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 possible signs of a heart attack, including chest pressure or tightness that does not settle, particularly with breathlessness, sweating, nausea, or pain spreading to the arm, jaw, back, or stomach.
Call emergency services immediately, even if the symptoms improve.
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 prompt medical advice for severe or worsening muscle weakness, especially if you also have dark urine, fever, or feel very unwell while taking cholesterol-lowering medicine.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if:
A cholesterol test is high and has not been reviewed
A close relative has FH or very high cholesterol
A parent, sibling, or child developed heart disease or had a stroke unusually young
You notice firm tendon swellings or yellow patches around your eyes
You are having side effects or difficulty taking prescribed treatment
You want to understand when your cholesterol should be rechecked
The article also says
Sudden facial drooping, arm weakness, speech difficulty, loss of vision, severe imbalance, or one-sided numbness may be signs of a stroke.
Every sign above is quoted from the sofidex article on High cholesterol. If you are not sure, err upward — it is always reasonable to be checked.