Cerebral softening, also known as encephalomalacia, is a localized softening of the
substance
Substance may refer to:
* Matter, anything that has mass and takes up space
Chemistry
* Chemical substance, a material with a definite chemical composition
* Drug, a chemical agent affecting an organism
Arts, entertainment, and media Music
* ' ...
of the
brain
The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...
, due to
bleeding
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, urethr ...
or
inflammation
Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...
. Three varieties, distinguished by their color and representing different stages of the disease progress, are known respectively as red, yellow, and white softening.
Causes
Stroke
Ischemia: A decrease or restriction of circulating blood flow to a region of the brain which deprives neurons of the necessary substrates (primarily
glucose
Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
); represents 80% of all strokes. A
thrombus
A thrombus ( thrombi) is a solid or semisolid aggregate from constituents of the blood (platelets, fibrin, red blood cells, white blood cells) within the circulatory system during life. A blood clot is the final product of the blood coagulatio ...
or
embolus
An embolus (; : emboli; from the Greek ἔμβολος "wedge", "plug") is an unattached mass that travels through the circulatory system, bloodstream and is capable of creating blockages. When an embolus Vascular occlusion, occludes a blood vess ...
plugs an artery so there is a reduction or cessation of blood flow. This
hypoxia or anoxia leads to neuronal injury, which is known as a
stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
. The death of neurons leads to a so-called softening of the
cerebrum
The cerebrum (: cerebra), telencephalon or endbrain is the largest part of the brain, containing the cerebral cortex (of the two cerebral hemispheres) as well as several subcortical structures, including the hippocampus, basal ganglia, and olfac ...
in the affected area.
Hemorrhage:
Intracerebral hemorrhage
Intracerebral hemorrhage (ICH), also known as hemorrhagic stroke, is a sudden bleeding into Intraparenchymal hemorrhage, the tissues of the brain (i.e. the parenchyma), into its Intraventricular hemorrhage, ventricles, or into both. An ICH is ...
occurs in deep penetrating vessels and disrupts the connecting pathways, causing a localized pressure injury and in turn injury to brain tissue in the affected area.
Hemorrhaging
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, ...
can occur in instances of embolic ischemia, in which the previously obstructed region spontaneously restores blood flow. This is known as a
hemorrhagic infarction and a resulting red infarct occurs, which points to a type of cerebral softening known as
red softening.
[Shah, Sid. "Stroke Pathophysiology." Foundation for Education and Research in Neurological Emergencies. 1-7]
edu/com/ferne/pdf/pathophys0501.pdf.
Circle of Willis
In a study on the
circle of Willis
The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including huma ...
and its relation to
cerebral vascular disorders, a comparison on various anomalies between normal brains (those without the condition of cerebral softening) and brains with cerebral softening were looked at to observe trends in the differences of the anatomical structure of the circle of Willis. Statistically significant results were found in the percentage of normal brains that had a normal circle of Willis and those that had cerebral softening and had a normal circle of Willis. The results yielded 52% of normal brains having a normal circle of Willis, while only 33% of brains with cerebral softening had a normal circle of Willis. There were also a higher number of string-like vessels in brains with cerebral softening (42%), than there were in normal brains (27%). These results point to an assumption of a higher incidence rate of anomalies in brains with cerebral softening versus those that do not have cerebral softening.
Types of softening
Red softening
Red softening is one of the three types of cerebral softening. As its name suggests, certain regions of cerebral softening result in a red color. This is due to a hemorrhagic infarct, in which blood flow is restored to an area of the brain that was previously restricted by an
embolism
An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule (fat embolism), a bubble of air or other gas (air embolism, gas embolism), amniotic ...
. This is termed a "red infarct" or also known as red softening.
Upon
autopsy
An autopsy (also referred to as post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of deat ...
of several subjects, Dr. Cornelio Fazio found that the most common areas of this type of softening occurred where there was a
hemorrhage
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, ...
of the middle
cerebral artery
The cerebral arteries describe three main pairs of arteries and their branches, which perfuse the cerebrum of the brain.
The three main arteries are the:
* ''Anterior cerebral artery'' (ACA), which supplies blood to the medial portion of the bra ...
or the superior or deep branches to it. The subjects' softened area was not always near the arteries but where the capillaries perfused the brain tissue. The symptoms were similar to that of a stroke.
White softening
White softening is another form of cerebral softening. This type of softening occurs in areas that continue to be poorly perfused, with little to no blood flow. These are known as "pale" or "anemic infarcts" and are areas that contain dead
neuronal tissue
A neuron (American English), neurone (British English), or nerve cell, is an excitable cell that fires electric signals called action potentials across a neural network in the nervous system. They are located in the nervous system and help to ...
, which result in a softening of the cerebrum.
Yellow softening
Yellow softening is the third type of cerebral softening. As its name implies, the affected softened areas of the brain have a yellow appearance. This yellow appearance is due to
atherosclerotic plaque
An atheroma, or atheromatous plaque, is an abnormal 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 of fibrous conne ...
build-up in interior brain arteries coupled with yellow lymph around the
choroid plexus
The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central ...
, which occurs in specific instances of brain trauma.
[Br Med J 1898;1:140]
Stages
Early life
Newborn cerebral softening has traditionally been attributed to trauma at birth and its effect on brain tissue into adulthood. However, more recent research shows that cerebral softening in newborns and the degeneration of
white matter
White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...
is caused by
asphyxia
Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects all the tissues and organs, some more rapidly than others. There are m ...
and/or later infection. There is no causal evidence to support the hypothesis that problems in labor contribute to the development of softening in infant white matter. Also, further evidence shows a possible connection between low sugar and high protein levels in
cerebral spinal fluid
Cerebrospinal fluid (CSF) is a clear, colorless transcellular body fluid found within the meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricles of the brain.
CSF is mostly produced by specialized ependym ...
that can contribute to disease or virus susceptibility leading to cerebral softening.
Later life
Cases of cerebral softening in infancy versus in adulthood are much more severe due to an infant's inability to sufficiently recover brain tissue loss or
compensate the loss with other parts of the brain. Adults can more easily compensate and correct for the loss of tissue use and therefore the mortality likelihood in an adult with cerebral softening is less than in an infant.
Documented cases
In this late 19th-century case study, a 10-year-old boy was found to have cerebral softening in specific parts of the brain, limiting specific sensory function. The identifiable softening enabled researchers to detect and partition cerebral areas related to different sensory perceptions.
Another case in the late 19th century showed that cerebral softening, when caused by hemorrhaging, can affect various neural pathways leading to
convulsions
A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is often used as a synony ...
,
spasm
A spasm is a sudden involuntary contraction of a muscle, a group of muscles, or a hollow organ, such as the bladder.
A spasmodic muscle contraction may be caused by many medical conditions, including dystonia. Most commonly, it is a musc ...
s,
coma
A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to Nociception, respond normally to Pain, painful stimuli, light, or sound, lacks a normal Circadian rhythm, sleep-wake cycle and does not initiate ...
and death.
A third case in 1898 followed the ten-day decline of a 66-year-old woman with cerebral softening. She had yellow softening which led to symptoms that started slowly with transient
facial paralysis
Facial nerve paralysis is a common problem that involves the paralysis of any structures innervated by the facial nerve. The pathway of the facial nerve is long and relatively convoluted, so there are a number of causes that may result in facial ...
on the right side of the face. The limbs later became cold and the right side of the body transiently progressed between semi-paralysis and
tetanus
Tetanus (), also known as lockjaw, is a bacterial infection caused by ''Clostridium tetani'' and characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body. Each spasm usually l ...
. Her heart rate and respiration rate became slow by days three and four. Later she developed a yellow jaundiced appearance in the
sclera
The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective outer layer of the eye containing mainly collagen and some crucial elastic fiber.
In the development of t ...
and skin that the doctor proposed as
paroxysmal hemoglobinuria upon autopsy. On the last days, the paralysis became more frequent, respiration rose and she developed
tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...
. She died on the evening of the tenth day. The autopsy revealed that the top of the brain down to the
lateral ventricle
The lateral ventricles are the two largest ventricular system, ventricles of the brain and contain cerebrospinal fluid. Each cerebral hemisphere contains a lateral ventricle, known as the left or right lateral ventricle, respectively.
Each later ...
were healthy, but below that there was a inch area on the left side of the brain that was softened and yellow. The
choroid plexus
The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central ...
was also matted and surrounded by vessels filled with yellow lymph. The floor of the left lateral ventricle,
thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
, and
corpus striatum
The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamatergi ...
were softened to the point of unrecognition. These physical abnormalities match the symptoms mentioned and are a prime example of yellow cerebral softening.
In 1858 doctor Thomas Inman described four of thirty discovered cases with cerebral softening. Each case was similar to the previous article. There was some
atheroma
An atheroma, or atheromatous plaque, is an abnormal accumulation of material in the tunica intima, inner layer of an arterial wall.
The material consists of mostly macrophage, macrophage cells, or debris, containing lipids, calcium and a variabl ...
in the internal brain arteries that led to the cerebral softening of the left side of the brain around the left
lateral ventricle
The lateral ventricles are the two largest ventricular system, ventricles of the brain and contain cerebrospinal fluid. Each cerebral hemisphere contains a lateral ventricle, known as the left or right lateral ventricle, respectively.
Each later ...
,
thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
and
corpus striatum
The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamatergi ...
. There were similar right sided numbness in some patients, coldness of the extremities, and impairments in vision. In some cases, the lungs and the
pleura
The pleurae (: pleura) are the two flattened closed sacs filled with pleural fluid, each ensheathing each lung and lining their surrounding tissues, locally appearing as two opposing layers of serous membrane separating the lungs from the med ...
were stuck together as well as the intestines to the
peritoneal wall. This again matches yellow cerebral softening.
References
{{Medical resources
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, ICD10 =
, ICD9 = {{ICD9, 348.89
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, MeshID = D004678
Brain disorders