83. Unconscious patient

Question 1

An adult male is found collapsed at home with a decreased level of
consciousness. He is brought to the accident department where his
Glasgow Coma Score is 5/15.
What are the possible causes of his comatose state?

Answer 1

An exhaustive list will not be required, but a sensible and systematic
approach looked for. Have a system for categorising your answer.
Listed below is one method. Another would be:

Trauma

Infection

Metabolic

Tumour

Drugs

Vascular – Ischaemia/haemorrhage.

Question 2

Consciousness depends on:

Answer 2

Intact cerebral hemispheres

A functioning
reticular activating system in the brainstem,
the midbrain,
the hypothalamus and the thalamus.

NB: Focal damage to the cortex does not affect conscious level.

Question 3

Diffuse brain insult

Answer 3

Diabetic coma

Hyponatraemia

Hypoxia (due to respiratory insufficiency or blood loss, etc.)

Uraemia

Hepatic encephalopathy

Infection, e.g. meningitis

Post-ictal state

Question 4

Brainstem pathology

Answer 4

Subarachnoid haemorrhage

Ischaemic event

Intra-cerebral bleed

Drugs (hypnotics / sedatives)

Tonsillar herniation

Compression by tumour

Question 5

Midbrain pathology

Answer 5

Compression by supratentorial mass

Question 6

Trauma leads to loss of consciousness

Answer 6

by global ischaemic damage
(e.g. extradural haematoma causing raised ICP and decreased CPP)

or by pressure on the brainstem.

Question 7

How would you manage this patient in the accident department?

Answer 7

ABC approach to resuscitation

With a GCS of 5, the patient is comatose (GCS≤8) and not able to protect his
airway. He should therefore be intubated and ventilated. Treatment should
aim to prevent any secondary brain injury.

History from any family/paramedics/nursing staff. Ask about:
Speed of onset (sudden onset suggests vascular cause)
Self-poisoning
Trauma
PMH, e.g. epilepsy or diabetes

Question 8

Examination

Answer 8

General
Pulse
Blood pressure
Respiratory rate

Neurological signs
Lateralising signs
Pupillary responses

Infection
Temperature
Neck stiffness
Rash

Question 9

Investigations

Answer 9

will be directed by the history and examination

Trauma → CT scan

Self-poisoning → Toxicology screen

Metabolic cause → Urea and electrolytes

Blood glucose

Arterial blood gases

Blood cultures

Infection → Lumbar puncture

Question 10

The diagnosis

Answer 10

may not be immediately obvious and further tests for unusual
conditions may be needed

(e.g. thyroid function tests, porphyrins, serum calcium).

This will not alter resuscitation and supportive treatment.