When to seek urgent help

How to use this page

Most thyroid symptoms are uncomfortable rather than urgent, and most of the time the right step is to contact your GP or thyroid team in the usual way. But there are situations where you should not wait. The list below is not a diagnostic tool - it's a prompt to seek help without delay when certain things happen.

Call 999 or go to A&E immediately

• Chest pain, pressure, or tightness - especially alongside breathlessness, sweating, or pain spreading to your arm, jaw, or back.
• Sudden severe breathlessness that is getting worse quickly.
• Fainting or collapse, or feeling as though you are about to lose consciousness.
• Very fast or severely irregular heartbeat combined with feeling unwell - for example, feeling faint, breathless, or having chest pain. A racing heart alone can sometimes be a thyroid symptom to discuss with your team, but when it comes with these other feelings, do not wait.
• Sudden, severe swelling in the neck or difficulty breathing or swallowing after thyroid surgery - this needs emergency assessment immediately.
• Confusion or agitation, a very high fever, a racing or irregular heartbeat, or feeling extremely unwell if you have known or suspected hyperthyroidism - in rare cases, severely uncontrolled hyperthyroidism can tip into a dangerous emergency called a thyroid storm. Trust your instincts: if something feels very wrong, call 999.

After thyroid surgery: symptoms to take seriously

In the days after a thyroidectomy, the parathyroid glands - which sit near the thyroid - can occasionally be affected, causing calcium levels to fall. Symptoms of low calcium include:

• tingling or numbness around the lips, hands, or feet
• muscle cramps or spasms
• twitching or trembling

If you experience these after surgery, contact your surgical team or ward immediately. If you cannot reach them and symptoms are severe, go to A&E and explain you have recently had thyroid surgery.

If you are taking antithyroid medication (carbimazole or propylthiouracil)

A sore throat, mouth ulcers, a fever, flu-like symptoms, or unusual bruising or bleeding while taking carbimazole or propylthiouracil can very occasionally signal a rare but serious drop in white blood cells (agranulocytosis). Do not wait and see:

• This is the safety instruction your prescribing team should have given you when you started: stop the medication and go to A&E or call 111 straight away for an urgent blood test (a full blood count).

If you are unsure whether this applies to your medication, call 111.

Contact your GP or thyroid team urgently (same day or next day)

These situations are not 999 emergencies for most people, but they should not be left until a routine appointment:

• Palpitations (awareness of your heartbeat) that are new, persistent, or feel different from usual.
• Feeling very unwell in a way you cannot explain, especially if your thyroid condition is not well controlled.
• Any new or rapidly changing neck swelling.
• Signs of a significant mood change, including feeling very low, not coping, or thoughts of self-harm.

For anything emotional or mental health-related, there are free support lines available around the clock - no referral needed.

This site has limits - and that's important

ThyroidTools is a patient-led educational resource. It cannot assess your symptoms, interpret your results, or tell you what is wrong. These are things only a clinician can do. We aim to give you the knowledge to advocate for yourself - including knowing when to step away from a website and pick up the phone or call 999.

If you are ever unsure whether something needs urgent attention, err on the side of getting help. You can also use the questions tool to prepare for appointments when things are not urgent.