Types of Traumatic Brain Injury

Understanding the different classifications of TBI — by mechanism, injury pattern, and severity — is essential for proper diagnosis and treatment planning.

75%

of TBIs are mild (concussions)

90%

of TBIs are closed injuries

50%

higher mortality rate in penetrating TBI

Primary Classifications

By mechanism of injury

Closed TBI (Non-Penetrating)

Most common type — skull remains intact

  • Blunt force trauma
  • Falls
  • Sports injuries
  • Includes concussions

Penetrating TBI (Open)

Object pierces the skull — high mortality

  • Gunshot wounds
  • Shrapnel
  • Sharp objects
  • High infection risk

Diffuse Axonal Injury (DAI)

Widespread tearing of nerve fibers

  • High-speed accidents
  • Prolonged coma risk
  • Microscopic damage
  • Poor prognostic indicator

Classification by Severity

Glasgow Coma Scale (GCS) and clinical criteria

Mild TBI (Concussion)

GCS Score: 13-15

LOC: 0-30 minutes

PTA: < 24 hours

  • 80-90% of all TBIs
  • Typically normal CT imaging
  • Recovery: weeks to months

Moderate TBI

GCS Score: 9-12

LOC: 30 min - 24 hours

PTA: 1-7 days

  • 10-15% of TBIs
  • Abnormal CT in many cases
  • Recovery: 6-12 months

Severe TBI

GCS Score: 3-8

LOC: > 24 hours

PTA: > 7 days

  • 5-10% of TBIs
  • Almost always abnormal imaging
  • Recovery: years or lifelong

Special TBI Categories

Additional classifications based on specific mechanisms

Coup-Contrecoup Injury

Brain injury at both the impact site (coup) and opposite side (contrecoup) as the brain rebounds inside the skull.

  • Common in acceleration-deceleration injuries
  • Often affects frontal and temporal lobes
  • Can cause contusions at both sites

Intracranial Hemorrhage

Bleeding within the skull — multiple subtypes:

  • Epidural hematoma: Arterial bleed, rapid onset
  • Subdural hematoma: Venous bleed, often slower
  • Subarachnoid hemorrhage: On brain surface
  • Intracerebral hemorrhage: Within brain tissue

Quick Comparison Guide

Types of TBI at a glance

Type Mechanism Common Causes Prognosis
Closed TBIBlunt forceFalls, MVAs, sportsVariable
Penetrating TBIObject penetrates skullGunshots, shrapnelPoorer
Diffuse Axonal InjuryRotation/accelerationHigh-speed MVAsOften severe
ContusionDirect impactFalls, assaultsVariable
HematomaBleedingTrauma, anticoagulationEmergency

Prevention Strategies

Reducing the risk of TBI across different scenarios

Closed TBI Prevention

  • Wear seatbelts in vehicles
  • Use helmets for biking, sports
  • Install handrails and grab bars
  • Remove fall hazards at home

Penetrating TBI Prevention

  • Workplace safety protocols
  • Proper firearm storage
  • Use protective eyewear/gear
  • Safe tool handling practices

CTE & Repeated Injury

  • Limit head impact exposure
  • Proper concussion management
  • Return-to-play protocols
  • Long-term monitoring for athletes

Diagnostic Process

How TBI type and severity are determined

Neurological Exam
Initial assessment
CT/MRI Imaging
Structural evaluation
Cognitive Testing
Functional assessment
GCS Assessment
Severity scoring
Related Resources: Secondary TBI • Recovery Process • TBI & Mental Health
This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider for diagnosis and treatment of TBI.