Hyperthyroidism
Also known as Overactive thyroid, Thyrotoxicosis
This article is general health information for the selected condition. It is not a diagnosis and does not replace clinical judgement. If you have questions or need treatment advice, please consult a qualified healthcare professional.
What is hyperthyroidism?
Hyperthyroidism means the thyroid produces too much hormone, accelerating metabolism. Graves disease, an autoimmune condition, is the most common cause. Symptoms of weight loss, anxiety and palpitations are often attributed to stress, which delays diagnosis. It is confirmed by a simple blood test and is very treatable.
Causes
- Graves disease, an autoimmune stimulation of the thyroid
- Toxic multinodular goitre
- A single overactive thyroid nodule
- Thyroiditis, including after pregnancy
- Excess thyroid hormone medication
- Iodine excess including from amiodarone
Symptoms
- Weight loss despite a good or increased appetite
- Palpitations or a fast irregular heartbeat
- Anxiety, irritability and restlessness
- Heat intolerance and excessive sweating
- Tremor of the hands
- Frequent bowel movements
- Difficulty sleeping and muscle weakness
- Bulging eyes or eye discomfort in Graves disease
Risk factors
- Female sex
- Family history of thyroid or autoimmune disease
- Recent pregnancy
- Smoking, particularly for eye disease in Graves
- Other autoimmune conditions
- High iodine intake
Diagnosis
- Suppressed TSH with raised free T4 or T3
- Thyroid receptor antibodies for Graves disease
- Thyroid ultrasound
- Radioactive iodine uptake scan to identify the cause
- ECG if the heart rate is irregular
Treatment
- Antithyroid medicines such as carbimazole
- Beta blockers for symptom relief while awaiting effect
- Radioactive iodine treatment
- Surgery to remove part or all of the thyroid
- Specialist eye care for thyroid eye disease
- Stopping smoking, which worsens eye disease considerably
Self care
- Take antithyroid medicine consistently and attend blood tests
- Report sore throat, mouth ulcers or fever urgently while on carbimazole
- Stop smoking, especially with eye involvement
- Use lubricating eye drops and sunglasses for eye symptoms
- Sleep with the head raised if the eyes are puffy
- Reduce caffeine while your heart rate is fast
- Rest during the early weeks of treatment
When to see a doctor
Book an appointment if:
- Unexplained weight loss with a fast heartbeat
- Persistent anxiety with tremor and heat intolerance
- Neck swelling
- Eye changes including bulging, double vision or pain
- Symptoms returning after treatment
- Planning pregnancy, since treatment needs adjusting
Some symptoms need emergency care rather than an appointment. See the warning signs listed above.
Prevention
- Hyperthyroidism cannot usually be prevented
- Stopping smoking reduces the risk of severe eye disease
- Avoid excess iodine supplements
- Regular monitoring if taking thyroid hormone replacement
- Family screening where several relatives are affected
Outlook
Treatment controls hyperthyroidism effectively. Around half of people with Graves disease remain well after a course of antithyroid medicine, while others need radioactive iodine or surgery, which are definitive but usually lead to lifelong thyroid hormone replacement. Eye disease follows its own course and can persist after thyroid levels normalise, particularly in smokers.
Common questions
Why must I report a sore throat on carbimazole?
Carbimazole rarely causes agranulocytosis, a sudden drop in infection fighting white cells. A sore throat, mouth ulcers or fever needs an urgent blood count the same day, because untreated it can be life threatening.
What is thyroid storm?
A rare emergency where thyroid hormone levels surge, causing high fever, a very fast heart rate, agitation and confusion, often triggered by infection or surgery. It requires immediate hospital treatment.
References
Important: Dard AI is not a medical device and does not diagnose, treat, or replace clinician judgement. This article is general information only. Always consult a qualified healthcare professional about diagnosis and treatment, and seek emergency care for severe or rapidly worsening symptoms.