Managing thyroid disease in general practice.

Area of Science:

• Endocrinology
• Internal Medicine
• Diagnostic Testing

Background:

• Serum thyroid-stimulating hormone (TSH) is the primary screening tool for thyroid dysfunction.
• Additional thyroid function tests are often unnecessary unless TSH is unreliable (e.g., pituitary disease).
• The clinical significance of mildly elevated TSH in subclinical hypothyroidism is uncertain, especially in older adults.

Purpose of the Study:

• To outline the diagnostic and management strategies for thyroid dysfunction.
• To clarify the role of various tests in assessing hypothyroidism and hyperthyroidism.
• To provide guidance on the investigation of thyroid nodules and the use of imaging.

Main Methods:

• Review of current guidelines and evidence for thyroid function testing.
• Analysis of diagnostic utility of TSH, free thyroxine, free triiodothyronine, and thyroid antibodies.
• Evaluation of imaging modalities (radionuclide scanning, ultrasound) and fine needle aspiration biopsy for thyroid nodules.

Main Results:

• Overt and severe subclinical hypothyroidism (TSH > 10 mU/L) can be treated directly with thyroxine.
• Mildly elevated TSH (4-10 mU/L) management involves observation or treatment, with clinical response guiding dosage.
• Graves' disease, thyroiditis, and toxic nodular goiter are common causes of hyperthyroidism, requiring etiological diagnosis before treatment.

Conclusions:

• TSH testing is central to thyroid dysfunction diagnosis and management.
• Radionuclide scanning and TSH-receptor antibodies aid in hyperthyroidism diagnosis; ultrasound guides nodule assessment.
• Fine needle aspiration biopsy is key for thyroid nodules >1 cm or with suspicious sonographic features; routine screening in pregnancy remains controversial.