Epidural Hematoma

The term epidural hematoma refers to pooling blood (hematoma) outside the dura mater (epidural). It's one example of closed head trauma, which also includes subdural hematomas and sub-arachnoid hemorrhage.

Closed head injuries, similar to traumatic brain injuries, come from blunt trauma to the noggin that results in swelling of the brain. What actually causes the swelling—blood, fluid, inflammation, etc.—depends partly on where inside the cranium the damage is found.

The cranium is a closed space, for the most part. It's the part of the skull that encloses the brain. The other half of the skull is made up of the facial bones. Altogether, there are eight cranial bones (wide, curved plates) that are fused to make a football-shaped hollow bucket for your brain.

The Meninges

If the brain rested right against the skull, it would get damaged every time you moved around or bumped your head. To avoid that problem, and to facilitate blood flow, the inside of the cranium is lined with a thick, tough membrane called the dura mater (Latin for tough mother). It is the outermost layer of a triple thickness cushion between the tenderness of the brain and the immovable hardness of the skull. These layers are collectively called the meninges. The meninges cover not only the brain but also the spinal cord.

While the dura mater lines the cranium, there is also an extremely thin membrane covering the brain tissue. This membrane is called the pia mater (Latin for little mother). It is so small that it follows the contours of the brain including the nooks and crannies of the folds of brain matter.

Between the tough dura mater and the delicate pia mater, there is a spongy layer called the arachnoid because of its web-like appearance. The arachnoid layer provides the cushion between the dura mater and the pia mater. Its porous surface allows a nutritious bath of cerebrospinal fluid (CSF) to flow through it.

Most blood flow in the meninges occurs in the outermost part of the dura mater. It's where the arteries from the world outside the brain are able to bring blood to the insulation of what is arguably the most important organ of the body. Under the dura mater, where the arachnoid and pia mater layers live, blood flow is not as important because CSF provides most of the nutrients.

Pathophysiology

Epidural hematomas come from getting hit on the head. It usually takes a pretty significant blow to create an epidural hematoma, but there are conditions that can make it easier for a person to develop bleeding outside the dura mater. Patients with bleeding disorders or those who are taking blood thinners, for example, are at greater risk for epidural hematomas than the rest of the population. Elderly patients and patients with a history of heavy alcohol use are also more susceptible.

When a patient gets hit hard enough to rupture a blood vessel along the outside of the dura mater, the bleeding will quickly seep into the potential space between the skull and the dura mater, separating the two. The skull is not going anywhere. It's hard and unforgiving, not likely to move much. The dura mater is also pretty tough, but has more give and is going to lose this particular standoff. As the blood collects between the dura mater and the skull, the dura mater moves toward the center of the cranium, putting pressure on the brain.

Signs and Symptoms

All traumatic brain injuries present pretty much the same way, with pretty much the same signs and symptoms. They all have some combination of the following:

• Loss of consciousness
• Dizziness
• Headache
• Nausea and vomiting
• Confusion

This makes it impossible to tell the difference between different types of traumatic brain injuries without doing a CT scan of the cranium. In other words, you can't tell if it's an epidural hematoma at the scene of the injury. The person needs to be seen in the emergency department.

That aside, there are some very disturbing signs and symptoms that should be large red flags after a patient takes a hard knock to the noggin. These include: pupils that are unequal (one is larger than the other), very high blood pressure, slow and extra-strong pulse, or the patient is unable to wake up.

One very distinct sign of an epidural hematoma is colloquially named the "Talk and Die Syndrome." It refers to what brain surgeons call transient lucidity. In other words, the patient gets knocked out, wakes up and seems to be fine, then loses consciousness again. This combination strongly suggests an epidural hematoma that is growing very quickly and is often the way to differentiate between a concussion and a more serious brain injury.

Immediate First Aid

First aid for an epidural hematoma is limited to taking care of any other injuries. Most importantly, pay attention if the person loses consciousness. Anybody who loses consciousness gets a ride to the hospital in an ambulance. Call 911 for anyone who gets knocked unconscious from a blow to the head. There is no reason to keep a potentially brain-injured person awake, but you should check to see if you can wake them periodically.

Hospital Treatment

Serious epidural hematomas require surgery to drain the blood and release the pressure on the brain. Surgeons will typically remove a portion of the skull and drain the hematoma. Afterward, a drain might need to be installed for a day or so to let any additional bleeding out.