Overview

Radiation sickness is damage to your body caused by a large dose of radiation often received over a short period of time (acute). The amount of radiation absorbed by the body — the absorbed dose — determines how sick you'll be.

Radiation sickness is also called acute radiation syndrome or radiation poisoning. Radiation sickness is not caused by common imaging tests that use low-dose radiation, such as X-rays or CT scans.

Although radiation sickness is serious and often fatal, it's rare. Since the atomic bombings of Hiroshima and Nagasaki, Japan, during World War II, most cases of radiation sickness have occurred after nuclear industrial accidents, such as the 1986 explosion and fire that damaged the nuclear power plant at Chernobyl, Ukraine.

Symptoms

The severity of signs and symptoms of radiation sickness depends on how much radiation you've absorbed. How much you absorb depends on the strength of the radiated energy, the time of your exposures, and the distance between you and the source of radiation.

Signs and symptoms are also affected by the type of exposure — such as total or partial body. The severity of radiation sickness also depends on how sensitive the affected tissue is. For instance, the gastrointestinal system and bone marrow are highly sensitive to radiation.

Initial signs and symptoms

The initial signs and symptoms of treatable radiation sickness are usually nausea and vomiting. The amount of time between exposure and when these symptoms develop is a clue to how much radiation a person has absorbed.

After the first round of signs and symptoms, a person with radiation sickness may have a brief period with no apparent illness, followed by the onset of new, more-serious symptoms.

If you've had a mild exposure, it may take hours to weeks before any signs and symptoms begin. But with severe exposure, signs and symptoms can begin minutes to days after exposure.

Possible symptoms include:

Nausea and vomiting

Diarrhea

Headache

Fever

Dizziness and disorientation

Weakness and fatigue

Hair loss

Bloody vomit and stools from internal bleeding

Infections

Low blood pressure

When to see a doctor

An accident or attack that causes radiation sickness would no doubt cause a lot of attention and public concern. If such an event occurs, monitor radio, television or online reports to learn about emergency instructions for your area.

If you know you've been overexposed to radiation, seek emergency medical care.

Causes

Radiation is the energy released from atoms as either a wave or a tiny particle of matter. Radiation sickness is caused by exposure to a high dose of radiation, such as a high dose of radiation received during an industrial accident.

Sources of high-dose radiation

Possible sources of high-dose radiation include the following:

An accident at a nuclear industrial facility

An attack on a nuclear industrial facility

Detonation of a small radioactive device

Detonation of a conventional explosive device that disperses radioactive material (dirty bomb)

Detonation of a standard nuclear weapon

Radiation sickness occurs when high-energy radiation damages or destroys certain cells in your body. Regions of the body most vulnerable to high-energy radiation are cells in the lining of your intestinal tract, including your stomach, and the blood cell-producing cells of bone marrow.

Complications

Having radiation sickness can contribute to both short-term and long-term mental health problems, such as grief, fear and anxiety about:

Experiencing a radioactive accident or attack

Mourning friends or family who haven't survived

Dealing with the uncertainty of a mysterious and potentially fatal illness

Worrying about the eventual risk of cancer due to radiation exposure

Prevention

In the event of a radiation emergency, stay tuned to your radio or television to hear what protective actions local, state and federal authorities recommend. Recommended actions will depend on the situation, but you will be told to either stay in place or evacuate your area.

Shelter in place

If you're advised to stay where you are, whether you're at home or work or elsewhere, do the following:

Close and lock all doors and windows.

Turn off fans, air conditioners and heating units that bring air in from outside.

Close fireplace dampers.

Bring pets indoors.

Move to an inner room or basement.

Stay tuned to your emergency response network or local news.

Stay put for at least 24 hours.

Evacuate

If you're advised to evacuate, follow the instructions provided by your local authorities. Try to stay calm and move quickly and in an orderly manner. In addition, travel lightly, but take supplies, including:

Flashlight

Portable radio

Batteries

First-aid kit

Necessary medicines

Sealed food, such as canned foods, and bottled water

Manual can opener

Cash and credit cards

Extra clothes

Be aware that most emergency vehicles and shelters won't accept pets. Take them only if you're driving your own vehicle and going someplace other than a shelter.