Causes Clinical features Investigations Immediate management Prevention Prognosis

Clinical features Ask ambulance crews, family, friends and clinicians who know the patient about known allergies d recent symptoms d recent head injury d speed of onset of coma d previous episodes of coma d medical history d drug use d If you suspect an opiate overdose, ask about b drug paraphernalia where the patient was found needle track marks on skin history of iv drug use by bystanders Look for evidence of head injury d drug overdose d uraemia or other metabolic derangement d malignancy c stroke or cerebral haemorrhage c infection (brain, meninges, sepsis) c hypertension c If you suspect an opiate overdose, look for: b a reduced respiratory rate pinpoint pupils   Look for raised intracranial pressure by assessing the fundi. Look for: papilloedema d retinal vein pulsation c changes associated with diabetes or hypertension d Assess brainstem function d corneal reflex oculocephalic reflex (if no cervical spine trauma).  Rotate head from side to side; if the brainstem is intact, the eyes will move conjugately in the opposite direction from head rotation oculovestibular reflex (if unruptured tympanic membrane)  Inject 200mls of iced water into one external auditory meatus. A normal response is slow phase of nystagmus towards the irrigated ear)

Expiry date: September 2003
Levels of Evidence used in grading these guides