Synopsis
Protect the airway, reverse immediately treatable causes, and distinguish structural brain disease from systemic or toxic cerebral dysfunction.
- A glucose measurement belongs in the initial assessment of every unexplained reduction in consciousness.
- Record eye, verbal and motor Glasgow Coma Scale components, pupils and their trend; the total alone loses useful information.
- Alcohol on the breath or an apparent overdose does not exclude head injury, haemorrhage, infection or hypoglycaemia.
Investigation priorities
Identify a rapidly reversible substrate problem and assess ventilation or acidaemia.
Management branches
An insulin-treated adult becomes unconscious after a fall. Glucose is 2.1 mmol/L; IV access is present, breathing is adequate with airway support, and the left arm moves less than the right.
- Protect the airway, maintain cervical precautions appropriate to the fall, summon senior help and administer IV glucose immediately while another clinician records neurological findings.
- Give 200 mL of 10% glucose over 15 minutes, checking the prescribed volume so that a larger bag is not inadvertently infused. Recheck glucose ten minutes after treatment.
Key medicines
Glucose for severe hypoglycaemiaGive 200 mL of 10% glucose IV over 15 minutes, or 100 mL of 20% glucose over 15 minutes; both provide 20 g. Recheck glucose ten minutes later and repeat if it remains below 4 mmol/L.Check cannula patency and the exact volume. Consider the smaller volume in cardiac or renal failure. Once awake with glucose above 4 mmol/L, provide longer-acting carbohydrate and investigate recurrence risk.
Glucagon when IV access is unavailableGive 1 mg IM for severe insulin-associated hypoglycaemia while continuing attempts to obtain IV access.Response is less reliable with starvation, alcohol misuse, liver disease or sulfonylurea-associated hypoglycaemia. Recheck glucose and do not let unsuccessful glucagon delay IV glucose.