose

Severe radiation sickness is fatal in about 50% of cases and comes with an absorbed dose of 3.5 to 5.5 Gy and can result in the following signs and symptoms:

  • Nausea and vomiting less than one hour after exposure to radiation
  • Diarrhea
  • High fever
  • Any signs and symptoms associated with a lower absorbed dose

Very severe radiation sickness is usually fatal and results from absorbed dose greater than 5.5 to 8 Gy and can have the following signs and symptoms:

  • Nausea and vomiting less than 30 minutes after exposure to radiation
  • Dizziness
  • Disorientation
  • Low blood pressure (hypotension)
  • Any signs and symptoms associated with a lower absorbed dose


The treatment goals are to prevent further radioactive contamination, treat damaged organs, reduce symptoms, and manage pain.
Decontamination is achieved by removal of as much external radioactive particles as possible. Removal of clothing and shoes eliminates about 90 percent of external contamination. Washing with water and soap removes additional radiation particles from the skin.

A protein called granulocyte colony-stimulating factor promotes the growth of white blood cells and may counter the effect of radiation sickness on bone marrow. Treatment with this protein-based medication, which includes filgrastim (Neupogen) and pegfilgrastim (Neulasta), and may increase white blood cell production and help prevent subsequent infections. Severe damage to bone marrow may be helped with transfusions of red blood cells or blood platelets.

Some treatments may reduce damage to internal organs caused by specific types of radioactive particles. Medical personnel would use these treatments only if you’ve been exposed to a specific type of radiation. Potassium iodide is a nonradioactive form of iodine. Because iodine is essential for proper thyroid function, the thyroid becomes a “destination” for iodine in the body. If there is exposure to radioactive iodine (radioiodine), the thyroid will absorb radioiodine just as it would other forms of iodine. Treatment with potassium iodide may fill “vacancies” in the thyroid and prevent absorption of radioiodine. Radioiodine is eventually cleared from the body in urine. Prussian blue, a type of dye, binds to particles of radioactive elements known as cesium and thallium. The radioactive particles are then excreted in feces. This treatment speeds up the elimination of the radioactive particles and reduces the amount of radiation cells may absorb. Diethylenetriamine pentaacetic acid (DTPA) is a chelator which binds to metals. DTPA binds to particles of the radioactive elements plutonium, americium and curium. The radioactive particles pass out of the body in urine, thereby reducing the amount of radiation absorbed.

Beyond that, supportive treatments are offered, to whatever complications (symptoms, infections, etc.) which may appear. A person who has absorbed 8 Gy or greater has little chance of recover. Death can occur within two days to three weeks. People with a lethal radiation dose should receive medications to control pain, nausea, vomiting and diarrhea and be offered psychological or pastoral care.

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