GCS and coma

Question 1

What does the GCS assess?

Answer 1

The total GCS score is the sum of points from eye opening, verbal response, and motor response scores (from 3 to 15 points total)

Question 2

GCS - eye opening

Answer 2

Eye opening: spontaneous (4 points), to verbal command (3 points), to painful stimulation (2 points), none (1 point)

Question 3

GCS - motor response

Answer 3

Motor response: obeys verbal commands (6 points), localises to painful stimulus (5 points), flexor withdrawal to painful stimulus (4 points), decorticate (abnormal flexion) response to painful stimulus (3 points), decerebrate (abnormal extensor) response to painful stimulus (2 points), none (1 point)

Question 4

GCS - verbal response

Answer 4

Verbal response: oriented conversation (5 points), disorientated conversation (4 points), inappropriate words (3 points), incomprehensible sounds (2 points), none (1 point).

Question 5

Assessment of head injury

Answer 5

Head injuries can be classified as mild (GCS 13-15), moderate (GCS 8-13) and severe (GCS <8).

Question 6

Head injury - red flags for CT

Answer 6

• GCS < 13
• Skull base fracture should be suspected in patients with racoon eyes (periorbital ecchymosis),
  battle sign (post-auricular ecchymosis), CSF/blood leaking from nose/ears or haemotympanum
• Depressed skull fractures indicate high velocity injuries and the possibility of underlying damage to brain tissue
• lucid interval = extradural haematoma
• Post-traumatic seizure
• Focal neurological deficit
• current warfarin treatment

Question 7

What is coma?

Answer 7

Unrousabl unresponsiveness. There is an inability to waken and do not react to external stimuli.

Results from disturbance in the function of EITHER the brainstem reticular activating system above the mid pons OR of BOTH cerebral hemispheres.

Normally GCS < 8

“Total absence of awareness of both self
and the external environment”

Question 8

Causes of coma

Answer 8

Metabolic - such as hyponatremia (casues osmotic changes in the brain leading to cerebral oedema), uremia, drugs, alcohol, hyper or hypoglycaemia, hypoxia, hepatic encephalopathy and addisonian crisis.

Neurological – trauma, infection (such as meningitis and encephalitis), neoplasm, seizures.

Vascular – such as stroke, SAH, SDH, malignant MCA.

CO2 and CO excess

Question 9

Coma Hx

Time course/onset of coma

Answer 9

• A sudden onset of coma suggests: seizure or vascular origin –> especially a brainstem stroke or SAH.
• Rapid progression from hemispheric signs, such as hemiparesis, hemisensory deficit, or aphasia, to coma within min to hours = intracerebral haemorrhage
• Longer course (days to weeks or more) = 1. Tumor. 2. Abscess. 3. Chronic subdural hematoma.
• Coma preceded by a confusional state or delirium = metabolic or infection (meningitis, encephalitis)
• severe headaches before coma = trauma, SAH (thunderclap) or meningitis
• progressive headache, worse in morning, vomiting = raised ICP eg tumour

Question 10

Coma Assessment

Answer 10

A (secure airway), B (RR, ABG), C (CRP, BP, IV access)
D: - carry out GCS
- pupillary reflex: assess CN 2 and 3. pinpoint (miosis) indicates opiate OD, unresponsive dilated pupils indicate severe brainstem injury (poor prognosis)
- corneal reflex = look for blinking (CN 5 and 7)
- gag reflex = absence suggests medulla injury
- fundoscopy = papilloedema (sign of raised ICP)
- dont ever forget GLUCOSE

Question 11

Emergency management of the comatose patient - Immediately:

Answer 11

1. Ensure adequacy of airway (airway devices or endotracheal tube - GCS< 8 intubate), ventilation (give high flow oxygen), and circulation.
2. Draw blood for serum glucose, electrolytes, liver and renal function tests, PT, PTT, and FBC.
3. Start IV fuilds and administer 25g of dextrose, 100mg of thiamine, and 0.4-1.2mg of naloxone (opioid antagonist) IV.
4. Treat seizures.

Question 12

Metabolic coma - DDx

Answer 12

• Metabolic acidosis: 1. DKA. 2. Uremic encephalopathy.
  3. Lactic acidosis. 4. Methanol intoxication.
  5. Salicylate intoxication eg aspirin. 6. Sepsis (terminal).
• Respiratory acidosis: 1. Sedative drug intoxication.
  2. Pulmonary encephalopathy.
• Respiratory alkalosis: 1. Hepatic encephalopathy.
  2. Salicylate intoxication. 3. Sepsis.

Question 13

Pupil size - differentials

Answer 13

Small reactive = Metabolic encephalopathy, midbrain herniation
PP/Fixed = Pontine lesion, opiates, organophosphates
Dil/reactive = metabolic, midbrain, ecstasy, amphet’s
Dil/fixed = Ictal, Hypoxia, ischaemia, hypothermia, anticholinergics

Unequal pupils
Small/reactive = Horner’s
Dil / fixed = Uncal herniation, III nerve palsy