26 Critical Care Emergencies
UNCONSCIOUS PATIENT(b) watch out for deterioration in the level of consciousness,
ultimately with the development of Cheyne–Stokes breathing
and a unilateral fixed, dilated pupil
(c) call an airway-skilled doctor to pass a cuffed endotracheal
tube if one is not already in place
(d) arrange an urgent head CT scan, and refer the patient
immediately to the neurosurgical team, before critical mass
lesion signs develop.DIAGNOSIS
1 The patient’s cardiorespiratory status should have been stabilized by this
stage, bloods sent, a blood sugar level checked, an in-dwelling catheter and a
nasogastric tube placed, and an ECG and CXR performed.
2 Now focus on the underlying cause.
The most common causes of an unconscious patient are:
(i) Poisoning (accidental or deliberate, including alcohol, carbon
monoxide).
(ii) Hypoglycaemia.
(iii) Post-ictal state.
(iv) Stroke.
(v) Head injury.
(vi) Subarachnoid haemorrhage.
(vii) Respiratory failure.
(viii) Hypotension (shock – see p. 15).
3 Less common causes of an unconscious patient are:
(i) Meningitis or encephalitis.
(ii) Hepatic or renal failure.
(iii) Septicaemia.
(iv) Subdural haematoma.
(v) Hyperglycaemia (diabetic ketoacidosis [DKA] or hyperglycaemic,
hyperosmolar non-ketotic syndrome [HHNS]).
(vi) Hypothermia or hyperthermia.
4 Rare causes of an unconscious patient are:
(i) Cerebral space-occupying lesion.
(ii) Hyponatraemia or hypercalcaemia.
(iii) Myxoedema.
(iv) Addison’s disease.
(v) Hypertensive encephalopathy.
5 Finally, in those who have recently been abroad, consider:
(i) Cerebral malaria.
(ii) Typhus, yellow fever, trypanosomiasis and typhoid.
(iii) Rabies, viral haemorrhagic fever.
(iv) Severe acute respiratory syndrome (SARS) or avian influenza (bird flu).