Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services immediately if someone with known or possible hyperthyroidism has a high fever together with a very fast heartbeat, confusion, severe agitation, fainting, seizures, breathing difficulty, repeated vomiting, or extreme drowsiness.
Do not drive yourself if you may be seriously unwell.
Emergency assessment is also needed for chest pain, severe shortness of breath, collapse, or loss of consciousness, whether or not a thyroid problem is known.
Seek urgent same-day medical advice if hyperthyroid symptoms are rapidly worsening, an infection is accompanied by a racing heartbeat, or vomiting means prescribed thyroid medicine cannot be kept down.
Routine follow-up is appropriate for stable symptoms, planned thyroid blood tests, medicine reviews, and discussion of longer-term treatment after recovery.
New palpitations, unexplained weight loss, heat intolerance, or persistent shaking should be assessed, but these symptoms alone do not prove thyroid storm.
Every sign above is quoted from the sofidex article on Thyroid storm. If you are not sure, err upward — it is always reasonable to be checked.