Acute radiation syndrome

Acute radiation disease develops as a result of short-term (up to four days) exposure to large areas of the body ionizing radiation or the intake of radioactive substances (radionuclides), creating a total dose equivalent to or above 100-200 roentgen (R) external gamma radiation. Clinical card, pathogenesis and outcome of acute radiation sickness determined by the radiation dose. So, at one-shot irradiation in doses exceeding 400 R, possibly death. Direct causes of it are deep breach of the blood, hemorrhagic and infectious complications. The amount of radiation received by the entire surface of the body and causes death in 50 % of cases, is for a person 400-500 rubles With total irradiation dose of more than 1000 R a fatal outcome is inevitable. In the process of formation of the clinical syndrome and the main morphological manifestations of acute radiation sickness, if a man is recovering, there are four main periods: 1) primary General reaction; 2) visible clinical welfare (latent); 3) expressed clinical pravleniya: 4) recovery. In the period of acute radiation sickness funds are also four severity respectively absorbed doses of radiation (light dose of about 100 - 200 R), medium (200-400 R), heavy (400-600 R) and very severe (>600 rubles). In order of comparison, the dose from natural background radiation is negligible - an average of 100 milliroentgen per year.
Primary General reaction occurs after some time (minutes, hours) after exposure.
In 3-4 days the symptoms of primary reactions usually disappear and the disease passes into the phase of apparent clinical well - being latent form. Its duration depends on the dose and varies from 14 to 30 days.
By the end of the latent phase, patients feel deteriorating, appear on the skin of a point or spotted hemorrhage. Hemorrhage and necrosis occur on the mucous membranes of the mouth, gums razryhlitelya, bleed. Threat to the life of patients in this period are infectious complications and haemorrhages in vital organs.
For typical form of acute radiation sickness death usually occurs in 3-4 weeks from the time of exposure. At external examination of the corpses of people who have died from acute radiation sickness, draws the attention of the sharp total exhaustion and the presence of bedsores. Observed multiple hemorrhages in the skin and mucous membranes, atrophy, and the shedding of the epidermis, the atrophy of hair follicles and sebaceous glands. In the mouth expressed loosening of the gums, the mucous membranes nekrotizirovanne and soaked in blood. The surface of the tonsils grey-dirty colors, covered with fibrinous flight.
When an internal study of the corpse found bleeding in serous membranes, and swelling plethora of internal organs. In the heart along with hemorrhages in the epicardium, the myocardium and the endocardium note degenerative changes in muscles. Often see hemorrhage in the mucous membrane pneumatic ways and in the parenchyma of the lung, sometimes holding a share or all of a lung. In the tissue of the lung find multiple necrotic foci and lots of pneumonia characterized by a lack of neutrophilic leukocytes.
Bleeding in the stomach, depending on their old may be submitted fresh reddish or dark brown due to the formation of hydrochloric acid gelatine. In the lining of the intestinal hemorrhage can occur throughout, with foci of hemorrhage absorb bile and izyaslau.
In the liver expressed signs of fatty degeneration. The kidneys are degenerative-necrotic processes in the epithelium of the urinary tract and increased vascular permeability of the glomeruli. Buds appear swollen, bleeding in their fabric and okolopochechnuyu fibre. In the renal pelvis, ureter and bladder may be loose blood convolution.
Macroscopic picture of the endocrine glands and genitals also testifies to the disorder of blood circulation and availability of dystrophic changes. The thyroid gland is dull, adrenal gland over the loss of lipids become grey. The testicles can be loose and somewhat reduced; in the ovaries are marked hemorrhage.
The greatest changes are observed in the state of the blood-forming organs. Lymph nodes are swollen, the cut look juicy, red. Bone marrow loses pasty consistency, easily extruded in the form of bloody fluid or washed out from the bone spaces.
Histological examination revealed extravasate in tissues and organs. There has been a General impoverishment of the body of lymphoid tissue, a reduction in the number of lymphocytes in the spleen, lymph nodes and follicles. At the same time they expressed hyperplasia reticular stroma, swelling and multiple hemorrhages. Upon the occurrence of death in cases of protracted course of radiation sickness in the lymph nodes and spleen, along with clearly visible phenomena necrobiosis and atrophy may be signs of regeneration.
The main causes of death in acute radiation sickness are growing hypoplasia blood-forming organs with the development of infectious complications or massive haemorrhages in vital organs.
With increase in quantity of the absorbed energy disease will develop more rapidly or may be fatal in the process of irradiation.