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
Go to an emergency department promptly if the child is very unwell, unusually sleepy or difficult to wake, or has severe pain with fever and cannot move the leg.
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
Seek urgent same-day medical care if the child:
Has a fever with hip or leg pain
Cannot stand or put any weight on the leg
Has severe or rapidly worsening pain
Has a swollen, red or unusually warm joint
Recently had a significant fall or injury
Has pain that wakes them repeatedly at night
Appears generally unwell
These features may indicate a joint or bone infection that needs urgent treatment.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up if symptoms are not clearly improving after two or three days, have not resolved within one or two weeks, or return after recovery.
Earlier review is appropriate whenever the course differs from the plan given at the first assessment.
The article also says
A new unexplained limp or refusal to walk should be medically assessed, particularly in a young child who cannot explain the pain.
Do not assume that hip, thigh or knee pain is toxic synovitis without an evaluation.
Every sign above is quoted from the sofidex article on Toxic synovitis. If you are not sure, err upward — it is always reasonable to be checked.