The key difference between subdural and subarachnoid hemorrhage is that subdural hemorrhage is bleeding in the brain where blood leaks out from the torn blood vessel into the space below the dura mater membrane layer, while subarachnoid hemorrhage is bleeding in the brain where blood leaks out from the torn blood vessel into the space below the arachnoid layer.
Intracranial hemorrhage refers to any bleeding within the brain parenchyma and surrounding meningeal spaces. It is divided into epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, and intraparenchymal hemorrhage.
CONTENTS
1. Overview and Key Difference
2. What is Subdural Hemorrhage
3. What is Subarachnoid Hemorrhage
4. Similarities – Subdural and Subarachnoid Hemorrhage
5. Subdural vs. Subarachnoid Hemorrhage in Tabular Form
6. Summary – Subdural vs. Subarachnoid Hemorrhage
What is Subdural Hemorrhage?
Subdural hemorrhage is a type of intracranial hemorrhage that happens when there is bleeding below the dura mater membrane layer in the brain. Moreover, the symptoms of subdural hemorrhage may include headache, confusion and drowsiness, nausea and vomiting, slurred speech, dizziness, memory loss, disorientation, personality changes (especially in adults), and enlarged head in babies. Subdural hemorrhage can be caused by a head injury, such as a fall resulting in a head impact, a blow to the head in a car or bike accident, injuries sustained during engagement in dangerous sporting activities, or any other type of head trauma. The risk factors for subdural hemorrhage include older adults, athletes who play contact sports, people who take blood thinners, hemophiliacs, people with alcohol use disorder, and babies.
Figure 01: Subdural Hemorrhage
Subdural hemorrhage can be diagnosed through physical symptom evaluation, neurological examination, CT scan, and MRI. Furthermore, treatment options for subdural hemorrhage include decompression surgery and the placement of a drain for several days following the surgery to facilitate the continuous drainage of blood.
What is Subarachnoid Hemorrhage?
Subarachnoid hemorrhage is a type of intracranial hemorrhage that happens when there is bleeding below the arachnoid mater layer in the brain. The brain has three membrane layers that lie between the skull and the brain tissue. The outermost layer is called the dura mater, the middle layer is called the arachnoid mater, and the layer closest to the brain is called the pia mater. The symptoms of this condition include thunderclap headache, decreased consciousness and alertness, nausea, vomiting, stiff neck, sudden weakness, mood and personality changes, irritability, dizziness, and eye sensitivity in bright light.
Figure 02: Types of Hemorrhage
Subarachnoid hemorrhage can be caused by head trauma such as from a serious fall, vehicle accident, or brain aneurysm bursting. The risk factors for subarachnoid hemorrhage include an unruptured aneurysm in the brain, a history of a previously ruptured brain aneurysm or family history of aneurysms, cigarette smoking, high blood pressure, fibromuscular dysplasia (FMD), Ehlers-Danlos syndrome and other connective tissue diseases, a history of polycystic kidney disease, cocaine use, excessive alcohol consumption, and usage of blood thinners like warfarin.
Subarachnoid hemorrhage can be diagnosed through physical examination, CT scan, X-ray, CT angiography (CTA), lumbar puncture, and brain magnetic resonance imaging (MRI). Furthermore, subarachnoid hemorrhage is treated through life support, placing a draining tube in the brain to relieve pressure, medications to decrease swelling in the skull, managing blood pressure (IV), preventing artery spasms, painkillers, anti-anxiety drugs to relieve headaches, anti-seizure drugs, removing large collections of blood on the brain, and repairing the aneurysm.
What are the Similarities Between Subdural and Subarachnoid Hemorrhage?
- Subdural and subarachnoid hemorrhage are two different types of intracranial hemorrhage.
- Head injuries can cause both.
- Both can have similar symptoms, such as headaches, mood changes, personality changes, etc.
- Both can be diagnosed through physical examination and imaging tests.
- They can be treated through draining and specific surgeries.
What is the Difference Between Subdural and Subarachnoid Hemorrhage?
Subdural hemorrhage is a type of bleeding in the brain where blood leaks out from the torn blood vessel into the space below the dura mater membrane layer, while subarachnoid hemorrhage is a type of bleeding in the brain where blood leaks out from the torn blood vessel into the space below the arachnoid layer. Thus, this is the key difference between subdural and subarachnoid hemorrhage. Subdural hemorrhage can be caused by a head injury, such as a fall resulting in a head impact, a blow to the head in a car or bike accident, injuries sustained during engagement in dangerous sporting activities, or any other type of head trauma. On the other hand, subarachnoid hemorrhage can be caused by head trauma such as from a serious fall, vehicle accident, or brain aneurysm bursting.
The infographic below presents the differences between subdural and subarachnoid hemorrhage in tabular form for side-by-side comparison.
Summary – Subdural vs. Subarachnoid Hemorrhage
Intracranial hemorrhage occurs in the intracranial vault and encompasses four broad types of hemorrhage, including subdural and subarachnoid hemorrhage. Subdural hemorrhage is bleeding in the brain due to the blood leaking out from the torn blood vessel into the space below the dura mater membrane layer. On the other hand, subarachnoid hemorrhage is bleeding in the brain due to blood leaking out from the torn blood vessel into the space below the arachnoid layer. So, this is the key difference between subdural and subarachnoid hemorrhage.
Reference:
1.“Subdural Hemorrhage Causes, Symptoms, Treatments, New Jersey.” RWJBarnabas Health.
2.“Subarachnoid Hemorrhage.” Johns Hopkins Medicine.
Image Courtesy:
1. “Ct-scan of the brain with an subdural hematoma” By Lucien Monfils – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “An illustration of the different types of brain hemorrhage” By Myupchar (CC BY-SA 4.0) via Commons Wikimedia