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Acute radiation syndrome (ARS) is a serious illness resulting from exposure to high amounts of radiation in a very short period.

For instance, most people are familiar with the effects that rescue workers experienced when they responded to the Chornobyl nuclear power plant explosion in 1986. Many people have seen fictional movies or TV shows exploring the possibility of similar disasters happening in the future.

Although many movie and television accounts of ARS are dramatized, ARS is a real illness. It causes a range of severe symptoms and can be fatal if the exposure is high enough.

ARS is an illness that occurs due to exposure to high levels of radiation in a short period. ARS is sometimes also called radiation poisoning, radiation sickness, acute radiation sickness, or radiation sickness syndrome.

Experts often divide ARS into three major subtypes, each of which describes the part of the body it affects. These ARS subtypes are:

  • Bone marrow: This type of ARS affects white blood cells. It occurs after exposure to lower doses of radiation, and many people make a full recovery.
  • Gastrointestinal: This type affects the gastrointestinal system and has a faster course than bone marrow ARS. Recovery is possible but more difficult.
  • Cardiovascular/central nervous system: This type of ARS occurs after exposure to extremely high doses of radiation in a very short period. It is always fatal.

Key definitions for ARS

  • Radiation: This is the emission of energy waves or particles through space. There are four types of radiation: alpha radiation, the type of radiation in radon; beta radiation, the type of radiation that scientists use for carbon dating; neutrons, which play a role in nuclear reactions; and electromagnetic waves, including X-rays and gamma rays.
  • Alpha particles: These represent the heaviest type of radiation. They include substances such as uranium and radon.
  • Neutrons: This is the type of radiation created when uranium atoms split and cause a nuclear reaction.
  • Protons: These subatomic particles are present inside the nucleus of an atom.
  • X-rays and gamma rays: Both X-rays and gamma rays are types of electromagnetic radiation. They can play a part in medical treatments, sterilization, and more.
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There are four stages of ARS, no matter the subtype. The stages of ARS are:

  • Prodromal stage: This is the first stage of ARS. People in this stage generally experience nausea, vomiting, and diarrhea that can last for minutes or days. The severity of the symptoms will depend on the amount of exposure.
  • Latent stage: People in the latent stage look and feel healthy for hours, days, or weeks.
  • Manifest illness stage: This is the primary stage of ARS. People in this stage experience the symptoms associated with their type of ARS. This stage can last hours, days, weeks, or months.
  • Recovery or death: Fatal cases of ARS generally cause death within a few months of the initial exposure. Recovery from ARS can take several months.

In general, ARS symptoms include nausea, vomiting, weakness, and headaches, which can last for days, weeks, or months. Exposure to a very large amount of radiation can be fatal.

Although the symptoms may be similar in all cases of ARS, the subtype may determine the specific symptoms and their severity.

Bone marrow ARS

The symptoms of this subtype may include:

Gastrointestinal ARS

If you have gastrointestinal ARS, you might experience all of the symptoms of bone marrow ARS alongside:

Cardiovascular/central nervous system

This subtype of ARS can cause:

ARS is not contagious. Even people with direct exposure to radiation only get ARS if:

  • the dose of radiation was very high
  • they received the entire dose within a very short window
  • the radiation was able to penetrate the internal organs
  • the radiation was able to reach the person’s entire body

Although people with exposure to certain types of radiation can retain some gamma radiation in their skin, it is not enough to pass harmful effects on to others.

Additionally, this radiation won’t remain in the body. The exact time it will take for all radiation to leave the body depends on the exposure amount. It can take up to 2 years following a very significant exposure. However, all people who survive ARS are eventually totally free of radiation.

The first step in treating ARS is decontamination, which involves taking off any clothing and washing your body with soap and water. This removes all radioactive particles from the skin and ensures that no further exposure occurs.

After decontamination, you might need:

  • Treatment to promote the growth of white blood cells: Treatment to promote the growth of white blood cells can counter the effects of ARS that are damaging your bone marrow.
  • Blood transfusions: Transfusions of red blood cells and platelets can restore the damage that bone marrow ARS causes.
  • Potassium iodide: This treatment can help keep your thyroid from absorbing too much radiation.
  • Prussian blue: This treatment speeds up your body’s elimination of radiation through your digestive system.
  • Diethylenetriamine pentaacetic acid (DTPA): This helps your body pass radiation out of your body as a waste product in urine.
  • Pain medications: You might receive medication to help manage your pain and discomfort.
  • Nausea treatment: Treatment can help control nausea.
  • Medical rehydration: Hydration through IV fluids can sometimes be an option during the manifest illness stage.

The outlook for people with ARS depends on the amount of radiation exposure and the type of ARS.

For instance, cardiovascular/central nervous system ARS is always fatal, but many people with bone marrow ARS make a complete recovery.

Long-term studies on survivors of the atomic bombs in Japan have shown that full recovery is possible and that ARS does not affect family genetics.

You can learn more about ARS by reading the answers to some common questions below.

What is acute radiation in outer space?

Research shows that space radiation poses a significant risk to astronauts. Space radiation is different from the radiation humans have exposure to on Earth and is far more dangerous. In space, the acceleration of radiation to the speed of light strips away the electrons, leaving only the atom’s nucleus. Unlike UV radiation from the sun, it is not possible to block or avoid it. The amount of radiation exposure determines the risk of a variety of complications, including cancer and ARS.

What did Chornobyl radiation do to people?

According to the United Nations Scientific Committee on the Effect of Atomic Radiation, 134 first responders from the Chornobyl disaster received a diagnosis of ARS. Although some accounts and dramatizations (such as HBO’s “Chornobyl”) portray these people dying instantly, this is not historically accurate. Of the 134 affected people, 28 died within 4 months of the accident. Another 19 died over the next 2 decades. The remaining individuals recovered from ARS.

Is acute radiation syndrome fatal?

Cardiovascular/central nervous system ARS is fatal, but it’s possible to recover from the other ARS subtypes. Recovery depends on the amount of exposure and how quickly treatment occurs. Following exposure to lower doses of radiation, many people make a full recovery.

Outer space and radiation in TV and movies

ARS has been the subject of many films and TV series. Some focus on true-life events, such as the Hiroshima bombings or the Chornobyl disaster, but others are speculative and look into future or outer space settings where ARS might occur. Over the years, ARS has been a plot point in various popular TV shows, including “Doctor Who,” “House,” “Star Trek,” “CSI,” “24,” and “For All Mankind.”

It’s important to know that although ARS is a very real condition, it’s extremely rare.

You’ll only develop ARS if you have exposure to a very high amount of radiation over a very short period. Although 139 first responders to the Chornobyl disaster developed ARS, no civilians from the surrounding areas received a diagnosis. Research has linked radiation exposure to thyroid conditions and some types of cancer in the surrounding areas but not to additional cases of ARS. In fact, some studies indicate that the most significant effect of the disaster might have been a psychosocial effect on those living in the area.

Researchers are still studying the effects of space radiation and its possible impact on astronauts. Data indicates that some people are more susceptible than others to space radiation, but the reason for this is not currently known. Studies are in progress to find the answer to this question and to study other effects of space radiation. These studies will help protect the health of future astronauts.

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Acute radiation syndrome is a serious health condition resulting from exposure to a very large amount of radiation. The symptoms and their severity depend on the amount of exposure. In the most severe cases, ARS is fatal, but if you have exposure to smaller amounts of radiation, you can make a full recovery.

The treatment will focus on helping your body recover from any damage while speeding up the removal of the radiation. The management of symptoms such as pain and dehydration is also generally part of the treatment approach. The time to recover depends on the amount of exposure, but it may take weeks, months, or years.

Please note that we have chosen to use the Ukrainian spelling of Chornobyl rather than the Russian spelling of Chernobyl.