An epidural hematoma, sometimes called an extradural hematoma, accumulates blood that forms between the skull’s inner surface and the outer layer of the hard meninges (dura mater). Often, epidural hematomas are associated with a history of trauma and an associated skull fracture and are typically seen in younger individuals who have suffered head trauma. About 15-20% of epidural hematomas are fatal.
Unlike subdural hematoma, it is difficult to establish head trauma. Clearly, extradural hemorrhages are usually perceived by purely defined head trauma.
Clinical picture
A typical presentation is that of a younger patient with a blow to the head (often during sports activity or as a result of motorcycle accidents) who suffered (not necessarily) transient loss of consciousness. In one-third of patients, the clinical picture is characterized by the sudden loss of consciousness at the time of trauma. After the injury, return to normal consciousness ( lucid interval ), which usually lasts about half an hour, but usually have a constant and often severe headache. Over the next few hours, the disturbance of consciousness gradually develops again due to hematomas’ growth. By displacement of the cerebral hemispheres causes compression of the brainstem by uncle herniation. The characteristic symptom is ipsilateral anisocoria and areflexia (Hutchinson’s pupil), with a deepening coma that ends in death if emergency neurosurgical intervention is not undertaken.
If bleeding in the posterior cranial fossa is characterized by developing consciousness disorders, neck stiffness, and cerebellar symptoms. Shift brain tissue in the caudo-cranial direction causes damage to the brainstem or herniation through the foramen magnum, which causes rapid death. The hernia here is tonsillar and causes the Cushing’s Triassic: hypertension, bradycardia, and irregular breathing.
Pathophysiology
The bleeding source is typically a ruptured meningeal artery, usually the middle meningeal artery (a.meningea media). In 75% of cases, skull fractures are also present. Pain in the form of a severe headache is caused by detachment of the dura from the bone during the hematoma spread. The posterior cranial fossa is a rare site of injury in general, including subdural hematoma. Occasionally an epidural hematoma may result from venous bleeding, typically due to venous sinus injury due to a related fracture.
The fact that younger patients are more likely to be affected by this injury results from the demographics of patients with head injuries and the changes that occur in the dura mater in older patients – them. The dura is much more attached to the skull.
Epidural hematomas are unilateral in more than 95% of cases. 95% of them are also located supratentorial. Temporoparietally, 60% of them (pterion, which lies above the middle meningeal artery, are relatively weak and prone to injury), frontally 20%, parietal-occipital 20%. Less than 5% of epidural hematomas are located infratentorial in the posterior cranial fossa (which is more common due to bleeding from a sinus injury).
Because epidural hematomas are located between the skull and the parietal layer of the dura mater, which is actually the periosteum of the bone, the spread of the epidural hematoma is usually limited by cranial sutures, as the periosteum passes through a suture connected to the outer periosteal layer. This helps distinguish an epidural from a subdural hematoma – a subdural hematoma is not limited to sutures.
However, epidural hematomas can pass through the venous sinuses and elevate them if no sutures are present – the venous sinuses are located between the dura’s parietal and visceral layers.
There are exceptions, of course. For example, if the skull fracture itself passes over the sutures or if the sutures are abnormally dilated (e.g., physiological in a newborn).
Diagnosis
Treatment
As with other types of intracranial hematomas, blood can be removed surgically to reduce pressure on the brain. The hematoma is removed by trepanation or craniotomy.
Prognosis
The prognosis is good even with a relatively large hematoma if the hematoma is removed quickly. Small hematoma without mass effect or « swirl.»The sign can be treated conservatively, which sometimes results in the dura’s calcification. Delayed complications, usually associated with meningeal blood vessel injuries, such as pseudoaneurysm and AV fistula, are sometimes encountered. The prognosis is generally better if there was a lucid interval.
