Types of Shock and Management
There are four major categories of shock: hypovolemic shock, distributive shock, cardiogenic shock, and obstructive shock.
1. Anaphylactic Shock
Anaphylactic shock is a severe reaction to an allergen causing an acute multisystem allergic reaction. It causes arterial and venous vasodilation; increased capillary permeability and pulmonary vasoconstriction, which increase right ventricular afterload, reduce pulmonary blood fl ow, decrease left ventricular preload, and reduce CO.
2. Hypovolemic Shock
Hypovolemic shock is the most common cause of shock in children. Loss of volume decreases preload, which decreases stroke volume and CO, decreasing BP and tissue perfusion.
Causes of Hypovolemic include:
■ Diarrhea (most common cause in children)
■ Internal or external blood loss
■ Large burns
■ Severe dehydration
■ Osmotic diuresis, as with DKA
■ Third-space losses: fl uid shifting into interstitial spaces
3. Neurogenic Shock
Neurogenic shock is the sudden lack of sympathetic nervous system innervations to vascular smooth muscle, resulting in inappropriate vasodilation and hypotension. Heart rate cannot increase to compensate for hypotension. Causes include cervical spine or high thoracic spine injury.
4. Cardiogenic Shock
Cardiogenic shock is caused by myocardial dysfunction resulting in reduced CO and inadequate tissue perfusion. Causes include congenital heart anomalies, cardiomyopathy, myocarditis, arrhythmias, drug toxicity or poisoning, myocardial contusion or trauma, and sepsis.
5. Septic Shock
In septic shock, infectious organisms cause systemic infl ammation, initiating a cascade of physiological responses. These include infl ammatory mediators (cytokines), which cause vasodilation, increased capillary permeability, microvascular thrombosis leading to DIC, myocardial dysfunction, and reduced CO. Tissue perfusion is inadequate. Relative or absolute adrenal insuffi ciency may develop, contributing to reduced SVR.