Differences between subdural and epidural hematoma
When injuries of a certain magnitude occur in the head, serious consequences such as subdural hematoma or epidural hematoma can occur. Both are masses of coagulated blood (hematoma) caused by head trauma and deposited outside the brain, but inside the skull. However, these differ from each other based on their positions relative to the -dura mater-, which is one of the three membranes together with the arachnoid and -pia mater- that make up the meninges.
In this sense, in this article we present the differences between a subdural hematoma and an epidural hematoma, with the intention that our readers know in greater detail what each of them is about.
Subdural hematoma
The subdural hematoma is one that occurs between the dura and the arachnoid, where the dura is the first of the three membranes that make up the meninges and that cover the brain and the arachnoid is the second layer. Thus, up to 50% of acute subdural hematoma is associated with severe traumatic brain injury and is caused by hemorrhage of the bridging veins between the cerebral surface and the venous sinuses or also by bleeding of the cortical vessels found under the dura mater.
On the other hand, we can classify this type of hematomas according to the time of evolution, where acute hematomas are those that appear in the first 72 hours, subacute ones between 4 days and 3 weeks and chronic ones, generally, after 72 hours. 3 weeks to three or four months. However, most subdural hematomas are acute, since they manifest in the first 72 hours after the injury.
Additionally, subdural hematomas can grow significantly to the point of causing symptoms such as headaches, slurred speech, confusion, lethargy, lack of balance, or even a seizure. The treatment of the subdural hematoma varies depending on its amplitude, but let’s say that emergency surgery is performed in those greater than 5 mm. Thus, some studies have shown that patients with low-alarm subdural hematomas may be spared surgery if they are closely monitored for signs of deterioration.
epidural hematoma
An epidural hematoma is one that occurs between the skull and the dura mater. Up to 90% of this type of hematoma is associated with a skull fracture, which generally produces a tear in the middle meningeal artery or its branches. In addition to this, because the dura mater also covers the spinal cord, an epidural bleed can also occur in the spine. In most cases, epidural hematomas are caused by severe physical trauma and produce an increase in intracranial pressure, so its consequences can be fatal.
Similarly, epidural hematoma is mostly acute, since its symptoms appear immediately after trauma and are usually rapidly progressive, ranging from loss of alertness to data of severe intracranial hypertension. This hematoma is a neurosurgical emergency, so its treatment consists of performing a craniotomy or craniectomy if intracranial hypertension persists.
Once the characteristics of subdural and epidural hematomas have been explained, the following differences are presented:
| Subdural hematoma | epidural hematoma |
| This hematoma is located between the dura mater and the arachnoid. | This hematoma is located between the skull and the dura, although it can also appear in the spine. |
| It can be acute, subacute or chronic, depending on the time of evolution. | It is mostly acute, since its symptoms appear immediately after the injury. |
| The treatment of the subdural hematoma varies depending on its amplitude, and surgery or medical follow-up may be performed. | Treatment of epidural hematoma is emergency surgery (craniotomy or craniectomy). |
| Mortality ranges between 50 and 90% depending on the timing of surgery. | Mortality is between 20% and 55%, depending on the timing of the surgery. |
