Infarction is tissue death (
necrosis) due to
inadequate blood supply to the affected area. It may be caused by
artery blockages, rupture, mechanical compression, or
vasoconstriction. The resulting
lesion
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals.
Types
There is no designated classif ...
is referred to as an infarct
(from the Latin ''infarctus'', "stuffed into").
Causes
Infarction occurs as a result of prolonged
ischemia, which is the insufficient supply of oxygen and nutrition to an area of tissue due to a disruption in blood supply. The blood vessel supplying the affected area of tissue may be blocked due to an obstruction in the vessel (e.g., an
arterial embolus
Arterial embolism is a sudden interruption of blood flow to an organ or body part due to an embolus adhering to the wall of an artery blocking the flow of blood, the major type of embolus being a blood clot (thromboembolism). Sometimes, pulmon ...
,
thrombus, or
atherosclerotic plaque
An atheroma, or atheromatous plaque, is an abnormal and reversible accumulation of material in the inner layer of an arterial wall.
The material consists of mostly macrophage cells, or debris, containing lipids, calcium and a variable amount ...
), compressed by something outside of the vessel causing it to narrow (e.g.,
tumor
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
,
volvulus, or
hernia
A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Various types of hernias can occur, most commonly involving the abdomen, and specifically the groin. Groin her ...
), ruptured by trauma causing a loss of blood pressure downstream of the rupture, or vasoconstricted, which is the narrowing of the blood vessel by contraction of the muscle wall rather than an external force (e.g., cocaine vasoconstriction leading to
myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
).
Hypertension and
atherosclerosis are risk factors for both
atherosclerotic plaque
An atheroma, or atheromatous plaque, is an abnormal and reversible accumulation of material in the inner layer of an arterial wall.
The material consists of mostly macrophage cells, or debris, containing lipids, calcium and a variable amount ...
s and
thromboembolism
Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets ...
. In atherosclerotic formations, a plaque develops under a fibrous cap. When the fibrous cap is degraded by metalloproteinases released from macrophages or by intravascular shear force from blood flow, subendothelial thrombogenic material (
extracellular matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide s ...
) is exposed to circulating platelets and thrombus formation occurs on the vessel wall
occluding blood flow. Occasionally, the plaque may rupture and form an
embolus which travels with the blood-flow downstream to where the vessel narrows and eventually clogs the vessel lumen
Classification
By histopathology
Infarctions are divided into two types according to the amount of
blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...
present:
#
White infarction Anemic infarcts (also called white infarcts or pale infarcts) are white or pale infarcts caused by arterial occlusions, and are usually seen in the heart, kidney and spleen. These are referred to as "white" because of the lack of hemorrhaging and l ...
s (
anemic infarct Anemic infarcts (also called white infarcts or pale infarcts) are white or pale infarcts caused by arterial occlusions, and are usually seen in the heart, kidney and spleen. These are referred to as "white" because of the lack of hemorrhaging and l ...
s) affect solid organs such as the
spleen
The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes . ,
heart
The heart is a muscular Organ (biology), organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as ca ...
and
kidneys wherein the solidity of the
tissue substantially limits the amount of nutrients (
blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...
/
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...
/
glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...
/
fuel) that can flow into the
area
Area is the quantity that expresses the extent of a region on the plane or on a curved surface. The area of a plane region or ''plane area'' refers to the area of a shape or planar lamina, while '' surface area'' refers to the area of an op ...
of
ischaemic necrosis. Similar
occlusion to
blood flow and consequent
necrosis can occur as a result of severe
vasoconstriction as illustrated in severe
Raynaud's phenomenon that can lead to irreversible
gangrene.
#
Red infarctions (
hemorrhagic infarcts) generally affect the
lungs or other loose organs (
testis,
ovary,
small intestines). The
occlusion consists more of
red blood cell
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "hol ...
s and
fibrin strands. Characteristics of red infarcts include:
#* occlusion of a
vein
Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated ...
#* loose tissues that allow
blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...
to collect in the
infarcted zone
#* tissues with a dual
circulatory system
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
(lung, small intestines)
#* tissues previously congested from sluggish venous outflow
#*
reperfusion (
injury) of previously
ischemic tissue that is associated with
reperfusion-related
diseases, such as
myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
,
stroke
A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...
(
cerebral infarction), shock-
resuscitation, replantation
surgery
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pa ...
,
frostbite
Frostbite is a skin injury that occurs when exposed to extreme low temperatures, causing the freezing of the skin or other tissues, commonly affecting the fingers, toes, nose, ears, cheeks and chin areas. Most often, frostbite occurs in t ...
,
burns, and
organ transplant
Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transpor ...
ation.
By localization
* Heart:
Myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
(''MI''), commonly known as a ''heart attack'', is an infarction of the heart, causing some heart cells to die. This is most commonly due to occlusion (blockage) of a
coronary artery
The coronary arteries are the arterial blood vessels of coronary circulation, which transport oxygenated blood to the heart muscle. The heart requires a continuous supply of oxygen to function and survive, much like any other tissue or organ o ...
following the rupture of a
vulnerable atherosclerotic plaque, which is an unstable collection of
lipids
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids in ...
(fatty acids) and
white blood cells (especially
macrophages) in the wall of an
artery. The resulting
ischemia (restriction in blood supply) and
oxygen shortage, if left untreated for a sufficient period of time, can cause damage or kill heart muscle tissue (''
myocardium'').
* Brain:
Cerebral infarction is the
ischemic kind of
stroke
A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...
due to a disturbance in the blood vessels supplying blood to the brain. It can be atherothrombotic or embolic. Stroke caused by cerebral infarction should be distinguished from two other kinds of stroke:
cerebral hemorrhage and
subarachnoid hemorrhage. Cerebral infarctions vary in their severity with one third of the cases resulting in death. In response to ischemia, the brain degenerates by the process of liquefactive necrosis.
* Lung: Pulmonary infarction or
lung infarction
* Spleen:
Splenic infarction
Splenic infarction is a condition in which blood flow supply to the spleen is compromised, leading to partial or complete infarction (tissue death due to oxygen shortage) in the organ. Splenic infarction occurs when the splenic artery or one of ...
occurs when the
splenic artery or one of its branches are occluded, for example by a
blood clot
A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cr ...
. Although it can occur
asymptomatically, the typical symptom is severe
pain in the
left upper quadrant of the abdomen, sometimes radiating to the left shoulder. Fever and chills develop in some cases.
It has to be differentiated from other causes of
acute abdomen.
* Limb:
Limb infarction
A limb infarction is an area of tissue death of an arm or leg. It may cause ''skeletal muscle infarction'', avascular necrosis of bones, or necrosis of a part of or an entire limb.
Signs and symptoms
Early symptoms of an arterial embolism in the ...
is an infarction of an
arm or
leg. Causes include
arterial embolism
Arterial embolism is a sudden interruption of blood flow to an organ or body part due to an embolus adhering to the wall of an artery blocking the flow of blood, the major type of embolus being a blood clot (thromboembolism). Sometimes, pulmona ...
s and ''skeletal muscle infarction'' as a rare complication of long standing, poorly controlled
diabetes mellitus.
A major presentation is painful thigh or leg swelling.
[
* Bone: Infarction of ]bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
results in avascular necrosis
Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. Early on, there may be no symptoms. Gradually joint pain may develop which may limit the ability to move. ...
. Without blood, the bone tissue dies and the bone collapses. If avascular necrosis involves the bones of a joint, it often leads to destruction of the joint articular surfaces (see osteochondritis dissecans).
* Testicle: an infarction of a testicle is commonly caused by testicular torsion and may require removal of the affected testicle(s) if not undone by surgery quickly enough.
* Eye: an infarction can occur to the central retinal artery which supplies the retina causing sudden visual loss.
*Bowel: Bowel infarction is generally caused by mesenteric ischemia due to blockages in the arteries or veins that supply the bowel.
Associated diseases
Diseases commonly associated with infarctions include:
* Peripheral artery occlusive disease (the most severe form of which is gangrene)
* Antiphospholipid syndrome
* Sepsis
* Giant-cell arteritis (GCA)
* Hernia
A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Various types of hernias can occur, most commonly involving the abdomen, and specifically the groin. Groin her ...
* Volvulus
* Sickle-cell disease
Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red ...
References
External links
{{Authority control
Gross pathology
Causes of death