Management of Thyroid Eye Disease (TED) in Hypothyroidism
Thyroid eye disease (TED) in hypothyroid patients requires a symptom-directed approach with early referral to orbital specialists for comprehensive management to prevent vision loss and improve quality of life.
Epidemiology and Pathophysiology
- TED occurs predominantly in patients with Graves' disease but can rarely present in euthyroid or hypothyroid patients with chronic autoimmune thyroiditis (up to 5% of cases) 1
- Incidence: 16 per 100,000 per year in women and 2.9 per 100,000 per year in men 2
- Female predominance (8:1 ratio), typically presenting in the fourth to fifth decade 2
- Between 30-50% of TED patients develop restrictive myopathy 2
- TED follows a predictable course with an active inflammatory phase (18-24 months) followed by an inactive/burnt-out phase 3
Risk Factors for TED Development and Progression
- Smoking (most significant modifiable risk factor) 3
- Thyroid dysfunction (both hyper- and hypothyroidism) 3
- Elevated thyrotropin receptor antibodies 3, 1
- Radioactive iodine therapy without steroid prophylaxis 3, 4
- Hypercholesterolemia 3, 1
- Male sex, older age, and diabetes 1
Clinical Assessment
Key Diagnostic Elements:
Comprehensive ocular examination:
- Full sensorimotor examination to detect mechanical restriction
- Forced ductions to confirm restrictive strabismus
- Binocular field testing to map regions of single binocular vision
- Exophthalmometry to measure and monitor proptosis
- Surveillance for optic neuropathy (acuity, color vision, visual fields, pupillary exam)
- OCT and visual fields to screen for compressive optic neuropathy 2
Thyroid function assessment:
- TSH and free T4 to determine thyroid status 5
- Monitoring for optimal thyroid replacement in hypothyroid patients
Imaging:
- Orbital CT or MRI to confirm diagnosis and evaluate extraocular muscle size and orbital fat volume
- Typical findings: tendon-sparing enlargement of extraocular muscles and proptosis 2
Management Approach
1. Thyroid Function Optimization
- Normalize thyroid function with appropriate levothyroxine dosing
- Initial dosing at 0.5-1.5 μg/kg/day with monitoring every 4-6 weeks until stable 5
- Adjust dose in 12.5-25 mcg increments until TSH normalizes 5
- Target TSH within normal range (0.45-4.5 mIU/L) 5
2. Management of Mild TED
- Local supportive measures:
- Artificial tears and lubricants for dry eye symptoms
- Elevation of head while sleeping
- Selenium supplementation may be beneficial 1
- Monitor for progression to more severe disease
3. Management of Moderate-to-Severe Active TED
- Refer to orbital specialist (oculoplastic surgeon or neuro-ophthalmologist) 2
- Consider teprotumumab (IGF-1R inhibitor):
- Alternative treatments:
4. Management of Sight-Threatening TED
- Immediate referral to orbital specialist
- Urgent orbital decompression for optic neuropathy
- High-dose intravenous glucocorticoids 4
5. Surgical Interventions (for inactive/stable TED)
- Orbital decompression for proptosis
- Strabismus surgery for persistent diplopia
- Goal: re-establish single binocular vision in primary gaze and reading position 2
- Eyelid surgery for retraction or cosmetic concerns
Monitoring and Follow-up
- Regular assessment of TED activity and severity
- Monitor thyroid function tests every 4-6 weeks until stable, then annually 5
- Screen for other autoimmune disorders 5
- Collaborative care between endocrinologist and ophthalmologist 2
Important Considerations
- Avoid radioactive iodine therapy in TED patients when possible; if necessary, provide steroid prophylaxis 4
- Smoking cessation is essential as smoking increases risk and severity of TED 2, 3
- Quality of life assessment should be incorporated into management 1
- Complete resolution rarely occurs in moderate-to-severe TED, even with optimal treatment 3