Shock: Everything You Need To Know

Shock is the state of insufficient blood flow to the tissues of the body as a result of problems with the circulatory system.[1][2] Initial symptoms of shock may include weakness, fast heart rate, fast breathing, sweating, anxiety, and increased thirst.[1] This may be followed by confusion, unconsciousness, or cardiac arrest, as complications worsen.[1]

Shock is divided into four main types based on the underlying cause: low volume, cardiogenic, obstructive, and distributive shock.[2] Low volume shock, also known as hypovolemic shock, may be from bleeding, diarrhea, or vomiting.[1] Cardiogenic shock may be due to a heart attack or cardiac contusion.[1] Obstructive shock may be due to cardiac tamponade or a tension pneumothorax.[1] Distributive shock may be due to sepsis, anaphylaxis, injury to the upper spinal cord, or certain overdoses.[1][4]

The diagnosis is generally based on a combination of symptoms, physical examination, and laboratory tests.[2] A decreased pulse pressure (systolic blood pressure minus diastolic blood pressure) or a fast heart rate raises concerns.[1] The heart rate divided by systolic blood pressure, known as the shock index (SI), of greater than 0.8 supports the diagnosis more than low blood pressure or a fast heart rate in isolation.[5][6]

Treatment of shock is based on the likely underlying cause.[2] An open airway and sufficient breathing should be established.[2] Any ongoing bleeding should be stopped, which may require surgery or embolization.[2] Intravenous fluid, such as Ringer's lactate or packed red blood cells, is often given.[2] Efforts to maintain a normal body temperature are also important.[2] Vasopressors may be useful in certain cases.[2] Shock is both common and has a high risk of death.[3] In the United States about 1.2 million people present to the emergency room each year with shock and their risk of death is between 20 and 50%.[3]