RADIATION SICKNESS

Radiation sickness is the result of exposure to ionizing radiation the body of man.

Clinical manifestations of the disease depend on the total radiation dose and the time of its distribution in the body. Depending on the nature of the spatial distribution of the dose distinguish radiation sickness caused uniform (common), local and non-uniform irradiation, and the dose distribution in time - acute and chronic radiation sickness. Progression of the disease may be due to external irradiation and exposure to radionuclides entering the body.

Acute radiation syndrome in humans develops in a short time (from several minutes to 1-3 days) in the whole body irradiation dose exceeding 1 Gy. It may occur when the human presence in the area of ​​emissions or radioactive fallout, abuse of powerful radiation sources, leading to the accident, the use of total body irradiation for medical purposes.

The main manifestations of acute radiation sickness defined lesion of hematopoiesis with the development of bone marrow aplasia and complications caused by cytopenias - hemorrhagic syndrome, infectious lesions in organs, sepsis; violation of physiological intestinal epithelium reproduction exposing the mucosa, protein loss of fluid and electrolytes; severe intoxication due to the massive destruction of radiosensitive tissues (bone marrow, small intestine and skin - with extensive lesions weakly penetrating external beta radiation); direct CNS violation of its functions, especially the central regulation of blood circulation and respiration. Accordingly isolated medullary, intestinal, toksemicheskuyu, cerebral neuro-transition therebetween and forms an acute radiation syndrome arising after total body irradiation, respectively, in the following dosage ranges: 1 - 10, 10 - 50, 50-100 and 100 Gy.

Effective treatment lends itself to bone marrow form of acute radiation sickness. In the period of its formation clearly distinguished four phases: the phase of the primary reaction, the latent phase, the phase of the height, or marked clinical manifestations, and the phase of early recovery. The duration of the disease is about 2 - 3 months from the time of exposure (in more severe lesions of up to 3 - 6 months)

Acute radiation pulmonary disease (I) level occurs when exposed to ionizing radiation at a dose of 1-2.5 Gy. Moderately primary reaction (dizziness, nausea, rarely) observed after 2 to 3 hours after irradiation. Changes in skin and mucous membranes are generally not detected. The latent phase lasts 25-30 days. The number of lymphocytes (in 1 ml of blood) during the first 1-3 days is reduced to 1000 - 500 cells (1-0,5 • 109 / L), the height of leukocytes in diseases - to 3500-1500 (3,5 - 1,5 • 109 / l) platelet counts in the 26-28 th day - up to 60 000-10 000 (60-40 • 109 / l); ESR moderately increases. Infectious complications are rare. Bleeding is not observed. Recovery slow but complete.

Acute radiation syndrome secondary (II) degree develops when exposed to ionizing radiation at a dose of 2.5 - 4 Gy. Initial reactions (headache, nausea , and sometimes vomiting) occurs after 1 -2 hours. The appearance of the skin erythema possible. The latent phase lasts 20 - 25 days. The number of lymphocytes in the first 7 days is reduced to 500, the number of granulocytes in the phase height (20 -30 th day) - 500 cells in 1 ml of blood (0,5 • 109 / l); ESR - 25 -40 mm / h. Characterized by infectious complications, mucosal changes the mouth and throat, with platelet counts less than 40 000 per 1 ml of blood (40 • 109 / L) revealed slight signs of bleeding - petechiae in the skin. Possibly fatal, especially in a belated and inadequate treatment.

Acute radiation sickness severe (III) degree is observed at. ionizing radiation at a dose of 4 - 10 Gy. Initial reaction occurs in 30 - 60 minutes and pronounced (repeated vomiting , fever, headache , skin erythema). The number of lymphocytes in the first day is 300 - 100 leukocytes 9-17 th day - at least 500, thrombocytes - less than 20 000 per 1 ml of blood. The duration of the latent phase does not exceed 10 to 15 days. At the height of the disease a marked fever , lesions of the mucous membranes of the mouth and throat, infectious complications of different etiology (bacterial, viral, fungal) and localization (lungs, intestines, etc.), Moderate bleeding. The increasing frequency of deaths (within the first 4 - 6 weeks).

Acute radiation sickness is very severe (IV) occurs when the degree of exposure to ionizing radiation at a dose of 10 Gy. Symptomatology deep lesions caused hematopoiesis characterized persistent lymphopenia early - less than 100 cells per 1 ml of blood (0,1 • 109 / l), agranulocytosis, beginning with the 8th day thrombocytopenia - less than 20 000 per 1 ml of blood (20 • 109 / l) and then anemia. With increasing doses of heavier existence, the length of the latent phase is reduced, becomes paramount involvement of other organs (intestines, skin, brain) and general intoxication. Lethal outcomes almost inevitable.

With increasing severity of acute radiation sickness in people who survived the period of its formation, decreases the fullness of recovery, residual effects are more pronounced lesions of blood (thrombocytopenia and neutropenia), is developing a cataract , progressing degenerative changes in the skin, the signs of fatigue appear.

Treatment is to provide an aseptic mode (special or adapted wards), the prevention of infectious complications and the appointment of symptomatic drugs. With the development of agranulocytosis and fever, even without the detection of foci of infection, use broad-spectrum antibiotics and indications (herpes infection) antiviral drugs. To increase the effectiveness of anti-infectious therapy prescribed drugs hyperimmune plasma and gamma globulin.

Substitution platelet deficiency (less than 20 000 cells in 1 ml of blood) by administering to produce platelet mass, possibly obtained from a single donor (300 • 109 / l cells per infusion) after its pre-irradiation dose of 15 Gy. According to the testimony (anemia - less than 2.5 million red blood cells in 1 ml of blood) transfusion of washed fresh produce red blood cells.

With a total irradiation dose range of 8-12 Gy, the absence of contraindications and the presence of the donor bone marrow transplant is justified in view of tissue compatibility.

Local lesions of the mucous membranes require special care and systematic treatment of the mouth, nose, throat bactericidal and mucolytic drugs. For the treatment of skin lesions and pain relief spray used and the collagen film, moisturizing and tanning bandage with antiseptic, and later ointment dressings with hydrocortisone derivatives on the basis of wax and propolis. Unhealed wound and ulcer lesions excised, followed by plastics. Correction fluid and electrolyte and other metabolic disorders conducted by the general rules of intensive care.

In cases of massive defeats acute radiation sickness is often combined with thermal effects, chemical or mechanical factors. In these cases, you need to simplify treatment because of the difficulties of their implementation in full (the appointment of long-acting drugs into the treatment of burns and wounds under the bandage, the observance of the simplest mode of aseptic and others.).

The main means of prevention are measures restricting the levels of exposure of the whole body and its parts: screening, limit time spent in intense radiation fields, taking special preventive means.

Chronic radiation sickness can occur at a dose rate of 0.005 Gy per day, and the accumulation of a relatively short period of time the total dose of radiation exceeding a total gamma irradiation of 1.5 Gy, t. E. With a substantial excess of accepted standards of occupational exposure.

The clinical picture is determined by the radiosensitivity of tissues and exposure priority area: hypothyroidism and thyroid dysfunction occur when you receive radioactive iodine, anemia - under the influence of radioactive phosphorus, aplastic anemia, and swelling of bone tissue-the action of radium, etc. In general, long-term exposure is gradually developing cytopenia.. , revealed the lability of heart rate and blood pressure with a tendency to hypotension, reduced secretory function and enzymatic changes and motility of the gastrointestinal tract. If inhalation of certain gases or radionuclides and their application to the skin in these areas may develop long-term change (e.g., cancer of the lung, dyskeratosis and cancer of the skin).

Prevention of chronic radiation sickness is in strict compliance with accepted norms and rules of working with radioactive sources. Sustainable employment, as a rule, allows people who have had chronic radiation sickness, save disabled.