The term acute radiation syndrome (ARS) is used to describe the onset and progression of symptoms after exposure to ionizing radiation, and the clinical course is divided into four phases [1] [2]:

• Prodromal phase - Gastrointestinal complaints, such as nausea, vomiting, diarrhea, weakness and weight loss due to profound damage of the intestinal mucosa are main features. In doses of 1-2 grays (Gy), symptoms appear two or more hours after exposure, whereas very severe and lethal exposures (6-8 and > 8 Gy, respectively) produce symptoms in less than 30 minutes [3]. Headaches, altered consciousness, and fever may be observed as well [3]. Cutaneous radiation syndrome (CRS) is the term used to describe skin-related changes that range from mild erythema in this period to more severe lesions encountered later on [4].
• Latent phase - Myelosuppression is the hallmark of latent phase, developing between 1 and 5 weeks after initial exposure, again depending on the severity of exposure [5]. Lymphopenia, granulocytopenia, and thrombocytopenia are most prominent findings, accompanied by anorexia and generalized fatigue [1]. Pneumonitis, pulmonary edema, and varying degrees of skin depilation are other notable symptoms [1] [3].
• Illness manifestation phase - Considered as the "critical phase" of radiation exposure, it is characterized by the dose-dependent occurrence of impaired central nervous system activity (headaches, impaired cognitive function, disorientation, ataxia, and convulsions), the progression of vomiting and fever to life-threatening bloody diarrhea, cardiovascular collapse, and shock. Additionally, acute respiratory distress syndrome (ARDS), purpura, electrolyte disturbances and infection due to severe myelosuppression that may lead to sepsis are frequently reported [1] [2].
• Final outcome - Patients either recover from the deleterious effects induced by radiation, or suffer from fatal organ damage, and the most significant predictors of outcome are the dosage received and heterogeneity of dosage, as either single or multiple organs may be affected [3].

• Fatigue

  They presented with run-down symptoms of neck strain associated with throbbing headache, irritability, loss of appetite, fatigue, memory difficulties, and numbness of extremities. [ncbi.nlm.nih.gov]

  Lymphopenia, granulocytopenia, and thrombocytopenia are most prominent findings, accompanied by anorexia and generalized fatigue. Pneumonitis, pulmonary edema, and varying degrees of skin depilation are other notable symptoms. [symptoma.com]

  Later symptoms, which may last hours or months, include loss of appetite, fatigue, fever, nausea, vomiting, diarrhea and possibly even seizures, coma and death. Radiation poisoning also usually causes skin damage. [healthland.time.com]

  Acute Radiation Syndrome occurs at 150-350 rem, presenting nausea, fatigue, hair loss, and skin reddening. [mirion.com]

  The leading causes of most of those early deaths were disruption to the smooth operation of hospitals, the exacerbation of pre-existing health problems, and the transfer trauma or general 'mental fatigue' from dramatic changes in life situation. [world-nuclear.org]

• Anemia

  Some patients may also present with autoimmune cytopenia (anemia and thrombocytopenia). Patients share several clinical features with Nijmegen breakage syndrome and LIG 4 deficiency (see these terms). [orpha.net]

  Anemia develops slowly, because preexisting red blood cells have a longer life span than white blood cells and platelets. Survivors have an increased incidence of radiation-induced cancer, including leukemia. [msdmanuals.com]

• Rigor

  […] licensing Supervision of personnel Use of dosimetry badges Training or certification Dental office design and radiation shielding Record keeping Equipment Radiographic training requirements for dental office personnel frequently differ from and are less rigorous [ada.org]

  […] the least common among people with radiation-induced hypopituitarism.[35] Changes in prolactin-secretion is usually mild, and vasopressin deficiency appears to be very rare as a consequence of radiation.[35] Radiation therapy accidents[edit] There are rigorous [en.wikipedia.org]

• Chills

  CHILL. Refrigerate food promptly. For more information on food irradiation and other food safety issues, contact USDA's Meat and Poultry Hotline at 1-888-MPHotline (1-888-674-6854) or visit www.fsis.usda.gov. [ Top of Page ] [web.archive.org]

• Nausea

  Some examples of the symptoms seen in radiation sickness include nausea, skin burns, hair loss and reduced organ function. In severe cases, exposure to a large amount of radiation can even cause death. [news-medical.net]

  The first symptoms of ARS are typically nausea, vomiting and diarrhea. These symptoms, the CDC says, start within minutes to days after the exposure, and can last for minutes or days. [healthland.time.com]

  The term acute radiation syndrome (ARS) is used to describe the onset and progression of symptoms after exposure to ionizing radiation, and the clinical course is divided into four phases: Prodromal phase - Gastrointestinal complaints, such as nausea, [symptoma.com]

  Effects of Whole-Body Irradiation From External Radiation or Internal Absorption Phase of Syndrome Feature Dose Range (Gy)* ,† 1–2 2–6 6–8 8–30 > 30 Prodrome Incidence of nausea and vomiting 5–50% 50–100% 75–100% 90–100% 100% Time of onset of nausea and [merckmanuals.com]

• Vomiting

  External contamination is performed by surveying the skin, while internal contamination requires sampling of the ears, the mouth, as well as urine, feces and vomit. [symptoma.com]

  Median doses cause initial anorexia, lethargy and vomiting then normality for several weeks followed by vomiting, nasal discharge, dysentery, recumbency, septicemia and a profound pancytopenia. Death is the most common outcome. [medical-dictionary.thefreedictionary.com]

  vomiting after exposure 2–6 h 1–2 h 10–60 min 10 min Minutes Duration of nausea and vomiting 24 h 24–48 h 48 h 48 h N/A (patients die in 48 h) Severity and incidence of diarrhea None None to mild ( 10%) Moderate to Severe ( > 10%) Severe ( > 95%) Severe [merckmanuals.com]

  vomiting after exposure‡ 2–6 hours 1–2 hours 10–60 minutes < 10 minutes Minutes Duration of nausea and vomiting < 24 hours 24–48 hours < 48 hours < 48 hours N/A (patients die in < 48 hours) Severity and incidence of diarrhea None None to mild (< 10%) [msdmanuals.com]

• Diarrhea

  […] acute radiation syndrome (ARS) is used to describe the onset and progression of symptoms after exposure to ionizing radiation, and the clinical course is divided into four phases: Prodromal phase - Gastrointestinal complaints, such as nausea, vomiting, diarrhea [symptoma.com]

  High doses cause intense diarrhea and dehydration and extensive skin necrosis. [medical-dictionary.thefreedictionary.com]

  The first symptoms of ARS are typically nausea, vomiting and diarrhea. These symptoms, the CDC says, start within minutes to days after the exposure, and can last for minutes or days. [healthland.time.com]

  However, some prodromal symptoms (eg, nausea, vomiting, diarrhea, tremors) are nonspecific, and causes other than radiation should be considered. [msdmanuals.com]

• Abdominal Pain

  In some emergency departments, an increasingly large number of patients with abdominal pain or headache are evaluated with CT scanning. X-rays (including CT scans) should be ordered judiciously. [emedicine.medscape.com]

  Extensive radiation to the abdomen (for lymph node, testicular, or ovarian cancer) can lead to chronic ulcers, scarring, and narrowing or perforation of the intestine, causing symptoms such as abdominal pain, vomiting, vomiting blood, and dark, tarry [merckmanuals.com]

• Xerostomia

  It prevents xerostomia in patients undergoing radiation therapy. [merckmanuals.com]

  It is used clinically to prevent xerostomia in patients undergoing radiation therapy. Adverse effects include nausea and vomiting, hypotension, and decreased serum calcium. Exposure of an unborn child to this drug could cause birth defects. [msdmanuals.com]

  Dry mouth (xerostomia) and dry eyes (xerophthalmia) can become irritating long-term problems and severely reduce the patient's quality of life. [en.wikipedia.org]

• Blister

  >15,000 mSvor more locally to the skin can cause skin reddening and blistering. [radiationanswers.org]

  […] serotonin receptor antagonist when suspected exposure is >2 Gy (↓) Loperamide, as needed for control of diarrhea (↓) Cutaneous Topical class II–III corticosteroids, topical antibiotics, and topical antihistamines applied to radiation burns, ulcer, or blisters [msdmanuals.com]

• Alopecia

  They also presented with alopecia areata which is felt to be causally linked to the radiation exposure. [ncbi.nlm.nih.gov]

Physicians must be careful when interpreting symptoms, as gastrointestinal and central nervous system complaints are nonspecific and may arise in a myriad of conditions. For this reason, patient history is the vital component of the diagnostic workup. The detailed information regarding the onset of symptoms, potential exposure to radioactive substances at the workplace, as well as presence of similar findings in other coworkers is vital in making a presumptive diagnosis [6]. The use of a Geiger-Muller probe attached to a Geiger counter to inspect patients for contamination is pivotal for confirming radiation exposure, and the entire body should be examined [6]. External contamination is performed by surveying the skin, while internal contamination requires sampling of the ears, the mouth, as well as urine, feces and vomit [6]. Laboratory studies should include complete blood counts (CBC) performed on a daily basis after admission, with a particular emphasis on total lymphocyte count, which is considered to be one of the most valid indicators of the dose of radiation received [6]. If a total lymphocyte count is > 1500/mL, the radiation dose is expected to be around 0.4 Gy, and the chance of survival is very high, whereas counts of < 500/mL indicate exposure to > 4 Gy and carry a poorer prognosis [6]. A lymphocyte count of < 100/mL is universally fatal [6]. In addition to lymphocyte count, serum amylase, and C-reactive protein (CRP) levels should be evaluated, as they are elevated in proportion to the dose received [3] [6]. In the setting of profound skin changes, procedures such as bone scintigraphy, capillary microscopy and nuclear magnetic resonance imaging should be performed, if possible [4].

Growth delay was observed in both cell lines during SAHA treatment; 2 μM SAHA treatment decreased clonogenicity and induced cell cycle block in G1 phase but 0.2 μM SAHA treatment did not show either of them. [ncbi.nlm.nih.gov]

[…] the dose required for a treatment, arranging for the dose to be delivered and making arrangements for safety of the patient and staff, and disposing of any residual radioactive material. [medical-dictionary.thefreedictionary.com]

Treatment can include radiation used in cancer therapy, where the radiation dose is focused on a small area of the body. [web.archive.org]

The absence of cellular atypia may account for a favorable prognosis and enables clear distinction from more serious diagnoses such as lentigo maligna melanoma. [ncbi.nlm.nih.gov]

If a total lymphocyte count is > 1500/mL, the radiation dose is expected to be around 0.4 Gy, and the chance of survival is very high, whereas counts of < 500/mL indicate exposure to > 4 Gy and carry a poorer prognosis. [symptoma.com]

Significant comorbidities, injuries, and burns worsen prognosis. [merckmanuals.com]

Prognosis Without treatment, the immunodeficiency may result in severe infection, sepsis and early death. The documents contained in this web site are presented for information purposes only. [orpha.net]

The role of radiation exposure in the etiology of pituitary adenoma is discussed, along with a literature review of radiation-induced tumors. [ncbi.nlm.nih.gov]

Etiology This disease is caused by mutations in the NHEJ1 (or Cernunos) gene (2q35). [orpha.net]

This case report supports experimental and epidemiological evidence implicating ultraviolet radiation as a risk factor for cataract formation. [ncbi.nlm.nih.gov]

Epidemiologic studies have shown that persons exposed to high levels of ionizing radiation have an increased risk of cancer, particularly leukemia, and later in life, breast and thyroid cancer. 1 In addition, some epidemiologic studies have found that [pediatrics.aappublications.org]

Klervi Leraud of the Radiobiology and Epidemiology Department at Fontenay-aux-Roses in Cedex, France. [scientificamerican.com]

Pathophysiological effects of radiation on atherosclerosis development and progression, and the incidence of cardiovascular complications. Med Phys 2002 ; 29 : 2391 -403. ↵ Ross R. Atherosclerosis—an inflammatory disease. [bmj.com]

According to the Centers for Disease Control and Prevention (CDC), potassium iodide prevents the thyroid gland from quickly absorbing radioactive iodine if inhaled. However, as the New York Times explains : Dr. [David J.] [healthland.time.com]

How can radiation exposure be prevented? There are steps you can take to prevent or reduce radiation exposure: If your health care provider recommends a test that uses radiation, ask about its risks and benefits. [nlm.nih.gov]

The findings of the study will be disseminated through peer-reviewed scientific journals, conference presentations, and a report will be submitted to the relevant public health authorities in the Korea Centers for Disease Control and Prevention to help [ncbi.nlm.nih.gov]

Further Reading Causes of Radiation Exposure Radiation Exposure Prevention Radiation Exposure Treatment Radiation Poisoning History Radiation and Electric Power Transmission [news-medical.net]

1. Heslet L, Bay C, Nepper-Christensen S. Acute radiation syndrome (ARS) – treatment of the reduced host defense. Int J Gen Med. 2012;5:105-115.
2. Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 18e. New York, NY: McGraw-Hill; 2012.
3. Macià i Garau M, Lucas Calduch A, López EC. Radiobiology of the acute radiation syndrome. Rep Pract Oncol Radiother. 2011;16(4):123-130.
4. Peter RU, Gottlöber P. Management of cutaneous radiation injuries: diagnostic and therapeutic principles of the cutaneous radiation syndrome. Mil Med. 2002;167(2):110-112.
5. Dörr H, Meineke V. Acute radiation syndrome caused by accidental radiation exposure - therapeutic principles. BMC Med. 2011;9:126.
6. Porter RS, Kaplan JL. Merck Manual of Diagnosis and Therapy. 19th Edition. Merck Sharp & Dohme Corp. Whitehouse Station, N.J; 2011.