SHOCK

Shock causes systemic hypoperfusion due to either reduced cardiac output or reduced circulating blood volume.The most common causes of shock are cardiogenic (cardiac pump failure due, for example, to myocardial infarction), hypovolemic (due, for example, to blood loss), and sepsis (due to infections).Septic shock results from the host innate immune response to bacterial or fungal cell molecules (most commonly endotoxin), with systemic production of cytokines, such as TNF and IL-1, that affect endothelial and inflammatory cell activation.Hypotension, DIC, and metabolic disturbances constitute the clinical triad of septic shock.Shock of any form causes pathology by inducing prolonged tissue hypoxic injury.


Shock is the final common pathway for a number of potentially lethal clinical events, including severe hemorrhage, extensive trauma or burns, large myocardial infarction, massive pulmonary embolism, and microbial sepsis. Regardless of the underlying pathology, shock gives rise to systemic hypoperfusion; it can be caused either by reduced cardiac output or by reduced effective circulating blood volume. The end results are hypotension, impaired tissue perfusion, and cellular hypoxia. Although the hypoxic and metabolic effects of hypoperfusion initially cause only reversible cellular injury, persistence of shock eventually causes irreversible tissue injury and can culminate in the death of the patient.