Head Injuries

Question 1

What is the mean arterial blood pressure?

Answer 1

60-160mmHg

Question 2

What is the cerebral perfusion pressure (CPP) equation?

Answer 2

Cerebral Perfusion Pressure (CPP) = Mean Arterial Pressure (MAP) - Intracranial Pressure (ICP) (pressure inside the skull and thus brain tissue and CSF)

Question 3

What does the Monro-Kellie doctrine state?

Answer 3

That the cranial vault is a fixed space (the sum of volumes of brain, cerebrospinal fluid (CSF) and intracerebral blood is constant i.e. an increase in one should cause a decrease in another.

Question 4

State 3 clinical features of an increased ICP.

Answer 4

Vomiting. Headaches. Seizures. Reduced GCS. Cushing ‘s triad (hypertension, bradycardia and irregular respirations). Dilated pupils. Contralateral hemiparesis (weakness on one side of body). Focal neurology (CNS impairments e.g. weakness in left arm. Cerebral oedema. Herniation.

Question 5

What is meant by herniation?

Answer 5

Very high pressures within skull, therefore brain squeezed across structures.

Question 6

State the 3 types of brain herniation.

Answer 6

Uncal. Central. Subfalcine.

Question 7

State 3 signs of uncal herniation.

Answer 7

Dilated pupil (mydriasis). Ptosis (droopy eyelid - paralysis of levator papebrae superiorsis muscles). ‘Down and out’ position of eye due paralysis of superior, medial, inferior rectus and inferior oblique muscles. Contralateral hemiparesis due to compression of corticospinal tract.

Question 8

What is a primary brain injury?

Answer 8

It’s when there is immediate damage to brain tissue from initial trauma/insult.

Question 9

What is secondary brain injury?

Answer 9

It’s when the brain injury forms hours/days after damage (due to oedema, ischaemia, mass effect). It’s caused by systemic insults e.g. hypovolaemia, hypoxia, hypercapnia, acidosis, hyperglycaemia, hyperthermia.

Question 10

What 3 things should you check for with airways and breathing?

Answer 10

1) ensure adequate oxygenation (>92%) 2) aim for PaCO2 in normal range (PaCO2 2.5-5kPa)

Question 11

What mean arterial pressure (MAP) should you check for?

Answer 11

MAP greater than 80mmHg.

Question 12

State 3 things you should check for under disability.

Answer 12

1) pupils (look for palsy/droopy eyelid) 2) GCS less than 8 3) check blood pressure 4) check blood glucose

Question 13

What are the 3 parts to the Glasgow Coma Score (GCS)?

Answer 13

1) Eye opening response 2) Verbal response 3) Motor response.

Question 14

How should we treat seizures?

Answer 14

Lorazepam +/- phenytoin.

Question 15

Why should you position patients at 30 degrees?

Answer 15

To reduce intracranial pressure (ICP).

Question 16

State 2 things to think about in regards to exposure.

Answer 16

1) pain management to avoid increases in ICP 2) think about infection control (wound management) 3) control temperature

Question 17

State 3 signs of a basal skull fracture.

Answer 17

1) battle’s sign (indication of a fracture of the middle cranial fossa of skull) 2) panda’s eyes 3) haemotympanum (blood in the tympanic cavity) 4) CSF ottorrhea/rhinorrhea (discharge from the ear)

Question 18

What colour does new blood appear in CT scan?

Answer 18

White.

Question 19

What colour does older blood appear in CT scan?

Answer 19

Grey.

Question 20

What type of haemorrhage results in a biconvex shape on CT scan and a lucid interval (temporary improvement in patients consciousness)?

Answer 20

Extradural haemorrhage.

Question 21

Which type of haemorrhage appears crescent shaped on the CT scan, and is normally caused by a road-traffic accident?

Answer 21

(Acute) Subdural haemorrhage.

Question 22

How is a subarachnoid haemorrhage normally treated?

Answer 22

Nimodipine 60mg (taken orally/or via NG tube to prevent and treat neurological defects).

Question 23

How does a subarachnoid haemorrhage appear on a CT scan?

Answer 23

White appearance in ventricles.

Question 24

Which arteries does a subarachnoid haemorrhage affect?

Answer 24

Leptomeningeal arteries and veins.

Question 25

How does a intracerebral haemorrhage appear on a CT scan?

Answer 25

Mass on a CT scan. (Location and size determine the neurological signs).

Question 26

What is a cerebral contusion?

Answer 26

Is a bruise to the brain tissue.

Question 27

How does a cerebral contusion appear on a CT scan?

Answer 27

Small bleeds (white spots on a CT scan). Often frontal/temporal due to impact of brain tissue with sphenoid ridge/orbital plates.

Question 28

What is a diffuse axonal injury?

Answer 28

It happens when the brain rapidly shifts inside the skull - accelerating/decelerating cause shearing/severing of neuronal axons. Use an MRI.

Question 29

What is a concussion?

Answer 29

Stretching of white matter fibres.

Question 30

State 3 symptoms of a concussion.

Answer 30

Nausea. Amnesia. Confusion. Loss of consciousness. Dizziness. Lack of concentration.

Question 31

State 3 reasons to return to the ED.

Answer 31

Increased drowsiness. Unconsciousness. Worsening headache. Confusion. Vomiting. Focal neurological problems. Dizziness. Seizures. Any visual problems such as blurring of vision. Blood leaking from the nose/ear.