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:
Severe chest pain, fainting, or major difficulty breathing
A very fast or irregular heartbeat with dizziness or weakness
High fever with confusion, severe agitation, vomiting, or diarrhea
Sudden severe worsening in someone known to have hyperthyroidism
These symptoms can have causes other than hyperthyroidism, but they need immediate assessment.
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
Contact your healthcare service promptly if you are pregnant or planning pregnancy and have known or possible hyperthyroidism.
Treatment and monitoring may need to be adjusted.
Seek urgent same-day advice if you take an antithyroid medicine and develop fever, a severe sore throat, mouth ulcers, yellow skin or eyes, or dark urine.
You may need urgent blood tests.
Get urgent eye care for new double vision, changes in colour vision, reduced vision, or difficulty closing your eyelids.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you have ongoing symptoms such as an unexplained fast heartbeat, shakiness, heat intolerance, weight loss, neck swelling, or frequent bowel movements.
These symptoms have many possible causes, and blood tests can help clarify what is happening.
Every sign above is quoted from the sofidex article on Hyperthyroidism. If you are not sure, err upward — it is always reasonable to be checked.