Acute blood loss emerges at wound of vessels or their destruction by pathological process: bleeding from stomach ulcer, from varicose veins of esophagus at cirrhosis, from hemorrhoid veins, pulmonary bleeding tuberculosis. Plentiful and sudden bleedings cause anemia.
Acute loss of 0.5 liters of blood by the healthy person of average weight causes light weakness, vertigo like at donating blood by donor. Loss of 700 ml of blood causes more expressed symptoms, and exceeding 50-65% of blood loss is lethal.
Degree of anemia depends and on existence of infection. At anaerobic infection (gangrene) anemia is most expressed and persistent as strengthened hemolysis is added.
At an acute anemia mass of circulating blood decreases, blood is depleted by erythrocytes, oxygen carriers. Then oxygen starvation comes.
Under the influence of blood loss marrow is activated. In tubular bones the yellow brain temporarily turns in red (active), strenuously restoring blood.
At acute big blood loss the patient is pale, weak, in severe cases faints. It has dyspnea, twitching of muscles, yawning, nausea and vomiting (brain anemia), sometimes hiccup, cold sweat, pulse is frequent, weak, and pressure is decreased.
Having recovered consciousness the patient complains of thirst. Gradually the state improves; there is a pulse, pressure increases. After loss of blood its tanks (spleen, skin) are emptied.
Anemia stimulates a hemopoiesis. The recovery rate depends on the amount of blood loss, on age of the patient and on timeliness of treatment. Fresh or tinned blood is transfused to the patient.