Mechanisms of Adaptation Failure
The transition of shock into the decompensation stage is caused by the exhaustion of the body's protective reserves, increasing internal organ dysfunction, and the continuous impact of the extreme stressor. The core problem of this stage is the profound breakdown of integrated physiological and functional systems.
Neuroendocrine regulation loses its efficacy and ceases to control tissue processes. Even if blood hormone levels and neural impulse frequencies remain high (or conversely, decrease), target cells fail to respond appropriately. This occurs due to receptor hyposensitization, triggered by severe electrolyte imbalances, worsening metabolic acidosis, and structural damage to cell membranes (primarily neuronal membranes). Consequently, vital physiological activities undergo progressive depression.
Hemodynamic Catastrophy
Circulatory disorders become the pivotal factor in the pathogenesis of decompensation. The protective adaptive mechanism of blood flow centralization collapses: the tone of capacitance and resistance blood vessels drops globally. Simultaneously, acute heart failure progresses, accompanied by severe arrhythmias and a drop in myocardial contractility.
- Critical Blood Pressure Drop: Systolic blood pressure falls to critical levels — 60–30 mmHg.
- Renal Shutdown: Due to such critically low perfusion pressure, glomerular filtration stops completely, inevitably leading to uremia.
- Microcirculatory Disturbances: The fluid phase of blood actively leaks through capillary walls into the interstitial space. Circulating blood volume (CBV) continues to drop precipitously, while blood viscosity increases significantly.
In the hemostatic system, a profound imbalance arises among the clotting, anticoagulation, and fibrinolytic systems. This triggers DIC (disseminated intravascular coagulation), leading to total organ hypoperfusion, multiple microthromboses, hemorrhages, and subsequently, dystrophic and necrotic tissue changes.
Hypoxia, Toxemia, and Metabolic Shifts
Against the background of systemic vascular collapse, reduced circulating blood volume, and progressive respiratory failure, a mixed-type progressive hypoxia develops. Cells are forced to switch to an anaerobic energy production mode, causing severe uncompensated metabolic acidosis.
Metabolism alters drastically, exacerbating organ damage:
- Dominance of Catabolism: Proteins, lipids, carbohydrates, and complex compounds (lipoproteins, phospholipids) undergo massive breakdown. Anabolic and synthetic processes halt almost entirely.
- Cellular Edema: Marked intracellular hyperhydration develops.
- Destruction of Cellular Structures: Lipid peroxidation (LPO) is activated, enzyme systems are suppressed, cell membranes are degraded, and intercellular interactions are irreversibly disrupted.
Concurrently, severe toxemia develops. The bloodstream is poisoned by abnormal metabolic byproducts (lactic, pyruvic, and fatty acids, polypeptides, biogenic amines). Cytotoxic compounds—denatured proteins, intracellular enzymes, and ions—leak from destroyed necrotic cells into the circulation. Due to liver and kidney failure, indoles, phenols, skatoles, uric acid, and urea rapidly accumulate in the body.
Clinical Manifestations and Organ Damage
Decompensation clinically manifests as systemic failure of vital organs, described by specific shock phenomena.
| Organ System | Characteristic Clinical Manifestations and Alterations |
|---|---|
| Nervous System | Confusion, lethargy, hyporeflexia, critically low efficacy of neuroendocrine regulation. |
| Cardiovascular System | Arterial hypotension, vascular collapse, heart failure, arrhythmias, capillariotrophic insufficiency. |
| Respiratory System | Acute respiratory failure, development of "shock lung" phenotype. |
| Blood System | Blood pooling, increased viscosity, development of thrombohemorrhagic syndrome (DIC). |
| Liver and Kidneys | Acute hepatic and renal failure, "shock liver" and "shock kidney" phenomena. |