injuries and poisoning
Radiation Injury
Symptoms of Radiation Injury
Symptoms depend on whether radiation exposure involves the whole body or is limited to a small portion of the body. At high doses, whole-body exposure causes acute radiation illness, and partial-body exposure causes local radiation injury. Acute radiation illness typically occurs in people whose entire body has been exposed to very high doses of radiation all at once or over a short period of time. Doctors divide acute radiation illness into three groups (syndromes) based on the main organ system affected, although there is overlap among these groups: Hematopoietic syndrome: Affects tissues that produce blood cells Gastrointestinal syndrome: Affects the digestive tract Cerebrovascular syndrome: Affects the brain and nervous system Acute radiation illness usually progresses through three stages: Early symptoms such as nausea, loss of appetite, vomiting, tiredness and, when very high radiation doses are received, diarrhea (collectively called the prodrome) A symptom-free period (latent stage) Various patterns of symptoms (syndromes), depending on the amount of radiation received Which syndrome develops, its severity, and its rate of progression depend on the radiation dose. As the dose increases, symptoms develop earlier, progress more rapidly (for example, from prodromal symptoms to the various organ system syndromes), and become more severe. The severity and time course of the early symptoms are fairly consistent from person to person for a given amount of radiation exposure. Thus, doctors can often estimate a person’s radiation exposure based on the timing, nature, and severity of the early symptoms. However, the presence of injuries, burns, or severe anxiety can complicate this estimate. is caused by the effects of radiation on the bone marrow, spleen, and lymph nodes—the primary sites of blood cell production (hematopoiesis). Loss of appetite (anorexia), lethargy, nausea, and vomiting may begin 1 to 6 hours after exposure to 1 to 6 Gy of radiation. These symptoms resolve within 24 to 48 hours after exposure, and people feel well for a week or more. During this symptom-free period, the blood-producing cells in the bone marrow, spleen, and lymph nodes begin to waste away and are not replaced, leading to a severe shortage of white blood cells, followed by a shortage of platelets and then red blood cells. The shortage of white blood cells ( Lymphocytopenia and Thegastrointestinal syndromeis due to the effects of radiation on the cells lining the digestive tract. Severe nausea, vomiting, and diarrhea may begin in less than 1 hour after exposure to 6 Gy or more of radiation. The symptoms may lead to severe dehydration, but they resolve within 2 days. During the next 4 or 5 days (latent stage), people feel well, but the cells lining the digestive tract, which normally act as a protective barrier, die and are shed. After this time, severe diarrhea—often bloody—returns, once more resulting in dehydration. Bacteria from the digestive tract may invade the body, causing severe infections. People who have received this much radiation also develop the hematopoietic syndrome, which results in bleeding and infection and increases their risk of death. After exposure to 6 Gy or more of radiation, death is common. However, with advanced medical support, about 50% of people may survive. Thecerebrovascular syndromeoccurs when the total dose of radiation exceeds 20 to 30 Gy. People rapidly develop confusion, nausea, vomiting, bloody diarrhea, tremors, and shock. The latent phase is brief or absent. Within hours, blood pressure falls, accompanied by seizures and coma. The cerebrovascular syndrome is always fatal within a few hours to 1 or 2 days. Radiation therapy for cancer is one of the most common causes of local radiation injuries. Symptoms depend on the amount of radiation, the rate at which it is received, and the area of the body treated. Nausea, vomiting, and loss of appetite may occur during or shortly after irradiation of the brain or abdomen. Large amounts of radiation to a limited area of the body often damage the skin over that area. Skin changes include hair loss, redness, peeling, sores, and, possibly eventual thinning of the skin and dilated blood vessels just beneath the skin's surface (spider veins). Radiation to the mouth and jaw can cause permanent dry mouth, resulting in an increased number of dental caries and damage to the jawbone. Radiation to the lungs can cause lung inflammation (radiation pneumonitis). Very high doses can result in severe scarring (fibrosis) of lung tissue, which can cause disabling shortness of breath and later death. The heart and its protective sac (pericardium) can become inflamed after extensive radiation to the chest, causing symptoms such as chest pain and shortness of breath. High accumulated doses of radiation to the spinal cord can cause catastrophic damage, leading to paralysis, incontinence, and loss of sensation. 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 stools. Occasionally, severe injuries develop long after the completion of radiation therapy. Kidney function may decline 6 months to a year after people have received extremely large amounts of radiation, resulting in Overview of Anemia and 