Diagnosis and Treatment of Radiation Disease

Diagnosis of Radiation Disease

In the hemogram, there is a second sharp decrease in the number of leukocytes due to neutrophils (preserved neutrophils with pathological granularity), lymphocytosis, plasmatization, thrombocytopenia, anemia, reticulocytopenia, a significant increase in ESR.

The onset of regeneration confirms an increase in the number of leukocytes, the appearance of reticulocytes in the hemogram, as well as a sharp shift of the leukocyte formula to the left.

The bone marrow picture at lethal doses of radiation remains devastated throughout the entire phase III disease. At lower doses, after a 7-12-day period of aplasia, blast elements appear in the myelogram, and then the number of cells of all generations increases. With moderate severity of the process in the bone marrow from the first days of phase III, against the background of a sharp decrease in the total number of myelokaryocytes, signs of hematopoietic repair are detected.

Biochemical studies reveal hypoproteinemia, hypoalbuminemia, a slight increase in the level of residual nitrogen, and a decrease in the amount of blood chlorides.

Phase IV – the phase of direct recovery – begins with normalizing the temperature, improving the general condition of patients.

In the event that a severe course of acute radiation sickness has occurred, patients have long pasty face and limbs. The remaining hair fades, becomes dry and brittle, the growth of new hair at the site of baldness resumes at 3-4 months after irradiation.

Pulse and blood pressure normalize, sometimes moderate hypotension sometimes remains for a long time.

For some time, trembling hands, a static violation of coordination, a tendency to increase tendon and periostenal reflexes, some unstable focal neurological symptoms. The latter are regarded as the result of functional disorders of cerebral circulation, as well as the exhaustion of neurons against the background of general asthenia.

A gradual recovery of peripheral blood counts is noted. The number of leukocytes and platelets increases and by the end of the 2nd month reaches the lower limit of normal. In the leukocyte formula, there is a sharp shift to the left to promyelocytes and myeloblasts, the content of stab forms reaches 15-25%. The number of monocytes is normalized. By the end of the 2-3 month of the disease, reticulocytosis is detected.

Until the 5-6th week of the disease, anemia continues to increase with the phenomena of red blood cell anisocytosis due to macroforms.

In the myelogram, signs of pronounced recovery of hematopoietic cells are revealed: an increase in the total number of myelokaryocytes, the predominance of immature erythro- and leukopoiesis cells over mature ones, the appearance of megakaryocytes, an increase in the number of cells in the mitosis phase. Biochemical parameters are normalized.

The characteristic long-term consequences of severe acute radiation sickness are the development of cataracts, moderate leuko-, neutro- and thrombocytopenia, persistent focal neurological symptoms, sometimes endocrine changes.

V persons exposed to radiation, in the long term, leukemia develops 5-7 times more often.

The mechanism of development of the observed changes in the hematopoiesis at different stages of the course of acute radiation sickness is associated with different radiosensitivity of individual cellular elements. So, blast forms and lymphocytes of all generations are highly radiosensitive. Promyelocytes, basophilic erythroblasts and immature monocytoid cells are relatively radiosensitive. Highly resistant mature cells.

On the first day after total irradiation in a dose exceeding 1 Gy, there is a massive death of lymphoid and blast cells, and with an increase in the radiation dose, more mature hematopoietic cell elements.

In this case, the mass death of immature cells does not affect the number of granulocytes and red blood cells of the peripheral blood. The exception is only lymphocytes, which in themselves are highly radiosensitive. The occurring neutrophilic leukocytosis is mainly of a redistributive nature.

Simultaneously with interphase death, mitotic activity of hematopoietic cells is suppressed while maintaining their ability to mature and enter peripheral blood. As a result of this, myelocaryocytopenia develops.

Severe neutropenia in phase III of the disease is a reflection of the depletion of the bone marrow and the almost complete absence of all granulocytic elements in it.

Around the same time, a maximum decrease in platelet count in peripheral blood is observed.

The number of red blood cells decreases even more slowly, since their lifespan is about 120 days. Even with the complete cessation of red blood cells, their number will decrease by about 0.85% daily. Therefore, a decrease in the number of red blood cells and the content of Hb is usually found only in the IV phase – the recovery phase, when the natural decrease in red blood cells is already significant and is not yet compensated by the newly formed.

Radiation Disease Treatment

In the case of irradiation at a dose of 2.5 g and above, deaths are possible. A dose of 4 ± 1 g is tentatively considered to be average lethal for humans, although in cases of irradiation at a dose of 5-10 g, clinical recovery with proper and timely treatment is still possible. When irradiated in a dose of more than 6 g, the number of survivors is practically reduced to zero.

To determine the correct management tactics for patients, as well as predicting acute radiation sickness for irradiated patients, dosimetric measurements are carried out that indirectly indicate the quantitative parameters of the radioactive effect on the tissues.

The dose of ionizing radiation absorbed by the patient can be established on the basis of a chromosome analysis of hematopoietic cells, determined in the first 2 days after irradiation. During this period, for 100 peripheral blood lymphocytes, chromosomal abnormalities amount to 22–45 fragments in the first degree, 45–90 fragments in the second degree, 90–135 fragments in the third, and more than 135 fragments in the fourth, extremely severe disease.

In the first phase of the disease, Aeron is used to stop nausea and prevent vomiting, in cases of repeated and indomitable vomiting, chlorpromazine and atropine are prescribed. In case of dehydration, infusions of saline are necessary.

In severe acute radiation sickness, the doctor provides detoxification therapy (for example, polyglucin) during the first 2-3 days after exposure. To combat collapse, well-known drugs are used – cardiamine, mesatone, norepinephrine, as well as kinin inhibitors: trasilol or contracal.

Prevention and treatment of infectious complications

The system of measures aimed at the prevention of external and internal infections uses various types of insulators with sterile air supply, sterile medical materials, care items and food. The skin and visible mucous membranes are treated with antiseptics, and nonabsorbable antibiotics (gentamicin, kanamycin, neomycin, polymyxin-M, ristomycin) are used to suppress the activity of the intestinal flora. At the same time, large doses of nystatin (5 million units or more) are prescribed inside. In cases of a decrease in the level of white blood cells below 1000 in 1 mm3, the prophylactic use of antibiotics is advisable.

In the treatment of infectious complications, large doses of intravenously administered broad-spectrum antibacterial drugs are prescribed (gentamicin, zeporin, kanamycin, carbenicillin, oxacillin, methicillin, lincomycin). When attaching a generalized fungal infection, amphotericin B is used.

It is advisable to strengthen antibacterial therapy with biological drugs of directed action (antistaphylococcal plasma and γ-globulin, anti-pseudomonas plasma, hyperimmune plasma against Escherichia coli).

If within 2 days there is no positive effect, the doctor changes the antibiotics and then prescribes them taking into account the results of bacteriological cultures of blood, urine, feces, sputum, smears from the oral mucosa, as well as external local infectious foci that are produced on the day of admission and further -in one day. In cases of attachment of a viral infection with effect, acyclovir can be used.

The fight against bleeding includes the use of hemostatic agents of general and local action. In many cases, drugs that strengthen the vascular wall (dicinone, steroid hormones, ascorbic acid, rutin) and increase blood coagulability (E-ACC, fibrinogen) are recommended.

In the vast majority of cases, thrombocytopenic bleeding can be stopped by transfusion of an adequate number of freshly prepared donor platelets obtained by thrombocytosis. Platelet transfusions are indicated in cases of deep thrombocytopenia (less than 20 109 / l), which occurs with hemorrhages on the skin of the face, upper half of the body, on the fundus, with local visceral bleeding.

Anemic syndrome in acute radiation sickness rarely develops. Red blood cell transfusions are prescribed only with a decrease in hemoglobin level below 80 g / l.

Used transfusions of freshly prepared red blood cells, washed or thawed red blood cells. In rare cases, it may be necessary to individually select not only the AB0 and Rh-factor systems, but also other red blood cell antigens (Kell, Duffy, Kidd).

Treatment of ulcerative necrotic lesions of the mucous membranes of the gastrointestinal tract.

In the prevention of ulcerative necrotic stomatitis, rinsing the mouth after eating (2% soda solution or 0.5% novocaine solution), as well as antiseptic agents (1% hydrogen peroxide, 1% solution 1: 5000 furatsilina; 0.1% gramicidin, 10% water-alcohol emulsion of propolis, lysozyme). In cases of candidiasis, nystatin, levorin are used.

It is recommended to lubricate the surface cleared of necrosis with oils (peach, rosehip, sea buckthorn).

One of the serious complications of agranulocytosis and direct exposure to radiation is necrotic enteropathy. The use of biseptolum or antibiotics sterilizing the gastrointestinal tract helps to reduce clinical manifestations or even prevent its development. With the manifestation of necrotic enteropathy, the patient is prescribed complete starvation. In this case, only the intake of boiled water and means that stop diarrhea (dermatol, bismuth, chalk) is allowed. In severe cases, diarrhea uses parenteral nutrition.

Bone marrow transplantation

An allogeneic histocompatible bone marrow transplant is indicated only in cases characterized by irreversible depression of hematopoiesis and a deep suppression of immunological reactivity.

Therefore, this method has limited capabilities, since there are still not enough effective measures to overcome tissue incompatibility reactions.

The selection of a bone marrow donor is necessarily based on the transplantation antigens of the HLA system. In this case, the principles established for allomyelotransplantation with preliminary immunosuppression of the recipient (the use of methotrexate, irradiation of blood transfusion media) must be observed.

Special attention should be paid to general uniform irradiation, used as a pre-transplant immunosuppressive and antitumor agent in a total dose of 8-10 Gy. The observed changes differ in a certain regularity; in different patients, the severity of individual symptoms is not the same.

The primary reaction that occurs after radiation exposure at a dose of more than 6 Gy is the appearance of nausea (vomiting), chills against a background of fever, tendency to hypotension, dryness of the mucous membranes of the nose and lips, bluish complexion, especially lips and neck. The general irradiation procedure is carried out in a specially equipped irradiator under constant visual observation of the patient using television cameras in a two-way communication environment. If necessary, the number of breaks can be increased.

Of the other symptoms that naturally occur as a result of “therapeutic” complete irradiation, it is necessary to note inflammation of the parotid gland in the first hours after irradiation, redness of the skin, dryness and swelling of the mucous membranes of the nasal passages, sensation of pain in the eyeballs, conjunctivitis.

The most formidable complication is hematologic syndrome. As a rule, this syndrome develops in the first 8 days after a patient receives a radiation dose.