Vasodilatory shock, vasogenic shock, or vasoplegic shock is a
medical emergency
A medical emergency is an acute injury or illness that poses an immediate risk to a person's life or long-term health, sometimes referred to as a situation risking "life or limb". These emergencies may require assistance from another, qualified p ...
belonging to
shock
Shock may refer to:
Common uses Collective noun
*Shock, a historic commercial term for a group of 60, see English numerals#Special names
* Stook, or shock of grain, stacked sheaves
Healthcare
* Shock (circulatory), circulatory medical emergen ...
along with
cardiogenic shock
Cardiogenic shock (CS) is a medical emergency resulting from inadequate blood flow due to the dysfunction of the ventricles of the heart.Textbooks of Internal MedicinHarrison's Principles of Internal Medicine 16th Edition, The McGraw-Hill Compan ...
,
septic shock
Septic shock is a potentially fatal medical condition that occurs when sepsis, which is organ injury or damage in response to infection, leads to dangerously low blood pressure and abnormalities in cellular metabolism. The Third International Con ...
,
allergen-induced shock and
hypovolemic shock
Hypovolemic shock is a form of shock caused by severe hypovolemia (insufficient blood volume or extracellular fluid in the body). It could be the result of severe dehydration through a variety of mechanisms or blood loss. Hypovolemic shock is a ...
. When the blood vessels suddenly relax, it results in
vasodilation
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...
. In vasodilatory shock, the blood vessels are too relaxed leading to extreme vasodilation and
blood pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...
drops and blood flow becomes very low. Without enough blood pressure, blood and oxygen won't be pushed to reach the body's
organs
In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...
. If vasodilatory shock lasts more than a few minutes,
the lack of oxygen starts to damage the body's organs.
Vasodilatory shock like other types of shock should be treated quickly, otherwise it can cause permanent organ damage or death as a result of
multiple organ dysfunction.
Treatment typically involves uses of
vasopressor,
inotropes
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.
The term ''inotro ...
,
fluid boluses, and introduction of
resuscitation
Resuscitation is the process of correcting physiological disorders (such as lack of breathing or heartbeat) in an acutely ill patient. It is an important part of intensive care medicine, anesthesiology, trauma surgery and emergency medicine. W ...
.
In case vasodilatory shock fails to respond to high doses of vasopressors (defined as ≥ 0.5 mg/kg/min norepinephrine-equivalent dose
), meaning it's vasopressor-resistant and advances to being called refractory vasodilatory shock or simply refractory shock.
Adjunctive therapies include
angiotensin II
Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adre ...
,
hydrocortisone
Hydrocortisone is the name for the hormone cortisol when supplied as a medication. Uses include conditions such as adrenocortical insufficiency, adrenogenital syndrome, high blood calcium, thyroiditis, rheumatoid arthritis, dermatitis, asthma, ...
,
thiamine
Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient, that cannot be made in the body. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thi ...
,
catecholamine
A catecholamine (; abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine.
Catechol can be either a free molecule or a subst ...
s,
ascorbic acid
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...
and combinations of thereof.
Signs and symptoms
*Confusion or lack of alertness
*Loss of consciousness
*A sudden and ongoing rapid heartbeat
*Sweating
*Pale skin
*A weak pulse
*Rapid breathing
*Decreased or no urine output
*Cool hands and feet
Cause
A
bacterial infection
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of ...
in the bloodstream,
a severe
allergic reaction
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
(
anaphylaxis
Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the follow ...
),
systemic inflammatory response syndrome
Systemic inflammatory response syndrome (SIRS) is an inflammatory state affecting the whole body. It is the body's response to an infectious or noninfectious insult. Although the definition of SIRS refers to it as an "inflammatory" response, i ...
,
or damage to the
nervous system
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...
(
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
and
nerve
A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system.
A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the e ...
s) may cause vasodilatory shock.
[ ] Besides, nearly all kinds of
distributive shock
Distributive shock is a medical condition in which abnormal distribution of blood flow in the smallest blood vessels results in inadequate supply of blood to the body's tissues and organs. It is one of four categories of shock, a condition where ...
such as
septic shock
Septic shock is a potentially fatal medical condition that occurs when sepsis, which is organ injury or damage in response to infection, leads to dangerously low blood pressure and abnormalities in cellular metabolism. The Third International Con ...
,
neurogenic shock
Neurogenic shock is a distributive type of shock resulting in hypotension (low blood pressure), often with bradycardia (slowed heart rate), caused by disruption of autonomic nervous system pathways. It can occur after damage to the central nervou ...
,
anaphylactic shock
Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the follow ...
,
drug and toxin-induced shock
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insuffla ...
,
endocrine shock can turn out into refractory vasodilatory shock when the original shock becomes more severe.
The most common cause of vasodilatory shock is
sepsis
Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...
.
Except sepsis, other causes comprise severe acute
pancreatitis
Pancreatitis is a condition characterized by inflammation of the pancreas. The pancreas is a large organ behind the stomach that produces digestive enzymes and a number of hormones. There are two main types: acute pancreatitis, and chronic pancr ...
,
post cardiopulmonary bypass vasoplegia and other triggers for a systemic inflammatory response syndrome.
Low serum calcium values might take a role in vasodilatory shock.
Pathophysiology
In the cases of
cardiogenic shock
Cardiogenic shock (CS) is a medical emergency resulting from inadequate blood flow due to the dysfunction of the ventricles of the heart.Textbooks of Internal MedicinHarrison's Principles of Internal Medicine 16th Edition, The McGraw-Hill Compan ...
resulting from
heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
or acute
hemorrhagic shock
Hypovolemic shock is a form of shock caused by severe hypovolemia (insufficient blood volume or extracellular fluid in the body). It could be the result of severe dehydration through a variety of mechanisms or blood loss. Hypovolemic shock is a ...
caused by a large volume of
blood loss
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
, the body constricts peripheral vessels to reverse the low arterial pressure that causes inadequate tissue perfusion.
With vasodilatory shock, it is difficult for the peripheral vascular smooth muscle to constrict.
In refractory vasodilatory shock, peripheral vascular smooth muscle responds poorly to therapy with vasopressor drugs.
Vasopressin deficiency may play an important role in vasodilatory shock.
In refractory vasodilatory shock, the patient has both vasopressin secretion deficit and an advanced resistance to vasopressin-induced blood-pressure changes.
Some have hypothesized that patients with vasopressin deficiency, including a decrease in baroreceptor stimulation, appear to have impaired autonomic reflexes.
Tone may be inhibited by
atrial stretch receptors
Low pressure baroreceptors are baroreceptors that relay information derived from blood pressure within the autonomic nervous system. They are stimulated by stretching of the vessel wall. They are located in large systemic veins and in the walls ...
and vasopressin release may be inhibited by
nitric oxide
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its che ...
or high circulating levels of
norepinephrine
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad'', ...
.
Vasodilatory shock is often involved with the dysfunction of physiologic compensatory mechanisms such as the
sympathetic nervous system
The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of th ...
,
vasopressin arginine system and
renin-angiotensin aldosterone system.
Diagnosis
The definition of refractory shock or vasodilatory shock varies. In 2018, the American College of Chest Physician stated that it is presents if there is an inadequate response to high-dose vasopressor therapy defined as ≥ 0.5 mg/kg/min norepinephrine-equivalent dose.
Management
Reversing the underlying causes of vasodilatory shock, stabilizing hemodynamic, preventing renal, myocardial, and other organs from injuries due to hypoperfusion and hypoxia, and taking necessary measures to safeguard against complications including
venous thromboembolism
Venous thrombosis is blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off (embolizes) and flows to the lungs to ...
are served as the top priorities during the treatment.
The initial treatment aiming at restoring effective blood pressure in patients that have refractory shock typically starts with introducing norepinephrine and dopamine.
Vasopressin comes as the second-line agent.
However, high-dose therapy is linked to excessive coronary, splanchnic vasoconstriction, and hypercoagulation.
Excessive vasoconstriction can cause cardiac output reduction or even fatal heart complication particularly in those with weak
myocardial function.
In those whose vasodilatory shock is caused by hypocalcemic cardiomyopathy in the context of dilated
cardiomyopathy
Cardiomyopathy is a group of diseases that affect the heart muscle. Early on there may be few or no symptoms. As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure. A ...
with documented both reduced heart ejection fraction and contractile performance,
the uses of calcium and active
vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...
or
recombinant human parathyroid hormone treatment are viable since there were many successful cases reported while given the physiological role of calcium on muscle contraction.
A successful treatment requires leveraging the respective unique contributions of a multi-disciplinary team not only
critical care doctors and often,
infectious disease
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...
specialists but also
respiratory therapy
A respiratory therapist is a specialized healthcare professional, healthcare practitioner trained in Intensive care medicine, critical care and cardio-pulmonary medicine in order to work therapeutically with people who have acute critical condi ...
,
nursing
Nursing is a profession within the health care sector focused on the care of individuals, families, and communities so they may attain, maintain, or recover optimal health and quality of life. Nurses may be differentiated from other health ...
,
pharmacy
Pharmacy is the science and practice of discovering, producing, preparing, dispensing, reviewing and monitoring medications, aiming to ensure the safe, effective, and affordable use of medicines. It is a miscellaneous science as it links heal ...
and others in collaboration.
Epidemiology
Observational studies
In fields such as epidemiology, social sciences, psychology and statistics, an observational study draws inferences from a sample (statistics), sample to a statistical population, population where the dependent and independent variables, independ ...
suggest that, about 6% to 7% of
critically ill
Intensive care medicine, also called critical care medicine, is a medical specialty that deals with seriously or critically ill patients who have, are at risk of, or are recovering from conditions that may be life-threatening. It includes pro ...
people may end up developing refractory shock.
Prognosis
Early recognition and rapid treatment initiation are crucial to saving life.
If vasodilatory shock being left untreated, even brief
hypotensive
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dias ...
periods can result in
myocardial
Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that ...
and
renal
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...
injury.
It can also increased
mortality
Mortality is the state of being mortal, or susceptible to death; the opposite of immortality.
Mortality may also refer to:
* Fish mortality, a parameter used in fisheries population dynamics to account for the loss of fish in a fish stock throug ...
in the
critically ill
Intensive care medicine, also called critical care medicine, is a medical specialty that deals with seriously or critically ill patients who have, are at risk of, or are recovering from conditions that may be life-threatening. It includes pro ...
.
Refractory shock has an all-cause mortality rate greater than 50% within a month
.
References
{{Intensive care medicine
Intensive care medicine
Medical emergencies
Causes of death