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Shock - Symptoms and Causes
Shock is more appropriately referred to as a clinical syndrome than a primary disease process. A large number of disease processes can cause shock and we will discuss a number of them in this section. Shock can be defined as a state of profound and widespread reduction in tissue perfusion. A change that leads first to reversible, and then, if prolonged, to irreversible cell (and organ) death. The signs and symptoms of shock are the same for all types of shock. Low blood pressure (usually a mean arterial pressure less than 60 mmHG), rapid heart rate, decreased urine output, change in mentation, and cool mottled extremities (decreased blood flow to the skin) are common features.
THE CAUSES OF SHOCK
1. Cardiogenic shock: This refers to a state of decreased tissue perfusion that occurs secondary to inadequate pumping function of the heart. This can occur secondary to a heart attack, heart valve disorder (aortic stenosis), cardiac arrhythmia, or from cardiac decompensation, seen in those with septic shock (see below).
2. Cardiopulmonary Obstructive shock: This can occurs as the result "obstruction" of the cardiopulmonary circuit. Examples include massive pulmonary embolism, pericardial tamponade, pneumothorax, and severe constrictive pericarditis.
3. Hypovolemic shock: This includes hemorrhagic shock (blood loss) and fluid depletion (dehydration).
4. Distributive shock: This group shares the common characteristic of decreasing the "vascular tone" in the body. The net result is a decrease in tissue and organ perfusion. Examples include anaphylactic shock, toxic byproducts (drug overdose), adrenal gland insufficiency, septic shock (bacterial infection), and neurogenic shock (seen in patients after sustaining a head injury or spinal cord injury).
Patients can suffer from more than one type of shock simultaneously. This fact can often make treatment more complicated. The evaluation of the patient in shock will be complex. Studies include chest x-ray, EKG, and arterial blood gas analysis. Other blood studies include CBC and electrolyte profile. Urinalysis, urine and blood cultures will also be performed. Invasive hemodynamic monitoring devices such as the Swan-Ganz catheter can assist the physician in making therapeutic decisions. Treatment is based on the underlying cause for shock. Intravenous fluids, blood transfusion, and intravenous blood pressure supporting medications will be necessary in some cases. Antibiotics will be necessary in cases of suspected sepsis. Anaphylactic shock is discussed in the DISEASE FILE under anaphylaxis. Those suffering from adrenal insufficiency (rare) will require supplemental cortisone intravenously.Prognosis is quite variable and relates directly to the underlying cause and presence of pre-existing disease.
Hope this article will provide you information about shock.
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