Difference Between Extradural Hematoma and Subdural Hematoma

Extradural Hematoma vs. Subdural Hematoma

A hematoma is a medical term for a blood clot, formed when bleeding occurs in an organ or cavity. Extradural hematoma or epidural hematoma (EDH) is a clot that forms on the external side of the brain’s protective layer of tissue (dura mater), whereas acute subdural hematoma (ASDH) appears within the first few days after head injury, on the interior surface of the dura. Both medical conditions are serious and involve compression (pressing) of brain tissue, typically occurring as a result of significant head trauma, skull injury and short periods of lost consciousness.

Similarity

Both extradural hematoma and subdural hematoma are serious medical conditions that can result in pressing and compression of the underlying brain, usually followed by a head injury. Both involve bleeding either on the external of brain or either internally or externally of the dura mater.

Extradural hematoma

An extradural or epidural hematoma (EDH) occurs when there is accumulation of blood in the area between the dura and cranial bone or spine. 

Subdural hematoma

A subdural hematoma (SDH) or subdural hemorrhage happens when a blood vessel in the area between the brain and its outermost covering (the subdural space) is damaged.

Difference between extradural hematoma and subdural hematoma

Definition

Extradural hematoma

When there is accumulation of blood in the space between the dura and the skull. Usually associated with a lucid interval.

Subdural hematoma

Subdural hematoma (SDH) occurs when there is bleeding in the space between the brain and its exterior covering. It is serious and could be a medical emergency as the key cause in this case is a heady injury acute severe enough to result in bursting of the blood vessels. 

Causes

Extradural hematoma

• Skull trauma in the temporoparietal region caused by a head injury.
• Non-trauma causes include – tumors that cause bleeding, coagulopathy, vascular malformations, infection/abscess.

Subdural hematoma

• Severe head injury due to fall
• Severe alcoholism sometimes results in blood thinning and result in subdural hematomas.

Symptoms

Extradural hematoma

• Lucid interval followed by unconsciousness.
• Nausea and vomiting 
• Severe headache
• Drowsiness
• Vision problems
• Seizures

Subdural hematoma

• Gradually increasing headache and confusion
• Feeling of being sick
• Slurred speech
• Difficulty swallowing
• Excess sleepiness
• Fainting
• Muscle weakness

Source of bleeding

Extradural hematoma

In this case, it is usually through arteries

Subdural hematoma

In this case, it is usually through veins

CT appearance

Extradural hematoma

Formation of biconvex lens – limited by suture lines

Subdural hematoma

Formation of crescent shaped – crosses suture lines

Which hematoma is more common – extradural hematoma and subdural hematoma?

Intracranial (within the skull) extradural or epidural hematomas (EDH) occur in around two percent of patients who undergo serious injuries to head, whereas acute subdural hematomas (SDH) happen in five to twenty-five percent of people with serious and chronic head injuries. Hence, acute subdural hematomas (SDH) are more common in comparison to subdural hematomas. 

Summary

The points of difference between extradural hematoma and subdural hematoma have been summarized as below:

FAQ:

What is the difference between a subdural hematoma and subarachnoid hematoma?

Subdural hematoma (SDH) is a type of bleeding that occurs inside the head and subarachnoid hematoma (SAH) is defined as the bleeding in the area between the brain and the subarachnoid space (surrounding space)

What is the difference between epidural and extradural hematoma?

Extradural hematoma is another name for epidural hematoma.

What is the difference between subdural and epidural?

Epidural is middle meningeal artery tear and subdural is the tear of the bridging veins.

What are the 2 differences between epidural and subdural hematomas?

Epidural hematoma is the bleeding that happens between the skull and the dura (the tough membrane on the outside surrounding the brain and spinal cord) and subdural hematoma happens when there is bleeding between the dura and the arachnoid.

What are the three types of subdural hematomas?

The three types of subdural hematomas include:

• Acute – dangerous and symptoms develop in no time.
• Subacute – symptoms take time to appear.
• Chronic 

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