PATIENT EDUCATION
Thyroid Disorders
Thyroid hormone affects energy use, heart rate, temperature control, bowel function, menstrual cycles and many other body systems. Both underactive and overactive thyroid conditions can cause symptoms that overlap with other illnesses.
Select a topic below to view more information.
Englishதமிழ்हिन्दी
Tiredness, Feeling Cold or Weight Gain
What you'll notice or feel
- Persistent fatigue or slowed thinking.
- Feeling colder than people around you.
- Constipation, dry skin or hair changes.
- Weight gain that is not fully explained by lifestyle change.
Common causes
- An underactive thyroid (hypothyroidism).
- Autoimmune thyroid disease such as Hashimoto disease.
- Previous thyroid surgery, radioactive iodine or some medicines.
- Non-thyroid causes such as anaemia, sleep problems or depression.
What it could be
- Hypothyroidism confirmed by thyroid-function testing.
- Temporary thyroid dysfunction after thyroiditis.
- Another cause if thyroid tests are normal.
Initial self-care
- Arrange thyroid-function testing rather than treating symptoms alone.
- Take prescribed thyroid medicine consistently and as directed.
- Do not change dose based on symptoms without checking blood tests.
- Keep a list of supplements because some can interfere with thyroid tests or treatment.
When to see a doctor urgently
- Marked drowsiness, confusion, very low body temperature or severe deterioration.
- Severe breathlessness, collapse or chest symptoms.
When to see a doctor
- Symptoms persist for several weeks.
- You are already on thyroid replacement and symptoms or blood tests have changed.
- You are pregnant or planning pregnancy and have known thyroid disease.
Palpitations, Heat Intolerance or Weight Loss
What you'll notice or feel
- Fast heartbeat, palpitations or tremor.
- Feeling unusually hot or sweaty.
- Weight loss despite normal or increased appetite.
- Anxiety, irritability, loose stools or difficulty sleeping.
Common causes
- An overactive thyroid (hyperthyroidism).
- Graves disease.
- An overactive thyroid nodule or multinodular goitre.
- Temporary thyroiditis or excessive thyroid replacement.
What it could be
- Hyperthyroidism requiring confirmation with TSH and thyroid hormone measurements.
- Thyroiditis, which can have a temporary overactive phase.
- A heart-rhythm or anxiety problem if thyroid tests are normal.
Initial self-care
- Avoid excess caffeine if it worsens palpitations.
- Continue prescribed medication unless advised otherwise.
- Record pulse rate and symptoms if practical.
- Arrange prompt thyroid-function testing.
When to see a doctor urgently
- Very rapid heartbeat with fever, severe agitation, confusion, vomiting or collapse.
- Chest pain, severe breathlessness or fainting.
When to see a doctor
- Palpitations are recurrent.
- You have persistent tremor, heat intolerance or unexplained weight loss.
- You are taking anti-thyroid medication and develop fever or severe sore throat.
Changes in Periods, Fertility or Pregnancy
What you'll notice or feel
- Periods becoming heavier, lighter, irregular or absent.
- Difficulty conceiving or repeated fertility concerns.
- Changes in thyroid symptoms during pregnancy or after delivery.
- Unexpected changes in weight, temperature tolerance or energy alongside menstrual changes.
Common causes
- Both underactive and overactive thyroid states can disturb menstrual cycles.
- Pregnancy changes thyroid hormone requirements.
- Postpartum thyroiditis can occur after pregnancy.
- PMOS and other hormonal causes may produce similar symptoms.
What it could be
- Thyroid dysfunction contributing to menstrual or fertility problems.
- Thyroid disease requiring closer monitoring in pregnancy.
- A separate reproductive or endocrine condition.
Initial self-care
- If pregnancy is possible, arrange medical review before changing thyroid medication.
- Take prescribed thyroid replacement consistently.
- Bring previous thyroid results to pregnancy or fertility appointments.
- Avoid unregulated thyroid or iodine supplements.
When to see a doctor urgently
- Severe palpitations, collapse or marked breathlessness during pregnancy.
- Severe vomiting or rapidly worsening illness with known thyroid disease.
When to see a doctor
- You are planning pregnancy and have thyroid disease.
- A pregnancy test is positive while you are on thyroid treatment.
- Menstrual changes persist or fertility is a concern.
Neck Swelling or Goitre
What you'll notice or feel
- A visible fullness at the front of the neck.
- A lump that moves when swallowing.
- A feeling of pressure, tightness or a change in collar fit.
- Sometimes no pain or thyroid symptoms at all.
Common causes
- General enlargement of the thyroid gland (goitre).
- One or more thyroid nodules.
- Autoimmune thyroid disease or thyroiditis.
- Less commonly, a thyroid cancer.
What it could be
- A benign goitre or thyroid nodule.
- Thyroid inflammation.
- A nodule requiring ultrasound risk assessment and possibly sampling.
Initial self-care
- Do not repeatedly press or massage a neck lump.
- Arrange clinical examination and thyroid-function testing.
- Ultrasound may be recommended depending on the examination.
- Keep previous scans or thyroid reports for comparison.
When to see a doctor urgently
- Breathing difficulty, rapidly progressive neck swelling or inability to swallow saliva.
- A new neck swelling with severe pain, fever or significant illness.
When to see a doctor
- Any persistent new neck lump should be assessed.
- The swelling is enlarging, firm or associated with a voice change.
- There is a family history of thyroid cancer or previous neck radiation.
Abnormal Thyroid Blood Test Without Symptoms
What you'll notice or feel
- A raised or low TSH found on a routine blood test.
- Little or no obvious thyroid-related symptoms.
- Previous results that have fluctuated.
- An abnormal result during illness, pregnancy or while taking supplements/medicines.
Common causes
- Early or mild thyroid disease.
- Temporary changes related to acute illness.
- Pregnancy-related changes in thyroid physiology.
- Medication or supplement interference with laboratory testing.
What it could be
- Subclinical hypothyroidism or hyperthyroidism.
- A transient result that requires repeat testing rather than immediate treatment.
- Established thyroid disease requiring treatment depending on the overall context.
Initial self-care
- Do not self-start thyroid hormone or anti-thyroid medicines.
- Bring a complete medication and supplement list to review.
- Repeat testing may be appropriate before deciding on treatment.
- Use the same laboratory when serial comparison is important, if feasible.
When to see a doctor urgently
- Urgency usually depends on symptoms rather than an isolated mildly abnormal result.
- Seek urgent care for severe palpitations, chest pain, collapse or marked confusion.
When to see a doctor
- Results remain abnormal on repeat testing.
- You are pregnant, planning pregnancy or have significant heart disease.
- You have a known pituitary disorder, where thyroid tests need specialist interpretation.
YOUR CONSULTATION
What to Expect at Your Visit
- Review of symptoms, medications, supplements, pregnancy status and family history.
- Examination of pulse, tremor, skin, eyes and thyroid gland when appropriate.
- Thyroid blood tests usually start with TSH and are expanded according to the result and clinical context.
- Thyroid antibodies may help identify autoimmune thyroid disease in selected cases.
- Ultrasound is used when there is a thyroid nodule or structural concern; not every thyroid disorder needs a scan.
- Treatment and monitoring depend on whether the thyroid is underactive, overactive, inflamed or structurally abnormal.
* IMPORTANT: A Note Before You Go
Thyroid symptoms are common but nonspecific. A diagnosis should be based on the combination of clinical assessment and appropriately interpreted thyroid-function tests.
This page provides general educational information and cannot replace an individual medical assessment. If symptoms are persistent, worsening or concerning, arrange appropriate medical review.
NEED AN ASSESSMENT?
Arrange an Endocrinology Consultation
For non-emergency assessment or follow-up, appointments are booked through the hospital’s central appointment desk on 0422 432 4433. For severe or rapidly worsening symptoms, seek urgent medical care rather than waiting for a routine appointment.