Shock is a failure of the circulatory system and is a life-threatening
medical emergency. Its key feature is inadequate blood flow to vital organs. It
is considered a syndrome (a group of signs and symptoms that occur together) and
can arise from any of a number of causes. It is usually associated with low
blood pressure and decreased urine production.
Signs and Symptoms
Common signs and symptoms of shock include the following:
Low blood pressure, at times undetectable
Reduced alertness and awareness, confusion, and sleepiness
Cold, moist, and often bluish and pale hands and feet
Weak and/or rapid pulse
Rapid breathing and hyperventilation
Decreased urine volume
In septic shock (from overwhelming blood
infection)—shaking chills, rapid temperature increase,
warm, flushed skin, and rapid pulse
In shock related to heart problems—lung
congestion, rapid pulse, heart murmur, engorged neck veins
What Causes It?
Shock can be caused by problems with the heart itself (cardiogenic shock),
conditions that block blood flow to or from the heart (extracardiac obstructive
shock), severe loss of fluids (hypovolemic shock), or abnormal flow of fluids
into the tissues, despite normal or increased heart function (distributive
Heart problems that can cause shock include the following:
Heart attack (myocardial infarction)
Rupture of the wall between the heart's ventricles (main pumping
Aneurysm (bulging) in a ventricle wall
Prolonged open heart surgery involving heart/lung bypass
Dysfunction or inflammation of the heart muscle (cardiomyopathy or
Irregular heartbeat, too rapid or too slow
Defective heart valves, either real or artificial, including narrowing
of the aortic valve, leading to decreased blood flow from the heart
Increased thickness of the wall of one of the ventricles, blocking
blood flow out of the heart
Extracardiac obstructive shock can result from the following:
Pericardial tamponade (buildup of fluid that puts pressure on the
heart, preventing it from filling with enough blood)
Massive pulmonary embolism (blockage of blood flow to the lungs by a
blood clot, gas bubble, bit of tissue, or other object)
Tension pneumothorax (collapse of the lungs caused by air that
collects outside them due to a rupture in the lungs or chest wall)
Severe high blood pressure in the vessels coursing through the
Hypovolemic shock can result from the following:
Severe bleeding from an injury or disease process
Severe loss of fluids, as from prolonged vomiting or diarrhea, or from
Diabetes insipidus (a metabolic disorder that causes extreme thirst
and urine output)
Distributive shock can result from the following:
Bacterial infection in the blood (septic shock)
Anaphylaxis (severe, body-wide allergic reaction)
Abnormal opening of blood vessels due to neurologic dysfunction
Addisonian crisis (a severe adrenal gland
Who's Most At Risk?
The following conditions and characteristics increase the risk for
Serious injury and trauma
Heart conditions such as heart disease or heart attack
Bacterial infection that has spread to the blood
Loss of a large volume of fluids from severe diarrhea or vomiting
Excess alcohol use
Allergic reaction to a drug, food, or environmental exposure
What to Expect at Your Provider's Office
Shock is an emergency and requires immediate conventional treatment. The
healthcare provider will diagnose shock based on your signs and symptoms and any
information readily available about underlying disease or recent injury. He or
she will check blood pressure, assess mental status (memory, orientation, and
alertness), measure urine output and obtain urine cultures, and order blood
tests to check heart, lung, and kidney function and search for evidence of
sepsis (blood infection). Imaging and other
procedures—such as X ray, electrocardiography (ECG),
echocardiography—may be performed to check the status
of the heart. A heart catheterization may also be used to determine the cause
and severity of the individual case of shock.
To help prevent shock, people should have heart disease and other conditions
that may predispose them to shock appropriately treated. Those who have severe
allergies should avoid allergens that may trigger anaphylactic shock and carry
self-injectable epinephrine to treat anaphylaxis.
The main goals of treatment are to maintain blood pressure and to make sure
the person's vital organs get enough blood and oxygen. First aid for shock
includes laying the person down, raising the legs to help blood return to the
heart, stopping any bleeding, ensuring warmth, and performing cardiopulmonary
resuscitation (CPR), if needed. Emergency medical staff will administer oxygen
and, in the case of hypovolemic and septic shock, intravenous fluids.
The following medications may be used to treat shock:
Agents to increase pressure in the arteries and increase cardiac
output, such as dopamine, dobutamine, and norepinephrine
Medications to either dilate or constrict the blood vessels (depending
on the cause of shock)
Corticosteroids for anaphylactic shock, to stabilize the patient and
Antibiotics for septic shock, to combat wide-ranging infection
Morphine to dilate veins and decrease anxiety
Thrombolytic therapy (drugs that dissolve clots as they form) may be
considered in the case of myocardial infarction or pulmonary embolism
Surgical and Other Procedures
Depending on the cause of shock, surgery may be required to repair heart
valves or rupture of a ventricle, artificially augment blood flow from the
heart, or remove an embolism.
Complementary and Alternative Therapies
Shock is always life-threatening and requires emergency conventional care.
Some CAM therapies, however, may be helpful as an adjunct to conventional
treatment. For instance, certain nutrients may help protect against the harmful
effects of shock and improve the outcome.
Oxidative stress (damage to cells caused by the body's normal use of oxygen)
may play a role in shock. Several studies have suggested that treatment with
antioxidants that help rid the body of free radicals (harmful by-products of the
oxidative process) may protect against some types of shock. Other nutrients may
also be protective.
Carnitine may be helpful in treating cardiogenic, septic, and
hypovolemic shock. A study of 115 patients with septic, cardiac, or traumatic
shock showed that acetyl-L-carnitine helped improve the conditions of patients
with all three types of shock. Improvements included returning heart rate and
blood pressure to normal and boosting oxygen delivery throughout the body.
L-carnitine has also been reported to prevent cardiogenic shock in people
suffering from a heart attack.
Coenzyme Q10 (CoQ10), an antioxidant, may be beneficial in treating
hypovolemic and septic shock. One study of hemorrhagic (bleeding-related) shock
in animals showed that CoQ10 helped protect lung function and improve blood
flow. A study on animals with septic shock showed that CoQ10 improved heart
function, blood flow, and blood pressure; another suggested that pretreatment
with CoQ10 improved lung function of the animals who later developed septic
Glutamine added to parenteral nutrition (nutrients given through the
veins when someone cannot take oral nutrition) may protect the intestines and
prevent complications from septic shock. This addition of glutamine has been
reported to decrease deaths among critically ill patients and is thought to be
safe when used along with standard treatment.
N-acetylcysteine (NAC) improved the immune system response in mice
that had septic shock caused by endotoxins (toxins released from bacterial
cells). It is not clear what this means for preventing or treating shock in
Omega-3 Fatty Acids -- Animal studies investigating the role of
essential fatty acids in the outcomes from shock show positive effects from
omega-3 essential fatty acids and negative effects from omega-6 essential fatty
acids. Omega-3 fatty acids appear to fight inflammation, while omega-6 fatty
acids appear to promote it. Studies of rats and guinea pigs suggest a diet rich
in polyunsaturated omega-3 fatty acids compared with omega-6 fatty acids may
protect against the harmful effects of septic shock. Diets of people in the
United States and other industrialized countries tend to be high in omega-6 and
low in omega-3 fatty acids.
Vitamins B3-- At least two animal studies have
suggested that nicotinamide (a form of vitamin B3) may help protect
against bacterial endotoxin that causes septic shock. In one study, mice that
were given nicotinamide after being injected with endotoxin were more likely to
survive than were mice that did not receive nicotinamide. In another study of
rats that had endotoxic shock, blood pressure improved in those that received
nicotinamide compared to those that did not receive this supplement.
Vitamin B12 -- Studies in animals with endotoxic shock
suggest that blood pressure may be improved in that clinical situation by taking
hydroxocobalamin (a form of vitamin B12).
Plant-based medicines that support the immune system may be beneficial in
treating septic shock. For instance, an Ayurvedic formula containing the
following ingredients helped reduce the blood levels of bacteria in rats
infected with Escherichia coli (an infection that can spread to the
bloodstream, potentially causing septic shock)compared to rats that
received a placebo:
Ashwagandha (Withania somnifera)
Indian gooseberry (Phyllanthus emblica)
Sweet basil (Ocimum sanctum)
Tamarisk (Tinospora cordifolia)
A series of newly developed herbal remedies based on traditional Chinese
medicine were evaluated for use in 183 people with septic shock. Injections of
the following herbs thought to regulate the flow of qi (life energy),
appeared to promote blood circulation and help prevent failure of the
circulatory system as well as lower the death rate significantly in the
treatment group compared to the control group:
Scientific studies of homeopathic remedies for the treatment of shock
specifically have not been conducted. The remedy Aconite, however, is
often used by homeopathic doctors for emergency conditions.
In animals with hypovolemic shock from bleeding, electroacupuncture (small
electrical currents applied to acupuncture needles) raised blood pressure,
protected cardiac function, and normalized the levels of various protective
substances in blood. On the other hand, there have been four case reports of
death from shock secondary to acupuncture - one from
infection leading to septic shock and the other three caused by bleeding from
the heart leading to hypovolemic shock.
In most cases, the outcome of shock depends on receiving immediate and proper
treatment. If attended to early, shock is reversible in many cases depending on
its cause. Immediate treatment for anaphylactic shock, for example, usually
results in complete recovery. But any case of shock is life threatening,
regardless of its cause, particularly in the elderly. Shock often causes organ
damage (including the kidneys, brain, and liver), cardiac arrest, and
Those who have suffered from shock will most likely be admitted to intensive
care. Following treatment, the healthcare provider will carefully monitor the
person's condition, including temperature, blood pressure, cardiac function,
urine flow, blood chemistry, and blood cells.
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Review Date: December 2000
Reviewed By: Participants in the review process include: Richard Glickman-Simon, MD,
Department of Family Medicine, New England Medical Center, Tufts University,
Boston, MA; Jacqueline A. Hart, MD, Department of Internal Medicine,
Newton-Wellesley Hospital, Harvard University and Senior Medical Editor
Integrative Medicine, Boston, MA.
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