Hashimoto thyroiditis and hyperthyroidism: what to know

Hashimoto thyroiditis is an immune condition affecting the thyroid. In an early inflammatory phase, damaged thyroid cells may release hormone already stored in the gland. This can produce symptoms of hyperthyroidism, such as a racing or irregular heartbeat, feeling anxious, sweating more, heat intolerance, loose stools, or difficulty sleeping. The gland is not necessarily making extra hormone at this stage. As stored hormone clears, thyroid levels may fall and the condition can move towards an underactive phase. Blood tests usually include thyroid-stimulating hormone and free thyroid hormones; antibody testing and examination may add context.

Arrange a medical review for thyroid blood tests and a plan to repeat them. Record palpitations, bowel changes, sleep disruption, sweating, weight change, and medicines or supplements that may affect results. Take prescribed treatment exactly as directed, and do not start iodine products or thyroid medicines without advice. Rest, drink fluids, and limit stimulants if they make your heartbeat or anxiety worse. A clinician may focus on symptom relief while the inflammatory phase settles, then monitor for a later underactive thyroid.

Seek urgent help for chest pain, severe breathlessness, fainting, confusion, or a very fast or irregular heartbeat that does not settle. Contact a clinician promptly if symptoms are worsening, you are pregnant, or you have known heart disease. A sudden deterioration with fever, marked agitation, vomiting, or extreme weakness needs emergency assessment.

Ask which thyroid results show the current phase, when testing should be repeated, whether your symptoms need treatment, and how you will be monitored for hypothyroidism.