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
Seek emergency care if you have:
New or worsening difficulty breathing
Noisy, high-pitched breathing
Rapid neck swelling that is affecting your airway
Inability to swallow saliva
Chest pain, fainting, or a severe sustained rapid heartbeat
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 a nodule enlarges quickly, becomes painful, or is accompanied by fever.
Sudden swelling can sometimes result from bleeding into a cyst and should be assessed, particularly if you take medicines that affect blood clotting.
These symptoms are uncommon, but they require urgent assessment rather than waiting for a routine thyroid appointment.
3
Does any of this apply?
Book an appointment
Arrange a routine medical appointment if you discover a new neck lump or notice that a known thyroid nodule is growing.
Also seek assessment for persistent hoarseness, repeated difficulty swallowing, unexplained symptoms of an overactive thyroid, or enlarged lymph nodes in your neck.
Every sign above is quoted from the sofidex article on Thyroid nodule. If you are not sure, err upward — it is always reasonable to be checked.