Following a blow to the head, the greatest threat to life is traumatic intracranial hemorrhage—bleeding that occurs between the skull and the brain. Acute Epidural Hematoma (EDH) and Acute Subdural Hematoma (ASH) are particularly urgent conditions. Their degree of emergency and prognosis differ significantly depending on the site of occurrence, the source of bleeding, and the shape of the hematoma on CT scans (e.g., lenticular vs. crescentic).
This article provides a comprehensive comparison of EDH, ASH, and Traumatic Subarachnoid Hemorrhage (tSAH)based on their causes, imaging findings, and outlooks. Understanding the risks of brain herniation and complications like delayed vasospasm is essential for rapid diagnosis and appropriate treatment.
Comparison of Traumatic Intracranial Hemorrhages
| Feature | Acute Epidural Hematoma (EDH) | Acute Subdural Hematoma (ASH) | Traumatic Subarachnoid Hemorrhage (tSAH) |
| Location | Between the skull and dura mater | Between the dura mater and arachnoid mater | Between the arachnoid and pia mater (brain surface) |
| Main Source | Arteries (e.g., Middle Meningeal Artery); often associated with fractures | Tearing of bridging veins or bleeding from cerebral contusions | Small surface vessels or bleeding from cerebral contusions |
| CT Findings | Convex/Lens-shaped (Rugby ball shape); well-defined borders as the dura peels off the bone | Crescent-shaped (Banana shape); spreads along the brain surface | High-density areas in subarachnoid spaces/sulci (white linear or hazy patterns) |
| Onset Speed | Relatively fast (rapid progression due to arterial bleeding) | Very fast (often progresses immediately after injury) | Occurs at the time of injury |
| Treatment | Emergency craniotomy for hematoma removal is the rule. Rapid response is vital. | Emergency craniotomy and hematoma removal; management of brain edema is also essential. | Usually conservative treatment (rest, blood pressure control). Surgery only if massive or combined with severe contusion. |
| Prognosis | Relatively good if surgery is performed quickly and primary brain damage is minimal. | Very poor (high mortality rate) as it is often accompanied by severe cerebral contusions. | Good if isolated, as the blood is naturally absorbed. Prognosis depends on the severity of associated contusions. |
| Consciousness | May feature a “Lucid Interval” (temporary recovery of consciousness before rapid decline). | Often results in severe impairment of consciousness immediately after injury. | May range from mild headache/confusion to severe symptoms if complications occur. |
Key Clinical Points
1. Risk of Brain Herniation
Both EDH and ASH can cause the brain to shift or be pushed downward (brain herniation) due to increasing pressure from the hematoma. This is a direct threat to life. ASH is particularly dangerous because it is frequently associated with severe brain swelling (edema) and underlying contusions, making it one of the most critical neurosurgical emergencies.
2. Characteristics of Traumatic Subarachnoid Hemorrhage (tSAH)
- Good Prognosis in Isolation: If the bleeding is minor, it dissolves into the cerebrospinal fluid and is absorbed naturally; therefore, surgical removal is rarely necessary.
- Complications are Key: tSAH becomes severe primarily when accompanied by other major injuries like cerebral contusions or Diffuse Axonal Injury (DAI).
- Delayed Risks: Patients must be monitored for delayed complications (days to weeks later), such as Cerebral Vasospasm (narrowing of brain vessels) and Hydrocephalus (impaired drainage of cerebrospinal fluid).
Summary
The emergency level and prognosis of these traumatic hemorrhages vary based on the shape seen on CT and the source of the bleeding. Accurate diagnosis and rapid, pathology-specific treatment are the keys to saving lives and improving long-term outcomes.
