Subclinical hyperthyroidism

Question 1

What is subclinical hyperthyroidism?

Answer 1

Suppressed TSH (usually <0.1 mU/L) with normal free T4 and T3 levels

Question 2

Which thyroid hormones are normal in subclinical hyperthyroidism?

Answer 2

Free thyroxine (T4) and triiodothyronine (T3)

Question 3

What biochemical abnormality defines subclinical hyperthyroidism?

Answer 3

Low or suppressed TSH with normal thyroid hormone levels

Question 4

What is the most common cause of subclinical hyperthyroidism in elderly patients?

Answer 4

Multinodular goitre

Question 5

Which patient group is particularly affected by multinodular goitre–related subclinical hyperthyroidism?

Answer 5

Elderly females

Question 6

How can thyroid hormone treatment mimic subclinical hyperthyroidism?

Answer 6

Excessive thyroxine replacement suppresses TSH with normal T4/T3

Question 7

Why is subclinical hyperthyroidism clinically important?

Answer 7

It increases cardiovascular and skeletal risks despite minimal symptoms

Question 8

Which cardiac arrhythmia is most strongly associated with subclinical hyperthyroidism?

Answer 8

Atrial fibrillation

Question 9

How does subclinical hyperthyroidism affect bone health?

Answer 9

Increases bone resorption and risk of osteoporosis

Question 10

Which neurocognitive outcome may be increased in subclinical hyperthyroidism?

Answer 10

Dementia

Question 11

How may subclinical hyperthyroidism affect quality of life?

Answer 11

May cause subtle symptoms such as anxiety, palpitations, or fatigue

Question 12

Why is immediate treatment not always required in subclinical hyperthyroidism?

Answer 12

TSH levels often normalise spontaneously

Question 13

When should treatment be considered?

Answer 13

When TSH suppression is persistent

Question 14

What is a reasonable initial treatment strategy if intervention is required?

Answer 14

A therapeutic trial of low-dose antithyroid medication for ~6 months

Question 15

What is the aim of short-term antithyroid therapy in subclinical hyperthyroidism?

Answer 15

To induce remission and normalise TSH

Question 16

What key complication should prompt active management of subclinical hyperthyroidism?

Answer 16

Atrial fibrillation or osteoporosis risk

Question 17

What single lab result best distinguishes subclinical from overt hyperthyroidism?

Answer 17

Normal T4 and T3 levels