You find someone unresponsive, drowsy or behaving strangely. You do not yet know why, and the four commonest reversible causes need different things. This chapter is organised the way the problem actually presents — by what you see, not by what it turns out to be.
1. Seizures
Most seizures stop on their own within two minutes and need nothing but protection and time.
- Do: note the time it started, cushion the head, move hard objects away, loosen anything tight at the neck. Afterwards, recovery position, and stay until they are fully oriented — which commonly takes 10–30 minutes.
- Do not: restrain them, move them unless they are in danger, or put anything in the mouth. Nobody swallows their tongue; you will break teeth or fingers.
Call 999 for a seizure if
- It lasts more than five minutes, or a second follows without full recovery in between — this is status epilepticus and it is a time-critical emergency.
- It is their first ever seizure.
- They are injured, the seizure happened in water, or they are pregnant or diabetic.
- They do not regain consciousness properly, or breathing does not return to normal.
- Otherwise, a known epileptic with a typical seizure that self-terminates does not automatically need an ambulance — and calling one every time is a real burden on people who have several a month.
Febrile convulsions, in children roughly 6 months to 5 years, are frightening and usually benign. Same management: protect, time it, recovery position. Call 999 for a first one, one lasting over five minutes, or a child who does not recover quickly. Cooling the child does not prevent recurrence, and stripping and fanning a shivering child is not a treatment.
2. Stroke
FAST — Face, Arm, Speech, Time — catches most strokes at the front of the brain and is close to blind to the roughly one in five affecting the back, which present as sudden vertigo, double vision or unsteadiness and get called labyrinthitis. Note the time they were last definitely normal, give nothing by mouth and no aspirin, and call 999.
Stroke has its own chapter, because the treatment windows, the drugs, the risks, the search for a cause and the prevention of a second one are more than a section can hold: stroke.
3. Diabetic emergencies
| Hypoglycaemia | DKA / hyperglycaemia | |
|---|---|---|
| Speed | Minutes. Sudden | Hours to days. Gradual |
| Looks like | Sweaty, pale, shaky, irritable or aggressive, confused, slurred speech. Frequently mistaken for drunkenness | Thirst, passing large volumes of urine, weight loss, abdominal pain, vomiting, deep sighing breathing, a sweet or pear-drop smell, drowsiness |
| Glucose | Below 4.0 mmol/L | Usually high, but can be near normal — euglycaemic DKA occurs in people on SGLT2 inhibitors |
| Do | Fast-acting sugar if fully alert — glucose tablets, juice, non-diet cola. Recheck at 15 minutes, repeat, then a longer-acting carbohydrate | 999. This needs fluids and insulin in hospital |
| Do not | Nothing by mouth if drowsy or not fully alert — 999 instead. Do not give insulin | Do not give sugar. Do not assume they are drunk |
If you cannot tell which it is and cannot measure, treat as hypoglycaemia. Sugar given to someone in DKA makes very little difference over the minutes before the ambulance. Sugar withheld from someone hypoglycaemic can cause brain injury.
DKA in someone not yet diagnosed is the version that kills, particularly in children. Thirst, weight loss, passing urine constantly and abdominal pain over a week or two get attributed to a virus or growing pains, and the child presents collapsed. Any child with those symptoms needs a finger-prick glucose the same day — it takes thirty seconds and it is the single test that prevents this.
4. Opioid overdose and naloxone
The lethal event is respiratory depression: breathing slows, then stops, and the heart follows. The classic picture is pinpoint pupils, unresponsive, and slow or absent breathing.
- Naloxone reverses it, and anyone can give it in an emergency. UK law permits any person to administer naloxone to save a life. It is still a prescription-only medicine, so pharmacies cannot sell it over the counter — but since December 2024 a much wider group can supply take-home and carry-with-you kits without a prescription, including drug services, pharmacy professionals, registered nurses and midwives, paramedics, police, prison and probation staff.
- It does nothing if there are no opioids on board, which is why giving it on suspicion is reasonable.
- Rescue breaths matter more than the naloxone. The person is dying of not breathing. If they are not breathing normally, that is the emergency, and naloxone is an adjunct to airway and breathing support rather than a substitute for it.
- It wears off before the opioid does — often in 20 to 90 minutes, against opioids lasting far longer. They can stop breathing again after waking up. This is why 999 is not optional even when the reversal looks complete, and why walking away from someone who has "come round" is dangerous.
- Synthetic opioids may need repeated doses. Fentanyl and the nitazenes now in the UK supply are potent enough that one dose is often not enough. Keep going with further doses and with breaths.
- Expect precipitated withdrawal — they may wake agitated, nauseated and angry. Unpleasant, not dangerous, and not a reason to withhold it.