Intracranial hemorrhage
Encyclopedia
An intracranial hemorrhage is a hemorrhage, or bleeding, within the skull
Human skull
The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...

.

Causes

Intracranial bleeding occurs when a blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

 within the skull is ruptured or leaks. It can result from physical trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...

 (as occurs in head injury
Head injury
Head injury refers to trauma of the head. This may or may not include injury to the brain. However, the terms traumatic brain injury and head injury are often used interchangeably in medical literature....

) or nontraumatic causes (as occurs in hemorrhagic stroke) such as a ruptured aneurysm
Aneurysm
An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. Aneurysms can commonly occur in arteries at the base of the brain and an aortic aneurysm occurs in the main artery carrying blood from the left ventricle of the heart...

. Anticoagulant
Anticoagulant
An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...

 therapy, as well as disorders with blood clotting
Coagulopathy
Coagulopathy is a condition in which the blood’s ability to clot is impaired. This condition can cause prolonged or excessive bleeding, which may occur spontaneously or following an injury or medical and dental procedures.The normal clotting process depends on the interplay of various proteins in...

 can heighten the risk that an intracranial hemorrhage will occur.

Prognosis

Intracranial hemorrhage is a serious medical emergency
Medical emergency
A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...

 because the buildup of blood within the skull can lead to increases in intracranial pressure
Intracranial pressure
Intracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...

, which can crush delicate brain tissue or limit its blood supply. Severe increases in intracranial pressure can cause potentially deadly brain herniation
Brain herniation
Brain herniation, also known as cistern obliteration, is a deadly side effect of very high intracranial pressure that occurs when the brain shifts across structures within the skull...

, in which parts of the brain are squeezed past structures in the skull.

Diagnosis

CT scan (computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

) is the definitive tool for accurate diagnosis of an intracranial hemorrhage.

Classification

Types of intracranial hemorrhage are roughly grouped into intra-axial and extra-axial. The hemorrhage is considered a focal brain injury
Focal and diffuse brain injury
Focal and diffuse brain injury are ways to classify brain injury: focal injury occurs in a specific location, while diffuse injury occurs over a more widespread area. It is common for both focal and diffuse damage to occur as the result of the same event; many traumatic brain injuries have aspects...

; that is, it occurs in a localized spot rather than causing diffuse damage over a wider area.

Intra-axial hemorrhage

Intra-axial hemorrhage is bleeding within the brain itself, or cerebral hemorrhage. This category includes intraparenchymal hemorrhage
Intraparenchymal hemorrhage
Intraparenchymal hemorrhage is one extension of intracerebral hemorrhage with bleeding within brain parenchyma....

, or bleeding within the brain tissue, and intraventricular hemorrhage
Intraventricular hemorrhage
An intraventricular hemorrhage , often abbreviated "IVH," is a bleeding into the brain's ventricular system, where the cerebrospinal fluid is produced and circulates through towards the subarachnoid space...

, bleeding within the brain's ventricle
Ventricular system
The ventricular system is a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord.-Components:The system comprises four ventricles:* right and left lateral ventricles* third ventricle...

s (particularly of premature infants
Premature birth
In humans preterm birth refers to the birth of a baby of less than 37 weeks gestational age. The cause for preterm birth is in many situations elusive and unknown; many factors appear to be associated with the development of preterm birth, making the reduction of preterm birth a challenging...

). Intra-axial hemorrhages are more dangerous and harder to treat than extra-axial bleeds.

Extra-axial hemorrhage

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:

Epidural hematoma

Epidural hematoma (EDH) is a rapidly accumulating hematoma between the dura mater
Dura mater
The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...

 and the cranium. These patients have a history of head trauma with loss of consciousness, then a lucid period, followed by loss of consciousness. Clinical onset occurs over minutes to hours. Many of these injuries are associated with lacerations of the middle meningeal artery
Middle meningeal artery
The middle meningeal artery is typically the third branch of the first part of the maxillary artery, one of the two terminal branches of the external carotid artery...

. A "lenticular", or convex, lens-shaped extracerebral hemorrhage that does not cross suture lines will likely be visible on a CT scan of the head. Although death is a potential complication, the prognosis is good when this injury is recognized and treated.

Subdural hematoma

Subdural hematoma occurs when there is tearing of the bridging vein between the cerebral cortex and a draining venous sinus. At times they may be caused by arterial lacerations on the brain surface. Acute subdural hematomas are usually associated with cerebral cortex injury as well and hence the prognosis is not as good as extra dural hematomas. 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. A crescent shaped hemorrhage compressing the brain that does cross suture lines will be noted on CT of the head. Craniotomy and surgical evacuation is required if there is significant pressure effect on the brain.Complications include focal neurologic deficits depending on the site of hematoma and brain injury, increased intra cranial pressure leading to herniation of brain and ischemia due to reduced blood supply and seizures.

Subarachnoid hemorrhage

A subarachnoid hemorrhage is bleeding
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...

 into the subarachnoid space
Subarachnoid space
In the central nervous system, the subarachnoid cavity is the interval between the arachnoid membrane and pia mater....

—the area between the arachnoid membrane and the pia mater
Pia mater
Pia mater often referred to as simply the pia, is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord. The word finds its roots in Latin, meaning literally "tender mother." The other two meningeal membranes are the dura mater and the arachnoid mater....

 surrounding the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. Besides from head injury, it may occur spontaneously, usually from a ruptured cerebral aneurysm
Cerebral aneurysm
A cerebral or 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.- Signs and symptoms :...

. Symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

s of SAH include a severe headache
Headache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...

 with a rapid onset ("thunderclap headache
Thunderclap headache
A thunderclap headache is a headache that is severe and sudden-onset. It is defined as a severe headache that takes seconds to minutes to reach maximum intensity. It can be indicative of a number of medical problems, most importantly subarachnoid hemorrhage, which can be potentially life-threatening...

"), vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...

, confusion or a lowered level of consciousness, and sometimes seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...

s. The diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

 is generally confirmed with a CT scan
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

 of the head, or occasionally by lumbar puncture
Lumbar puncture
A lumbar puncture is a diagnostic and at times therapeutic procedure that is performed in order to collect a sample of cerebrospinal fluid for biochemical, microbiological, and cytological analysis, or very rarely as a treatment to relieve increased intracranial pressure.-Indications:The...

. Treatment is by prompt neurosurgery
Neurosurgery
Neurosurgery is the medical specialty concerned with the prevention, diagnosis, treatment, and rehabilitation of disorders which affect any portion of the nervous system including the brain, spine, spinal cord, peripheral nerves, and extra-cranial cerebrovascular system.-In the United States:In...

 or radiologically guided interventions
Interventional radiology
Interventional radiology is a specialty of radiology, in which image-guided procedures are used to diagnose and treat a multitude of diseases across all body systems...

 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 called "coiling
Guglielmi Detachable Coil
A Guglielmi Detachable Coil, or GDC, is a platinum coil commonly used in intracranial non-invasive surgery for the occlusion of brain aneurysms. It was invented by Italian interventional neuroradiologist Dr...

", which is carried out by instrumentation through large blood vessels. However, this procedure has higher recurrence rates than the more invasive craniotomy with clipping.

Extra-axial hemorrhage

Bleeding that occurs within the skull but outside of the brain tissue, falls into three subtypes:
  • Epidural hemorrhage (extradural hemorrhage) which occur between the dura mater
    Dura mater
    The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...

     (the outermost meninx) and the skull, is caused by trauma. It may result from laceration of an artery, most commonly the middle meningeal artery
    Middle meningeal artery
    The middle meningeal artery is typically the third branch of the first part of the maxillary artery, one of the two terminal branches of the external carotid artery...

    . This is a very dangerous type of injury because the bleed is from a high-pressure system and deadly increases in intracranial pressure
    Intracranial pressure
    Intracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...

     can result rapidly. However , it is the least common type of meningeal bleeding and is seen in 1% to 3% cases of head injury .
    • Patients have a loss of consciousness (LOC), then a lucid interval
      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...

      , then sudden deterioration (vomiting, restlessness, LOC)
    • Head CT shows lenticular (convex) deformity.
  • Subdural hemorrhage results from tearing of the bridging veins in the subdural space
    Subdural space
    The subdural space is an artificial space created 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. In the cadaver, due to the absence of cerebrospinal fluid, the arachnoid mater...

     between the dura
    Dura mater
    The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...

     and arachnoid mater
    Arachnoid mater
    The arachnoid mater, literally from Latin "spider -like mother", is one of the three meninges, the membranes that cover the brain and spinal cord...

    .
    • Head CT shows crescent-shaped deformity
  • Subarachnoid hemorrhage
    Subarachnoid hemorrhage
    A subarachnoid hemorrhage , or subarachnoid haemorrhage in British English, is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain...

    , which occur between the arachnoid and pia
    Pia mater
    Pia mater often referred to as simply the pia, is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord. The word finds its roots in Latin, meaning literally "tender mother." The other two meningeal membranes are the dura mater and the arachnoid mater....

     meningeal layers, like intraparenchymal hemorrhage, can result either from trauma or from ruptures of aneurysm
    Aneurysm
    An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. Aneurysms can commonly occur in arteries at the base of the brain and an aortic aneurysm occurs in the main artery carrying blood from the left ventricle of the heart...

    s or arteriovenous malformation
    Arteriovenous malformation
    Arteriovenous malformation or AVM is an abnormal connection between veins and arteries, usually congenital. This pathology is widely known because of its occurrence in the central nervous system, but can appear in any location. An arteriovenous malformation is a vascular anomaly. It is a...

    s. Blood is seen layering into the brain along sulci
    Sulcus (neuroanatomy)
    In neuroanatomy, a sulcus is a depression or fissure in the surface of the brain.It surrounds the gyri, creating the characteristic appearance of the brain in humans and other large mammals....

     and fissure
    Fissure
    In anatomy, a fissure is a groove, natural division, deep furrow, elongated cleft, or tear in various parts of the body.-Brain:...

    s, or filling cistern
    Cistern (neuroanatomy)
    In neuroanatomy, a cistern is any opening in the subarachnoid space of the brain created by a separation of the arachnoid and pia mater. These spaces are filled with cerebrospinal fluid...

    s (most often the suprasellar cistern because of the presence of the vessel
    Blood vessel
    The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

    s of the circle of Willis
    Circle of Willis
    The Circle of Willis is a circle of arteries that supply blood to the brain...

     and their branchpoints within that space). The classic presentation of subarachnoid hemorrhage is the sudden onset of a severe headache (a thunderclap headache
    Thunderclap headache
    A thunderclap headache is a headache that is severe and sudden-onset. It is defined as a severe headache that takes seconds to minutes to reach maximum intensity. It can be indicative of a number of medical problems, most importantly subarachnoid hemorrhage, which can be potentially life-threatening...

    ). This can be a very dangerous entity, and requires emergent neurosurgical evaluation, and sometimes urgent intervention.

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