No. Delirium is caused by physical illness, injury, surgery or medicines. Almost nobody spots it early, including people who work in hospitals.
Nearly every family asks some version of this, and usually not out loud. We should have visited more. We should have pushed harder at the GP. We noticed she was not herself last Tuesday and did nothing about it. We let him have the operation.
Was it the operation?
Agreeing to an operation that was needed is not a mistake. Delirium afterwards is a known complication of surgery in older people, not the result of a wrong decision.
The same goes for hospital admission. Hospital wards do make delirium more likely, and that is a fair criticism of how wards are run. But getting someone treated for the illness that was making them ill was the right call.
Why delirium is so often missed
Delirium is missed most of the time, and it is missed by trained staff with a screening tool in their hand.
There are good reasons for that. Delirium comes and goes, so anyone who sees the person during a good hour sees nothing wrong. The commonest form is the quiet one, where someone is withdrawn and sleepy rather than agitated, and quiet patients do not attract attention. And the early signs look like ordinary tiredness, or old age, or simply being somewhere unfamiliar.
If you raised it and were not listened to
Some families do notice, say something, and are not listened to. If that is what happened, the failure was not yours. Say it again, to a different person, and use the word: this is not how she normally is, and I think it might be delirium.
What you can do now
Tell the team what normal looks like for this person, because they have no way of knowing. Be there when you can. And make sure the word delirium is in the discharge letter and known to the GP, because a past episode is the strongest warning sign for another one.
The illness caused this.
When to get help
New confusion that has come on over hours or days needs medical advice the same day. Phone the GP practice, or 111 when it is closed. Phone 999 if the person cannot be woken, has collapsed, or has new weakness or new trouble speaking. When you speak to someone, say what has changed. Then ask: could it be delirium?