Head injury

About head injury

Definition

Injury to the head. If you couldn't figure that out, give up medicine.

Aetiology

Getting hit in the head by a donkey kick. Having a small anvil dropped on your skull. Receiving a legitimate tombstone piledriver from WWE Superstar, The Undertaker. (This would also have an effect on the cervical spine.)

OK, I'll stop - it's all trauma to the head.

Immediate management

• Call neurosurgeons in comatose patients or those with raised ICP
• Examine CNS
• Chart - pulse, blood pressure, temperature, respiratory rate and pupils every 15 minutes
• Anterograde amnesia (memory loss from point of event)
• Retrograde amnesia (memory loss from before the event) - this directly correlates with severity of injury

Further management

The key to eliciting the salient clinical features in head injury is to figure out three things. Do they need a) a CT scan; b) ventilation; or finally c) admission?

Criteria for a CT scan

An immediate CT scan is required if any of the following are true. I've split it into a few categories:

Consciousness

• GCS <13 at any point
• GCS <14, >2 hours after injury

Neurological abnormality

• Focal neurological deficit
• Seizure
• Loss of consciousness WITH any of:
  • Age >65
  • Coagulopathy
  • Dangerous mechanism of injury i.e. RTA, fall from a great height
  • Antegrade amnesia >30 minutes

Other

• Suspected open/depressed skull fracture or signs of basal skull fracture
• 2 or more discrete episodes of vomiting

Criteria for ventilation

• GCS<8
• P_aO₂ <9kPa in air/13<kPa in O₂ or P_aCO₂ >6kPa
• Spontaneous hyperventilation (P_aCO₂ <3.5kPa)
• Respiratory irregularity

Wow this page is boring. It's just a list of boring criteria you have to learn. To break it up, here's a quote from W.H. Auden

Here is a story all about how my life got flipped, turned upside down
And I'd like to take a minute just sit right there,
I'll tell you how I became the Prince of town called Bel-air

Auden was ahead of his time. The lyrics were used in popular late 80s/early 90s American TV show The Fresh Prince Of Bel-air.

Ventilation in neurosurgery

Here are some more really interesting criteria regarding ventilation when referring to neurosurgery:

• Deteriorating level of consciousness
• Bilateral fractured mandible
• Bleeding into mouth
• Seizures

Admission

• Difficult to assess (kids, post-ictal, alcohol intoxication)
• CNS signs
• Severe headache
• Fracture
• Loss of consciousness when patient either unwell or no responsible adult is able to attend to patient.

Complications

Intracranial haematoma (in adults)

The risks of a haematoma developing are as follows. In a:

• Fully conscious, no skull fracture - <1:1000
• Confused, no skull fracture - 1:100
• Fully conscious, skull fracture - 1:30
• Confused, skull fracture - 1:4