Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Seek emergency help if you or someone with possible NDI:
Cannot drink enough to replace ongoing urine losses
Becomes confused, very drowsy, or difficult to wake
Has a seizure or collapses
Has severe weakness or loss of coordination
Is an infant with marked sleepiness, poor feeding, or signs of dehydration
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Children should be assessed promptly for constant thirst, unusually heavy wet diapers, poor feeding, repeated unexplained fever, vomiting, constipation, poor weight gain, or slower growth.
Contact your care team promptly if you have known NDI and develop vomiting, diarrhea, fever, reduced access to water, or a clear change in urine output.
You may need changes to your fluid plan, medicines, or monitoring.
3
Does any of this apply?
Book an appointment
Arrange a routine medical appointment if you develop persistent excessive thirst, repeatedly wake to urinate, or pass much more urine than usual.
These symptoms need assessment even if you can keep up by drinking.
The article also says
A person who is confused or unconscious should not be forced to drink because of the risk of choking.
Every sign above is quoted from the sofidex article on Nephrogenic diabetes insipidus. If you are not sure, err upward — it is always reasonable to be checked.