What Is a Subdural Hematoma?

When there is a collection of blood outside of the brain’s surface just beneath the skull, it leads to a subdural hematoma. The outermost layer of the brain is known as the dura, and bleeding is said to occur just in between the dura and the arachnoid, which is the next layer. This medical condition is a life-threatening one because it leads to increased pressure on the brain as well as bleeding and is known to be mostly caused due to a severe form of head injury. In certain cases, the subdural hematoma would just stop and tend to resolve on its own, but in other cases, there would be a need for a surgical form of drainage.

The bleeding does not occur inside the brain. But, as the blood accumulates outside the brain, it leads to a certain kind of pressure occurring inside the brain, which tends to increase. This pressure that is exerted on the brain is known to lead to symptoms of a subdural hematoma. If this pressure that arises inside the skull tends to increase to very high levels, this subdural hematoma can cause the individual to go into an unconscious state and then ultimately result in death. A subdural hematoma is known to be either acute or chronic in form. The acute form of subdural hematoma is known to be commonly formed due to a severe case of head injury. There have been approximately 15%–30% of cases of individuals who regain either complete or partial functioning of the brain after suffering from an acute case of subdural hematoma. The chronic case of subdural hematoma is known to develop due to a minor form of head injury. If there is blood clotting that forms on the surface of the brain, then it is known to cause subdural hematoma.

Symptoms

Individuals who suffer from chronic subdural hematoma would not experience any kind of symptoms, however, those with acute subdural hematoma would experience symptoms instantly. Also, the symptoms of subdural hematoma would also depend on the rate of bleeding that occurs in the individual:

• If the head injury is sudden, the individual would experience a severe case of bleeding and the person may lose consciousness and immediately go into the comatose stage.
• The individual would tend to appear normal for a few days after the head injury, but, slowly, they would start to feel confused and then go into an unconscious state after several days. This is known to be caused due to the slow rate of bleeding occurring outside the brain, thereby leading to the slow enlargement of the subdural hematoma.
• If the subdural hematoma is slow growing, then it would not lead to noticeable symptoms for about two weeks or more after the bleeding starts.

Below are a few of the common symptoms experienced by individuals:

Seizure attacks, trouble with vision, numbness, severe form of headaches, gradual change in the behavior of the individual, excessive drowsiness, speech that is slurred, weakness or feeling tired all the time, apathy, loss of consciousness, and coma.

It is important to visit the doctor right away if one experiences any of the above symptoms. However, there can be instances wherein these symptoms would reflect some other medical condition as well, which is of a serious nature. The symptoms of the chronic case of subdural hematoma can be very similar to the symptoms that are experienced in medical conditions such as tumors, some other troubles with the brain, dementia, or stroke.

Causes

The subdural hematoma is known to occur when the vein becomes ruptured in between the skull and the surface of the brain.

If an individual has sustained a major form of brain injury, the area becomes filled with blood, thereby leading to life-threatening symptoms. This is known as an acute subdural hematoma, and it is considered to be one of the dangerous forms of subdural hematoma. Most of the time, acute subdural hematoma is known to be caused due to a severe blow to the head, car or auto accident, or falling. The acute subdural hematoma is said to form rather quickly and the symptoms also appear very fast. There have been around 50%–80% of people who have developed acute subdural hematoma and who have died due to the complications that arose from them. The chronic subdural hematoma is known to mostly occur as a result of a mild or repeated case of head injury. These are very commonly seen in elderly individuals who tend to repeatedly bang their head or get hit due to falling. In a few cases, the chronic subdural hematoma is known to occur without any known cause. Due to the higher instances of this occurring in elderly individuals, it can also become a leading cause of brain shrinkage as they tend to age. This leads to extra space being present in the skull, thereby allowing the veins to become damaged easily in the case of a head injury. The symptoms in chronic cases are not easily detectable for several days or weeks. The chronic cases are easier to treat than the acute ones, but they can also prove to be fatal for the individual.

Diagnosis

The diagnosis of a subdural hematoma can be done with the help of imaging tests such as an MRI scan or a CT scan. These tests provide the doctor with a detailed look at the skull, brain, veins, and the other blood vessels of the individual. These scans are also known to be helpful in revealing if there is any blood present in the brain. At the same time, the doctor would also ask for a blood test to be carried out so as to check the complete blood count. The complete blood count, or CBC, helps to measure the red blood cell count, the platelet count, and the white blood cell count in the individual. In the case of a low red blood cell count, it can indicate that there is a significant amount of blood loss happening. Apart from the above, the doctor would also carry out a physical examination to watch out for the heart rate and blood pressure to find any evidence of internal bleeding in the individual.

Treatment

In the case of an acute subdural hematoma, it can only be treated in an operating room. There is a surgical method known as a craniotomy which can be used to remove the large subdural hematoma that has formed. This method is normally used for treating acute subdural hematoma. In this particular surgical procedure, the doctor or surgeon would look to remove a portion of the skull so as to access the clot or the hematoma. This can be done through the suction and irrigation method of removal. A craniotomy becomes a lifesaving method in the case of acute subdural hematoma, but there would be still risks. The doctor can also use a burr hole for draining in the case of chronic subdural hematoma as well as the acute one, which are smaller than one centimeter. First, the surgeon would create a small hole in the skull and then they would place a rubber tube in it. The blood accumulated in the hematoma would be drained out through these holes. There have been around a 70%–90% of recovery rate, and patients have also experienced a significant amount of functioning of the brain after the completion of this procedure. Apart from the surgical route, the doctor would also suggest a few anti-seizure medications to avoid an instance of seizure attacks that can be caused due to the subdural hematoma. Brain injury can also be treated with the help of medications.