Posthemorrhagic anemia is a complex of clinical and hematological changes resulting from acute or chronic blood loss. Disease is characterized by pallor, shortness of breath, darkening of the eyes, dizziness, hypothermia, arterial hypotension; in severe cases – lethargy, thready pulse, shock, loss of consciousness. Pathology is diagnosed according to the clinical picture and a blood test; instrumental studies are conducted to determine the source of bleeding. With the development of this condition, it is necessary to eliminate the source of blood loss, conduct transfusion and symptomatic therapy.
Meaning
Posthemorrhagic anemia is hypohemoglobinemia that develops as a result of hemorrhagic syndrome and is accompanied by a noticeable decrease in the circulating blood volume (CBV). Posthemorrhagic anemia occurs with erythropenia, but often without a decrease in the concentration of hemoglobin (Hb). Normally, the level of total Hb and the volume of circulating red blood cells are respectively: in men – not less than 130 g / l and 29-30 ml / kg of weight, in women – not less than 120 g / l and 22-23 ml / kg. Posthemorrhagic anemia can complicate the course of a variety of pathological conditions in surgery, hematology, gynecology, gastroenterology, cardiology, etc. Posthemorrhagic anemia can be acute or chronic. The chronic form is a variant of iron deficiency anemia, since the mechanism of development and symptoms of pathology are caused by increasing iron deficiency.
Causes
The immediate cause of posthemorrhagic anemia is acute or chronic blood loss resulting from external or internal bleeding. Acute posthemorrhagic anemia occurs with rapid, massive blood loss, usually caused by mechanical damage to the walls of large blood vessels or heart cavities during various injuries and surgical operations, rupture of the walls of the heart chambers in the infarction zone, rupture of the aortic aneurysm and branches of the pulmonary artery, rupture of the spleen, rupture of the fallopian tube during ectopic pregnancy.
Acute posthemorrhagic anemia is characteristic of profuse uterine bleeding (menoragia, metroragia), may accompany the course of stomach ulcers and duodenal ulcers. In newborns, posthemorrhagic anemia can be caused by placental bleeding, birth trauma.
Chronic posthemorrhagic anemia is caused by prolonged, often occurring losses of small amounts of blood in gastrointestinal, hemorrhoidal, renal, nasal bleeding, violations of blood clotting mechanisms (DIC syndrome, hemophilia). Tumor processes (stomach cancer, colon cancer), proceeding with the destruction of tissues and organs, lead to the development of internal bleeding and posthemorrhagic anemia. Hypohemoglobinemia may be associated with increased permeability of capillary walls in leukemia, radiation sickness, infectious septic processes, vitamin C deficiency.
Pathogenesis
The main factors in the development of posthemorrhagic anemia are the phenomena of vascular insufficiency, hypovolemia with a decrease in the total volume of plasma and circulating shaped elements, in particular, erythrocytes that transport oxygen. This process is accompanied by a decrease in blood pressure, blood filling of internal organs and tissues, hypoxemia, hypoxia and ischemia, and the development of shock.
The degree of severity of protective and adaptive reactions of the body is determined by the volume, speed and source of bleeding. In the early reflex-vascular phase of blood loss compensation (the first day), due to the excitation of the sympathetic-adrenal system, vasoconstriction and increased resistance of peripheral vessels are observed, hemodynamic stabilization due to the centralization of blood circulation with primary blood supply to the brain and heart, a decrease in blood return to the heart and cardiac output. The concentration of erythrocytes, Hb and hematocrit are still close to normal (“latent” anemia).
The second hydremic phase of compensation (2-3 days) is accompanied by autohemodilution – the entry of tissue fluid into the bloodstream and the replenishment of plasma volume. Increased secretion of catecholamines and aldosterone by the adrenal glands, vasopressin by the hypothalamus contributes to the stability of the level of electrolytes in blood plasma. There is a progressive decrease in the indicators of erythrocytes and Hb (total and per unit volume), hematocrit; the value of the color index is normal (posthemorrhagic normochromic anemia).
In the third, bone marrow compensation phase (4-5 days), anemia becomes hypochromic due to iron deficiency, the formation of erythropoietin by the kidneys increases with activation of the reticuloendothelial system, erythropoiesis of the bone marrow, foci of extramedullary hematopoiesis. In the red bone marrow there is hyperplasia of the erythroid germ and an increase in the total number of normocytes, in peripheral blood there is a significant increase in the number of young forms of erythrocytes (reticulocytes) and leukocytes. The levels of Hb, erythrocytes and hematocrit are lowered. Normalization of the level of erythrocytes and Hb in the absence of further blood loss occurs after 2-3 weeks. With massive or prolonged blood loss, posthemorrhagic anemia acquires a hyporegenerative character, and shock develops when the adaptive systems of the body are depleted.
Symptoms
Clinical signs of posthemorrhagic anemia are of the same type regardless of the cause of blood loss, determined by its volume and duration.
In the first day after acute blood loss, patients experience sharp weakness, pale skin and mucous membranes, shortness of breath, darkening and flashing of flies in the eyes, dizziness, tinnitus, dry mouth, decreased body temperature (especially limbs), cold sweat. The pulse becomes frequent and weak, arterial hypotension appears. The consequence of hemorrhagic syndrome is anemia of internal organs, fatty degeneration of the myocardium, liver, central nervous system and other organs. Children, especially newborns and the 1st year of life, suffer blood loss much harder than adult patients.
Posthemorrhagic anemia with massive and rapid blood loss is accompanied by hemorrhagic collapse, a sharp drop in blood pressure, a threadlike arrhythmic pulse, adynamia and lethargy, rapid shallow breathing with the possible development of vomiting, convulsions, loss of consciousness. If the pressure drops to a critical level, causing acute disruption of blood supply and hypoxia of organs and systems, death occurs from paralysis of the respiratory center and cardiac arrest.
Slowly developing posthemorrhagic anemia is characterized by less pronounced manifestations, as it manages to be partially compensated by adaptive mechanisms.
Diagnostics
Diagnosis of posthemorrhagic anemia is carried out according to the clinical picture, laboratory and instrumental studies (general and biochemical blood and urine tests, ECG, ultrasound diagnostics, bone marrow puncture, trepanobiopsy). When examining a patient with acute posthemorrhagic anemia, attention is drawn to hypotension, rapid breathing, weak arrhythmic pulse, tachycardia, muffled heart tones, small systolic noise at the apex of the heart.
In the blood – an absolute decrease in erythrocyte mass; with continued blood loss, a progressive uniform drop in the content of Hb and erythrocytes is observed. With moderate blood loss, hematological signs of posthemorrhagic anemia are detected only on 2-4 days. Monitoring of diuresis, platelet levels, electrolytes and nitrogenous products in the blood, blood pressure and CBV is mandatory.
In acute posthemorrhagic anemia, there is no need to examine the bone marrow, it is carried out with difficult-to-diagnose blood loss. In bone marrow puncture samples, signs of anemia are an increase in the activity of the red bone marrow, in trepanobiopsy preparations – the replacement of adipose tissue of the bone marrow with red hematopoietic brain.
In the diagnosis of internal bleeding, acute anemia syndrome and laboratory data are indicative. In the spleen, liver, lymph nodes, foci of extramedullary hematopoiesis are detected, indicating an increased load on the hematopoietic system; in the blood – a transient decrease in iron levels, a slight increase in AlT.
To identify and eliminate the source of blood loss, patients need consultations with a hematologist, surgeon, gynecologist, gastroenterologist and other specialists; ultrasound of the abdominal cavity and pelvic organs, FGDS, etc. ECG with posthemorrhagic anemia may show a decrease in the amplitude of the T-wave in the standard and thoracic lead.
Treatment and prognosis
The primary thing in the treatment of posthemorrhagic anemia is to establish the source of bleeding and its immediate elimination through ligation and suturing of vessels, resection and suturing of damaged organs and tissues, increased blood clotting, etc.
To restore the CBV and reduce the degree of hemodynamic disorders, an urgent transfusion of canned blood, blood substitutes, plasma and plasma substitutes is carried out under the supervision of a transfusiologist. With minor but prolonged bleeding, transfusion of whole blood or plasma is indicated in small hemostatic doses. With a significant loss of CBV, transfusions should be performed in doses exceeding blood loss by 20-30%. Severe posthemorrhagic anemia is treated by transfusions of large doses of blood (“blood transplantation”). During the collapse, hemotransfusion is supplemented with hypertensive blood-substituting solutions.
After the restoration of the CBV, the correction of the qualitative composition of the blood is carried out – replenishment of its components: erythrocytes, leukocytes, platelets. With large simultaneous blood loss and stopped bleeding, massive doses of erythrocyte mass (> 500 ml) are needed. The effectiveness of blood transfusions is judged by the increase in blood pressure, hematological shifts.
It is also necessary to introduce protein and electrolyte solutions (albumin, phys. solution, glucose), restoring the water-salt balance. Iron preparations and B vitamins are used in the treatment of posthemorrhagic anemia. Symptomatic therapy is prescribed, aimed at normalizing functional disorders of the cardiovascular and respiratory systems, liver, kidneys, etc.
The prognosis of posthemorrhagic anemia depends on the duration and volume of bleeding. A sharp loss of 1/4 CBV leads to acute anemia and a state of hypovolemic shock, and the loss of 1/2 CBV is incompatible with life. Posthemorrhagic anemia with a slow loss of even significant amounts of blood is not so dangerous, because it can be compensated.