Head injury refers to trauma to the scalp, skull, or brain that may result in temporary or permanent neurological dysfunction. It encompasses a wide spectrum of pathologies, from superficial scalp injuries to life-threatening intracranial hemorrhages.
Etiology
Common causes include:
- Motor Vehicle Accidents : leading cause in all age groups.
- Falls : especially in children and elderly.
- Assaults
- Sports-related injuries
- Penetrating trauma (e.g. gunshot wounds, stab wounds)
Epidemiology :
- Male to female ratio: ~2:1
- More common in individuals < 35 years
Classification of Head Injury
A. By Severity (Glasgow Coma Scale - GCS)
| GCS Score | Severity |
|---|---|
| 13–15 | Mild |
| 9–12 | Moderate |
| ≤8 | Severe |
B. By Anatomical Layers Involved (Mnemonic: SCALP)
- S kin
- C onnective tissue (dense) – vascular layer
- A poneurosis (Galea aponeurotica)
- L oose areolar tissue – site of hematoma accumulation
- P ericranium – periosteum of the skull
C. By Pathology
- Primary injury : Occurs at the time of trauma
- Secondary injury : Occurs later due to complications like hypoxia, edema, or hematomas
Skull Fractures
1. Closed (Simple) Fractures
- Linear : Most common; often associated with epidural hematomas
- Comminuted : Multiple fragments
- Ping-pong fracture : Seen in infants; greenstick-like
- Depressed : Bone is pushed inward; risk of dural tear
- Basilar : Involving base of skull; may lead to CSF rhinorrhea/otorrhea
2. Open (Compound) Fractures
- Communication with the external environment
- Risk of infection and CSF leak
Brain Injuries
A. Primary Injuries
- Concussion : Transient loss of neurological function
- Contusion : Bruising of brain tissue
- Laceration : Tearing of brain parenchyma
- Diffuse Axonal Injury (DAI) :
- Result of shearing forces during acceleration/deceleration
- Common in high-speed trauma
- Poor prognosis; presents with coma or persistent vegetative state
B. Penetrating Injury
- Direct mechanical disruption from sharp objects
- Commonly involves skull base in children
C. Compression Injury
- Crush injuries leading to multiple linear fractures and cranial nerve involvement
Secondary Brain Injury
A. Intracranial Hematomas
1. Epidural Hematoma
- Location : Between skull and dura mater
- Cause : Middle meningeal artery rupture (often temporal bone fracture)
- Imaging : Biconvex (lentiform) shape on CT
- Clinical : "Lucid interval" followed by rapid deterioration
- Treatment : Emergency craniotomy or burr hole evacuation
2. Subdural Hematoma
- Location : Between dura and arachnoid mater
- Cause : Tearing of bridging veins
- Types :
- Acute : Rapid onset; high mortality
- Chronic : Slow accumulation; common in elderly, alcoholics
- Imaging : Crescent-shaped hematoma
- Treatment : Burr hole drainage or craniotomy
Clinical Presentation
- Altered mental status, confusion, loss of consciousness
- Headache, vomiting, seizures
- Focal neurological deficits (e.g., hemiparesis, cranial nerve palsies)
- Signs of raised ICP (e.g., papilledema, Cushing triad: hypertension, bradycardia, irregular respirations)
Diagnostic Evaluation
- Imaging : Non-contrast head CT is first-line
- Neurological exam : Regular GCS scoring
- Monitoring : ICP monitoring in severe head injury
Management
- Initial : ABCs (Airway, Breathing, Circulation)
- Supportive : Oxygen, fluid management, seizure prophylaxis
- Definitive : Surgical evacuation of hematomas, repair of skull fractures
- Rehabilitation : Multidisciplinary approach for physical, cognitive recovery
Complications
- Post-traumatic seizures
- Hydrocephalus
- Infections (meningitis, brain abscess)
- Chronic traumatic encephalopathy (CTE)
- Persistent vegetative state or death
