Shock

This article is about medicine. For the concept of shock in physics and mechanics, see Shock (mechanics).

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In medicine, shock is a biomedical life-threatening condition where the human body, in reaction to events, which may start a cyclical degenerative process ending in the person's death without immediate outside intervention.

Some common causes of shock:

• Hypovolemic[?] shock is caused by loss of blood volume. It is necessary to immediately control any bleeding. Intravenous fluids[?] and/or blood transfusions may be needed to save the person's life.

• Septic shock is caused by overwhelming infection and is treated by massive doses of antibiotics. Septic shock is often fatal.

• Cardiogenic[?] shock is when blood pressure falls because of failure of the heart to pump effectively. This can be due to damage to the heart or to obstruction of blood flow from the heart (cardiac tamponade[?]).

Symptoms and signs

These include pallor[?], hypotension[?], tachycardia, cold and clammy extremities and altered mental state.

Most forms of shock exhibit all these symptoms and signs but occasionally, as in septic or toxic shock, the patient's hands and feet may initially be warm rather than cold and clammy as the toxins cause peripheral vasodilatation[?].

Treatment

The proper treatment of shock is vital in the performance of first aid and comprises an essential part of the duties of the emergency medical technician, nurse, paramedic and doctor.

Quick diagnosis is of key importance. Resuscitation[?] should be started immediately, the modality of which depends on the patient's requirements. Virtually all patients with shock will require some kind of intravenous access; obtaining venous access quickly is of paramount importance. Most people in shock require intravenous fluids. However, under certain circumstances such as in cardiogenic shock, too much fluid can be fatal, so a knowledgeable professional rather than a lay person should make these decisions.

Prognosis

Shock is sometimes classified into two stages - reversible shock and irreversible shock. The distinction between reversible and irreversible shock is clinical (and sometimes retrospective) - reversible shock is potentially treatable whereas irreversible shock inevitably leads to death. Most cases of untreated reversible shock will progress to irreversible shock within about 6 hours of onset.