Head Injury: Traumatic Brain Injury Definition and Anatomy

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Questions and Answers

What percentage of traumatic brain injuries are caused by transportation?

26%

44% (correct)

13%

What is the primary function of the Monro-Kellie Doctrine?

To illustrate the relationship between venous and arterial volume in the brain (correct)

To describe the anatomy of the brain

To explain the pathophysiology of primary brain injury

To diagnose secondary brain injury

What is the annual mortality rate of children from road traffic accidents (RTC) per 100,000 in South Africa?

5.89 per 100,000

7.89 per 100,000

1.89 per 100,000

3.89 per 100,000 (correct)

What is the definition of traumatic brain injury?

An insult to the brain caused by an external physical force Signup and view all the answers

What percentage of traumatic brain injuries are caused by firearms?

8% Signup and view all the answers

What is the primary layer of protection for the brain?

Skull Signup and view all the answers

What is the volume of the brain's CSF?

75 mL Signup and view all the answers

What is the point of decompensation in the Volume-Pressure Curve?

35 mm Hg Signup and view all the answers

What is the total Glasgow Coma Scale (GCS) of a 20-year-old male in MVA?

8T Signup and view all the answers

What is an indication for a CT scan in a head injury patient?

GCS ≤ 14 Signup and view all the answers

What is a common indication for re-admission in head injury patients?

Seizures Signup and view all the answers

What is a sign of skull base fracture?

Raccoon eyes Signup and view all the answers

What is the target value for cerebral perfusion pressure?

60 mmHg Signup and view all the answers

When is a skull X-ray useful in a trauma setting?

Never useful Signup and view all the answers

What is the primary goal of ICP management steps?

To maintain ICP below 20 mmHg Signup and view all the answers

What is an indication for observation at home?

Normal CT and GCS 15 Signup and view all the answers

What is not an indication for a CT scan in a head injury patient?

Normal neurological examination Signup and view all the answers

What is the normal value for brain tissue oxygen tension?

20 - 35 mmHg Signup and view all the answers

What is the target value for partial pressure of oxygen in the arterial blood?

> 60 mmHg Signup and view all the answers

What is a contraindication for conservative management?

Focal neurological deficits Signup and view all the answers

What is a prognostic factor that increases mortality?

Elderly age Signup and view all the answers

What is a part of general monitoring in ICU?

ECG Signup and view all the answers

What is the cutoff for severe head injury based on the Glasgow Coma Scale?

GCS < 8 Signup and view all the answers

What is the primary goal of operative and non-operative strategies in managing head injuries?

Reducing mass effect and ICP Signup and view all the answers

What is the most common complication of hypotension in patients with head injuries?

More than 50% increase in mortality Signup and view all the answers

What is the definition of hypoxia in the context of head injuries?

PO2 < 60 mmHg, Sats < 90% Signup and view all the answers

Which of the following is a member of the multidisciplinary team that manages patients with head injuries?

Psychologists Signup and view all the answers

What is the term for a Glasgow Outcome Scale score of 1?

Dead Signup and view all the answers

Study Notes

Head Injury

Traumatic brain injury is an insult to the brain caused by an external physical force, resulting in a diminished or altered state of consciousness and impairment of cognitive abilities or physical functioning.

Anatomy

Scalp
Skull
Brain

Epidemiology

Transportation accounts for 44% of traumatic brain injuries
Falls account for 26% of traumatic brain injuries
Other causes include: • Firearms (8%) • Non-firearm assaults (9%) • Annual mortality of children from road traffic accidents is 3.89 per 100,000

Pathophysiology

Primary vs secondary brain injury
Monro-Kellie doctrine: the concept of a fixed volume of the cranial vault, where an increase in one component (blood, CSF, or brain tissue) leads to a decrease in another

Concepts

Autoregulation
Volume-pressure curve: • 60-55 mmHg: herniation • 50-40 mmHg: point of decompensation • 30-20 mmHg: compensation • 15-10 mmHg: volume of mass

Classification of Head Injury

Glasgow Coma Scale (GCS): • Eye opening: 1-4 points • Verbal response: 1-5 points • Motor response: 1-6 points • Total GCS: 3-15 points
Clinical scenario: a 20-year-old male in a motor vehicle accident, intubated, with a GCS score of 8

Approach to Head Injury

History: • Mechanism of injury • Loss of consciousness • Vomiting • Seizures • Intoxicants • Post-traumatic amnesia
Clinical examination: • Dilated non-reactive pupils • Hemiplegia/hemiparesis • Aphasia/dysphasia • Facial weakness • Cranial nerve palsy • Papilloedema
Signs of skull base fracture: • Raccoon eyes • Battle sign

Investigations

Skull X-ray: useful only for detecting skull fractures, but may waste time in the trauma setting
CT scan: • Indications:
- GCS ≤ 14
- Focal neurological deficits
- Deteriorating GCS
- Penetrating head injuries
- Post-traumatic seizures
- Loss of consciousness and amnesia
- Multiple trauma
- Skull fracture
- Patients who are intoxicated
- Patients on anti-coagulant therapy
- Mechanism of injury • Indications for observation at home:
- Normal CT
- GCS 15
- No focal deficits
- Easy access to ER
- Responsible adult to observe at home
- No complicating circumstances • Indications for re-admission:
- Drowsiness
- CSF leak
- Seizures
- New focal deficit
- Fever

Pathology

Primary injury: • Acute extradural hematoma • Acute subdural hematoma • Contusion/intracerebral hematoma • Diffuse cerebral injury • Skull fracture • Gunshot injuries • Penetrating stab injuries • Concussion in sports • Non-accidental injury
Secondary brain injury: • Prevention: maintain Po2 > 60 mmHg, systolic BP > 90 mmHg, glucose control, and appropriate IV fluids • Conservative management:
- GCS 13-15
- No focal deficits
- Neurological observations: ICU/high care (hourly) • Surgical management:
- ICU management:
 - General measures:
 - Head elevation 30 degrees
 - Neck neutral position
 - Urinary catheter
 - Analgesia
 - Gastro-protective agents
 - Anti-seizure prophylaxis
 - DVT prophylaxis
 - Nutrition
 - Fluids
 - Medical management:
 - Ventilation: PCo2 30-35 mmHg
 - Sedation
 - Mannitol
 - Hypertonic saline
 - General monitoring:
 - ECG
 - Saturations: 100%
 - Systolic BP: > 90 mmHg
 - Pulse
 - Temperature: maintain euthermia or mild hypothermia
 - CVP: 8-14 mmHg
 - Glucose: normoglycemic
 - ICP monitoring:
 - Indications:
 - GCS ≤ 8
 - Polytrauma
 - Prolonged ventilation
 - Hypotension
 - Posturing
 - ICP > 20 mmHg: abnormal
 - Brain tissue oxygen tension (PbtO2) monitoring:
 - Normal values: 20-35 mmHg
 - Cerebral perfusion pressure (CPP):
 - CPP = MAP – ICP
 - Targeted value: 60 mmHg
 - Values < 50 mmHg: cerebral ischemia and hypo-perfusion
 - Values > 70 mmHg: cardiorespiratory failure, ARDS

Prognostic Factors

Age: younger patients have a greater potential for survival and recovery
Mechanism of injury: e.g., motorbike crashes
GCS < 8
ICP > 45
Hypotension: > 50% increase in mortality with a single episode of hypotension
Hypoxia: PO2 < 60 mmHg, Sats < 90%

Glasgow Outcome Scale

1: Dead
2: Vegetative state
3: Severe disability
4: Moderate disability
5: Mild disability

Late Complications

Post-traumatic seizures
Hydrocephalus
Infections
Post-concussive syndrome: • Somatic: headaches, dizziness, anosmia, hearing difficulties, balance difficulties • Cognitive: difficulty concentrating, dementia, impaired judgment • Psychosocial: emotional problems, personality changes, loss of libido, tiredness, difficulty sleeping

Multidisciplinary Team

Physiotherapists
Occupational therapists
Psychologists
Social workers
Nurses
Doctors

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Description

This quiz covers the definition and anatomy of head injury, including traumatic brain injury, scalp, and skull. It's a valuable resource for medical students and professionals.