A 35-year-old construction worker is brought to the trauma center with a severe head injury (GCS 5) after a fall from scaffolding. Which is the most common primary intracranial injury in severe head trauma that requires immediate neurosurgical intervention?

Explanation

## Acute Subdural Hematoma: The Most Common Neurosurgical Emergency **Key Point:** Acute subdural hematoma (ASDH) is the **most common intracranial injury requiring neurosurgical evacuation** in severe head trauma. It results from tearing of cortical bridging veins that traverse the subdural space between the arachnoid membrane and dura mater. ### Epidemiology & Mechanism **High-Yield:** Acute subdural hematoma occurs in 10–20% of moderate-to-severe head injuries and is associated with the worst prognosis among mass lesions. It is caused by: 1. **Tearing of cortical bridging veins** — the primary mechanism. 2. **Cortical surface lacerations** — secondary source. 3. **Acceleration-deceleration injury** — the brain moves within the skull, stretching and tearing vessels. ### Clinical & Imaging Features | Feature | Acute Subdural Hematoma | Epidural Hematoma | | --- | --- | --- | | **Location** | Between arachnoid and dura (subdural space) | Between dura and skull (extradural) | | **Shape** | Crescent-shaped | Lens-shaped (biconvex) | | **Crosses sutures?** | Yes | No | | **Bleeding source** | Venous (cortical bridging veins) | Arterial (MMA) | | **Onset** | Rapid (minutes to hours) | Rapid (minutes to hours) | | **Prognosis** | Poor (high mortality ~60%) | Better if evacuated early | | **CT appearance** | Hyperdense, follows brain contour | Hyperdense, lens-shaped | ### Why ASDH is Most Common Neurosurgical Emergency 1. **Frequency:** Present in ~10–20% of severe head injuries (more common than EDH). 2. **Severity:** Associated with severe underlying brain injury (contusions, DAI). 3. **Mortality:** Highest mortality among intracranial mass lesions (~50–60% even with surgery). 4. **Urgency:** Requires immediate craniotomy/burr holes to prevent herniation. **Clinical Pearl:** The Glasgow Outcome Scale at 6 months is poor for ASDH, with only 20–30% achieving good recovery. This reflects the severity of the underlying brain parenchymal injury that accompanies the bleed. **Mnemonic:** **ASDH = Crescent, Crosses Sutures, Cortical Veins** — helps distinguish from EDH. ### GCS and Management Correlation A GCS of 5 indicates severe injury with brainstem involvement. Immediate CT, neurosurgical consultation, and airway protection are mandatory. If ASDH is confirmed, emergency evacuation is indicated. [cite:Harrison 21e Ch 434; Sabiston Textbook of Surgery 21e Ch 39]