Acute and chronic radiation sickness have peculiar development mechanisms. This eliminates the transition of the disease from one form to another.
Acute radiation sickness is manifested by syndromes that depend on the dose of external radiation, which leads to the identification of various disorders. The development of clinical symptoms also depends on the type of radiation with its own specific features. It is with them, mainly, that differences in the damaging effect on systems and organs are associated.
Acute radiation sickness with a typical course is divided into four degrees of severity.
A mild degree, as a rule, proceeds without any pronounced symptoms. In such cases, radiation injury should be considered.
A severe degree is accompanied by long-term (over one to two years) recovery processes. In cases of persistent changes persisting, it is said that acute radiation sickness has consequences.
The time of the appearance of the first phase of the general reaction of a primary nature to radiation damage depends on the dose and can be calculated in minutes or hours. The characteristic signs of the reaction include nausea, dry mouth or bitterness in the mouth, vomiting, fatigue, headache, drowsiness, weakness.
There are shock-like conditions, which are accompanied by a decrease in blood pressure, loss of consciousness. Possible diarrhea and fever. Such symptoms, as a rule, are observed with radiation damage in doses above 10 Gy.
The disease in the first phase with radiation damage of more than 3 Gy is accompanied by some biochemical shifts. These include a decrease in serum albumin levels, an increase in blood glucose, accompanied by a change in the sugar curve. In more severe cases, moderate transient bilirubinemia is noted. In turn, this indicates a violation in the liver of metabolic processes.
The second phase of the disease is characterized as a period of false clinical well-being. This so-called latent or latent phase is observed after the disappearance of the primary signs of the reaction after three to four days after radiation damage. This phase continues for fourteen to thirty-two days. This period is accompanied by an improvement in the well-being of patients while maintaining some lability in blood pressure and pulse rate. In case of radiation damage in a dose of more than 10 Gy, acute radiation sickness immediately passes from the first phase to the third. The completion of the latent phase is accompanied by a sharp deterioration in the condition of patients resembling a septic state. This condition is characterized by manifestations of increasing general weakness, fever, rapid pulse, and a decrease in blood pressure. Marked swelling and bleeding of the gums are noted . Lesions of the oral mucosa and gastrointestinal tract, manifested by numerous necrotic ulcers, are also detected.
The third phase proceeds accompanied by severe clinical symptoms. At the same time, the onset and intensity level of a number of syndromes are associated with the dose of radiation received. A long third phase is seven to twenty days.
The defeat of the circulatory system in this phase is dominant. Along with it, there is a suppression of immunity, the development of autointoxications and infections, a hemorrhagic symptom. Moreover, the disease is not characterized as chronic radiation sickness.
The fourth phase is the phase of direct recovery and begins with improvement and normalization of temperature.
If the disease proceeded in a severe form, there is a prolonged preservation of pastiness of the limbs and face, tarnishing, brittleness, dryness of the remaining hair. In the area of baldness, hair growth resumes three or four months after radiation damage.