What is Shock Syndrome

Shock is a complex and incompletely understood acute cardiovascular syndrome or heart disease which defies precise definition because of its various causes.

Shock is a complex and incompletely understood acute cardiovascular syndrome or heart disease which defies precise definition because of its various causes.

It is practical to consider shock as a disturbance of circulation resulting in ineffective or critical reduction of perfusion of vital tissues and a wide range of body systems’ effects.

The term is described as “classical” but highly variable pattern of signs and symptoms which usually includes arterial hypotension, altered sensorium, pallor, cold and clammy skin, rapid and weak pulse, air hunger, thirst, oliguria and a tendency to steadily progress toward an irreversible phase.

Recognition of early shock may be obscured by factors such as anxiety, complicating medical problems and surrounding circumstances. The “classical” signs of schock may appear suddenl and often represent fully developed shock.

In so-called, “warm shock” such as is seen in some patients with endotoxin septic shock, the skin I dry, pink and warm and the urine volume is adequate despite the arterial hypotension and peripheral pooling.

There are 3 major pathophysiologic mechanisms involved in the production of shock. These are hypovolemia which is decreased blood volume; cardiac insufficiency meaning the heart fails to pump; and altered vascular resistance or the abnormal constriction and dilation of the vessels.

Alteration of one or more of these factors may result in diminished flow of small vessel circulation. It is the adaptation or failure of adaptation of the microcirculation that is responsible for arteriovenous shunting, decreased urine output, fluid loss from the capillaries, sludging of red blood cells, stagnant tissue hypoxia, acidosis, hyperlacticadidemia, and cellualar injury, all of which occur in the shock syndrome. Little is known regarding the actual mechanisms of the metabolic vicious cycle leading to “irreversible shock”

Debility, malnutrition, senility temperature extremes, alcoholism, hypotensive drugs, anesthetics, autonomic disorders, diabetes, and andrenocorticoid disorders are factors which can predispose to shock.

There are three classifications of shock namely hypovolemic shock, cardiogenic shock and vascular shock.

Hypovolemic shock may result from loss of whole blood by hemorrhage due to external and internal injury; loss of whole blood through non traumatic internal hemorrhage such as bleeding peptic ulcer and ruptured varices; loss of blood and plasma in extensive fractures and injuries; and loss of fluids and electrolytes due to vomiting, diarrhea and endocrine disturbances.

Cardiogenic Shock is due to inability of the left ventricle of the heart to perform effectively as a pump in maintaining an adequate cardiac output occurs most frequently following myocardial infarction (MI), but I t also occurs in heart problems or as complications of other forms of severe shock.

Vascular Shock refers to the deficiency of circulating volume due to the incapacity of vascular system to expand. The increased vascular capacity may result from widespread dilatation of arteries and arterioles, arteriovenous shunting, or from venous pooling. Under vascular shock, the most common form is known as the septic shock.

Septic shock is most commonly caused by infection manifested by fever and chills associated with hypotension. Neurogenic or psychogenic shock is due to spinal cord injury, pain, trauma, fright, or vasodilator drugs. Without the following causes, the patient usually revives promptly using spirits of ammonia, but further observation is required to prevent possible recurrence.

For treatment, it is important bring the patient to the hospital to determine the specific causes and contributing factors, severity and duration of shock. Prevention is better than cure. Early recognition of shock is more effective than the treatment of established shock.

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Rita Zeytounian
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Posted on Apr 22, 2010