Closed Head Trauma

Question 1

What is the problem with scalp lacerations?

Answer 1

• Potential major source of blood loss
• Require repair in layers

Question 2

What divides the right and left cerebral hemispheres?

Answer 2

Falx cerebri

Question 3

What divides the cerebral hemispheres from the cerebellum/brainstem?

Answer 3

Tentorium cerebelli

Question 4

Cerebrospinal Fluid

Answer 4

Cushions brain and spinal cord against trauma

Made by choroid plexus in ventricles

Question 5

Cerebral Blood Flow

Answer 5

• Brain is only 2% of body weight but gets 15% of cardiac output
• CBF is profoundly influenced by CO2
• CBF also influenced by oxygen

Question 6

What does hypercapnia do to cerebral blood flow?

Answer 6

Causes cerebral vasodilation

Question 7

What does hypocapnia do to cerebral blood flow?

Answer 7

Causes cerebral vasoconstriction

Question 8

What does hypoxia do to cerebral blood flow?

Answer 8

Causes cerebral vasodilation

Question 9

Autoregulation

Answer 9

• The ability of the brain to maintain constant cerebral blood flow despite changes in cerebral perfusion pressure
• CBF remains constant with CPP 45-160mmHg
• Relies on vasodilation and vasoconstriction of cerebral vessels

Question 10

Intracranial Pressure (ICP)

Answer 10

• intracranial space is fixed volume
• normally contains 3 components:
  
  • Brain, blood, CSF
• Brain + Blood + CSF = constant sum
  
  • if one increases, another must decrease; otherwise, ICP rises
  • normal ICP < 15 mmHg
• If intracranial mass lesion, hematoma, or cerebral edema develops, ICP rises
  
  • CSF is displaced from brain ventricles
  • Then blood displaced from brain
  • Finally, brain itself is compressed

Question 11

Transtentorial (uncal) Herniation

Answer 11

• A process that causes rise in ICP (e.g. epidural hematoma) can force medial aspect of temporal lobe (uncus) through tentorium opening
• Compresses third cranial nerve (oculomotor) and the corticospinal tract

Question 12

Clinical Findings of Transtentorial Herniation

Answer 12

• Ipsilateral fixed, dilated pupil
• Contralateral weakness of arm/leg
• Deteriorating LOC

Question 13

Closed Head Injury Diffuse Lesions

Answer 13

• Concussion
• Diffuse axonal injury

Question 14

Closed Head Injury Focal Lesions

Answer 14

• Skull fractures
• Cerebral contusion
• Intracranial hemorrhage
• Epidural hematoma
• Subdural hematoma

Question 15

Concussion

Answer 15

• Transient LOC or alteration of