Intracranial Hemorrhage

Intracranial hemorrhage is a medical emergency that occurs in adults, but can also occur in children and neonates. As the name suggests, intracranial hemorrhage is bleeding and the accumulation of blood within the skull at an abnormal location leading to the formation of a hematoma. A hematoma is the collection of blood outside of blood vessel. Intracranial bleeding can lead to stroke, neurological deficit, brain matter herniation, and even death.


locus.
The pterion is the site where the parietal, temporal, frontal and sphenoid bones of the skull meet. The bony part of the skull at pterion is relatively thinner and direct trauma to the head can result in the fracture or dislocation of the suture at this site. The middle meningeal artery emerges from the neck region and travels across the pterion to divide into its branches. Other sites of epidural intracranial bleeds include the frontal area involving anterior ethmoidal arteries, the occipital area involving transverse or sigmoid sinus, and the vertex involving the superior sagittal sinus.

Clinical presentation
Patients present after trauma to the head associated with an episode of loss consciousness followed by a normal level of consciousness and ongoing headache (called the lucid interval). The duration of the lucid interval without neurological deterioration in epidural hemorrhage is generally short and ranges from several minutes to hours. The lucid interval is dangerous because patients will believe that nothing is wrong, but if the hematoma gets large enough, it can cause a brain herniation and death.
It is comparatively not as common as other types of intracranial bleeds but can be dangerous and lead to increased intracranial pressure (ICP). A unilateral cause of ICP can cause a midline shift of the brain because the hematoma pushes the brain towards the opposite side. Midline shifts are associated with a skull fracture in approximately 75 % of cases.
Both CT and MRI scan can be used to view epidural hematomas, but CT scans are faster and less expensive. CT scan shows a biconvex lens-like hematoma that cannot cross the suture lines.

Treatment
Epidural bleed can be treated conservatively or can be surgically evacuated. As a whole, this condition has a good prognosis if diagnosed early and managed as soon as possible.

Location
Between the skull and the outer endosteal layer of the dura mater Within the meningeal layer of the dura mater

Epidemiology
Subdural hemorrhages usually occur in car accidents. When the rapid head movement in one direction is suddenly stopped, for example, in a car accident or child abuse, leakage/tearing of veins leads to blood accumulating below the dura mater.
The etiology of subdural hematoma is different in different age groups. Subdural hematoma in infants is due to non-accidental injury, in young adults, the causes are a bike or car accidents and in old age subdural bleed usually follows after a fall. Minor head trauma can also cause subdural hemorrhage in patients receiving anticoagulants.
Subdural hemorrhage occurs between dura and arachnoid mater and involves the tearing of bridging veins. Leakage of blood from the bridging veins causes the accumulation of blood below the dura mater compressing the brain matter and raising the intracranial pressure. A crescent-shaped subdural hematoma that can cross suture lines is seen on the CT scan.
In contrast to epidural hematoma, subdural hematomas can cross the suture lines but are limited by reflections of dura mater, (falx cerebri, tentorium, and falx cerebelli). A patient with a subdural hemorrhage usually presents with severe headache and confusion.

Clinical features
Small-sized subdural hematomas can be asymptomatic and managed without surgical evacuation.
A large acute subdural hematoma can present with stupor or coma, hemiparesis, and unilateral pupillary enlargement and causes significant morbidity and mortality despite surgical evacuation.
Chronic or sub-acute presentation following minor or even unnoticed trauma can occur in elderly days to weeks after injury.
Image: "Subarachnoid hemorrhage in CT. One can see the blood hyperattenuating in the basal cisterns." by Hellerhoff. License: CC BY-SA 3.0 This type of hemorrhage occurs in the subarachnoid space just outside the pia mater. Patients with subarachnoid hemorrhages present with severe, sudden and sharp headache followed by vomiting and unconsciousness (commonly referred to as "the worst headache of their life"). This type of intracranial hemorrhage can be associated with a family history. It is also common in alcoholics and drug abuse patients.
One of the causes of subarachnoid hemorrhage is a rupture of an aneurysm or arteriovenous malformations in the brain. Aneurysms in the brain include saccular (berry) aneurysms, fusiform aneurysms, and microaneurysms (Charcot-Bouchard). Almost 2% of adults have intracranial aneurysms Reference: Harrison's 20/e).

Investigation of choice
CT-scan of the head/brain is the investigation of choice for the diagnosis of intracranial hemorrhages because it is fast and accurate enough to diagnose bleeds, specifically non-contrast CT-scan.
Epidural -convex lens that does not cross the suture lines, can cross the midline Subdural -concave lens that can cross the suture lines, can cross the midline

Subarachnoid -blood in lateral ventricles
Intracerebral -blood within brain matter

Emergency management of intracranial hemorrhage
Airway management Blood pressure maintenance, systolic to less than 140mm using nonvasodilating IV drugs such as nicardipine, labetalol, or esmolol.
Presumptive treatment for elevated ICP in especially stuporous or comatose patients: tracheal intubation and sedation, administration of osmotic diuretics such as mannitol or hypertonic saline, and elevation of the head of the bed while surgical consultation is obtained

Reversal of coagulopathy
Neurosurgical evaluation for surgical evacuation of the hematoma.