When should a patient be referred for hypothyroidism (underactive thyroid gland)?

When to Refer a Patient for Hypothyroidism

Patients with hypothyroidism generally do not require specialist referral as primary care physicians can effectively manage most cases with levothyroxine therapy and routine monitoring.

Initial Diagnosis and Management

• Hypothyroidism is diagnosed based on laboratory testing showing elevated TSH with low free T4 (overt hypothyroidism) or elevated TSH with normal free T4 (subclinical hypothyroidism) 1
• Primary care physicians can initiate and manage levothyroxine therapy for most patients with hypothyroidism 2
• Treatment should be started at 1.5 to 1.8 mcg/kg/day in younger patients without comorbidities 2
• Lower starting doses (12.5 to 50 mcg/day) should be used in patients over 60 years or with known/suspected ischemic heart disease 2

Indications for Specialist Referral

Endocrinology Referral

• Patients with unusual clinical presentations or concern for central hypothyroidism (low TSH with low free T4) 3
• Difficulty titrating hormone therapy despite appropriate dosing adjustments 3
• Persistent symptoms despite normalized TSH levels and adequate levothyroxine dosing 2
• Severe hypothyroidism with myxedema coma (bradycardia, hypothermia, altered mental status) - requires immediate hospitalization and endocrinology consultation 3
• Pregnancy with pre-existing hypothyroidism that is difficult to control 4
• Patients with concomitant adrenal insufficiency, as steroids should be initiated before thyroid hormone replacement 3

Special Populations Requiring Specialist Input

• Pregnant women with hypothyroidism who need close monitoring and dose adjustments (increase dosage by 30% up to nine doses per week) 2
• Children with hypothyroidism who require careful monitoring of growth, development, and bone maturation 4
• Patients with secondary or central hypothyroidism (pituitary or hypothalamic disease) who need free T4 monitoring rather than TSH 5
• Patients with cardiac disease who require careful titration of levothyroxine 5

Monitoring and Follow-up

• For most stable patients, TSH should be monitored every 6-12 months 4
• TSH should be checked 6-8 weeks after any dose change 4
• Target TSH for primary hypothyroidism is typically 0.5-2.0 mIU/L 5
• In central hypothyroidism, free T4 levels should be maintained in the upper half of the normal range 5

Common Pitfalls to Avoid

• Overtreatment is common and associated with increased risk of atrial fibrillation and osteoporosis 5
• When TSH remains elevated despite adequate levothyroxine dosing, consider poor compliance, malabsorption, or drug interactions before referral 5
• Avoid initiating thyroid hormone replacement in patients with adrenal insufficiency without first addressing cortisol deficiency 3
• Imaging studies (ultrasound, CT, MRI, radioiodine uptake scans) are not indicated in the routine workup of hypothyroidism 3

Remember that most patients with hypothyroidism can be effectively managed in primary care settings, with specialist referral reserved for complex or refractory cases 2, 5.