Shock | |
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US Navy EMT trainees and firemen using IV fluid replacement in treating a trauma training mannequin to prevent hypovolemic shock | |
Specialty | Critical care medicine |
Symptoms | Initial: Weakness, fast heart rate, fast breathing, sweating, anxiety, increased thirst[1] Later: Confusion, unconsciousness, cardiac arrest[1] |
Types | Low volume, cardiogenic, obstructive, distributive[2] |
Causes | Low volume: Severe bleeding, vomiting, diarrhea, dehydration, or pancreatitis[1] Cardiogenic: severe heart attack (especially of the left or right ventricles), severe heart failure, cardiac contusion[1] Obstructive: Cardiac tamponade, tension pneumothorax[1] Distributive: Sepsis, spinal cord injury, certain overdoses[1] |
Diagnostic method | Based on symptoms, physical exam, laboratory tests[2] |
Treatment | Based on the underlying cause[2] |
Medication | Intravenous fluid, vasopressors[2] |
Prognosis | Risk of death 20 to 50%[3] |
Frequency | 1.2 million per year (US)[3] |
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: hypovolemic, cardiogenic, obstructive, and distributive shock.[2] Hypovolemic shock, also known as low volume 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]