{{Short description|Result of nuclear radiation exposure}} {{Redirect|Radiation poisoning}} {{Infobox medical condition | name = Acute radiation syndrome | synonyms = Radiation poisoning, radiation sickness, radiation toxicity | image = Autophagosomes.jpg | caption = Radiation causes cellular degradation by [[autophagy]] | field = [[Critical care medicine]], [[Hematology]], [[Emergency medicine]] | symptoms = '''Early''': Nausea, vomiting, skin burns, loss of appetite<ref name=CDC2019/><br/>'''Later''': Infections, bleeding, dehydration, confusion<ref name=CDC2019/> | complications = [[Radiation-induced cancer|Cancer]];<ref name="Cancer">{{cite web |url=http://dels.nas.edu/resources/static-assets/materials-based-on-reports/reports-in-brief/beir_vii_final.pdf |title=Beir VII: Health Risks from Exposure to Low Levels of Ionizing Radiation |work=The National Academy |access-date=2019-12-02 |archive-date=2020-03-07 |archive-url=https://web.archive.org/web/20200307120103/http://dels.nas.edu/resources/static-assets/materials-based-on-reports/reports-in-brief/beir_vii_final.pdf |url-status=dead }}</ref> [[Infection]] | onset = Within days (dose-dependent)<ref name=CDC2019/> | duration = | types = Bone marrow syndrome, gastrointestinal syndrome, neurovascular syndrome<ref name=CDC2019/><ref name=SMJ2010/> | causes = Large [[absorbed dose|amounts]] of [[ionizing radiation]] over a short period of time<ref name=CDC2019/> | risks = | diagnosis = Based on history of exposure and symptoms<ref name=NORD2019/> | differential = Sepsis; [[Heat stroke]]; [[Gastroenteritis]] | prevention = [[ALARA]] principle (time, distance, shielding); [[Potassium iodide]]; decontamination of skin regions | treatment = [[Supportive care]] ([[blood transfusions]], [[antibiotics]], [[colony stimulating factors]], [[stem cell transplant]])<ref name=SMJ2010/> | medication = [[Filgrastim]], [[antiemetic]]s, [[analgesics]] | prognosis = Depends on the exposure dose<ref name=NORD2019/> | frequency = Rare<ref name=SMJ2010/> }}
<!-- Definition and symptoms --> '''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 [[absorbed dose|amounts]] of [[ionizing radiation]] in a short period of time.<ref name="CDC2019">{{cite web|date=22 April 2019|title=A Fact Sheet for Physicians|url=https://www.cdc.gov/radiation-emergencies/hcp/clinical-guidance/ars.htmlCDC_AA_refVal=https%3A%2F%2Femergency.cdc.gov%2Fradiation%2Farsphysicianfactsheet.asp|access-date=17 May 2019|website=[[Centers for Disease Control and Prevention|CDC]]|series=CDC Radiation Emergencies Acute Radiation Syndrome|language=en-us|archive-date=18 May 2019|archive-url=https://web.archive.org/web/20190518165919/https://www.cdc.gov/nceh/radiation/emergencies/arsphysicianfactsheet.htm?CDC_AA_refVal=https%3A%2F%2Femergency.cdc.gov%2Fradiation%2Farsphysicianfactsheet.asp|url-status=live}}</ref> Symptoms can start within an hour of exposure, and can last for several months.<ref name=CDC2019/><ref name=SMJ2010/><ref name="Review09">{{cite journal|vauthors=Xiao M, Whitnall MH|date=January 2009|title=Pharmacological countermeasures for the acute radiation syndrome|journal=Curr Mol Pharmacol|volume=2|issue=1|pages=122–133|doi=10.2174/1874467210902010122|pmid=20021452}}</ref> Early symptoms are usually nausea, vomiting and loss of appetite.<ref name=CDC2019/> In the following hours or weeks, initial symptoms may appear to improve, before the development of additional symptoms, after which either recovery or death follows.<ref name=CDC2019/>
<!-- Cause and diagnosis --> ARS involves a total dose of greater than 0.7 [[Gray (unit)|Gy]] (70 [[Rad (unit)|rad]]), that generally occurs from a source outside the body, delivered within a few minutes.<ref name=CDC2019/> Sources of such radiation can occur accidentally or intentionally.<ref>{{cite journal |last1=Chao |first1=NJ |title=Accidental or intentional exposure to ionizing radiation: biodosimetry and treatment options. |journal=Experimental Hematology |date=April 2007 |volume=35 |issue=4 Suppl 1 |pages=24–7 |doi=10.1016/j.exphem.2007.01.008 |pmid=17379083|doi-access=free }}</ref> They may involve [[nuclear reactors]], [[cyclotrons]], certain devices used in [[cancer therapy]], [[nuclear weapons]], or [[radiological weapons]].<ref name=NORD2019/> 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.<ref name=CDC2019/><ref name=SMJ2010/> The [[Cell (biology)|cell]]s that are most affected are generally those that are rapidly dividing.<ref name=SMJ2010/> At high doses, this causes DNA damage that may be irreparable.<ref name=NORD2019/> Diagnosis is based on a history of exposure and symptoms.<ref name=NORD2019>{{cite web |title=Radiation Sickness |url=https://rarediseases.org/rare-diseases/radiation-sickness/ |website=National Organization for Rare Disorders |access-date=6 June 2019 |archive-date=12 August 2019 |archive-url=https://web.archive.org/web/20190812152608/https://rarediseases.org/rare-diseases/radiation-sickness/ |url-status=live }}</ref> Repeated [[complete blood count]]s (CBCs) can indicate the severity of exposure.<ref name=CDC2019/>
<!-- Treatment and prognosis --> Treatment of ARS is generally [[supportive care]]. This may include [[blood transfusions]], [[antibiotics]], [[colony-stimulating factors]], or [[stem cell transplant]].<ref name=SMJ2010/> Radioactive material remaining on the skin or in the stomach should be removed. If [[Iodine-131|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.<ref name=NORD2019/>
<!-- Epidemiology and history --> ARS is generally rare.<ref name=SMJ2010>{{cite journal |last1=Donnelly |first1=EH |last2=Nemhauser |first2=JB |last3=Smith |first3=JM |last4=Kazzi |first4=ZN |last5=Farfán |first5=EB |last6=Chang |first6=AS |last7=Naeem |first7=SF |title=Acute radiation syndrome: assessment and management. |journal=Southern Medical Journal |date=June 2010 |volume=103 |issue=6 |pages=541–546 |doi=10.1097/SMJ.0b013e3181ddd571 |pmid=20710137 |s2cid=45670675 |url=https://zenodo.org/record/1234911 |access-date=2019-06-24 |archive-date=2019-06-26 |archive-url=https://web.archive.org/web/20190626230448/https://zenodo.org/record/1234911 |url-status=live }}</ref> A single event can affect a large number of people.<ref>{{Citation |last=Acosta |first=Robert |title=Radiation Syndrome |date=2025 |work=StatPearls |url=http://www.ncbi.nlm.nih.gov/books/NBK441931/ |access-date=2026-01-05 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=28722960 |last2=Warrington |first2=Steven J.}}</ref> The vast majority of cases involving ARS, alongside [[Effects of nuclear explosions|blast effects]], were inflicted by the [[atomic bombings of Hiroshima and Nagasaki]], with post-attack deaths in the tens of thousands. [[Nuclear and radiation accidents and incidents]] sometimes cause ARS; the worst, the [[Chernobyl disaster|Chernobyl nuclear power plant disaster]], caused 134 cases and 28 deaths.<ref name="CDC2019" /> ARS differs from [[chronic radiation syndrome]], which occurs following prolonged exposures to relatively low doses of radiation, and from [[radiation-induced cancer]].<ref>{{cite book |last1=Akleyev |first1=Alexander V. |title=Chronic Radiation Syndrome |date=2014 |publisher=Springer Science & Business Media |isbn=978-3642451171 |page=1 |url=https://books.google.com/books?id=tUm9BAAAQBAJ&q="chronic%20radiation%20syndrome"&pg=PA1 |language=en}}</ref><ref>{{cite book |last1=Gusev |first1=Igor |last2=Guskova |first2=Angelina |last3=Mettler |first3=Fred A. |title=Medical Management of Radiation Accidents |date=2001 |publisher=CRC Press |isbn=978-1420037197 |page=18 |url=https://books.google.com/books?id=p6b4qDorN4wC&pg=PA18 |language=en}}</ref>
==Signs and symptoms== {{See also|Effects of nuclear explosions on human health}} [[File:Radiation Sickness.png|thumb|upright=1.4|Radiation sickness]]
Classically, ARS is divided into three main presentations: [[Haematopoiesis|hematopoietic]], [[gastrointestinal]], and [[neurological|neuro]][[Blood vessel|vascular]]. These syndromes may be preceded by a [[prodrome]].<ref name=SMJ2010/> The speed of symptom onset is related to radiation exposure, with greater doses resulting in a shorter delay in symptom onset.<ref name=SMJ2010/> These presentations presume whole-body exposure, and many of them are markers that are invalid if the entire body has not been exposed. Each syndrome requires that the tissue showing the syndrome itself be exposed (e.g., gastrointestinal syndrome is not seen if the stomach and intestines are not exposed to radiation). Some areas affected are:
# Hematopoietic. This syndrome is marked by a drop in the number of [[blood cells]], called [[aplastic anemia]]. This may result in infections, due to a low number of [[white blood cells]], bleeding, due to a lack of [[platelets]], and [[anemia]], due to too few [[red blood cells]] in circulation.<ref name=SMJ2010/> These changes can be detected by blood tests after receiving a whole-body acute dose as low as {{convert|0.25|Gy|rad|lk=on}}, though they might never be felt by the patient if the dose is below {{convert|1|Gy|rad}}. Conventional trauma and burns resulting from a bomb blast are complicated by the poor wound healing caused by hematopoietic syndrome, increasing mortality. # Gastrointestinal. This syndrome often follows absorbed doses of {{convert|6|-|30|Gy|rad}}.<ref name=SMJ2010/> The signs and symptoms of this form of radiation injury include [[nausea]], [[vomiting]], [[anorexia (symptom)|loss of appetite]], and [[abdominal pain]].<ref name="Christensen2014">{{cite journal|vauthors=Christensen DM, Iddins CJ, Sugarman SL |title=Ionizing radiation injuries and illnesses|date=February 2014|journal=Emerg Med Clin North Am|volume=32|issue=1|pages=245–265|pmid=24275177|doi=10.1016/j.emc.2013.10.002}}</ref> Vomiting in this time-frame (1-2h post-exposure) is a marker for whole body exposures that are in the fatal range above {{convert|4|Gy|rad}}. Without exotic treatment such as [[bone marrow transplant]], death with this dose is common,<ref name=SMJ2010/> due generally more to infection than gastrointestinal dysfunction. # Neurovascular. This syndrome typically occurs at absorbed doses greater than {{convert|30|Gy|rad}}, though it may occur at doses as low as {{convert|10|Gy|rad}}.<ref name=SMJ2010/> It presents with neurological symptoms such as [[dizziness]], [[headache]], or [[decreased level of consciousness]], occurring within minutes to a few hours, with an absence of vomiting, and is almost always fatal, even with aggressive intensive care.<ref name=SMJ2010/>
Early symptoms of ARS typically include nausea, vomiting, headaches, fatigue, [[fever]], and a short period of [[Erythema|skin reddening]].<ref name=SMJ2010/> These symptoms may occur at radiation doses as low as {{convert|0.35|Gy|rad}}. These symptoms are common to many illnesses, and may not, by themselves, indicate acute radiation sickness.<ref name=SMJ2010/>
===Dose effects=== {{Whole-body absorbed dose symptom}}
A similar table and description of symptoms (given in [[Roentgen equivalent man|rems]], where 100 rem = 1 [[Sievert|Sv]]), derived from data from the effects on humans subjected to the [[atomic bombings of Hiroshima and Nagasaki]], the indigenous peoples of the [[Marshall Islands]] subjected to the [[Castle Bravo]] thermonuclear bomb, animal studies and lab experiment accidents, have been compiled by the [[United States Department of Defense|U.S. Department of Defense]].<ref>{{cite book|first1=Samuel|last1=Glasstone|title=The Effects of Nuclear Weapons|year=1962|publisher=U.S. Department of Defense, U.S. Atomic Energy Commission|url=https://books.google.com/books?id=Ovu108BraNUC|pages=588–597}}</ref>
A person who was less than {{convert|1|mile}} from the atomic bomb ''[[Little Boy]]''{{'s}} [[hypocenter]] at Hiroshima, Japan, was found to have absorbed about 9.46 grays (Gy) of ionizing radiation.<ref name="Geggel 2018">{{cite web | last=Geggel | first=Laura | title=Human Bone Reveals How Much Radiation Hiroshima Bomb Released – And It's Staggering | website=livescience.com | date=2018-05-01 | url=https://www.livescience.com/62445-hiroshima-atomic-bomb-radiation.html | access-date=2019-12-27 | archive-date=2019-12-27 | archive-url=https://web.archive.org/web/20191227112753/https://www.livescience.com/62445-hiroshima-atomic-bomb-radiation.html | url-status=live }}</ref><ref name="Phillips 2018">{{cite news | last=Phillips | first=Kristine | title=A single jawbone has revealed just how much radiation Hiroshima bomb victims absorbed | newspaper=Washington Post | date=2018-05-02 | url=https://www.washingtonpost.com/news/retropolis/wp/2018/05/02/a-single-jawbone-has-revealed-just-how-much-radiation-hiroshima-bomb-victims-absorbed/ | access-date=2019-12-27 | archive-date=2019-12-27 | archive-url=https://web.archive.org/web/20191227161830/https://www.washingtonpost.com/news/retropolis/wp/2018/05/02/a-single-jawbone-has-revealed-just-how-much-radiation-hiroshima-bomb-victims-absorbed/ | url-status=live }}</ref><ref name="Cullings Fujita Funamoto Grant 2006 pp. 219–254">{{cite journal | last1=Cullings | first1=Harry M. | last2=Fujita | first2=Shoichiro | last3=Funamoto | first3=Sachiyo | last4=Grant | first4=Eric J. | last5=Kerr | first5=George D. | last6=Preston | first6=Dale L. | title=Dose Estimation for Atomic Bomb Survivor Studies: Its Evolution and Present Status | journal=Radiation Research | publisher=Radiation Research Society | volume=166 | issue=1 | year=2006 | issn=0033-7587 | pmid=16808610 | doi=10.1667/rr3546.1 | pages=219–254| bibcode=2006RadR..166..219C | s2cid=32660773 }}</ref><ref name="Ozasa Grant Kodama 2018 pp. 162–169">{{cite journal | last1=Ozasa | first1=Kotaro | last2=Grant | first2=Eric J | last3=Kodama | first3=Kazunori | title=Japanese Legacy Cohorts: The Life Span Study Atomic Bomb Survivor Cohort and Survivors' Offspring | journal=Journal of Epidemiology | publisher=Japan Epidemiological Association | volume=28 | issue=4 | date=2018-04-05 | issn=0917-5040 | pmid=29553058 | pmc=5865006 | doi=10.2188/jea.je20170321 | pages=162–169}}</ref> The doses at the hypocenters of the Hiroshima and Nagasaki atomic bombings were 240 and 290 Gy, respectively.<ref name="Holdstock 1995 p.">{{cite book | last=Holdstock | first=Douglas | title=Hiroshima and Nagasaki : retrospect and prospect | publisher=Frank Cass | location=London; Portland, OR | year=1995 | isbn=978-1-135-20993-3 | oclc=872115191 | page=4 | url=https://books.google.com/books?id=ynUBAwAAQBAJ&pg=PA4}}</ref>
===Skin changes=== {{main|Radiation burn}}
[[File:Daghlian-hand.jpg|thumb|[[Harry K. Daghlian]]'s hand 9 days after he had manually stopped a [[Prompt criticality|prompt critical]] fission reaction during an accident with what later obtained the nickname the [[demon core]]. He received a dose of 5.1 [[Sievert|Sv]],<ref>{{Citation |last1 = McLaughlin |first1 = Thomas P. |last2 = Monahan |first2 = Shean P. |last3 = Pruvost |first3 = Norman L. |last4 = Frolov |first4 = Vladimir V. |last5 = Ryazanov |first5 = Boris G. |last6 = Sviridov |first6 = Victor I. |date = May 2000 |title = A Review of Criticality Accidents |place = [[Los Alamos, New Mexico]] |publisher = [[Los Alamos National Laboratory]] |pages = 74–75 |id = LA-13638 |url = http://www.orau.org/ptp/Library/accidents/la-13638.pdf |access-date = April 21, 2010 |url-status = live |archive-url = https://web.archive.org/web/20070927235352/http://www.orau.org/ptp/Library/accidents/la-13638.pdf |archive-date = September 27, 2007 }}</ref> or 3.1 [[Gray (unit)|Gy]].<ref name=hempelman/> He died 16 days after this photo was taken.]] [[List of cutaneous conditions#Ionizing radiation-induced|Cutaneous radiation syndrome]] (CRS) refers to the skin symptoms of radiation exposure.<ref name=CDC2019/> Within a few hours after irradiation, a transient and inconsistent [[erythema|redness]] (associated with [[itch]]ing) can occur. Then, a latent phase may occur and last from a few days up to several weeks, when intense reddening, [[blister]]ing, and [[Ulcer (dermatology)|ulceration]] of the irradiated site is visible. In most cases, healing occurs by regenerative means; however, very large skin doses can cause permanent hair loss, damaged [[Sebaceous gland|sebaceous]] and [[sweat gland]]s, [[atrophy]], [[fibrosis]] (mostly [[keloids]]), decreased or increased skin pigmentation, and ulceration or [[necrosis]] of the exposed tissue.<ref name=CDC2019/>
As seen at [[Chernobyl disaster|Chernobyl]], when skin is irradiated with high energy [[beta particles]], moist [[desquamation]] (peeling of skin) and similar early effects can heal, only to be followed by the collapse of the dermal vascular system after two months, resulting in the loss of the full thickness of the exposed skin.<ref>The medical handling of skin lesions following high-level accidental irradiation, IAEA Advisory Group Meeting, September 1987 Paris.</ref> Another example of skin loss caused by high-level exposure of radiation is during the [[Tokaimura nuclear accidents#1999 accident|1999 Tokaimura nuclear accident]], where technician Hisashi Ouchi had lost a majority of his skin due to the high amounts of radiation he absorbed during the irradiation. This effect had been demonstrated previously with pig skin using high energy beta sources at the Churchill Hospital Research Institute, in [[Oxford]].<ref>{{citation |author=Wells J |contribution=Non-Uniform Irradiation of Skin: Criteria for limiting non-stochastic effects |title=Proceedings of the Third International Symposium of the Society for Radiological Protection |series=Advances in Theory and Practice |isbn=978-0-9508123-0-4 |volume=2 |pages=537–542 |year=1982 |display-authors=etal}}</ref>
==Cause== [[File:Death by haematopoietic syndrome of radiation sickness- influence of dose rate.png|thumb|upright=1.4|Both dose and dose rate contribute to the severity of acute radiation syndrome. The effects of [[dose fractionation]] or rest periods before repeated exposure also shift the [[LD50]] dose upwards.]] [[File:PIA17601-Comparisons-RadiationExposure-MarsTrip-20131209.png|thumb|upright=1.4|Comparison of Radiation Doses – includes the amount detected on the trip from Earth to Mars by the [[Radiation assessment detector|RAD]] on the [[Mars Science Laboratory|MSL]] (2011–2013).<ref name="SCI-20130531a">{{cite journal |last=Kerr |first=Richard |title=Radiation will make astronauts' trip to Mars even riskier |date=31 May 2013 |journal=[[Science (journal)|Science]] |volume=340 |page=1031 |doi=10.1126/science.340.6136.1031 |issue=6136 |pmid=23723213 |bibcode=2013Sci...340.1031K }}</ref><ref name="SCI-20130531b">{{cite journal |title=Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory |journal=[[Science (journal)|Science]] |date=31 May 2013 |volume=340 |issue=6136 |pages=1080–1084 |doi=10.1126/science.1235989 |pmid=23723233 |last1=Zeitlin |first1=C. |last2=Hassler |first2=D. M. |last3=Cucinotta |first3=F. A. |last4=Ehresmann |first4=B. |last5=Wimmer-Schweingruber |first5=R. F. |last6=Brinza |first6=D. E. |last7=Kang |first7=S. |last8=Weigle |first8=G. |last9=Böttcher |first9=S. |last10=Böhm |first10=E. |last11=Burmeister |first11=S. |last12=Guo |first12=J. |last13=Köhler |first13=J. |last14=Martin |first14=C. |last15=Posner |first15=A. |last16=Rafkin |first16=S. |last17=Reitz |first17=G. |s2cid=604569 |display-authors=1 |bibcode=2013Sci...340.1080Z }}</ref><ref name="NYT-20130530">{{cite news |last=Chang |first=Kenneth |title=Data Point to Radiation Risk for Travelers to Mars |url=https://www.nytimes.com/2013/05/31/science/space/data-show-higher-cancer-risk-for-mars-astronauts.html |date=30 May 2013 |newspaper=New York Times |access-date=31 May 2013 |url-status=live |archive-url=https://web.archive.org/web/20130531031329/http://www.nytimes.com/2013/05/31/science/space/data-show-higher-cancer-risk-for-mars-astronauts.html |archive-date=31 May 2013 }}</ref><ref name="SN-20130629">{{cite journal|last=Gelling|first=Cristy|title=Mars trip would deliver big radiation dose; Curiosity instrument confirms expectation of major exposures|url=http://www.sciencenews.org/view/generic/id/350728/description/Mars_trip_would_deliver_big_radiation_dose|volume=183|issue=13|page=8|journal=[[Science News]]|date=June 29, 2013|access-date=July 8, 2013|url-status=live|archive-url=https://web.archive.org/web/20130715023856/http://www.sciencenews.org/view/generic/id/350728/description/Mars_trip_would_deliver_big_radiation_dose|archive-date=July 15, 2013|doi=10.1002/scin.5591831304|url-access=subscription}}</ref>]]
ARS is caused by exposure to a large dose of ionizing radiation {{nowrap|(> ≈{{hsp}}0.1 Gy)}} over a short period of time {{nowrap|(> ≈{{hsp}}0.1 Gy/h)}}. Alpha and beta radiation have low penetrating power and are unlikely to affect vital internal organs from outside the body. Any type of ionizing radiation can cause burns, but alpha and beta radiation can only do so if [[radioactive contamination]] or [[nuclear fallout]] is deposited on the individual's skin or clothing.
Gamma and neutron radiation can travel much greater distances and penetrate the body easily, so whole-body irradiation generally causes ARS before skin effects are evident. Local gamma irradiation can cause skin effects without any sickness. In the early twentieth century, radiographers would commonly calibrate their machines by irradiating their own hands and measuring the time to onset of [[erythema]].<ref>{{cite journal |author1=Inkret, William C. |author2=Meinhold, Charles B. |author3=Taschner, John C. |title=A Brief History of Radiation Protection Standards |journal=Los Alamos Science |year=1995 |issue=23 |pages=116–123 |url=http://www.fas.org/sgp/othergov/doe/lanl/00326631.pdf |access-date=12 November 2012|url-status=live|archive-url=https://web.archive.org/web/20121029111614/http://www.fas.org/sgp/othergov/doe/lanl/00326631.pdf |archive-date=29 October 2012 }}</ref>
===Accidental=== {{Main|Nuclear and radiation accidents and incidents}}
Accidental exposure may be the result of a [[criticality accident|criticality]] or [[radiotherapy]] accident. There have been [[#Notable incidents|numerous]] criticality accidents dating back to [[Manhattan project|atomic testing]] during World War II, while computer-controlled radiation therapy machines such as [[Therac-25]] played a major part in radiotherapy accidents. The latter of the two is caused by the failure of equipment software used to monitor the radiational dose given. Human error has played a large part in accidental exposure incidents, including some of the criticality accidents, and larger scale events such as the [[Chernobyl disaster]]. Other events have to do with [[orphan source]]s, in which radioactive material is unknowingly kept, sold, or stolen. The [[Goiânia accident]] is an example, where a forgotten radioactive source was taken from a hospital, resulting in the deaths of 4 people from ARS.<ref name=MTCDPub>{{cite book | title = The Radiological accident in Goiânia | publisher = International Atomic Energy Agency | location = Vienna | year = 1988 | isbn = 92-0-129088-8 | url = http://www-pub.iaea.org/MTCD/publications/PDF/Pub815_web.pdf | access-date = 2005-08-22 | archive-url = https://web.archive.org/web/20160312190235/http://www-pub.iaea.org/MTCD/publications/PDF/Pub815_web.pdf | archive-date = 2016-03-12 | url-status = live }}</ref> [[Crimes involving radioactive substances#Intentional or attempted theft of radioactive material|Theft and attempted theft]] of radioactive material by clueless thieves has also led to lethal exposure in at least one incident.<ref>{{Cite web |title=Grozny orphaned source, 1999 |url=http://www.johnstonsarchive.net/nuclear/radevents/1999RUS1.html |access-date=2022-04-02 |website=www.johnstonsarchive.net |archive-date=2022-05-16 |archive-url=https://web.archive.org/web/20220516150629/http://www.johnstonsarchive.net/nuclear/radevents/1999RUS1.html |url-status=live }}</ref>
Exposure may also come from routine spaceflight and [[solar flare]]s that result in radiation effects on earth in the form of [[solar storm]]s. During spaceflight, astronauts are exposed to both [[galactic cosmic ray|galactic cosmic radiation]] (GCR) and [[Solar proton event|solar particle event]] (SPE) radiation. The exposure particularly occurs during flights beyond [[low Earth orbit]] (LEO). Evidence indicates past SPE radiation levels that would have been lethal for unprotected astronauts.<ref>{{cite magazine |url=https://www.newscientist.com/article/dn7142 |title=Superflares could kill unprotected astronauts |magazine=New Scientist |date=21 March 2005 |url-status=live |archive-url=https://web.archive.org/web/20150327023245/http://www.newscientist.com/article/dn7142 |archive-date=27 March 2015 }}</ref> GCR levels that might lead to acute radiation poisoning are less well understood.<ref>{{cite book |author=National Research Council (U.S.). Ad Hoc Committee on the Solar System Radiation Environment and NASA's Vision for Space Exploration |url=http://www.nap.edu/catalog.php?record_id=11760 |title=Space Radiation Hazards and the Vision for Space Exploration |publisher=National Academies Press |year=2006 |isbn=978-0-309-10264-3 |url-status=live |archive-url=https://web.archive.org/web/20100328082542/http://www.nap.edu/catalog.php?record_id=11760 |archive-date=2010-03-28 |doi=10.17226/11760 }}</ref> The latter cause is rarer, with an event possibly occurring during the [[solar storm of 1859]].
===Intentional=== {{Main|Atomic bombings of Hiroshima and Nagasaki|Crimes involving radioactive substances|Radiological warfare}}
{{Pollution sidebar|Radiation}}
Intentional exposure is controversial as it involves the use of [[nuclear weapon]]s, [[Human radiation experiments|human experiments]], or is given to a victim in an act of murder. The intentional atomic bombings of Hiroshima and Nagasaki resulted in tens of thousands of casualties; the survivors of these bombings are known today as {{em|[[hibakusha]]}}. Nuclear weapons emit large amounts of [[thermal radiation]] as visible, infrared, and ultraviolet light, to which the atmosphere is largely transparent. This event is also known as "flash", where radiant heat and light [[Effects of nuclear explosions#Survivability|are bombarded]] into any given victim's exposed skin, causing radiation burns.<ref name="Nuclear Bomb Effects">{{cite web|title=Nuclear Bomb Effects|url=http://www.solcomhouse.com/nuclearholocaust.htm|work=The Atomic Archive|publisher=solcomhouse.com|access-date=12 September 2011|archive-date=5 April 2014|archive-url=https://web.archive.org/web/20140405093238/http://www.solcomhouse.com/nuclearholocaust.htm|url-status=dead}}</ref> Death is highly likely, and radiation poisoning is almost certain if one is caught in the open with no terrain or building masking-effects within a radius of 0–3 km from a 1{{nbs}}megaton airburst. The [[LD50|50% chance of death]] from the blast extends out to {{nowrap|≈{{hsp}}8 km}} from a 1{{nbs}}megaton atmospheric explosion.<ref>{{cite web |url=http://www.johnstonsarchive.net/nuclear/nukgr3.gif |title=Range of weapon effects |website=johnstonarchive.net |access-date=7 March 2022 |archive-date=12 November 2020 |archive-url=https://web.archive.org/web/20201112005510/http://www.johnstonsarchive.net/nuclear/nukgr3.gif |url-status=live }}</ref>
Scientific testing on humans within the United States occurred extensively throughout the atomic age. Experiments took place on a range of subjects including, but not limited to; the disabled, children, soldiers, and incarcerated persons, with the level of understanding and consent given by subjects varying from complete to none. Since 1997 there have been requirements for patients to give informed consent, and to be notified if experiments were classified.<ref name="AH">{{cite web|url=https://www.atomicheritage.org/history/human-radiation-experiments|title=Human Radiation Experiments|work=www.atomicheritage.org|date=July 11, 2017|access-date=December 1, 2019|archive-date=December 30, 2019|archive-url=https://web.archive.org/web/20191230002506/https://www.atomicheritage.org/history/human-radiation-experiments|url-status=live}}</ref> The [[Soviet nuclear program]] also included medical study of exposed citizens living near [[Semipalatinsk Test Site]], withholding information about nuclear testing or health risks.<ref>{{Cite news|title = Живущие в стеклянном доме|url = http://www.svoboda.org/content/article/27214509.html|newspaper = Радио Свобода|access-date = 2015-08-31|language = ru|first = Юрий|last = Федоров|archive-date = 2015-09-01|archive-url = https://web.archive.org/web/20150901185602/http://www.svoboda.org/content/article/27214509.html|url-status = live}}</ref><ref>{{Cite news|title = Slow Death In Kazakhstan's Land Of Nuclear Tests|url = https://www.rferl.org/a/soviet_nuclear_testing_semipalatinsk_20th_anniversary/24311518.html|newspaper = RadioFreeEurope/RadioLiberty|date = 2011-08-29|access-date = 2015-08-31|archive-date = 2016-09-20|archive-url = https://web.archive.org/web/20160920041939/http://www.rferl.org/content/soviet_nuclear_testing_semipalatinsk_20th_anniversary/24311518.html|url-status = live}}</ref> The program also involved severe radiation exposures to workers of the [[Mayak]] facility, especially the early work of [[Forced labor in the Soviet Union|forced laborers]] on the [[A-1 (nuclear reactor)|A-1 nuclear reactor]]. Criminal activity has involved murder and attempted murder carried out through abrupt victim contact with a radioactive substance such as [[polonium]] or [[plutonium]]. The death of [[Alexander Litvinenko]] is widely believed to be [[Radiological warfare#Radiological assassination|assassination via polonium poisoning]] and on the order of the Russian [[Federal Security Service|FSB]],<ref name="death">{{cite journal |last1=McFee |first1=R. B. |last2=Leikin |first2=J. B. |date=2009 |title=Death by polonium-210: lessons learned from the murder of former Soviet spy Alexander Litvinenko |url=https://www.researchgate.net/publication/24206298 |journal=Seminars in Diagnostic Pathology |volume=26 |issue=1 |pages=61–67 |doi=10.1053/j.semdp.2008.12.003 |pmid=19292030}}</ref> and polonium is also suspected as the cause of death for [[Cause of Yasser Arafat's death#Poisoning with polonium|Yasser Arafat]],<ref>{{cite web |date=July 10, 2012 |title=Arafat's death: what is Polonium-210? |url=http://www.aljazeera.com/video/asia-pacific/2012/07/2012746748407858.html |url-status=live |archive-url=https://web.archive.org/web/20190619142649/https://www.aljazeera.com/video/asia-pacific/2012/07/2012746748407858.html |archive-date=June 19, 2019 |access-date=June 19, 2019 |work=[[Al Jazeera English|Al Jazeera]]}}</ref> [[Yuri Shchekochikhin]], [[Lecha Islamov]] and [[Roman Tsepov]].<ref name="Sweeney">{{cite book |last1=Sweeney |first1=J. |title=Killer in the Kremlin |publisher=Penguin |year=2022 |isbn=9781804991206 |page=120}}</ref>
==Pathophysiology== The most commonly used predictor of ARS is the whole-body [[absorbed dose]]. Several related quantities, such as the [[equivalent dose]], [[effective dose (radiation)|effective dose]], and [[committed dose]], are used to gauge long-term stochastic biological effects such as cancer incidence, but they are not designed to evaluate ARS.<ref name="ICRP103">{{cite journal|title=The 2007 Recommendations of the International Commission on Radiological Protection |journal=Annals of the ICRP |year=2007 |volume=37 |series=ICRP publication 103 |issue=2–4 |url=http://www.icrp.org/publication.asp?id=ICRP%20Publication%20103 |access-date=17 May 2012 |isbn=978-0-7020-3048-2 |url-status=live |archive-url=https://web.archive.org/web/20121116084754/http://www.icrp.org/publication.asp?id=ICRP+Publication+103 |archive-date=16 November 2012 |author1=Icrp }}</ref> To help avoid confusion between these quantities, absorbed dose is measured in units of [[gray (unit)|grays]] (in [[SI]], unit symbol ''Gy'') or [[rad (unit)|rad]] (in [[CGS]]), while the others are measured in [[sievert (unit)|sieverts]] (in SI, unit symbol ''Sv'') or [[rem (unit)|rem]] (in CGS). 1 rad = 0.01 Gy and 1 rem = 0.01 Sv.<ref name="remdefinition">{{cite book |title=The Effects of Nuclear Weapons |edition=Revised |publisher=US Department of Defense |year=1962 |page=579}}</ref>
In most of the acute exposure scenarios that lead to radiation sickness, the bulk of the radiation is external whole-body gamma, in which case the absorbed, equivalent, and effective doses are all equal. There are exceptions, such as the Therac-25 accidents and the 1958 [[Cecil Kelley criticality accident]], where the absorbed doses in Gy or rad are the only useful quantities, because of the targeted nature of the exposure to the body.
[[Radiotherapy]] treatments are typically prescribed in terms of the local absorbed dose, which might be 60 Gy or higher. The dose is fractionated to about 2 Gy per day for ''curative'' treatment, which allows normal tissues to undergo [[DNA repair|repair]], allowing them to tolerate a higher dose than would otherwise be expected. The dose to the targeted tissue mass must be averaged over the entire body mass, most of which receives negligible radiation, to arrive at a whole-body absorbed dose that can be compared to the table above.{{citation needed|date=August 2017}}
===DNA damage=== Exposure to high doses of radiation causes [[DNA]] damage, later creating serious and even lethal [[Chromosome abnormality|chromosomal aberrations]] if left unrepaired. Ionizing radiation can produce [[reactive oxygen species]], and does directly damage cells by causing localized ionization events. The former is very damaging to DNA, while the latter events create clusters of DNA damage.<ref>{{cite journal |author1=Yu, Y. |author2=Cui, Y. |author3=Niedernhofer, L. |author4=Wang, Y. |title=Occurrence, biological consequences and human health relevance of oxidative stress-induced DNA damage |journal=Chemical Research in Toxicology |volume=29 |issue=12 |pages=2008–2039 |year=2016|doi=10.1021/acs.chemrestox.6b00265 |pmid=27989142 |pmc=5614522 }}</ref><ref name="Eccles L. 2011">{{cite journal |author1=Eccles, L. |author2=O'Neill, P. |author3=Lomax, M. |title=Delayed repair of radiation induced DNA damage: Friend or foe? |journal=Mutation Research |volume=711 |issue=1–2 |pages=134–141 |year=2011|doi=10.1016/j.mrfmmm.2010.11.003 |pmid=21130102 |pmc=3112496 }}</ref> This damage includes loss of [[nucleobases]] and breakage of the sugar-phosphate backbone that binds to the nucleobases. The DNA organization at the level of [[histones]], [[nucleosomes]], and [[chromatin]] also affects its susceptibility to [[radiation damage]].<ref>{{cite journal |author1=Lavelle, C. |author2=Foray, N. |title=Chromatin structure and radiation-induced DNA damage: From structural biology to radiobiology |journal=International Journal of Biochemistry & Cell Biology |volume=49 |pages=84–97 |year=2014|doi=10.1016/j.biocel.2014.01.012 |pmid=24486235 }}</ref> Clustered damage, defined as at least two lesions within a helical turn, is especially harmful.<ref name="Eccles L. 2011"/> While DNA damage happens frequently and naturally in the cell from endogenous sources, clustered damage is a unique effect of radiation exposure.<ref>{{cite journal |author=Goodhead, D. |title=Initial events in the cellular effects of ionizing radiations: Clustered damage in DNA |journal=International Journal of Radiation Biology |volume=65 |issue=1 |pages=7–17 |year=1994 |doi=10.1080/09553009414550021 |pmid=7905912}}</ref> Clustered damage takes longer to repair than isolated breakages, and is less likely to be repaired at all.<ref>{{cite journal |author1=Georgakilas, A. |author2=Bennett, P. |author3=Wilson, D. |author4=Sutherland, B. |title=Processing of bistranded abasic DNA clusters in gamma-irradiated human hematopoietic cells |journal=Nucleic Acids Research |volume=32 |issue=18 |pages=5609–5620 |year=2004|doi=10.1093/nar/gkh871 |pmid=15494449 |pmc=524283}}</ref> Larger radiation doses are more prone to cause tighter clustering of damage, and closely localized damage is increasingly less likely to be repaired.<ref name="Eccles L. 2011"/>
Somatic mutations cannot be passed down from parent to offspring, but these mutations can propagate in cell lines within an organism. Radiation damage can also cause chromosome and [[chromatid]] aberrations, and their effects depend on in which stage of the mitotic cycle the cell is when the irradiation occurs. If the cell is in [[interphase]], while it is still a single strand of chromatin, the damage will be replicated during the S1 phase of the [[cell cycle]], and there will be a break on both chromosome arms; the damage then will be apparent in both [[daughter cells]]. If the irradiation occurs after replication, only one arm will bear the damage; this damage will be apparent in only one daughter cell. A damaged chromosome may cyclize, binding to another chromosome, or to itself.<ref>{{cite book |author1=Hall, E. |author2=Giaccia, A. |title=Radiobiology for the Radiobiologist |publisher=Lippincott Williams & Wilkins |edition=6th |year=2006}}</ref>
==Diagnosis== Diagnosis is typically made based on a history of significant radiation exposure and suitable clinical findings.<ref name=SMJ2010/> An [[Complete blood count|absolute lymphocyte count]] can give a rough estimate of radiation exposure.<ref name=SMJ2010/> Time from exposure to vomiting can also give estimates of exposure levels if they are less than 10 Gy (1000 rad).<ref name=SMJ2010/>
==Prevention==
A guiding principle of radiation safety is ''as low as reasonably achievable'' (ALARA).<ref name=CDC2015Safe>{{cite web |title=Radiation Safety |url=http://www.cdc.gov/nceh/radiation/safety.html |website=Centers for Disease Control and Prevention |access-date=23 April 2020 |language=en-us |date=7 December 2015 |archive-date=7 May 2020 |archive-url=https://web.archive.org/web/20200507074245/https://www.cdc.gov/nceh/radiation/safety.html |url-status=live }}</ref> This means try to avoid exposure as much as possible and includes the three components of time, distance, and shielding.<ref name=CDC2015Safe/>
===Time=== The longer that humans are subjected to radiation the larger the dose will be. The advice in the [[Nuclear warfare|nuclear war]] manual entitled ''[[Nuclear War Survival Skills]]'' published by [[Cresson Kearny]] in the [[United States|U.S.]] was that if one needed to leave the shelter then this should be done as rapidly as possible to minimize exposure.<ref>{{cite book |last=Kearny |first=Cresson H. |author-link=Cresson Kearny |title=Nuclear War Survival Skills |url=http://oism.org/nwss/ |year=1988 |publisher=Oregon Institute of Science and Medicine |isbn=978-0-942487-01-5 |url-status=live |archive-url=https://web.archive.org/web/20171017183044/http://www.oism.org/nwss/ |archive-date=2017-10-17 |df=dmy-all}}</ref>
In chapter 12, he states that "[q]uickly putting or dumping wastes outside is not hazardous once fallout is no longer being deposited. For example, assume the shelter is in an area of heavy fallout and the dose rate outside is 400 [[Roentgen (unit)|roentgen (R)]] per hour, enough to give a potentially fatal dose in about an hour to a person exposed in the open. If a person needs to be exposed for only 10 seconds to dump a bucket, in this 1/360 of an hour he will receive a dose of only about 1 R. Under war conditions, an additional 1-R dose is of little concern." In peacetime, radiation workers are taught to work as quickly as possible when performing a task that exposes them to radiation, such as for instance during recovery of a radioactive source.
===Shielding=== {{See also|Radiation protection}}
Usually, matter attenuates radiation, so placing any mass (e.g., lead, dirt, sandbags, vehicles, water, even air) between humans and the source will reduce the radiation dose. This is not always the case, however; care should be taken when constructing shielding for a specific purpose. For example, although high atomic number materials are very effective in shielding [[photon]]s, using them to shield [[beta particle]]s may cause higher radiation exposure due to the production of [[bremsstrahlung]] x-rays, and hence low atomic number materials are recommended. Also, using material with a high [[neutron activation]] [[cross section (physics)|cross section]] to shield neutrons will result in the shielding material itself becoming radioactive and hence more dangerous than if it were not present.{{citation needed|date=November 2017}}
There are many types of shielding strategies that can be used to reduce the effects of radiation exposure. Internal contamination protective equipment such as respirators are used to prevent internal deposition as a result of inhalation and ingestion of radioactive material. Dermal protective equipment, which protects against external contamination, provides shielding to prevent radioactive material from being deposited on external structures.<ref>{{Cite web |url=https://www.remm.nlm.gov/radiation_ppe.htm |title=Personal Protective Equipment (PPE) in a Radiation Emergency |series=Radiation Emergency Medical Management |website=www.remm.nlm.gov |language=en |access-date=2018-06-26 |df=dmy-all |archive-date=2018-06-21 |archive-url=https://web.archive.org/web/20180621143558/https://www.remm.nlm.gov/radiation_ppe.htm |url-status=dead }}</ref> While these protective measures do provide a barrier from radioactive material deposition, they do not shield from externally penetrating gamma radiation. This leaves anyone exposed to penetrating gamma rays at high risk of ARS.
Naturally, shielding the entire body from high energy gamma radiation is optimal, but the required mass to provide adequate attenuation makes functional movement nearly impossible. In the event of a radiation catastrophe, medical and security personnel need [[Radiation protection#External penetrating radiation|mobile protection equipment]] in order to safely assist in containment, evacuation, and many other necessary public safety objectives.
Research has been done exploring the feasibility of partial body shielding, a radiation protection strategy that provides adequate attenuation to only the most radio-sensitive organs and tissues inside the body. Irreversible stem cell damage in the bone marrow is the first life-threatening effect of intense radiation exposure and therefore one of the most important bodily elements to protect. Due to the regenerative property of [[hematopoietic stem cell]]s, it is only necessary to protect enough bone marrow to repopulate the exposed areas of the body with the shielded supply.<ref>{{Cite journal |last1=Waterman |first1=Gideon |last2=Kase |first2=Kenneth |last3=Orion |first3=Itzhak |last4=Broisman |first4=Andrey |last5=Milstein |first5=Oren |date=September 2017 |title=Selective Shielding of Bone Marrow |journal=Health Physics |volume=113 |issue=3 |pages=195–208 |doi=10.1097/hp.0000000000000688 |pmid=28749810 |bibcode=2017HeaPh.113..195W |s2cid=3300412 |issn=0017-9078}}</ref> This concept allows for the development of lightweight mobile radiation protection equipment, which provides adequate protection, deferring the onset of ARS to much higher exposure doses. One example of such equipment is the [[StemRad#360 Gamma|360 Gamma]], a radiation protection belt that applies selective shielding to protect the bone marrow stored in the pelvic area as well as other radio sensitive organs in the abdominal region without hindering functional mobility.
===Reduction of incorporation=== Where radioactive contamination is present, an [[elastomeric respirator]], [[dust mask]], or good hygiene practices may offer protection, depending on the nature of the contaminant. [[Potassium iodide]] (KI) tablets can reduce the risk of cancer in some situations due to slower uptake of ambient radioiodine. Although this does not protect any organ other than the thyroid gland, their effectiveness is still highly dependent on the time of ingestion, which would protect the gland for the duration of a twenty-four-hour period. They do not prevent ARS as they provide no shielding from other environmental radionuclides.<ref>{{cite web |title=Radiation and its Health Effects |url=https://www.nrc.gov/about-nrc/radiation/rad-health-effects.html |publisher=Nuclear Regulatory Commission |access-date=2013-11-19 |url-status=live |archive-url=https://web.archive.org/web/20131014200532/http://www.nrc.gov/about-nrc/radiation/rad-health-effects.html |archive-date=2013-10-14 |df=dmy-all}}</ref>
===Fractionation of dose=== {{main|Dose fractionation}}
{{More citations needed section|date=November 2025}} If an intentional dose is broken up into a number of smaller doses, with time allowed for recovery between irradiations, the same total dose causes less [[cell death]]. Even without interruptions, a reduction in dose rate below 0.1 Gy/h also tends to reduce cell death.<ref name=ICRP103 /> This technique is routinely used in radiotherapy.
The human body contains many types of [[cell (biology)|cell]]s and a human can be killed by the loss of a single type of cells in a vital organ. For many short term radiation deaths (3–30 days), the loss of two important types of cells that are constantly being regenerated causes death. The loss of cells forming [[blood cells]] ([[bone marrow]]) and the cells in the digestive system ([[Intestinal villus|microvilli]], which form part of the wall of the [[intestines]]) is fatal.
==Management== [[File:Death by haematopoietic syndrome of radiation sickness- influence of medical care.png|thumb|Effect of medical care on acute radiation syndrome]] Treatment usually involves supportive care with possible symptomatic measures employed. The former involves the possible use of [[antibiotics]], [[blood products]], [[colony stimulating factors]], and [[stem cell transplant]].<ref name=SMJ2010/>
===Antimicrobials=== {{main|Treatment of infections after exposure to ionizing radiation}}
There is a direct relationship between the degree of the [[neutropenia]] that emerges after exposure to radiation and the increased risk of developing infection. Since there are no controlled studies of therapeutic intervention in humans, most of the current recommendations are based on animal research.{{citation needed|date=August 2017}}
The [[Treatment of infections after accidental or hostile exposure to ionizing radiation|treatment]] of established or suspected infection following exposure to radiation (characterized by neutropenia and fever) is similar to the one used for other febrile neutropenic patients. However, important differences between the two conditions exist. Individuals that develop neutropenia after exposure to radiation are also susceptible to irradiation damage in other tissues, such as the gastrointestinal tract, lungs and central nervous system. These patients may require therapeutic interventions not needed in other types of neutropenic patients. The response of irradiated animals to antimicrobial therapy can be unpredictable, as was evident in experimental studies where [[metronidazole]]<ref>{{cite journal |doi=10.1093/jac/33.1.63 |pmid=8157575 |author1=Brook, I. |author2=Ledney, G.D. |title=Effect of antimicrobial therapy on the gastrointestinal bacterial flora, infection and mortality in mice exposed to different doses of irradiation |journal=[[Journal of Antimicrobial Chemotherapy]] |issn=1460-2091 |volume=33 |issue=1 |pages=63–74 |year=1994 |url=https://zenodo.org/record/1234339 |access-date=2019-06-24 |archive-date=2020-09-25 |archive-url=https://web.archive.org/web/20200925040700/https://zenodo.org/record/1234339 |url-status=live }}</ref> and [[pefloxacin]]<ref>{{cite journal |vauthors=Patchen ML, Brook I, Elliott TB, Jackson WE |title=Adverse effects of pefloxacin in irradiated C3H/HeN mice: correction with glucan therapy |journal=Antimicrobial Agents and Chemotherapy |issn=0066-4804 |volume=37 |issue=9 |pages=1882–1889 |year=1993 |pmid=8239601 |pmc=188087 |doi=10.1128/AAC.37.9.1882}}</ref> therapies were detrimental.
Antimicrobials that reduce the number of the strict [[Anaerobic infection|anaerobic]] component of the gut flora (i.e., metronidazole) generally should not be given because they may enhance systemic infection by aerobic or [[facultative bacteria]], thus facilitating mortality after irradiation.<ref>{{cite journal |doi=10.1080/09553008814551081 |pmid=3283066 |vauthors=Brook I, Walker RI, MacVittie TJ |title=Effect of antimicrobial therapy on the bowel flora and bacterial infection in irradiated mice |journal=[[International Journal of Radiation Biology]] |issn=1362-3095 |volume=53 |pages=709–718 |year=1988 |issue=5 |url=https://zenodo.org/record/1234459 |access-date=2019-06-24 |archive-date=2020-09-23 |archive-url=https://web.archive.org/web/20200923135353/https://zenodo.org/record/1234459 |url-status=live }}</ref>
An empirical regimen of antimicrobials should be chosen based on the pattern of bacterial susceptibility and [[nosocomial infections]] in the affected area and medical center and the degree of neutropenia. Broad-spectrum empirical therapy (see below for choices) with high doses of one or more antibiotics should be initiated at the onset of fever. These antimicrobials should be directed at the eradication of Gram-negative aerobic bacilli (i.e., [[Enterobacteriaceae]], ''[[Pseudomonas]]'') that account for more than three quarters of the isolates causing sepsis. Because aerobic and facultative Gram-positive bacteria (mostly [[alpha-hemolytic streptococci]]) cause [[sepsis]] in about a quarter of the victims, coverage for these organisms may also be needed.<ref>{{cite journal |vauthors=Brook I, Ledney D |title=Quinolone therapy in the management of infection after irradiation |journal=[[Crit Rev Microbiol]] |year=1992 |volume=18 |issue=4 |pages=18235–18246 |doi=10.3109/10408419209113516 |pmid=1524673 }}</ref>
A standardized management plan for people with neutropenia and fever should be devised. Empirical regimens contain antibiotics broadly active against Gram-negative aerobic bacteria ([[Quinolone antibiotic|quinolones]]: i.e., [[ciprofloxacin]], [[levofloxacin]], a third- or fourth-generation cephalosporin with pseudomonal coverage: e.g., [[cefepime]], [[ceftazidime]], or an aminoglycoside: i.e. [[gentamicin]], [[amikacin]]).<ref>{{cite journal |vauthors=Brook I, Elliot TB, Ledney GD, Shomaker MO, Knudson GB |title=Management of postirradiation infection: lessons learned from animal models|journal=[[Military Medicine (journal)|Military Medicine]] |issn=0026-4075 |year=2004 |volume=169 |issue=3|pages=194–197 |pmid=15080238|doi=10.7205/MILMED.169.3.194|doi-access=free }}</ref>
==Prognosis== {{See also|Radiation-induced cancer}}
The prognosis for ARS is dependent on the exposure dose, with anything above 8 Gy being almost always lethal, even with medical care.<ref name=NORD2019/><ref>{{cite web|url=https://www.remm.nlm.gov/ars_timephases5.htm|title=Time Phases of Acute Radiation Syndrome (ARS) – Dose >8 Gy|publisher=Radiation Emergency Medical Management|access-date=December 1, 2019|archive-date=June 28, 2019|archive-url=https://web.archive.org/web/20190628210747/https://www.remm.nlm.gov/ars_timephases5.htm|url-status=dead}}</ref> [[#Skin changes|Radiation burn]]s from lower-level exposures usually manifest after 2 months, while reactions from the burns occur months to years after radiation treatment.<ref name="Andrews"/><ref name="pmid10580952">{{ cite journal |author1=Wagner, L. K. |author2=McNeese, M. D. |author3=Marx, M. V. |author4=Siegel, E. L. | title = Severe skin reactions from interventional fluoroscopy: case report and review of the literature | journal = Radiology | volume = 213 | issue = 3 | pages = 773–776 | year = 1999 | pmid = 10580952 | doi = 10.1148/radiology.213.3.r99dc16773}}</ref> Complications from ARS include an increased risk of developing radiation-induced cancer later in life. According to the controversial but commonly applied [[linear no-threshold model]], any exposure to ionizing radiation, even at doses too low to produce any symptoms of radiation sickness, can induce cancer due to cellular and genetic damage. The probability of developing cancer is a linear function with respect to the [[effective radiation dose]]. Radiation cancer may occur after ionizing radiation exposure following a latent period averaging 20 to 40 years.<ref name="pmid15486177">{{cite journal | author = Gawkrodger, D. J. | title = Occupational skin cancers | journal = Occupational Medicine | location = London | volume = 54 | issue = 7 | pages = 458–63 | year = 2004 | pmid = 15486177 | doi = 10.1093/occmed/kqh098 | doi-access = }}</ref><ref name="Andrews">{{ cite book |author1=James, W. |author2=Berger, T. |author3=Elston, D. | year = 2005 | title = Andrews' Diseases of the Skin: Clinical Dermatology | edition = 10th | publisher = Saunders | isbn = 0-7216-2921-0 }}</ref>
==History== Acute effects of ionizing radiation were first observed when [[Wilhelm Röntgen]] intentionally subjected his fingers to X-rays in 1895. He published his observations concerning the burns that developed that eventually healed, and misattributed them to ozone. Röntgen believed the [[free radical]] produced in air by X-rays from the ozone was the cause, but other free radicals produced within the body are now understood to be more important. David Walsh first established the symptoms of radiation sickness in 1897.<ref>{{cite journal |last1=Walsh |first1=D |title=Deep Tissue Traumatism from Roentgen Ray Exposure. |journal=[[The BMJ|British Medical Journal]] |date=31 July 1897 |volume=2 |issue=1909 |pages=272–3 |doi=10.1136/bmj.2.1909.272 |pmid=20757183|pmc=2407341 }}</ref>
Ingestion of radioactive materials caused many [[radiation-induced cancer]]s in the 1930s, but no one was exposed to high enough doses at high enough rates to bring on ARS.
The [[atomic bombings of Hiroshima and Nagasaki]] resulted in high acute doses of radiation to a large number of Japanese people, allowing for greater insight into its symptoms and dangers. Red Cross Hospital Surgeon [[Terufumi Sasaki]] led intensive research into the syndrome in the weeks and months following the Hiroshima and Nagasaki bombings. Sasaki and his team were able to monitor the effects of radiation in patients of varying proximities to the blast itself, leading to the establishment of three recorded stages of the syndrome. Within 25–30 days of the explosion, Sasaki noticed a sharp drop in white blood cell count and established this drop, along with symptoms of fever, as prognostic standards for ARS.<ref>{{cite book |last=Carmichael |first=Ann G. |title=Medicine: A Treasury of Art and Literature |year=1991 |publisher=Harkavy Publishing Service|location=New York|isbn=978-0-88363-991-7 |page=376}}</ref> Actress [[Midori Naka]], who was present during the atomic bombing of Hiroshima, was the first incident of radiation poisoning to be extensively studied. Her death on 24 August 1945 was the first death ever to be officially certified as a result of ARS (or "Atomic bomb disease").
There are two major databases that track radiation accidents: The American [[ORISE]] REAC/TS and the European [[IRSN]] ACCIRAD. REAC/TS shows 417 accidents occurring between 1944 and 2000, causing about 3000 cases of ARS, of which 127 were fatal.<ref>{{cite journal |last=Turai |first=István |author2=Veress, Katalin |title=Radiation Accidents: Occurrence, Types, Consequences, Medical Management, and the Lessons to be Learned |journal=Central European Journal of Occupational and Environmental Medicine |year=2001 |volume=7 |issue=1 |pages=3–14 |url=http://www.omfi.hu/cejoem/Volume7/Vol7No1/CE01_1-01.html |access-date=1 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20130515051324/http://www.omfi.hu/cejoem/Volume7/Vol7No1/CE01_1-01.html |archive-date=2013-05-15 |df=dmy-all}}</ref> ACCIRAD lists 580 accidents with 180 ARS fatalities for an almost identical period.<ref>{{cite journal |author1=Chambrette, V. |author2=Hardy, S. |author3=Nenot, J.C. |title=Les accidents d'irradiation: Mise en place d'une base de données "ACCIRAD" à I'IPSN |journal=Radioprotection |year=2001 |volume=36 |issue=4 |pages=477–510 |doi=10.1051/radiopro:2001105|url=http://www.radioprotection.org/articles/radiopro/pdf/2001/04/Chambrette.pdf |access-date=13 June 2012 |url-status=live |archive-url=https://web.archive.org/web/20160304224446/http://www.radioprotection.org/articles/radiopro/pdf/2001/04/Chambrette.pdf |archive-date=4 March 2016|doi-access=free }}</ref> The two deliberate bombings are not included in either database, nor are any possible radiation-induced cancers from low doses. The detailed accounting is difficult because of confounding factors. ARS may be accompanied by conventional injuries such as steam burns, or may occur in someone with a pre-existing condition undergoing radiotherapy. There may be multiple causes for death, and the contribution from radiation may be unclear. Some documents may incorrectly refer to radiation-induced cancers as radiation poisoning, or may count all overexposed individuals as survivors without mentioning if they had any symptoms of ARS.
===Notable cases=== <!--A name is required here, while an article on or about the individual is preferred--> The following table includes only individuals known to have symptoms of ARS. Excluded are cases of chronic radiation syndrome, such as the case of [[Albert Stevens]]. Chronic radiation syndrome is characterized by an exposure of lower doses of radiation, over a longer duration, than with ARS. The table also excludes cases where an individual was exposed to so much radiation that death occurred before medical assistance or dose estimations could be made, such as an attempted cobalt-60 thief who reportedly died 30 minutes after exposure.<ref>{{cite web |title=Criminal Dies Stealing Radioactive Material |url=https://www.nti.org/analysis/articles/criminal-dies-stealing-radioactive-material/|url-status=dead|archive-url=https://web.archive.org/web/20211006132919/https://www.nti.org/analysis/articles/criminal-dies-stealing-radioactive-material/|archive-date=2021-10-06 |website=Nuclear Threat Initiative |orig-date=1999|access-date=October 30, 2023}}</ref> The result column represents the time from exposure to the time of death. As ARS is measured by a whole-body [[absorbed dose]], the exposure column only includes units of gray (Gy).
{| class="wikitable sortable" |- ! Date ! Name ! Exposure [[Gray (unit)|Gy]] ! Incident/accident ! Result |- | August 21, 1945 | [[Harry Daghlian]] | align="center" data-sort-value="3.1" | 3.1 Gy<ref name=hempelman>{{cite conference|last1=Hempelman|first1=Louis Henry|last2=Lushbaugh|first2=Clarence C.|last3=Voelz|first3=George L.|title=What Has Happened to the Survivors of the Early Los Alamos Nuclear Accidents?|conference=Conference for Radiation Accident Preparedness|date=October 19, 1979|url=http://www.orau.org/ptp/pdf/accidentsurvivorslanl.pdf|access-date=January 5, 2013|publisher=[[Los Alamos Scientific Laboratory]]|location=Oak Ridge|id=LA-UR-79-2802|url-status=live|archive-url=https://web.archive.org/web/20140912141857/http://www.orau.org/ptp/pdf/accidentsurvivorslanl.pdf|archive-date=September 12, 2014}} Patient numbers in this document have been identified as: 1 – Daghlian, 2 – Hemmerly, 3 – Slotin, 4 – Graves, 5 – Kline, 6 – Young, 7 – Cleary, 8 – Cieleski, 9 – Schreiber, 10 – Perlman</ref> | [[Demon core#First incident|Harry Daghlian criticality accident]] | data-sort-value="25" | Death in 25 days |- | rowspan="2" | May 21, 1946 | [[Louis Slotin]] | align="center" data-sort-value="11" | 11 Gy<ref>{{cite report|last=Lawrence|first=James N. P.|title=Internal Memorandum on Los Alamos Criticality Accidents, 1945–1946, Personnel Exposures|date=6 October 1978|publisher=Los Alamos Scientific Laboratory|id=H-l-78}}</ref> | rowspan="2" | [[Demon core#Second incident|Slotin criticality accident]] | data-sort-value="9" | Death in 9 days |- | [[Alvin C. Graves]] | align="center" data-sort-value="1.9" | 1.9 Gy<ref name="hempelman"/> | data-sort-value="6935" | Death in 19 years<!--~6935 days--> |- | December 30, 1958 | [[Cecil Kelley criticality accident|Cecil Kelley]] | align="center" data-sort-value="36" | 36 Gy<ref>{{cite book|title= Professional guide to diseases|edition= 9th|editor-last= Harold|editor-first= Catherine|place= Philadelphia|publisher= Lippincott Williams & Wilkins|isbn= 978-0-7817-7899-2|oclc= 475981026|url= https://archive.org/details/isbn_9780781778992|year= 2009}}</ref> | [[Cecil Kelley criticality accident]] | data-sort-value="1.6" | Death in 38 hours<!--~1.6 days--> |- | July 24, 1964 | Robert Peabody | align="center" data-sort-value="100" | ~100 Gy<ref>{{cite book|first1=Thomas P.| last1=McLaughlin| first2=Shean P.| last2=Monahan| first3=Norman L.| last3=Pruvost| first4=Vladimir V.| last4=Frolov| first5=Boris G.| last5=Ryazanov| first6=Victor I.| last6=Sviridov|title=A Review of Criticality Accidents: 2000 Revision|year=2000|publisher=Los Alamos National Laboratory|location=Los Alamos, NM|pages=33–34|url=http://www.csirc.net/docs/reports/la-13638.pdf|url-status=usurped|archive-url=https://web.archive.org/web/20090911070650/http://www.csirc.net/docs/reports/la-13638.pdf|archive-date=2009-09-11|access-date=October 30, 2023}}</ref><ref>{{cite book|author=[United States Nuclear Regulatory Commission], Division of Compliance, Region I|title=UNC Recovery Sytems [sic]: Compliance Investigation Report|date=September 16, 1964|volume=3 - Supplemental Report with Exhibits|url=https://www.nrc.gov/docs/ML0601/ML060130267.pdf|url-status=live|archive-url=https://web.archive.org/web/20220107151039/https://www.nrc.gov/docs/ML0601/ML060130267.pdf|archive-date=2022-01-07|access-date=October 30, 2023}}</ref> | [[Wood River Junction, Rhode Island#Criticality accident|Robert Peabody criticality accident]] | data-sort-value="2" | Death in 49 hours<!--~2.04 days--> |- | April 26, 1986 | [[Aleksandr Akimov]] | align="center" data-sort-value="15" | 15 Gy<ref>{{cite book|url=https://books.google.com/books?id=7gQ0DwAAQBAJ&q=Akimov&pg=PT419|title=Chernobyl: the history of a nuclear catastrophe|author=Serhii Plokhii|publisher=Basic Books|year=2018|author-link=Serhii Plokhii|isbn=978-1541617087}}</ref> | [[Chernobyl disaster]] | data-sort-value="14" | Death in 14 days |- |April 26, 1986 |Andrei Tormozin | align="center" |8.7 Gy<ref>{{Cite web |last=UNSCEAR |first=UNSCEAR |date=August 1988 |title=UNSCEAR 1988 Report - Annex G |url=https://www.unscear.org/unscear/uploads/documents/publications/UNSCEAR_1988_Annex-G.pdf |url-status=live |website=UNSCEAR 1988 Report - Annex G}}</ref> |[[Chernobyl disaster]] |Death in 24 years |- | rowspan="2" | September 30, 1999 | Hisashi Ouchi | align="center" data-sort-value="11" | 17 Gy<ref name="Lamar 937">{{Cite journal |last=Lamar |first=Joe |date=1999-10-09 |title=Japan's worst nuclear accident leaves two fighting for life |journal=BMJ: British Medical Journal |volume=319 |issue=7215 |pages=937 |doi=10.1136/bmj.319.7215.937a |issn=0959-8138 |pmc=1116790 |pmid=10514143}}</ref> | rowspan="2" | [[Tokaimura nuclear accidents|Tokaimura nuclear accident]] | data-sort-value="9" | Death in 83 days |- | Masato Shinohara | align="center" data-sort-value="1.9" | 10 Gy<ref name="Lamar 937"/> | data-sort-value="210" | Death in 210 days |- | December 2, 2001 | Patient "1-DN" | align="center" data-sort-value="3.6" | 3.6 Gy<ref>{{Cite book |url=https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1660web-81061875.pdf |title=The radiological accident in Lia, Georgia. |date=2014 |publisher=[[International Atomic Energy Agency]] |isbn=978-92-0-103614-8 |location=Vienna |oclc=900016880}}</ref> <!--3.6 is an average of the 4 numbers mentioned per [[WP:CALC]].--> | [[Lia radiological accident]] | data-sort-value="893" | Death in 893 days |}
==Animals== Thousands of scientific experiments have been performed to study ARS in animals.{{citation needed|date=October 2017}} There is a simple guide for predicting survival and death in mammals, including humans, following the acute effects of inhaling radioactive particles.<ref>{{cite journal |author=Wells, J. |title=A guide to the prognosis for survival in mammals following the acute effects of inhaled radioactive particles |journal=Journal of the Institute of Nuclear Engineers |issn=0368-2595 |volume=17 |issue=5 |pages=126–131 |year=1976}}</ref>
==See also== {{Portal|Nuclear technology}} {{Div col|colwidth=20em}} * [[5-Androstenediol]] * [[Ionizing radiation#Health effects|Biological effects of ionizing radiation]] * [[Biological effects of radiation on the epigenome]] * [[CBLB502]] * [[Ex-Rad]] * [[List of civilian nuclear accidents]] * [[List of military nuclear accidents]] * [[Nuclear terrorism]] * [[Orders of magnitude (radiation)]] * [[Prehydrated electrons]] * [[Rongelap Atoll]] {{Div col end}}
==References== {{Reflist}}
:<small>''This article incorporates [[Copyright status of work by the U.S. government|public domain material]] from websites or documents of the U.S. [[Armed Forces Radiobiology Research Institute]] and the U.S. [[Centers for Disease Control and Prevention]]''</small>
== External links == {{Commons category}} * {{cite web|title=Emergency preparedness and subject matter expertise on the medical management of radiation incidents|url=https://orise.orau.gov/reacts/|url-status=live|publisher=U.S. [[Radiation Emergency Assistance Center Training Site REACts]] |archive-url=https://web.archive.org/web/20230505224545/https://orise.orau.gov/reacts/ |archive-date=2023-05-05}} * {{cite web |url=http://www.bt.cdc.gov/radiation/arsphysicianfactsheet.asp |publisher=U.S. [[Centers for Disease Control and Prevention]] |title=Fact sheet on Acute Radiation Syndrome |access-date=2006-07-22 |archive-url=https://web.archive.org/web/20060716035111/http://www.bt.cdc.gov/radiation/arsphysicianfactsheet.asp |archive-date=2006-07-16 |url-status=dead |df=dmy-all}} * {{cite web |url=http://www-pub.iaea.org/MTCD/publications/PDF/Pub1106_scr.pdf |title=The criticality accident in Sarov |publisher=[[International Atomic Energy Agency]] |year=2001}} – A well documented account of the biological effects of a criticality accident. * {{cite web |url=http://www.usuhs.mil/afrri |title=Armed Forces Radiobiology Research Institute |access-date=2011-07-01 |archive-date=2015-03-03 |archive-url=https://web.archive.org/web/20150303030215/http://www.usuhs.mil/afrri |url-status=dead }} * More information on bone marrow shielding can be found in the ''[https://journals.lww.com/health-physics/pages/default.aspx Health Physics Radiation Safety Journal]'' article: {{cite journal |title=Selective Shielding of Bone Marrow: An Approach to Protecting Humans from External Gamma Radiation|journal=Health Physics|volume=113|issue=3|pages=195–208|date=September 2017|last1=Waterman|first1=Gideon|last2=Kase|first2=Kenneth|last3=Orion|first3=Itzhak|last4=Broisman|first4=Andrey|last5=Milstein|first5=Oren|s2cid=3300412|doi=10.1097/HP.0000000000000688|pmid=28749810 |bibcode=2017HeaPh.113..195W }}, or in the [[OECD|Organisation for Economic Co-operation and Development (OECD)]] and the [[Nuclear Energy Agency|Nuclear Energy Agency (NEA)]]'s 2015 report: [https://www.oecd-nea.org/rp/docs/2014/crpph-r2014-5.pdf "Occupational Radiation Protection in Severe Accident Management"] {{medical resources |DiseasesDB = |ICD10 = {{ICD10|T|66||t|66}} |ICD9 = {{ICD9|990}} |ICDO = |OMIM = |MedlinePlus = 000026 |eMedicineSubj = article |eMedicineTopic = 834015 |MeshID = D011832 }}
{{Consequences of external causes}} {{Radiation}} {{Radiation poisoning}} {{Radiation protection}} {{Authority control}}
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