55. Blood loss.

Blood loss – pathological process occurring as a result of bleeding which is characterized by significant complex of pathological disturbances and compensatory reactions directed to circulating blood volume reducing and hypoxy caused by blood respiratory function inhibiting.

Aethilogical factors;

1. vessels integrity disorder at wounding or injury with pathological process (atherosclerosis, tumor, tuberculosis);

2. vascular wall permeability increasing (acute radiational disease);

3. blood coagulation decreasing (haemorrhagical diatesis).

Protective-compensatory reactions:

1. By term:

   1. urgent;

   2. non-urgent.

2. By direction:

   1. directed to vascular bed volume decreasing;

   2. directed to circulating blood volume increasing;

   3. directed to blood content restoration;

   4. directed to protection from hypoxy.

Circulating blood volume increasing:

1. tissular liquid transfer to vessels;

2. water and Na ions reabsorbtion enforcement by kidney (vasopressine, renine-angiotensine system, sympathy-adrenale system acyivation);

3. blood exit from depot to vascular bed.

Blood content restoration:

Circulatory (circulating blood volume reducing) and haemic (anaemic) hypoxy causes kidney hypoxy and, in turn, erythropoietin synthesis activation by juxta-glomerular apparatus.

Pathological changings at blood loss:

1. Systemic hamodynamics disorders (circulating blood volume diminishing, arterial pressure decreasing) and local circulation (microcirculation) disturbances up to shock development.

2. Acute post-haemorrhagic anaemia.

3. Hypoxy – first it is circulatory, then haemic (anaemic).

4. Non-gas acidosis - caused by hypoxy and lactate coming to blood.

5. Kidney excretory function disorder: hypotony leads to glomerular filtration inhibiting and finally acute renal insufficiency,oligo- and anuria, intoxication (azotemia or nitrogenemia).

56. Acute and chronic posthaemorrhagic anaemias.

Acute – is developed after rapid massive blood loss at vessels injury or their injuries with pathological process.

Characteristics:

Pathogenetically	Posthaemorrhagic
Aethiologically	Acquired
By red bone marrow regeneratory ability	Regeneratory
By colour index	First normochromic, then hypochromic
By haemopoiesis type	Erythroblastic
By clinical course	Acute

Blood picture:

1. In course of several hours after blood loss:

   1. Hb – N; b) Er- N; c) CI – N; d) Ht- N.

2. From several hours up to several days after acute blood loss:

   1. Hb - ↓; b) Er - ↓; c) CI - N; d) Ht - ↓.

3. From several days to 1-2 weeks:

   1. Hb - ↑; b) Er - ↑; c) CI - ↓; d) Ht - ↑.

Chronic anaemia – is developed as a result of repeated blood losses caused by vessels injury at several pathological conditions (menstrual cycle disorders, stomach ulcer disease, haemorrhoids) as well as vascular-platelet and coagulational haemostasis disorders (haemorrhagical diatesis). Iron loss at frequent bleedings gives this anaemia iron-deficient character.

Blood picture:

1. Hb decreasing;

2. CI decreasing;

3. Er degenerative forms (micro- and poikylocytosis, hypochromy);

4. Er number and Ht can be without changing.

Characteristics:

Pathogenetically	Posthaemorrhagic
Aethiologically	Acquired
By red bone marrow regeneratory ability	Hypoegeneratory
By colour index	Hypochromic
By haemopoiesis type	Erythroblastic
By clinical course	Chronic