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
Get emergency help for severe breathing difficulty, fainting, extreme drowsiness, new severe confusion, mottled or unusually pale skin, or rapidly worsening illness.
These can be signs of sepsis or another serious problem.
And for anyone, someone who:
is bleeding heavily and it will not stop with firm pressure
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 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
Arrange prompt medical advice if you have typical cystitis symptoms and are pregnant, male, a child, or have kidney disease, diabetes, a urinary catheter, a weakened immune system, or known urinary tract problems.
Seek same-day medical assessment if you develop:
Fever, shaking chills, or feeling markedly unwell
Pain in your side or back below the ribs
Repeated vomiting or difficulty keeping fluids down
Worsening symptoms despite treatment
Inability to urinate
Significant blood or blood clots in the urine
And for anyone, someone who:
has a wound that is hot, spreading red, or leaking pus
3
Does any of this apply?
Book an appointment
Routine follow-up is appropriate if symptoms have not started improving within about 48 hours of antibiotics, return soon after treatment, or keep recurring.
Persistent blood in the urine also needs follow-up after the suspected infection has cleared.
Every sign above is quoted from the sofidex article on Cystitis - acute. If you are not sure, err upward — it is always reasonable to be checked.