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
Call emergency services for a seizure, severe breathing difficulty, collapse, or loss of consciousness.
These symptoms can have many causes and should not be assumed to be rickets.
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 medical help if a child develops:
Painful muscle spasms or marked stiffness
Sudden worsening weakness
A suspected broken bone
Increasing difficulty breathing
Unusual sleepiness or reduced responsiveness
3
Does any of this apply?
Book an appointment
Arrange a routine medical assessment if a child has persistent or worsening bowed legs, bone pain, muscle weakness, delayed walking, slow growth, widened wrists or ankles, or repeated fractures.
Children with kidney, liver, or absorption conditions may need planned monitoring even when they feel well.
The article also says
Assessment is also appropriate if a child has risk factors for vitamin D or calcium deficiency and develops concerning symptoms.
Every sign above is quoted from the sofidex article on Rickets. If you are not sure, err upward — it is always reasonable to be checked.