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Introduction
- Acute Radiation sickness is caused by damage to human tissues due to sudden single exposure to very large amount of ionizing radiations.
- Ionizing radiations comprise of X rays, gamma rays, or those given off by bombardment of electrons, neutrons and protons.
- Use of ionizing radiations is found in medical testing and treatment, in industries for manufacturing processes and also in making weapons.
- Acute radiation sickness is also called as radiation poisoning or radiation toxicity.
- Acute radiation sickness is caused when the radiation dose is large (more than 70 rads or 0.7 Gy), the source of radiation is external i.e. outside the body of the patient, the radiations penetrate to reach the internal organs, the entire body or a significant part of it receives the radiation dose and the exposure occurs in a short period of time.
- Exposure to highly penetrating radiations may cause cell death. Damage to the bone marrow which causes loss of blood forming cells and damage to the cells in the digestive system may prove fatal.
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Symptoms & Signs
- The severity of symptoms will depend on the amount of radiation absorbed by the body. The symptoms may occur immediately after exposure or over the next few days to months. If the exposure is severe, the time gap between the exposure and the onset of symptoms will be very small and sudden death may occur.
- Fall in white blood cell count will result in infections, fall in red blood cell count will result in anemia and depleting platelet count will result in bleeding. These are called as hematopoietic symptoms and usually occur with the radiation dose between 70 to 1000 rads.
- Gastrointestinal symptoms such as nausea, vomiting, fever, dehydration and electrolyte imbalance and abdominal pain may occur in one to two hours after exposure and are seen with radiation dose of more than 1000 rad.
- Neurological effects such as dizziness, confusion and decreased level of consciousness will be seen with exposure to very large doses usually greater than 5000 rads. Death may occur within three days of exposure.
- The various phases following exposure are prodromal phase with symptoms like nausea, vomiting and diarrhea and it occurs from minutes to days following exposure. The next is the latent phase in which the patient looks healthy. It may last from few hours to few weeks. The next is the manifest illness phase in which most of the symptoms appear. It lasts from few hours to several months. In the fourth phase the patients will show recovery or may die. The recovery may take few weeks to years depending on the amount of exposure and the severity of symptoms.
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Causes & Risk factors
It may be caused due to accidental exposure to high doses of radiation as in nuclear power plant accidents or due to exposure to high radiation dose as in medical treatments. Most cases of radiation sickness have been reported after nuclear accidents.
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Tests & Diagnosis
Blood tests are done for complete blood count focusing on the lymphocyte count which will help to estimate radiation exposure. Time gap between exposure and onset of symptoms will also help to estimate radiation exposure. | |
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Prevention
Acute radiation sickness can be prevented by minimizing the exposure dose and reducing the dose rate. Increasing distance from the radiation source reduces the exposure dose. Exposure to radiation workers can be reduced by minimizing the time period for which they are exposed to the radiations.
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Treatment Options
- First aid should be provided. Check breathing and pulse. Cardiopulmonary resuscitation may be required. Remove the person’s clothing to stop further contamination. Fluid, electrolytes and nutrition should be maintained.
- For treatment of acute radiation sickness, antibiotic are given. Antimicrobials like metronidazole should not be given because they reduce the anaerobes but enhance infection by aerobic bacteria which can be fatal. Broad-spectrum antibiotic therapy that works on the gram negative and gram positive aerobic bacteria should be given.
- Blood transfusions may also be required. Stem cell transplant may be required.
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