In a non‑pregnant adult with mild‑to‑moderate hyperthyroidism, can I manage the patient in primary care or should I refer to endocrinology?

Management of Mild-to-Moderate Hyperthyroidism in Primary Care

Patients with overt hyperthyroidism should be referred to endocrinology for specialist management, though you can initiate beta-blockers and sometimes antithyroid drugs in primary care while awaiting the referral. 1

Initial Assessment and Stabilization in Primary Care

Before referring, you should:

• Confirm biochemical hyperthyroidism with low TSH and elevated free T4 or free T3 levels to establish the diagnosis 2
• Initiate beta-blocker therapy (such as propranolol or metoprolol) for symptomatic relief of tachycardia, tremor, and anxiety while the patient awaits specialist evaluation 1
• Consider starting methimazole in primary care if the referral will be delayed, particularly in younger patients without contraindications, though definitive management decisions should be made by endocrinology 3

Why Referral to Endocrinology is Recommended

The evidence strongly supports specialist management for several critical reasons:

• Determining the underlying cause requires specialized testing including TSH-receptor antibodies, thyroid peroxidase antibodies, thyroid ultrasonography, and potentially scintigraphy to differentiate between Graves' disease (70% of cases), toxic nodular goiter (16%), thyroiditis (3%), or drug-induced hyperthyroidism (9%) 2
• Treatment selection is complex and depends on the specific etiology, patient age, pregnancy status, presence of orbitopathy, goiter size, and antibody levels—decisions that require endocrine expertise 3, 2
• Antithyroid drug management requires careful monitoring for serious adverse effects including agranulocytosis, hepatotoxicity, and vasculitis, which occur in a small but significant percentage of patients 3

Special Circumstances Requiring Immediate Specialist Involvement

Certain presentations mandate urgent endocrinology referral:

• Pregnancy or women planning pregnancy require immediate specialist management, as antithyroid drugs cause birth defects when used in weeks 6-10 of pregnancy, and treatment must be carefully switched between methimazole and propylthiouracil at specific timepoints 4
• Moderate to severe symptoms including significant weight loss, severe tachycardia, or thyroid storm require immediate endocrinology consultation and possible hospitalization 5
• Presence of Graves' orbitopathy requires coordinated care between endocrinology and ophthalmology, as radioactive iodine treatment is contraindicated with active/severe eye disease 3
• Elderly patients who may have atrial fibrillation or other cardiac complications need specialist evaluation, as hyperthyroidism is easily overlooked in this population and carries increased mortality risk 2, 1

What You Can Safely Manage in Primary Care

The only hyperthyroid condition appropriate for primary care management without referral is:

• Mild, transient thyroiditis (such as postpartum thyroiditis or viral thyroiditis) where the hyperthyroid phase is expected to be self-limited and resolve within 3-4 weeks, requiring only beta-blockers for symptom control 5, 1

Critical Pitfalls to Avoid

• Never start antithyroid drugs without confirming the diagnosis with appropriate antibody testing and imaging, as destructive thyroiditis (which requires no antithyroid drugs) can present identically to Graves' disease on initial biochemical testing 2
• Never delay referral in pregnant women, as untreated hyperthyroidism causes pregnancy complications, preterm birth, and impaired fetal cognitive development 4
• Maintain high clinical suspicion in elderly patients presenting with atrial fibrillation, weight loss, or unexplained fatigue, as hyperthyroidism is frequently missed in this population 1