Intracranial hemorrhage (ICH), also known as intracranial bleed, is
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, urethra, vag ...
within
Within may refer to:
* ''Within'' (William Joseph album) (2004), by pianist William Joseph
* ''Within'' (Embraced album) (2000), by Swedish melodic black metal band Embraced
* Within (company), a virtual reality content and technology company ba ...
the
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
.
[ Subtypes are ]intracerebral bleed
Intracerebral hemorrhage (ICH), also known as cerebral bleed, intraparenchymal bleed, and hemorrhagic stroke, or haemorrhagic stroke, is a sudden bleeding into the tissues of the brain, into its ventricles, or into both. It is one kind of bleed ...
s ( intraventricular bleeds and intraparenchymal bleed
Intraparenchymal hemorrhage (IPH) is one form of intracerebral bleeding in which there is bleeding within brain parenchyma. The other form is intraventricular hemorrhage (IVH).
Intraparenchymal hemorrhage accounts for approximately 8-13% of all ...
s), subarachnoid bleeds, epidural bleed
Epidural hematoma is when bleeding occurs between the tough outer membrane covering the brain (dura mater) and the skull. Often there is loss of consciousness following a head injury, a brief regaining of consciousness, and then loss of consciou ...
s, and subdural bleeds. More often than not it ends in a lethal outcome.
Intracerebral bleeding affects 2.5 per 10,000 people each year.
Signs and symptoms
Intracranial hemorrhage is a serious 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 ...
because the buildup of blood within the skull can lead to increases in intracranial pressure
Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury (mmHg) and at rest, is normally 7–15 Millimeter of mercury, mmHg ...
, which can crush delicate brain tissue or limit its blood supply. Severe increases in intracranial pressure (ICP) can cause brain herniation
Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the te ...
, in which parts of the brain are squeezed past structures in the skull.
Causes
Trauma is the most common cause of intracranial hemorrhage. It can cause epidural hemorrhage, subdural hemorrhage, and subarachnoid hemorrhage. Other condition such as hemorrhagic parenchymal contusion and cerebral microhemorrhages can also be caused by trauma.
Non-traumatic causes of hemorrhage includes: hypertension
Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...
, cerebral amyloid angiopathy
Cerebral amyloid angiopathy (CAA) is a form of angiopathy in which amyloid beta peptide deposits in the walls of small to medium blood vessels of the central nervous system and meninges. The term ''congophilic'' is sometimes used because the pre ...
, hemorrhagic conversion of ischemic infarction, cerebral aneurysms, dural arteriovenous fistulae, cerebral venous sinus thrombosis
Cerebral venous sinus thrombosis (CVST), cerebral venous and sinus thrombosis or cerebral venous thrombosis (CVT), is the presence of a blood clot in the dural venous sinuses (which drain blood from the brain), the cerebral veins, or both. Symp ...
, cerebral vasculitis
Cerebral vasculitis (sometimes the word angiitis is used instead of "vasculitis") is vasculitis (inflammation of the blood vessel wall) involving the brain and occasionally the spinal cord. It affects all of the vessels: very small blood vessels ( ...
and mycotic aneurysm
An infected aneurysm is an aneurysm arising from bacterial infection of the arterial wall. It can be a common complication of the hematogenous spread of bacterial infection.
William Osler first used the term "mycotic aneurysm" in 1885 to describe ...
.
More than half of all cases of intracranial hemorrhage are the result of hypertension.
Diagnosis
CT scan ( computed tomography) of the brain (without any iodinated contrast
Iodinated contrast is a form of intravenous radiocontrast agent containing iodine, which enhances the visibility of vascular structures and organs during radiographic procedures. Some pathologies, such as cancer, have particularly improved visibil ...
), is the initial imaging choice because of its high speed, good accessibility in hospitals, high sensitivity in detecting brain injuries or brain diseases, thus helping to triage
In medicine, triage () is a practice invoked when acute care cannot be provided for lack of resources. The process rations care towards those who are most in need of immediate care, and who benefit most from it. More generally it refers to prio ...
patients in emergency department in a timely manner and urgent neurosurgical intervention can be administered. Examples of brain diseases that require urgent intervention are: large volume hemorrhage, brain herniation
Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the te ...
, and cerebral infarction
A cerebral infarction is the pathologic process that results in an area of necrotic tissue in the brain (cerebral infarct). It is caused by disrupted blood supply ( ischemia) and restricted oxygen supply ( hypoxia), most commonly due to thromboemb ...
. Other advantages of CT over MRI scan are ability to detect bony fractures, vascular injury, and cerebrospinal fluid
Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates.
CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...
(CSF) leak. It also does not need to screen for MRI safety of implants/foreign body especially for penetrating or blast injuries.
However, MRI has higher sensitivity than CT scan for the detection of epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, nonhemorrhagic cortical contusions
A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises occur close ...
, hemorrhagic parenchymal
Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms.
Etymology
The term ''parenchyma'' is New Latin from the word ...
contusions, brainstem injuries, and white matter axonal injuries. If CT scan shows normal findings, but the subject has persistent neurological symptoms, MRI is also indicated. However, MRI safety concerns on metallic foreign bodies, limited availability, longer imaging time, high sensitivity to motion, and higher cost limits the usefulness of MRI.
Swirl sign on CT scan (areas of low densities with surrounding areas of high densities) is indicative of active intracranial bleeding, high chance of death within one month, and poor subject's function in three months if the subject is still alive.
When ICP is increased the heart rate may be decreased.
Traumatic
Types of intracranial hemorrhage are roughly grouped into intra-axial and extra-axial. Intra-axial hemorrhage is bleeding within the brain itself, or cerebral hemorrhage
Intracerebral hemorrhage (ICH), also known as cerebral bleed, intraparenchymal bleed, and hemorrhagic stroke, or haemorrhagic stroke, is a sudden bleeding into the tissues of the brain, into its ventricles, or into both. It is one kind of bleed ...
. This category includes intraparenchymal hemorrhage
Intraparenchymal hemorrhage (IPH) is one form of intracerebral bleeding in which there is bleeding within brain parenchyma. The other form is intraventricular hemorrhage (IVH).
Intraparenchymal hemorrhage accounts for approximately 8-13% of all ...
, or bleeding within the brain tissue, and intraventricular hemorrhage
Intraventricular hemorrhage (IVH), also known as intraventricular bleeding, is a bleeding into the brain's ventricular system, where the cerebrospinal fluid is produced and circulates through towards the subarachnoid space. It can result from phys ...
, bleeding within the brain's ventricles (particularly of premature infants). Intra-axial hemorrhages are more dangerous and harder to treat than extra-axial bleeds. Hemorrhagic parenchymal contusions and cerebral microhemorrhages are examples of traumatic intra-axial bleeds.
Extra-axial hemorrhage, bleeding that occurs within the skull but outside of the brain tissue, falls into three subtypes: epidural hematoma, subdural hematoma, and subarachnoid hemorrhage.
Hemorrhagic parenchymal contusion
This condition most commonly occurred in those with significant head movement or head impact. It is caused by injuries of small arterial or venous vessels, causing hemorrhage within the brain parenchyma, and give rise to hyperdense lesion on CT scan. MRI is more sensitive than CT scan in detecting such small hemorrhagic contusions, with the use of gradient echo sequence. Contusions are more commonly seen in the brain parenchyma near base of the skull such as inferior frontal lobes and temporal lobes as a result of Coup contrecoup injury
In head injury, a coup injury occurs under the site of impact with an object, and a contrecoup injury occurs on the side opposite the area that was hit. Coup and contrecoup injuries are associated with cerebral contusions,
a type of traumatic bra ...
. Those with parenchymal contusion would require frequent follow-up imaging because such contusions may grow large enough to become hemorrhage and exerts significant mass effect on the brain.
Cerebral microhemorrhages is a smaller form of hemorrhagic parenchymal contusion and are typically found in white matter
White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribution ...
. Such microhemorrhages are difficult to be detected on CT scan, but easily detected on gradient echo and susceptibility weighted imaging on MRI scan as hypointense susceptibility blooming. Such microhemorrhages are frequently associated with diffuse axonal injury
Diffuse axonal injury (DAI) is a brain injury in which scattered lesions occur over a widespread area in white matter tracts as well as grey matter. DAI is one of the most common and devastating types of traumatic brain injury and is a major cause ...
and located near the grey
Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be composed o ...
-white matter junction.
Epidural hemorrhage
Epidural hemorrhage (extradural hemorrhage, EDH) which occur between the dura mater
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. ...
(the outermost meningeal layer) and the skull, is caused by trauma. It does not cross the suture lines of the skull because the superifical dural layer is attached tightly to the skull along the suture lines. Unless rarely, fracture involves the suture lines (more common in children), then epidural hematoma may cross the suture lines. As the blood accumulated in the epidural space is confined within suture lines, accumulation of additional blood will cause bulging in this space, and thus resulting in a typical "biconvex" appearance on CT scans. EDH can be due to arterial or venous rupture depending on the locations. Arterial injuries results in more rapidly growing hematoma when compared to venous injuries. At the pterion
The pterion is the region where the frontal, parietal, temporal, and sphenoid bones join. It is located on the side of the skull, just behind the temple.
Structure
The pterion is located in the temporal fossa, approximately 2.6 cm beh ...
region, middle meningeal artery
The middle meningeal artery ('' la, arteria meningea media'') is typically the third branch of the first portion of the maxillary artery. After branching off the maxillary artery in the infratemporal fossa, it runs through the foramen spinosum to ...
is most commonly affected. When fracture is crossing areas where dural venous sinuses
The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous channels found between the endosteal and meningeal layers of dura mater in the brain. They receive blood from the cerebral veins, receive cereb ...
resides, venous hemorrhage can occur such as falx cerebri
The falx cerebri (also known as the cerebral falx) is a large, crescent-shaped fold of dura mater that descends vertically into the longitudinal fissure between the cerebral hemispheres of the human brain,Saladin K. "Anatomy & Physiology: The Uni ...
, tentorium cerebelli
The cerebellar tentorium or tentorium cerebelli (Latin for "tent of the cerebellum") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.
Structure
The cerebellar tentorium is an arche ...
, and vertex (where superior sagittal sinus
The superior sagittal sinus (also known as the superior longitudinal sinus), within the human head, is an unpaired area along the attached margin of the falx cerebri. It allows blood to drain from the lateral aspects of anterior cerebral hemispher ...
resides). Anterior temporal EDH is usually caused by sphenoparietal sinus
The sphenoparietal sinus is a paired dural venous sinus situated along the posterior edge of the lesser wing of either sphenoid bone. It drains into the cavernous sinus.
Anatomy
A sphenoparietal sinus is situated under each lesser wing of the s ...
. Such EDH is limited and does not require surgery because its extension is confined within sphenosquamosal suture
The sphenosquamosal suture is a cranial suture between the sphenoid bone and the squama of the temporal bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.
The tem ...
and orbital fissure. In 20 to 50% of epidural hemorrhage cases, there is a lucid interval
In emergency medicine, a lucid interval is a temporary improvement in a patient's condition after a traumatic brain injury, after which the condition deteriorates. A lucid interval is especially indicative of an epidural hematoma. An estimated 20 ...
where a person regained consciousness after being knocked unconscious and then followed by deterioration of consciousness after that.
When the epidural hematoma is large enough, it will cause mass effect on contralateral brain which lead to midline, subfalcine (below the falx cerebri
The falx cerebri (also known as the cerebral falx) is a large, crescent-shaped fold of dura mater that descends vertically into the longitudinal fissure between the cerebral hemispheres of the human brain,Saladin K. "Anatomy & Physiology: The Uni ...
), and trans-tentorial (crossing tentorium cerebelli
The cerebellar tentorium or tentorium cerebelli (Latin for "tent of the cerebellum") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.
Structure
The cerebellar tentorium is an arche ...
) herniations. This phenomenon can cause the subject to lose consciousness and eventually death. Therefore, large EDH requires emergent surgical clot evacuation. Embolisation
Embolization refers to the passage and lodging of an embolus within the bloodstream. It may be of natural origin (pathological), in which sense it is also called embolism, for example a pulmonary embolism; or it may be artificially induced (t ...
of middle meningeal artery is performed if the hemorrhage is medium or small.
Subdural hemorrhage
Subdural hemorrhage
A subdural hematoma (SDH) is a type of bleeding in which a collection of blood—usually but not always associated with a traumatic brain injury—gathers between the inner layer of the dura mater and the arachnoid mater of the meninges surround ...
(SDH) results from tearing of the bridging veins in the subdural space
The subdural space (or subdural cavity) is a potential space that can be opened by the separation of the arachnoid mater from the dura mater as the result of trauma, pathologic process, or the absence of cerebrospinal fluid as seen in a cadaver. ...
between the dura and arachnoid mater
The arachnoid mater (or simply arachnoid) is one of the three meninges, the protective membranes that cover the brain and spinal cord. It is so named because of its resemblance to a spider web. The arachnoid mater is a derivative of the neural c ...
. It can cross the suture lines, but not across dural reflections such as falx cerebri or tentorium cerebelli. Therefore, subdural hematoma always limited to one side of the brain. Density of SDH reduces as it progresses from acute to chronic forms. However, areas with low density may not represent chronic SDH entirely as unclotted blood products that are due to active bleed can also give low density appearance on CT scans especially those with coagulopathy
Coagulopathy (also called a bleeding disorder) is a condition in which the blood's ability to coagulate (form clots) is impaired. This condition can cause a tendency toward prolonged or excessive bleeding (bleeding diathesis), which may occur spo ...
. Those with SDH that have same density with brain parenchyma may represent acute bleed such as those with anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
, arachnoid tear, and the mixing of hemorrhage and CSF. SDH usually have high or mixed densities during first two days of trauma, followed by isodensity at 11 days after trauma, and hypodensity after 14 days of trauma. Membranes with granulation tissue
Granulation tissue is new connective tissue and microscopic blood vessels that form on the surfaces of a wound during the healing process. Granulation tissue typically grows from the base of a wound and is able to fill wounds of almost any size ...
can rupture within SDH, and give high density appearance on CT scan. Over a prolonged period of time, calcifications can form. SDH can be treated with burr hole
Trepanning, also known as trepanation, trephination, trephining or making a burr hole (the verb ''trepan'' derives from Old French from Medieval Latin from Greek , literally "borer, auger"), is a surgical intervention in which a hole is drille ...
drainage, craniotomy
A craniotomy is a surgical operation in which a bone flap is temporarily removed from the skull to access the brain. Craniotomies are often critical operations, performed on patients who are suffering from brain lesions, such as tumors, blood clots ...
or port system placement for blood clot evacuation, or middle meningeal artery embolisation.
Subdural hematoma maybe less acute than epidural hematoma due to slower blood accumulation, but it still has the potential to cause brain herniation that may require surgical evacuation. Clinical features depend on the site of injury and severity of injury. Patients may have a history of loss of consciousness but they recover and do not relapse. Clinical onset occurs over hours. Complications include focal neurologic deficits depending on the site of hematoma and brain injury, increased intracranial pressure leading to herniation of brain and ischemia
Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems wi ...
due to reduced blood supply and seizures.
Subarachnoid hemorrhage
A ''subarachnoid hemorrhage'' (SAH) is 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, urethra, vag ...
into the subarachnoid space
In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in th ...
—the area between the arachnoid membrane
The arachnoid mater (or simply arachnoid) is one of the three meninges, the protective membranes that cover the brain and spinal cord. It is so named because of its resemblance to a spider web. The arachnoid mater is a derivative of the neural cr ...
and the pia mater
Pia mater ( or ),[Entry "pia mater"](_blank)
in
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 ...
. Trauma can also cause SAH when the arteries and veins coursing through the subarachnoid space are ruptured. It is usually located at the cerebral sulci near the vertex of the head and spare the basal cisterns on CT scan. Severe trauma can cause SAH in all parts of the brain. When the SAH volume is large, rarely it can cause cerebral infarction a few days after trauma due to arterial vasospasm. Although CT scan is performed more often than MRI to detect SAH, MRI is more sensitive than CT in this aspect. SAH shows hyperintense signal of Fluid-attenuated inversion recovery
Fluid-attenuated inversion recovery (FLAIR) is an MRI sequence with an inversion recovery set to null fluids. For example, it can be used in brain imaging to suppress cerebrospinal fluid (CSF) effects on the image, so as to bring out the perivent ...
(FLAIR) sequence and blooming artifact on susceptibility weighted imaging
Susceptibility weighted imaging (SWI), originally called BOLD venographic imaging, is an MRI sequence that is exquisitely sensitive to venous blood, hemorrhage and iron storage. SWI uses a fully flow compensated, long echo, gradient recalled echo ( ...
(SWI).
Computed tomography angiography
Computed tomography angiography (also called CT angiography or CTA) is a computed tomography technique used for angiography—the visualization of arteries and veins—throughout the human body. Using contrast injected into the blood vessels, im ...
(CT angiography) or Magnetic resonance angiography
Magnetic resonance angiography (MRA) is a group of techniques based on magnetic resonance imaging (MRI) to image blood vessels. Magnetic resonance angiography is used to generate images of arteries (and less commonly veins) in order to evaluate t ...
(MR angiography) should be done if fracture involves the carotid canal
The carotid canal is a passageway in the temporal bone of the skull through which the internal carotid artery enters the middle cranial fossa from the neck.
Structure
The carotid canal is located within the middle cranial fossa, at the petrous ...
, because in such cases, posttraumatic vasospasm can occur, thus cutting blood supply to the brain. Besides, intracranial hemorrhage that are atypical for trauma should also be investigated further with CT or MR angiography to look for other causes of intracranial bleeds apart from trauma causes. Such atypical patterns includes: isolated SAH in the basal cisterns, isolated large-volume SAH in the Sylvian fissure
In neuroanatomy, the lateral sulcus (also called Sylvian fissure, after Franciscus Sylvius, or lateral fissure) is one of the most prominent features of the human brain. The lateral sulcus is a deep fissure in each hemisphere that separates the ...
, and isolated SAH in the anterior interhemispheric fissure
The longitudinal fissure (or cerebral fissure, great longitudinal fissure, median longitudinal fissure, interhemispheric fissure) is the deep groove that separates the two cerebral hemispheres of the vertebrate brain. Lying within it is a continu ...
. These cases warrants investigations to look for aneurysms that can cause such bleeding.
Non-traumatic
Hypertensive bleed
Intracranial bleed in hypertensive subjects usually occurs at 50 to 60 years of life with 30 to 50% chance of death. Such hemorrhages are typically located in the basal ganglia
The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...
, cerebellum
The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebel ...
, or occipital lobes
The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin ''ob'', "behind", and ''caput'', "head".
The occipital lobe is the v ...
. Other location such as bleed within the cerebral cortex and intracranial bleed in people younger than 50 years should prompt further investigations on other causes of bleed such as brain tumour or cerebral arteriovenous malformation
A cerebral arteriovenous malformation (cerebral AVM, CAVM, cAVM) is an abnormal connection between the arteries and veins in the brain—specifically, an arteriovenous malformation in the cerebrum.
Signs and symptoms
The most frequently observed ...
. The bleed can be very small without any significant effect on surrounding brain or large hemorrhage that exerts mass effecct on adjacent brain. Follow up CT scan is recommended. Those with extension of bleed into the ventricular system
The ventricular system is a set of four interconnected cavities known as cerebral ventricles in the brain. Within each ventricle is a region of choroid plexus which produces the circulating cerebrospinal fluid (CSF). The ventricular system is con ...
, expansion of bleeding, or increasing cerebral oedema
Cerebral edema is excess accumulation of fluid (edema) in the intracellular or extracellular spaces of the brain. This typically causes impaired nerve function, increased pressure within the skull, and can eventually lead to direct compressio ...
on CT scan gives poorer prognosis. CT angiography (CTA) of brain can be performed to investigate the source of bleeding. An image during the delayed phase of the CTA may be taken to look for pooling of contrast that signifies active bleeding (known as "Spot sign"). Presence of "Spot sign" signifies poor clinical outcome for the subject.
Cerebral amyloid angiopathy
Cerebral amyloid angiopathy (CAA) is the deposition of Amyloid beta
Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid precursor protein (APP), which is ...
peptide protein within the brain. Accumulation of such peptide proteins within the walls of the arteries can cause weakening of the walls and causes microhemorrhages, SAH within the cerebral sulci
In neuroanatomy, a sulcus (Latin: "furrow", pl. ''sulci'') is a depression or groove in the cerebral cortex.
It surrounds a gyrus (pl. gyri), creating the characteristic folded appearance of the brain in humans and other mammals. The larg ...
or large cerebral intraparenchymal bleed. SAH in CAA can be differentiated from vasculitis
Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily caused b ...
by its presentations. SAH in CAA usually occurs in those who age more than 60 years, temporary motor and sensory deficits, and intracranial bleed in white matter adjacent to cerebral cortex. Basal ganglia, posterior fossa, and brainstem are spared. Boston criteria is used to determine the likelihood of a cerebral hemorrhage due to CAA. Definitive diagnosis of CAA is by performing brain biopsy
Brain biopsy is the removal of a small piece of brain tissue for the diagnosis of abnormalities of the brain. It is used to diagnose tumors, infection, inflammation, and other brain disorders. By examining the tissue sample under a microscope, the ...
CT scan may show hyperdense intra-axial hemorrhage in the subcortical region. Diffuse white matter hypodensities in both cerebral hemispheres may represents microangiopathic changes. On MRI these lesions will be presented as blooming artifact on gradient echo and susceptibility weighted imaging.
Hemorrhagic conversion of ischemic infarction
43% of those with infarcted brain tissue will develop hemorrhagic conversion. Risk of hemorrhagic is further increased with recanalisation of veins or arteries. Several types of hemorrhages can occur such as petechial hemorrhages around the infarcted margin (HI1), confluent petechial hemorrhages within the infarcted tissue (HI2), hematoma occupying less than 30% of the infarcted tissue (PH1), hematoma involving greater than 30% of infarcted tissue with small mass effect (PH2), and hematoma involving greater than 30% of the infarcted tissue with significant mass effect. However, only PH2 is clinically significant. Those who has infarction should be monitored frequently with CT brains to access hemorrhagic conversions or worsening vasogenic oedema that may require neurosurgical decompression. Dual energy CT scan maybe useful to differentiate the high densities caused by reperfusion hemorrhage (bleeding after endovascular stroke treatment) and high density due to iodinated contrast administered during cerebral angiography
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms.
It was pioneered in 1927 by the Portugues ...
.
Cerebral aneurysm
Besides from head injury, it may occur spontaneously, usually from a ruptured cerebral aneurysm
An intracranial aneurysm, also known as a brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel.
Aneurysms in the posterior circul ...
(focal outpouchings with weakened walls on the arteries on the brain surface that are prone to rupture). Symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
s of SAH include a severe headache
Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
Headaches can occur as a result ...
with a rapid onset (thunderclap headache
A thunderclap headache is a headache that is severe and has a sudden onset. It is defined as a severe headache that takes seconds to minutes to reach maximum intensity. Although approximately 75% are attributed to "primary" headaches—headache d ...
), vomiting
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose.
Vomiting can be the result of ailments like Food-poisoning, foo ...
, confusion or a lowered level of consciousness
An altered level of consciousness is any measure of arousal other than normal. Level of consciousness (LOC) is a measurement of a person's arousability and responsiveness to stimuli from the environment.
A mildly depressed level of consciousne ...
, and sometimes seizure
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...
s. CT scan has 100% sensitivity of detecting SAH at 6 to 24 hours after symptoms onset. The diagnosis
Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engin ...
is generally confirmed with a CT scan of the head. If CT scan is normal but SAH is still strongly suspected, lumbar puncture
Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to ...
can be done at six to twelfth hours after the onset of headache. This is determine the presence of blood within the cerebrospinal fluid
Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates.
CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...
(CSF). Those with SAH will have blood and bilirubin
Bilirubin (BR) (Latin for "red bile") is a red-orange compound that occurs in the normal catabolic pathway that breaks down heme in vertebrates. This catabolism is a necessary process in the body's clearance of waste products that arise from the ...
within CSF because of degradation red blood cells
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 language, Greek ''erythros'' for "red" and ''k ...
. Meanwhile, those who has blood within CSF due to traumatic lumbar puncture will not have bilirubin within CSF.[ SAH is generally located within basal cisterns, extends diffusely to all subarachnoid spaces (]cerebral sulci
In neuroanatomy, a sulcus (Latin: "furrow", pl. ''sulci'') is a depression or groove in the cerebral cortex.
It surrounds a gyrus (pl. gyri), creating the characteristic folded appearance of the brain in humans and other mammals. The larg ...
) or into the ventricular system
The ventricular system is a set of four interconnected cavities known as cerebral ventricles in the brain. Within each ventricle is a region of choroid plexus which produces the circulating cerebrospinal fluid (CSF). The ventricular system is con ...
, or brain parenchyma
Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms.
Etymology
The term ''parenchyma'' is New Latin from the word Ï ...
. Modified Fisher scale is used to describe the volume and distribution of SAH, just predicting the probability of cerebral artery vasospasm after SAH.
Treatment is by prompt neurosurgery
Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and peri ...
or radiologically guided interventions with medications and other treatments to help prevent recurrence of the bleeding and complications. Since the 1990s, many aneurysms are treated by a minimal invasive procedure known as endovascular coiling
Endovascular coiling is an endovascular treatment for intracranial aneurysms and bleeding throughout the body. The procedure reduces blood circulation to the aneurysm through the use of microsurgical detachable platinum wires, with the clinician in ...
, which is carried out by instrumentation through large blood vessels. However, this procedure has higher recurrence rates than the more invasive craniotomy with clipping
Clipping may refer to:
Words
* Clipping (morphology), the formation of a new word by shortening it, e.g. "ad" from "advertisement"
* Clipping (phonetics), shortening the articulation of a speech sound, usually a vowel
* Clipping (publications) ...
.[
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Cerebral ateriovenous malformation
Cerebral ateriovenous malformation (Cerebral AVM) is characterised by abnormal shunting between cerebral arteries and veins without going through capillaries. Instead the blood goes through a collection of small vessels from arteries to veins. These collection of abnormal small vessels is termed as "nidus". This condition happens in 0.1% of the population has a risk of 2 to 4% per year for intracranial bleeding. Once ruptured, it results in intraparenchymal hemorrhage, intraventricular hemorrhage and SAH. Rupture of cerebral AVM often occurs in young people and children. Cerebral AVM can be diagnosed by computed tomography angiography
Computed tomography angiography (also called CT angiography or CTA) is a computed tomography technique used for angiography—the visualization of arteries and veins—throughout the human body. Using contrast injected into the blood vessels, im ...
(CTA) brain, magnetic resonance angiography
Magnetic resonance angiography (MRA) is a group of techniques based on magnetic resonance imaging (MRI) to image blood vessels. Magnetic resonance angiography is used to generate images of arteries (and less commonly veins) in order to evaluate t ...
(MRA) brain, or digital subtraction angiography
Digital subtraction angiography (DSA) is a fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a "pre-contra ...
(DSA). DSA is important to determine whether there is nidal or perinidal aneurysm.
Dural arteriovenous fistulae
Dural arteriovenous fistulae (DAVF) is the direct connection between dural or cerebral arteries with dural venous sinuses or cortical veins. It accounts for 10 to 15% of intracranial arteriovenous shunts. DAVF lacks a nidus. Signs and symptoms of DAVF are: headache, tinnitus
Tinnitus is the perception of sound when no corresponding external sound is present. Nearly everyone experiences a faint "normal tinnitus" in a completely quiet room; but it is of concern only if it is bothersome, interferes with normal hearin ...
, neurological deficits involving cranial nerves
Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and f ...
, and increased intracranial pressure. DAVF once ruptured, will produce intraparenchymal hemorrhage or SAH. Increase in number of vessels near dural venous sinuses as seen on CTA is suggestive of DVAF. 4DCT
Four-dimensional computed tomography (4DCT) is a type of CT scanning which records multiple images over time. It allows playback of the scan as a video, so that physiological processes can be observed and internal movement can be tracked. The nam ...
may increase the sensitivity of detecting DAVF. In MRI scans, susceptibility weighted imaging
Susceptibility weighted imaging (SWI), originally called BOLD venographic imaging, is an MRI sequence that is exquisitely sensitive to venous blood, hemorrhage and iron storage. SWI uses a fully flow compensated, long echo, gradient recalled echo ( ...
(SWI) and arterial spin labelling sequences (labelling protons in blood without the use of contrast media to determine blood flow) are useful in evaluating DAVF. The patterns of draining veins from the fistula determines the risk of DAVF rupture. Increased pressure within the dural venous sinuses causes backpressure into the cortical veins, thus making cortical veins more prone to rupture. The risk of hemorrhage is graded by Cognard and Borden grading systems. These grading systems are based upon the DSA.
Cortical venous/cerebral venous sinus thrombosis
Dural venous sinus thrombosis (DVST) and cortical venous thrombosis (CVT) commonly presents with headache, increased intracranial pressure, or seizures. DVST is more common than CVT. DVST are frequently caused by infections in the skull base, dehydration, thrombophilia
Thrombophilia (sometimes called hypercoagulability or a prothrombotic state) is an abnormality of blood coagulation that increases the risk of thrombosis (blood clots in blood vessels). Such abnormalities can be identified in 50% of people who ...
, meningioma
Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing o ...
, and other dural tumours. On CT scans, brain parenchymal hemorrhage that does not confined to specific arterial territory along with hyperdense appearance on dural venous sinuses raises the suspicion of DVST. Further evaluation with CT venography, MR venography, and post gadolinium MRI provides accurate diagnosis of venous thrombosis and follow-up after treatment. These studies demonstrate thrombus as filling defect or lack of signal.
Vasculitis/vasculopathy
Those with vasculitis may be presented with headache, behavioural changes, neurological deficits, or intracranial bleeding. Sulcal SAH is the most common form of intracranial bleed caused by vasculitis. On CT scans, sulcal SAH is seen as hyperdensity within the cerebral sulcus, while on MRI, it is seen as hyperintensity on FLAIR sequence, and hypointensity on GRE/SWI sequence. DSA is important in making the diagnosis of vasculitis or vasculopathy.
Mycotic aneurysm
It is arterial outpouchings arise from distal cerebral arteries. These are pseudoaneurysm
A pseudoaneurysm, also known as a false aneurysm, is a locally contained hematoma outside an artery or heart due to damage to the vessel wall. The injury goes through all the three layers of the arterial wall causing a leak, which is contained b ...
, caused by thrombus clogging the distal arteries, which results in inflammation and small tears at the site of occlusion. These inflammation and thrombis can caused by infective endocarditis
Infective endocarditis is an infection of the inner surface of the heart, usually the valves. Signs and symptoms may include fever, small areas of bleeding into the skin, heart murmur, feeling tired, and low red blood cell count. Complications ...
, artificial heart valve
An artificial heart valve is a one-way valve implanted into a person's heart to replace a heart valve that is not functioning properly (valvular heart disease). Artificial heart valves can be separated into three broad classes: mechanical hear ...
or other heart problems. Similar to vasculitis, rupture of mycotic aneurysm also causes SAH in cerebral sulci, mostly located in the vertex. If mycotic aneurysm is located more proximally, it will produce diffuse SAH pattern. CTA or MRA would produce focal outpouching or increase in diameter of the vessel. Meanwhile, GRE/SWI MRI sequence would produce focal hypointensity. Small mycotic aneurysms are difficult to be seen on CT or MRI. Thus, DSA is useful in identifying these lesions.
Management
For those who is already on blood thinners such as aspirin
Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
or clopidogrel
Clopidogrel — sold under the brand name Plavix, among others — is an antiplatelet medication used to reduce the risk of heart disease and stroke in those at high risk. It is also used together with aspirin in heart attacks and following t ...
for prevention of 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 may ...
or stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
, traumatic intracranial hemorrhage should prompt the use of platelet function assays ( PFA-100) to assess the effect of these antiplalelet agents. After that, plateletpheresis
Plateletpheresis (more accurately called thrombocytapheresis or thrombapheresis, though these names are rarely used) is the process of collecting thrombocytes, more commonly called platelets, a component of blood involved in blood clotting. The t ...
can be started to increase the aggregation of platelets, thus stopping the intracranial bleed. In those with impaired kidney functions, desmopressin
Desmopressin, sold under the trade name DDAVP among others, is a medication used to treat diabetes insipidus, bedwetting, hemophilia A, von Willebrand disease, and high blood urea levels. In hemophilia A and von Willebrand disease, it should on ...
or cryoprecipitate
Cryoprecipitate, also called cryo for short, is a frozen blood product prepared from blood plasma. To create cryoprecipitate, fresh frozen plasma thawed to 1–6 °C is then centrifuged and the precipitate is collected. The precipitate is re ...
can be used instead.
From limited observational data, it may be relatively safe to restart blood thinners
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where the ...
after an ICH as it is asscoated with reduced thromboembolic complications with similar risk of recurrent hemorrhage when compared to those did not start blood thinners after an ICH.
Comparison
References
Further reading
* Shepherd S. 2004
"Head Trauma."
Emedicine.com.
* Vinas FC and Pilitsis J. 2004
Emedicine.com.
* Julian A. Mattiello, M.D., Ph.D. Michael Munz, M.D. 2001
"Four Types of Acute Post-Traumatic Intracranial Hemorrhage"
The New England Journal of Medicine
External links
{{Authority control
Neurotrauma
Stroke