Traumatic Brain Injury

Question 1

How does contact phenomeena vs inertial forces change the site of brain injury?

Answer 1

Contact Phenomena: direct contact of the head against and object, resulting in focal injuries to skull, surface of brain ie fracturs, hematomas, contusions/laceration

Inertial Forces: Angular acceleration/deceleration resulting in shear stress forces (ie/ brain movement within the skull), resulting in diffuse injury deep within parenchyma of brain, diffuse axonal injury and vascular damage.

Question 2

Skull fractures can lead to neurological complications such as:

Answer 2

Basal skull can have a number of complications:

Anosmia (CN1), deafness (CN VII), EOM palsy (CN III, IV, VI), Facial paresis (CN VII)

CSF leak

Vascular injury (carotid, vertebral)

Pituitary stalk injury

usually because of shear forces

Question 3

Answer 3

epidural hematoma (EDH)–> “lemon”

Middle meningeal artery injury

critically important to recognize Herniation syndrome

can readily progress to lethal lesion-timing is critical!

Question 4

Answer 4

subdural hematoma (SDH)–> “banana”

Tearing of bridging veins, may be associated with adjacent parenchymal injury, swelling and arterial bleeding.

Question 5

Coup vs Contre Coup.

How can contusions progress?

Answer 5

Coup: bruising in brain at site of blow, where the skull has been deformed

Contre-coup: bruise in the brain where it strikes the skull when the head stops moving.

May enlarge over time→ F/U CT scans needed.

Can progress with edema

Some hemorrhagic contusions can be epileptogenic.

Question 6

Cerebral swelling vs Cerebral edema

Answer 6

Cerebral swelling: vaso-reactive post traumatic phenomenon that occurs within hours of injury. Increased cerebral blood flow with increased vascular volume/congestion and elevation of pressure

Cerebral edema: a delayed secondary complication of head injury. OFten accompanies hematomas (strokes can also cause cerebral edema) and contusions, usually worsens over the first 24-72 hours.

Question 7

Characteristic CT scan findings that indicate DAI:

Main mechanism of injury that causes DAI?

Answer 7

Unconsciousness from outset. Acceleration-deceleration injury

Angular forces applied to the brain

Characteristic CT scan findings that indicate DAI:

• Cerebral swelling “increased pressure’
• Petechial hemorrhages “shear”
• Hemorrhages dorsolateral pons, corpus callosum

Question 8

ICU MANAGEMENT OF ICP

Answer 8

intubation/ventilation with normal CO2

Elevate the head of bed 30 degrees, maintaining neutral position to promote venous drainage.

Sedation with morphine, midazolam, propofol

Maintain normal lytes, control fevers.

• CSF drainage
• Cerebral perfusion pressure MAP-ICP maintain >60 mmHg.
• Fluids
• Vasopressors, dopamine, norepinephrine
• Ventilation adjust PCO2
• Mannitol

Question 9

a person in the ICU has ICP that is refractory to mannitol, midazolam, propofol, vent setting adequate w normal CO2, and MAP-ICP is maintained >60mmHg.

Even with all this, they still have high ICP.
Now what?

Answer 9

Treating refractory ICP

Treating REFRACTORY ICP

Hypothermia

Barbituate coma: decreases metabolic needs of brain, but there is a risk of hypotension

Decompressive craniectomies–> esp if we’re worried about malignant edeama

Question 10

T/F you should do aa pupil exam after giving sedatives and paralytics

Answer 10

false.Pupil Exam; should be performed after resuscitation, before administration of sedatives or paralytics. Afferent: optic nerve, Efferent: IIIrd CN palsy via midbrain.

Question 11

Pupil asymmetry: pupils that are greater than __mm difference in size are considered asymmetric

Fixed and dilated pupils: pupils that are greater than or equal to ___mm in diameter and constrict less than___mm in reaction to bright, direct light are considered fixed and dilated

Answer 11

Pupil asymmetry: pupils that are greater than 1mm difference in size are considered asymmetric

Fixed and dilated pupils: pupils that are greater than or equal to 4mm in diameter and constrict less than 1mm in reaction to bright, direct light are considered fixed and dilated

Question 12

If a GCS continues to lower, there is probably an expanding ___ ___

Answer 12

intracranial hematoma

Question 13

Outline the CT head rules for high and medium risk

Answer 13

CT only required in MINOR HEAD INJURY if one of the following:

• High Risk for neurosurgical intervention
• GCS score <15 at 2h after injury
• Suspected open of depressed skull fracture
• Any sign of basal skull fracture
• Vomiting two episodes
• Age 65 years+

Medium Risk (for brain injury on CT)

• I. Amnesia before impact >30 min
• Ii. Dangerous mechanism (peds vs car, ejected from car, fall from > 3feet or five stairs
• Iii. Not for non trauma, anticoagulants, GCS< 13,
• Age < 16
• Obvious open fracture

Question 14

__ is a significant cause of morbidity (60 fold higher mortality) and mortality in neurosurgical patients

Answer 14

Clinical signs as sodium levels worsen may include impaired response to stimuli, respiratory insufficiency, bradycardia, pupillary dilation

Left untreated, hyponatremia may result in seizures, cerebral edema, apnea, coma and death

Hyponatremia is a cause of refractory increased ICP in TBI patients.

Cerebral ischemia occurred in 25% of patients without hyponatremia corrected vs 12% in patients who had their hyponatremia corrected.

Question 15

__ __ are the most common post traumatic hematoma in children, with 65-75% of them being associated with a skull fracture.

Answer 15

Epidural hematomas are the most common post traumatic hematoma in children, with 65-75% of them being associated with a skull fracture.

Question 16

How are sport concussions graded

Answer 16

1-3:

1→ transient confusion <15 minutes duration

2→ transient confusion >15 minutes

3→ any loss of consciousness

Complications:

Post concussive syndrome; relatively uncommon, but can last from weeks to months, has fatigue, low energy, poor concentration→ can be activity induced

Second impact syndrome; severe life threatening cerebral swelling with repeat brain injury soon after first.