shock


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Shock

 

Definition

Shock is a medical emergency in which the organs and tissues of the body are not receiving an adequate flow of blood. This deprives the organs and tissues of oxygen (carried in the blood) and allows the buildup of waste products. Shock can result in serious damage or even death.

Description

There are three stages of shock: Stage I (also called compensated, or nonprogressive), Stage II (also called decompensated or progressive), and Stage III (also called irreversible).
In Stage I of shock, when low blood flow (perfusion) is first detected, a number of systems are activated in order to maintain/restore perfusion. The result is that the heart beats faster, the blood vessels throughout the body become slightly smaller in diameter, and the kidney works to retain fluid in the circulatory system. All this serves to maximize blood flow to the most important organs and systems in the body. The patient in this stage of shock has very few symptoms, and treatment can completely halt any progression.
In Stage II of shock, these methods of compensation begin to fail. The systems of the body are unable to improve perfusion any longer, and the patient's symptoms reflect that fact. Oxygen deprivation in the brain causes the patient to become confused and disoriented, while oxygen deprivation in the heart may cause chest pain. With quick and appropriate treatment, this stage of shock can be reversed.
In Stage III of shock, the length of time that poor perfusion has existed begins to take a permanent toll on the body's organs and tissues. The heart's functioning continues to spiral downward, and the kidneys usually shut down completely. Cells in organs and tissues throughout the body are injured and dying. The endpoint of Stage III shock is the patient's death.

Causes and symptoms

Shock is caused by three major categories of problems: cardiogenic (meaning problems associated with the heart's functioning); hypovolemic (meaning that the total volume of blood available to circulate is low); and septic shock (caused by overwhelming infection, usually by bacteria).
Cardiogenic shock can be caused by any disease, or event, which prevents the heart muscle from pumping strongly and consistently enough to circulate the blood normally. Heart attack, conditions which cause inflammation of the heart muscle (myocarditis), disturbances of the electrical rhythm of the heart, any kind of mass or fluid accumulation and/or blood clot which interferes with flow out of the heart can all significantly affect the heart's ability to adequately pump a normal quantity of blood.
Hypovolemic shock occurs when the total volume of blood in the body falls well below normal. This can occur when there is excess fluid loss, as in dehydration due to severe vomiting or diarrhea, diseases which cause excess urination (diabetes insipidus, diabetes mellitus, and kidney failure), extensive burns, blockage in the intestine, inflammation of the pancreas (pancreatitis), or severe bleeding of any kind.
Septic shock can occur when an untreated or inadequately treated infection (usually bacterial) is allowed to progress. Bacteria often produce poisonous chemicals (toxins) which can cause injury throughout the body. When large quantities of these bacteria, and their toxins, begin circulating in the bloodstream, every organ and tissue in the body is at risk of their damaging effects. The most damaging consequences of these bacteria and toxins include poor functioning of the heart muscle; widening of the diameter of the blood vessels; a drop in blood pressure; activation of the blood clotting system, causing blood clots, followed by a risk of uncontrollable bleeding; damage to the lungs, causing acute respiratory distress syndrome; liver failure; kidney failure; and coma.
Initial symptoms of shock include cold, clammy hands and feet; pale or blue-tinged skin tone; weak, fast pulse rate; fast rate of breathing; low blood pressure. A variety of other symptoms may be present, but they are dependent on the underlying cause of shock.

Diagnosis

Diagnosis of shock is based on the patient's symptoms, as well as criteria including a significant drop in blood pressure, extremely low urine output, and blood tests that reveal overly acidic blood with a low circulating concentration of carbon dioxide. Other tests are performed, as appropriate, to try to determine the underlying condition responsible for the patient's state of shock.

Treatment

The most important goals in the treatment of shock include: quickly diagnosing the patient's state of shock; quickly intervening to halt the underlying condition (stopping bleeding, re-starting the heart, giving antibiotics to combat an infection, etc.); treating the effects of shock (low oxygen, increased acid in the blood, activation of the blood clotting system); and supporting vital functions (blood pressure, urine flow, heart function).
Treatment includes keeping the patient warm, with legs raised and head down to improve blood flow to the brain, putting a needle in a vein in order to give fluids or blood transfusions, as necessary; giving the patient extra oxygen to breathe and medications to improve the heart's functioning; and treating the underlying condition which led to shock.

Prognosis

The prognosis of an individual patient in shock depends on the stage of shock when treatment was begun, the underlying condition causing shock, and the general medical state of the patient.

Prevention

The most preventable type of shock is caused by dehydration during illnesses with severe vomiting or diarrhea. Shock can be avoided by recognizing that a patient who is unable to drink in order to replace lost fluids needs to be given fluids intravenously (through a needle in a vein). Other types of shock are only preventable insofar as one can prevent their underlying conditions, or can monitor and manage those conditions well enough so that they never progress to the point of shock.

Resources

Periodicals

Kerasote, Ted. "After Shock: Recognizing and Treating Shock." Sports Afield 217 (May 1997): 60+.

Key terms

Cardiogenic — Originating with the heart.
Deprivation — A condition of having too little of something.
Hypovolemic — Having a low volume.
Perfusion — Blood flow through an organ or tissue.
Sepsis — An overwhelming infection throughout the body, usually caused by bacteria in the bloodstream.

shock

 [shok]
1. a sudden disturbance of mental equilibrium.
2. a condition of acute peripheral circulatory failure due to derangement of circulatory control or loss of circulating fluid. It is marked by hypotension and coldness of the skin, and often by tachycardia and anxiety. Untreated shock can be fatal. Called also circulatory collapse.

Mechanisms of Circulatory Shock. The essentials of shock are easier to understand if the circulatory system is thought of as a four-part mechanical device made up of a pump (the heart), a complex system of flexible tubes (the blood vessels), a circulating fluid (the blood), and a fine regulating system or “computer” (the nervous system) designed to control fluid flow and pressure. The diameter of the blood vessels is controlled by impulses from the nervous system which cause the muscular walls to contract. The nervous system also affects the rapidity and strength of the heartbeat, and thereby the blood pressure as well.



Shock, which is associated with a dangerously low blood pressure, can be produced by factors that attack the strength of the heart as a pump, decrease the volume of the blood in the system, or permit the blood vessels to increase in diameter.
Types of Circulatory Shock. There are five main types: Hypovolemic (low-volume) shock occurs whenever there is insufficient blood to fill the circulatory system. Neurogenic shock is due to disorders of the nervous system. Anaphylactic (allergic) shock and septic shock are both due to reactions that impair the muscular functioning of the blood vessels. And cardiogenic shock is caused by impaired function of the heart.
Hypovolemic (Low-Volume) Shock. This is a common type that happens when blood or plasma is lost in such quantities that the remaining blood cannot fill the circulatory system despite constriction of the blood vessels. The blood loss may be external, as when a vessel is severed by an injury, or the blood may be “lost” into spaces inside the body where it is no longer accessible to the circulatory system, as in severe gastrointestinal bleeding from ulcers, fractures of large bones with hemorrhage into surrounding tissues, or major burns that attract large quantities of blood fluids to the burn site outside blood vessels and capillaries. The treatment of hypovolemic shock requires replacement of the lost volume.
Neurogenic Shock. This type, often accompanied by fainting, may be brought on by severe pain, fright, unpleasant sights, or other strong stimuli that overwhelm the usual regulatory capacity of the nervous system. The diameter of the blood vessels increases, the heart slows, and the blood pressure falls to the point where the supply of oxygen carried by the blood to the brain is insufficient, which can bring on fainting. Placing the head lower than the body is usually sufficient to relieve this form of shock.
Anaphylactic (Allergic) Shock. This type (see also anaphylaxis) is a rare phenomenon that occurs when a person receives an injection of a foreign protein but is highly sensitive to it. The blood vessels and other tissues are affected directly by the allergic reaction. Within a few minutes, the blood pressure falls and severe dyspnea develops. The sudden deaths that in rare cases follow bee stings or injection of certain medicines are due to anaphylactic reactions.
Septic Shock. This type, resulting from bacterial infection, is being recognized with increasing frequency. Certain organisms contain a toxin that seems to act on the blood vessels when it is released into the bloodstream. The blood eventually pools within parts of the circulatory system that expand easily, causing the blood pressure to drop sharply. Gram-negative shock is a form of septic shock due to infection with gram-negative bacteria.
Cardiogenic Shock. This type may be caused by conditions that interfere with the function of the heart as a pump, such as severe myocardial infarction, severe heart failure, and certain disorders of rate and rhythm.
Pathogenesis of shock. (ARDS = adult respiratory distress syndrome, GI = gastrointestinal, IL = interleukin, TNF = tumor necrosis factor.) From Damjanov, 2000.
anaphylactic shock see anaphylactic shock.
cardiogenic shock shock resulting from primary failure of the heart in its pumping function, as in myocardial infarction, severe cardiomyopathy, or mechanical obstruction or compression of the heart; clinical characteristics are similar to those of hypovolemic shock.
colloidoclastic shock colloidoclasia.
cultural shock feelings of helplessness and discomfort experienced by an outsider attempting to comprehend or effectively adapt to a different cultural group or unfamiliar cultural context.
electric shock see electric shock.
hypovolemic shock shock resulting from insufficient blood volume for the maintenance of adequate cardiac output, blood pressure, and tissue perfusion. Without modification the term refers to absolute hypovolemic shock caused by acute hemorrhage or excessive fluid loss. Relative hypovolemic shock refers to a situation in which the blood volume is normal but insufficient because of widespread vasodilation as in neurogenic shock or septic shock. Clinical characteristics include hypotension; hyperventilation; cold, clammy, cyanotic skin; a weak and rapid pulse; oliguria; and mental confusion, combativeness, or anxiety.
insulin shock a hypoglycemic reaction to overdosage of insulin, a skipped meal, or strenuous exercise in an insulin-dependent diabetic, with tremor, dizziness, cool moist skin, hunger, and tachycardia; if untreated it may progress to coma and convulsions.
respirator shock circulatory shock due to interference with the flow of blood through the great vessels and chambers of the heart, causing pooling of blood in the veins and the abdominal organs and a resultant vascular collapse. The condition sometimes occurs as a result of increased intrathoracic pressure in patients who are being maintained on a mechanical ventilator.
septic shock shock associated with overwhelming infection, usually by gram-negative bacteria, although it may be produced by other bacteria, viruses, fungi, and protozoa. It is thought to result from the action of endotoxins or other products of the infectious agent on the vascular system causing large volumes of blood to be sequestered in the capillaries and veins; activation of the complement and kinin systems and the release of histamine, cytokines, prostaglandins, and other mediators may be involved. Clinical characteristics include initial chills and fever, warm flushed skin, increased cardiac output, and a lesser degree of hypotension than with hypovolemic shock; if therapy is ineffective, it may progress to the clinical picture associated with hypovolemic shock.
shell shock old term for posttraumatic stress disorder.
spinal shock the loss of spinal reflexes after injury of the spinal cord that appears in the muscles innervated by the cord segments situated below the site of the lesion.

shock

(shok),
1. The condition in which the cells of the body receive inadequate amounts of oxygen secondary to changes in perfusion; most commonly secondary to blood loss or sepsis.
2. A sudden physical or biochemical disturbance that results in inadequate blood flow and oxygenation of an animal's vital organs.
3. A state of profound mental and physical depression consequent to severe physical injury or to emotional disturbance.
4. A state characterized by inadequacy of blood flow throughout the body to the extent that damage occurs to the cells of the tissues; if the shock is prolonged, the cardiovascular system itself becomes damaged and begins to deteriorate, resulting in a vicious cycle that leads to death.
[Fr. choc, fr. Germanic]

shock

(shŏk)
n.
1. A massive, acute physiological reaction usually to physical trauma, infection, or allergy, characterized by a marked loss of blood pressure, resulting in a diminished blood flow to body tissues and a rapid heart rate.
2. The sensation and muscular spasm caused by an electric current passing through the body or a body part.
v. shocked, shocking, shocks
v.tr.
1. To induce a state of physical shock in (an animal or person).
2.
a. To subject (an animal or person) to an electric shock.
b. To administer electric current to (a patient) to treat cardiac arrest or life-threatening arrhythmias.
c. To administer electroconvulsive therapy to (a patient).

SHOCK

Cardiology A clinical trial–Should We Emergently Revascularize Occluded Coronaries for Cardiogenic shock comparing the efficacy of emergency revascularization and initial medical stabilization in managing Pts with MI complicated by cardiogenic shock. See Cardiogenic shock.

shock

A condition characterized by signs and Sx due to a cardiac output below that required to fill the arteries with blood of sufficient pressure to adequately perfuse organs and tissue Clinical Hypotension, poor peripheral perfusion, hyperventilation, tachycardia, oliguria, cyanosis, mental clouding, a sense of great anxiety and foreboding, confusion and, sometimes, combativeness Causes Trauma with major multiorgan system injury, septicemia, fluid loss–blood or intractible diarrhea, burns, high voltage electric current, abrupt loss of myocardial activity Classification Based on related mechanisms of cardiac dysfunction–pump failure, ↓ volume–loss of blood or extracellular fluid or changes in arterial resistance or venous capacity Pathogenesis Shock activates sympathetic nervous system via the carotic and aortic baroreceptors, ↑ catecholamines, vasoconstriction of 'non-essential' organs–intestine, kidneys, skin to maintain blood flow to vital organs–heart and brain; with time, hypotension becomes irreversible. See Anaphylactic shock, Bacteremic shock, Calcium shock, Cardiogenic shock, Cardiopulmonary obstructive shock, Culture shock, Heat shock, Hypotension, Hypovolemic shock, Insulin shock, Psychologic shock, Refractory septic shock, Septic shock, Spinal shock.

shock

(shok)
1. A sudden physical or mental disturbance.
2. A state of profound mental and physical depression consequent upon severe physical injury or an emotional disturbance.
3. A severe disturbance of hemodynamics in which the circulatory system fails to maintain adequate perfusion of vital organs; may be due to reduction of blood volume (hemorrhage, dehydration), cardiac failure, or dilation of the vascular system in toxemia or septicemia.
4. The abnormally palpable impact, appreciated by a hand on the chest wall, of an accentuated heart sound.
[Fr. choc, fr. Germanic]

shock

1. A syndrome featuring low blood pressure, a prejudiced blood supply to important organs such as the brain and heart, and low kidney output. Causes of shock include severe blood loss, burns, severe infection, allergy, heart damage from CORONARY THROMBOSIS and head injury. Untreated shock may be rapidly fatal. The main element in treatment is the rapid restoration of the circulating blood volume by transfusion and the use of the drug VASOPRESSIN to help to maintain the blood pressure.
2. A temporary state of psychological overburdening from severe mental distress, often associate with stupefaction.

shock

(shok)
1. State in which cells of body receive inadequate amounts of oxygen secondary to changes in perfusion; most commonly due to blood loss or sepsis.
2. Sudden physical or biochemical disturbance that results in inadequate blood flow and oxygenation of an animal's vital organs.
3. State of profound mental and physical depression consequent to severe physical injury or to emotional disturbance.
[Fr. choc, fr. Germanic]

Patient discussion about shock

Q. SHOCK-WHAT IS IT? clinical anaphylactic shock

A. shock is when the fluid volume in the blood decreases to a dangerous amount. then the body "panics" because most of the organs don't get oxygen and don't remove carbon dioxide and die. so the body start to shut down "unnecessary" organ's blood flow. like skin and such.
this is death closing in on you in minutes.

Q. I was shocked to note that vaccination in the children could cause autism too. Is that true? Very recently I have delivered a cute male baby and I could see a change in me after my delivery in the sense that I always think about him. My sister’s son who is 5 years old is diagnosed with Autism and I just can’t see the sufferings of my sister with him. She experiences difficulty in almost all dealings with him right from brushing, giving bah and making him to study….etc. Now I fear that my son should not get in to autism although I know that this is too early to think about disorder in my son. But as my sister’s son got in to this disorder, this has affected me a lot. Hope you can understand my feelings towards my baby. When I browsed through the net, I was shocked to note that vaccination in the children could cause autism too. Is that true? Can I get some idea…..

A. Hey! I appreciate your care for the new born. But to be honest, fearing at this stage will only trouble you and your baby in the sense that your emotions could catch your baby especially when you breast feed. I want you to be cheerful so as to bring up a healthy child. The signs of autism in the new born are something which should not be thought about at this stage. All you may have to think is to bring up him nicely without any disease. As regards vaccinations that could create autism in children, there is no proof that a vaccine causes Autism. It is only a belief and all the children are vaccinated and not all get autism. It is not a fair idea to suspect vaccination as vaccinations are administered in a new born child after carrying out the necessary tests.

Q. Is electric shock efficient for ocd? Is it dangerous? My husband has OCD for 15 years now. He was also diagnosed with mania-depressia. He takes so many medications and nothing really helps. We were offered to try electric shock and I'm scared. Is it dangerous? What are the chances of this method to work for him?

A. Electroconvulsive therapy (ECT) is indeed considered effective for OCD, although it's not the first line of treatment. It does have its risks, including memory loss, disorientation and sort of confusion. There is also a change in the activity of the heart but it's rarely significant.

Generally it can be said that it's not an absolutely safe treatment, but it may help, especially if other drugs don't help.

You may read more here:
http://www.nlm.nih.gov/medlineplus/ency/article/003324.htm

More discussions about shock
References in periodicals archive ?
It is also observed that when a shock hits, the main strategy adopted by households is to use their assets in some way rather than to ask for help from friends and relatives, while private and public social safety nets exist but offer little effective protection.
To measure the degree of covariance of the occurrence of a shock at a particular location all primary sampling units (PSUs) in which no one reported experiencing a shock in last five years were excluded from this exercise.
In all modelled cases the lower body temperature settles and the larger value of the linear heat flux density is gained in the monotube shock absorbers.
The company will commence its planned global multicentric Phase IIb study in septic shock patients later this year to demonstrate efficacy of nangibotide and bring a clinically relevant proof of clinical activity in septic shock patients.
Shock was further classified as compensated shock, in which the blood pressure is maintained and a stage of decompensated shock, with hypotension.
When a patient with sepsis-triggered Takotsubo cardiomyopathy develops shock, it is difficult to distinguish cardiogenic shock from septic shock.
(2) She then builds a model to explain her empirical findings and shows that the oil firm's ability to cover high fixed costs in the sector, which depends on the size of the oil price shock, is important in understanding the responses.
Much finer structure can be captured by the resolution of both 201 x 801 and 401 x 1601, especially the shock waves, spline line, and flow structure interactions.
A central premise of our research program is that measuring and modeling shocks at the micro level (to firms and sectors) is essential for understanding the macro consequences of globalization.
The simulation of dynamic recoil process was achieved via applying homogeneous experiment design and influence study of shock parameters using Matlab [7, 8].
As the ripples rapidly evolved, they became steeper, like waves swelling near the shore, until eventually creating shocks analogous to a breaking wave.
Hydraulic shock absorbers are a critical component of a wide variety of products.