Acute radiation sickness (ARS) or acute radiation syndrome negatively influences all organ systems, especially that of the hematopoietic system. The reason for it is the dependence on stem cells that are primarily affected in a situation of acute radiation exposure. Ionizing radiation causes damage to double-stranded DNA molecules resulting in the loss of proliferative function and damage to affected cells [1].

Acute radiation sickness expresses itself in three phases: prodromal, latent and manifestation phase.

The prodromal phase includes symptoms of the gastrointestinal (GI) tract such as nausea, vomiting, and diarrhea with consequent fluid, electrolyte loss, and anorexia. Non-specific symptoms like a headache, hypotension, fever, erythema are also present [2]. It is important to differentiate these symptoms from those of GI infections or other pathologies involving this system.

The latent phase is characterized by the discontinuation of symptoms seen in prodromal phase or mild exhibition of them. The duration of this phase is dependent on the dose of radiation certain subject was exposed to [2].

Manifestation phase follows after latent phase. The manifestation of ARS involves multiple organ systems, firstly that of the hematopoietic system [3].

• Hematopoietic syndrome takes place if the dose of exposure is in a range of 2-3 grays (Gy) [4]. Consequences of this syndrome are based on depletion of blood cells i.e. thrombocytopenia, leukopenia, and anemia [5].
• Cerebrovascular syndrome results from inflammation and damage to the blood vessels. The symptoms of this syndrome are cognitive impairments like disorientation, confusion, seizures and loss of balance. On examination, patients may be ataxic or have signs of papilledema. The absence of deep tendon and corneal reflexes is also noted [5].
• GI syndrome includes symptoms listed in prodromal phase in addition to abdominal cramps. Additionally, there is a serious risk of infections as a result of disturbances in mucosal barrier. Leukopenia caused by the hematopoietic syndrome too increases predisposition to infection. Destruction of mucosa can also lead to bleeding from GI tract, enhancing the presentation of anemia [5].
• In early stages, cutaneous syndrome manifests as erythema and edema. In contrast, late in the disease, signs like desquamation, ulceration, and onycholysis become evident [5] [6].

More serious complications of severe cases in ARS are accountable for systemic inflammatory response syndrome (SIRS) with following multi-organ failure (MOF) [1].

• Fever

  Non-specific symptoms like a headache, hypotension, fever, erythema are also present. It is important to differentiate these symptoms from those of GI infections or other pathologies involving this system. [symptoma.com]

  The hematopoietic syndrome occurs at 1-8 Sv, and is characterized by the following clinical signs and symptoms: 2 Nausea, vomiting, and diarrhea Mucositis, skin erythema, and fever Lymphocytopenia within 48 hours, neutropenia, and thrombocytopenia within [upmc-cbn.org]

  Symptoms Mild (1-2 Gy) Moderate (2-4 Gy) Severe (4-6 Gy) Very Severe (6 Gy) Lethal ( 8 Gy) Phase Symptoms Time to Onset 30 days 18-28 days 8-18 days 7 days 3 days Clinical Manifestations Fatigue Fever High Fever High Fever High Fever Weakness Weakness [large.stanford.edu]

  The bone marrow syndrome is characterized by anorexia (lack of appetite), fever, and malaise. There is a drop in all blood cell counts for several weeks. The primary cause of death is infection and hemorrhage. [medicinenet.com]

  Patients at this level suffer vomiting, diarrhea, dizziness, and fever. Without treatment, you could die just a few weeks after exposure. [gizmodo.com]

• Fatigue

  Symptoms include bleeding from the nose, mouth, gums, and rectum, bloody stool, bruising, confusion, dehydration, diarrhea, fainting and fatigue. [prnewswire.com]

  Some symptoms that are common with radiation sickness include nausea and vomiting, headache, fever, dizziness, disorientation, fatigue, bloody vomit and stools, hair loss, low blood pressure, and poor wound healing. [wikihow.com]

  Onset 30 days after prodrome Duration Depends on dose and underlying host factors Possible clinical effects Fatigue Weakness Lethality None likely from radiation alone Medical response As needed for signs/symptoms Counseling and long-term effects monitoring [remm.nlm.gov]

  Radiation Sickness Pathology Cause(s) Exposure to ionizing radiation, such as x-rays or radioactive substances Symptoms Nausea, hair loss, fatigue, blistering of skin Mortality Rate High Treatments Adrenaline, fluids, palliative care Show Information [house.wikia.com]

  […] known occurrence of solar particle events (SPE) and the inability to predict their occurrence, there is a possibility the crew will suffer from acute radiation sickness (ARS) with the highest likelihood of prodromal symptoms of nausea, vomiting, and fatigue [humanresearchroadmap.nasa.gov]

• Anemia

  Destruction of mucosa can also lead to bleeding from GI tract, enhancing the presentation of anemia. In early stages, cutaneous syndrome manifests as erythema and edema. [symptoma.com]

  […] characterized by the following clinical signs and symptoms: 2 Nausea, vomiting, and diarrhea Mucositis, skin erythema, and fever Lymphocytopenia within 48 hours, neutropenia, and thrombocytopenia within 20-30 days Impaired wound healing, bleeding, and anemia [upmc-cbn.org]

  Following a latent period of six months to one year after extremely high does of radiation, protein in the urine, kidney insufficiency, anemia and high blood pressure may develop. [rarediseases.org]

  Manifestations depend on dosage, ranging from anorexia, nausea, vomiting, and mild leukopenia, to thrombocytopenia with hemorrhage, severe leukopenia with infection, anemia, central nervous system damage, and death. radiation sickness n. [medical-dictionary.thefreedictionary.com]

  It can dramatically reduce the number of red blood cells, causing anemia and and increased risk of fainting. Credit: istockphoto Radiation sickness can cause visible ulcers in or on the mouth. [cbsnews.com]

• Malaise

  Acute radiation sickness is characterized by nausea, vomiting, diarrhea, anorexia, headache, malaise and rapid heartbeat (tachycardia). With mild ARS, the discomfort subsides within a few hours or days. [rarediseases.org]

  The bone marrow syndrome is characterized by anorexia (lack of appetite), fever, and malaise. There is a drop in all blood cell counts for several weeks. The primary cause of death is infection and hemorrhage. [medicinenet.com]

  […] syndrome to appear Length of the prodromal period of hematologic syndrome Length if the latent period of hematologic syndrome Declines during the latent period of hematologic syndrome although there are no other signs of illness Vomiting, diarrhea, malaise [quizlet.com]

  Systemic reactions to radiation include a general feeling of malaise, loss of appetite or nausea and vomiting, and headache. [medical-dictionary.thefreedictionary.com]

  • Symptoms are anorexia, fever, and malaise. • Drop in all blood cell counts occurs for several weeks. • Primary cause of death is infection and hemorrhage. • Survival decreases with increasing dose. • Most deaths occur within a few months after exposure [emergency.cdc.gov]

• Weight Loss

  Clinical Symptoms of Acute Radiation Syndrome (Open Table in a new window) Acute Radiation Syndrome Clinical Symptoms 0.7 Gy Hematopoietic syndrome - anemia, neutropenia 10 Gy Gastrointestinal syndrome - nausea, vomiting, dehydration, weight loss, anorexia [emedicine.medscape.com]

  Third-stage symptoms are fever, infection, vomiting, bloody diarrhea, hemorrhages, dehydration, weight loss, hair loss, and ulcers. Death usually occurs in this phase if the damage has been sufficiently severe. [britannica.com]

  loss, or fever confirmation of initial dose estimate using chromosome aberration cytogenetic bioassay when possible. [emergency.cdc.gov]

• Vomiting

  For example, damage to the GI is scored by evaluating the time of onset, severity, the frequency of vomiting or diarrhea. [symptoma.com]

  Following a dose higher than 2 Sv, most people will vomit. [upmc-cbn.org]

  Medications should be administered to treat symptoms like vomiting, diarrhea, pain and burns. Fluids, electrolytes and nutrition should be maintained. Psychological support should also be offered to these patients. [medindia.net]

  The diagnosis of ARS was initially considered for 237 persons based on symptoms of nausea, vomiting, and diarrhea. Ultimately, the diagnosis of ARS was confirmed in 134 persons. [ncbi.nlm.nih.gov]

• Nausea

  The prodromal phase includes symptoms of the gastrointestinal (GI) tract such as nausea, vomiting, and diarrhea with consequent fluid, electrolyte loss, and anorexia. [symptoma.com]

  The diagnosis of ARS was initially considered for 237 persons based on symptoms of nausea, vomiting, and diarrhea. Ultimately, the diagnosis of ARS was confirmed in 134 persons. [ncbi.nlm.nih.gov]

  These include the prodromal phase where the patient suffers from symptoms like nausea, vomiting and diarrhea, a latent phase where the patient shows apparent recovery, a manifest illness phase where most of the symptoms appear, and a fourth phase of either [medindia.net]

  The hematopoietic syndrome occurs at 1-8 Sv, and is characterized by the following clinical signs and symptoms: 2 Nausea, vomiting, and diarrhea Mucositis, skin erythema, and fever Lymphocytopenia within 48 hours, neutropenia, and thrombocytopenia within [upmc-cbn.org]

• Diarrhea

  For example, damage to the GI is scored by evaluating the time of onset, severity, the frequency of vomiting or diarrhea. [symptoma.com]

  Medications should be administered to treat symptoms like vomiting, diarrhea, pain and burns. Fluids, electrolytes and nutrition should be maintained. Psychological support should also be offered to these patients. [medindia.net]

  The diagnosis of ARS was initially considered for 237 persons based on symptoms of nausea, vomiting, and diarrhea. Ultimately, the diagnosis of ARS was confirmed in 134 persons. [ncbi.nlm.nih.gov]

  The hematopoietic syndrome occurs at 1-8 Sv, and is characterized by the following clinical signs and symptoms: 2 Nausea, vomiting, and diarrhea Mucositis, skin erythema, and fever Lymphocytopenia within 48 hours, neutropenia, and thrombocytopenia within [upmc-cbn.org]

• Loss of Appetite

  Initial symptoms of Acute Radiation Sickness occur within 1 hour to 2 days of exposure and include: Nausea Vomiting Anorexia (loss of appetite) Diarrhea If you experience any of these symptoms following exposure to radiation, it is CRITICAL that you seek [potassiumiodide.com]

  These symptoms include loss of appetite, fatigue, fever, nausea, vomiting, diarrhea, and possibly even seizures and coma. This seriously ill stage may last from a few hours up to several months. [emergency.cdc.gov]

  Systemic reactions to radiation include a general feeling of malaise, loss of appetite or nausea and vomiting, and headache. [medical-dictionary.thefreedictionary.com]

  During the prodromal period patients might experience loss of appetite, nausea, vomiting, fatigue, and diarrhoea; after extremely high doses, additional symptoms such as fever, prostration, respiratory distress, and hyperexcitability can occur. [health.gov.au]

  Other symptoms can include diarrhea, weakness, fatigue, loss of appetite, fainting, dehydration, inflammation of tissues, bleeding from the nose, mouth, gums or rectum, and anemia. [cbc.ca]

• Blood in Stool

  Possible symptoms may include: Headache Diarrhea Fever Vomiting and nausea Dizziness Ulcers of the mouth Redness and swelling of exposed areas Sloughing of the skin Open wounds on the skin Blood in stool Bleeding from the rectum, mouth, nose, and gums [syndromespedia.com]

• Xerostomia

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

• Alopecia

  Erythema The correct order of layers of skin, from outermost to innermost: Epidermis, Dermis, Subcutaneous The skin erythema dose necessary to affect 50% of the people irradiated is termed: SED50 The SED50 is estimated to be approximately: 600 Epilation or alopecia [studystack.com]

  Moderate exposure may cause headache, nausea, vomiting, anorexia, and diarrhea; long-term exposure may result in sterility, fetal damage in pregnant women, leukemia or other forms of cancer, alopecia, and cataracts. radiation sickness The generic term [medical-dictionary.thefreedictionary.com]

• Petechiae

  Petechiae and mucosal bleeding result from thrombocytopenia, which develops within 3 to 4 wk and may persist for months. Anemia develops slowly, because preexisting RBCs have a longer life span than WBCs and platelets. [merckmanuals.com]

• Subcutaneous Nodule

  الصفحة 729 - Rheumatoid nodules Subcutaneous nodules, over bony prominences, or extensor surfaces, or in juxta-articular regions, observed by a physician. 6. Serum rheumatoid factor Demonstration of abnormal amounts of serum rheumatoid factor... ‏ [books.google.com]

• Epistaxis

  […] entering an irradiation chamber when the source is unshielded); history of proximity to an unknown (usually metallic) object with a history of nausea and vomiting, especially if nausea and vomiting are unexplained by other causes; tendency to bleed (epistaxis [health.gov.au]

• Headache

  Non-specific symptoms like a headache, hypotension, fever, erythema are also present. It is important to differentiate these symptoms from those of GI infections or other pathologies involving this system. [symptoma.com]

  Systemic reactions to radiation include a general feeling of malaise, loss of appetite or nausea and vomiting, and headache. [medical-dictionary.thefreedictionary.com]

  A radiation dose as low as 0.35 Gy could feel a bit like you have the flu—expect nausea and vomiting, headaches, fatigue, and fever. If the body is exposed to a higher dose, somewhere between 1-4 Gy, blood cells begin to die. [gizmodo.com]

  Some symptoms that are common with radiation sickness include nausea and vomiting, headache, fever, dizziness, disorientation, fatigue, bloody vomit and stools, hair loss, low blood pressure, and poor wound healing. [wikihow.com]

  Vomiting Onset: 2 hours after exposure or later Percent of victims who vomit at this dose: 10-50% Diarrhea None Headache Slight Level of consciousness Unaffected Body temperature Normal Medical response Outpatient observation Hospitalization generally [remm.nlm.gov]

• Papilledema

  On examination, patients may be ataxic or have signs of papilledema. The absence of deep tendon and corneal reflexes is also noted. GI syndrome includes symptoms listed in prodromal phase in addition to abdominal cramps. [symptoma.com]

It is possible to assess acute radiation sickness with a proposed medical treatment protocols for radiation accident victims (METREPOL). It is convenient in distinguishing affected organ systems based on clinical presentation. The protocol calculates severity and possible damage done to the neurovascular, gastrointestinal, cutaneous and hematopoietic systems. For example, damage to the GI is scored by evaluating the time of onset, severity, the frequency of vomiting or diarrhea [7] [8]. A score of 1 is given to a patient who does not need acute medical attention and should be referred to an outpatient clinic for further follow ups. A score of 2 is given to a patient who is in high need of professional care. And a score of 3 is given to those who are likely to suffer from multiple organ failures (MOF) and have an overall low risk of survival [7] [8].

Blood tests are of paramount importance to control the dynamics of the patient as the hematopoietic system is greatly radiosensitive. To achieve proper care, repeated blood count of granulocytes, platelets, and lymphocytes are needed about every 6 hours for the first 24h and reticulocyte count every 24h [5]. Standard biochemical tests are also necessary. If there is suspicion of radionucleotide ingestion, the analyses of urine and feces will provide appropriate evidence [5].

Biodosimetry of chromosome aberrations in lymphocytes is useful in determining the possible dose of radiation, as the severity of aberrations strongly correlate to the dosage of radiation given [5]. During biodosimetry, analysis of translocations, dicentrics and chromosome consolidations are sought [9].

Physical dosimetry is convenient for providing analysis for individual dose taken but is a technique limited in availability. It is also possible to obtain high-quality radiation dosage data from an in vivo electron paramagnetic resonance (EPR) dosimetry that works by evaluating nail or teeth [10].

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