Traumatic brain injury (TBI), also referred to as head injury, is one of the most critical and common causes of mortality and long-term disability in trauma care. It results from external mechanical force causing brain dysfunction. This guide is designed for MBBS students, NEET PG aspirants, interns, and emergency healthcare professionals seeking a clear, visual, and practical understanding of the mechanisms, types, complications, and treatments of TBI.
What is Traumatic Brain Injury?
TBI is defined as any trauma to the head that leads to injury to the brain, skull, or both. It can result from a variety of mechanisms, including falls, road traffic accidents, assaults, and sports injuries.
Primary and Secondary Brain Injury
Primary Brain Injury:
- Occurs at the moment of trauma.
- Caused by the mechanical impact (e.g., blunt force, penetrating injury).
- Examples: Coup, contrecoup, shear injury, intracranial hemorrhage.
Secondary Brain Injury:
Occurs after the initial insult.
Caused by complications such as:- Hypoxia
- Hypotension
- Raised intracranial pressure (ICP)
- Infection
- Cerebral edema
Types of Mechanism of Head Injury
- Blunt Blow
- Crush Injuries
- Rotational/Deceleration Injuries
- Coup and Contrecoup
- Penetrating Missile Injury
Each mechanism results in different patterns of injury:
Coup injury:
Direct blow to the head, injury at the site of impact.
Contrecoup injury:
Brain rebounds and strikes the opposite side of the skull.
Rotational injuries:
Cause shear forces within the brain, leading to axonal injury.
Types of Brain Injuries
1. Vascular Injuries
- Intracerebral hematoma
- Subdural hematoma
- Extradural (epidural) hematoma
2. Bony Injuries
- Simple skull fracture
- Depressed skull fracture
- Base of skull fracture
3. Secondary Injuries
- Hypoxia
- Hypotension
- Infection
Clinical Features of TBI
- History of trauma or deceleration
- Headache, vomiting
- Altered or reduced consciousness
- Focal neurological signs
- Seizures
- Pupil abnormalities (dilated, fixed pupils)
- Cushing's triad (↑ BP, ↓ HR, irregular respiration)
- Battle sign, raccoon eyes (in base of skull fractures)
Glasgow Coma Scale (GCS)
| Response Type | Score |
|---|---|
| Eye Opening | 4 (spontaneous) to 1 (none) |
| Verbal | 5 (oriented) to 1 (none) |
| Motor | 6 (obeys commands) to 1 (none) |
GCS Scores:
- 13–15: Mild TBI
- 9–12: Moderate TBI
- ≤8: Severe TBI
Investigations
- CT Scan: Modality of choice for diagnosis
- MRI: For diffuse axonal injury
- Skull X-ray: Limited use
- Blood tests: U&E, FBC, glucose
Management of TBI
Trivial Head Injury
- Observation for 24 hours
- No imaging if GCS = 15 and no red flags
Indications for CT Scan:
- GCS ≤14
- Focal neurology
- Seizures
- Suspected skull fracture
- CSF leak
- Alcohol or drug intoxication
Indications for Admission:
- Confusion, drowsiness
- Inadequate social support at home
Indications for Neurosurgical Referral:
- Skull fracture with low GCS
- Persistent neurological signs
- Progressive decline in GCS
- Suspected penetrating injury
Emergency Management for Severe Head Injury
- Airway: Protect airway, intubate if GCS ≤8
- Breathing: Oxygenation to avoid hypoxia
- Circulation: Avoid hypotension, IV fluids
- Cervical spine immobilization
- Rapid transfer to CT and neurosurgical team
Raised Intracranial Pressure (ICP)
Causes:
- Cerebral edema
- Hematoma
- Hyperemia
- Hydrocephalus
Signs:
- Headache
- Vomiting
- Papilledema
- Decreased consciousness
Treatments to Reduce ICP:
- Head elevation
- Hyperventilation (↓ PaCO₂)
- Mannitol or hypertonic saline
- Barbiturates (reduce brain metabolism)
- Ventriculostomy or craniectomy if required
Complications of TBI
Skull Fractures
- Basal fractures: raccoon eyes, CSF rhinorrhea
- No treatment unless compound or symptomatic
Hematomas
- Extradural: Lucid interval, middle meningeal artery tear
- Acute Subdural: Venous bleeding, progressive loss of consciousness
- Chronic Subdural: Elderly, slow expansion over weeks
- Intracerebral: Poor prognosis, irreversible damage
Infection
- Meningitis or brain abscess if dura is breached
Seizures
- Common post-traumatic complication
Long-term Sequelae
- Cognitive deficits
- Memory loss
- Paralysis
- Depression and mood disorders
Prognosis of Head Injury
| GCS at Admission | Mortality Rate |
|---|---|
| 13–15 (Mild) | 1% |
| 9–12 (Moderate) | 5% |
| <8 (Severe) | 40% |
60% of moderate TBI and 100% of severe TBI cases may result in long-term disability.
Prevention of Head Injury
- Use of helmets in two-wheelers
- Seat belts and airbags in cars
- Fall prevention in elderly
- Public education on sports safety
FAQs on Traumatic Brain Injury
What is the first step in managing a head injury?
Ensure airway protection and cervical spine stabilization. Perform an ABCDE primary survey.
How do you detect raised ICP clinically?
Look for headache, vomiting, decreased consciousness, and Cushing’s reflex (↑BP, ↓HR).
When is CT mandatory in head injury?
If GCS is ≤14, focal neurology, seizures, intoxication, or skull fracture suspected.
Conclusion
Traumatic brain injury is a medical emergency that demands rapid recognition, appropriate imaging, and timely management. The focus must always be on preventing secondary injury through oxygenation, blood pressure control, and monitoring for raised ICP.
GCS remains the gold standard for quick neurological evaluation. Recognizing the red flags and knowing when to refer or admit can dramatically improve outcomes in head injury cases.
