Subclinical Hyperthyroidism

Subclinical hyperthyroidism is defined by a suppressed serum TSH with normal free T4 and T3. Patients are often asymptomatic or have mild symptoms. Causes: early Graves disease, autonomously functioning nodule, excessive exogenous levothyroxine. Long-term risks: bone loss (osteoporosis), atrial fibrillation, cardiovascular morbidity. Treat based on age, symptoms, TSH level and underlying cause.

Common Symptoms

Usually asymptomatic; mild palpitations; heat intolerance; tremor; low TSH with normal T4/T3

Causes and Pathogenesis

Mild overproduction of thyroid hormone (or over-replacement) suppresses pituitary TSH before circulating T4/T3 rise above the normal range.

Treatment

Adjust levothyroxine dose if over-replaced; treat underlying Graves/nodule; monitor bone density and heart rhythm

Preventive Measures

Avoid over-replacement; monitor TSH on thyroid-hormone therapy; bone protection in postmenopausal women.

Department to Visit

It is recommended to visit the Endocrinology department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.