Overview
Definition:
Thyroid eye disease (TED), also known as Graves' ophthalmopathy (GO), is an autoimmune condition primarily affecting the orbit, characterized by inflammation and enlargement of the extraocular muscles and orbital fat
In children, it is less common than in adults and often associated with Graves' disease.
Epidemiology:
TED is rare in children, accounting for less than 5% of all TED cases
It predominantly affects prepubertal and adolescent girls
The incidence is significantly lower than in adults, with most pediatric cases linked to autoimmune thyroid disease, most commonly Graves' disease.
Clinical Significance:
Prompt recognition and appropriate management of pediatric TED are crucial to prevent vision-threatening complications such as optic nerve compression, corneal ulceration, and strabismus, which can significantly impact a child's quality of life and visual development
Early intervention improves outcomes.
Clinical Presentation
Symptoms:
Proptosis or exophthalmos
Eyelid retraction causing a staring appearance
Diplopia (double vision), especially on upward gaze
Periorbital edema
Redness or injection of the conjunctiva
Chemosis
Pain or a feeling of fullness in the eyes
Dry eyes or excessive tearing
Blurred vision or decreased visual acuity
Photophobia.
Signs:
Proptosis/Exophthalmos as measured by Hertel exophthalmometer
Eyelid retraction (Dalrymple's sign)
Lid lag on downgaze (Von Graefe's sign)
Infrequent blinking (Stellwag's sign)
Limited extraocular muscle movement, leading to strabismus and diplopia
Conjunctival injection and chemosis
Optic nerve dysfunction may manifest as reduced visual acuity, afferent pupillary defect, or dyschromatopsia.
Diagnostic Criteria:
Diagnosis is typically based on clinical findings in the presence of confirmed autoimmune thyroid disease (primarily Graves' disease)
The EUGOGO (European Group on Graves' Orbitopathy) and R.I.A.C.H.I
(Revised Activity Score in Childhood Graves' Disease) criteria can be adapted
Key features include proptosis, eyelid retraction, diplopia, and evidence of orbital inflammation or congestion
Radiographic confirmation (CT/MRI) may be needed to assess orbital involvement.
Diagnostic Approach
History Taking:
Detailed history of onset and progression of eye symptoms
History of known or suspected thyroid dysfunction (Graves' disease, Hashimoto's thyroiditis)
Family history of autoimmune thyroid disease or TED
Constitutional symptoms like weight loss, palpitations, tremors, heat intolerance
Medications taken by the child
Exposure to iodine or radiation.
Physical Examination:
Comprehensive ophthalmological examination including visual acuity, visual fields, color vision, pupillary reflexes
Palpation of the thyroid gland
Measurement of exophthalmos using a Hertel exophthalmometer
Assessment of eyelid retraction and lid lag
Evaluation of ocular motility for limitations and diplopia
Fundus examination to check for papilledema or optic disc pallor
Slit-lamp examination of the conjunctiva and cornea.
Investigations:
Thyroid function tests: TSH, free T4, free T3, TPO antibodies, TRAb (TSH receptor antibodies) to confirm or diagnose Graves' disease
Orbital imaging: CT or MRI scans of the orbits can demonstrate extraocular muscle enlargement, orbital fat hypertrophy, and optic nerve sheath thickening, aiding in diagnosis and assessing disease severity and activity
Visual evoked potentials (VEPs) may be used to assess optic nerve function.
Differential Diagnosis:
Other causes of proptosis in children: orbital cellulitis, orbital tumors (e.g., rhabdomyosarcoma, optic glioma), orbital pseudotumor, neuroblastoma metastasis, and cavernous sinus thrombosis
Differentiating TED requires correlating eye signs with thyroid status and orbital imaging findings.
Management
Initial Management:
Control of hyperthyroidism is paramount
Antithyroid medications (e.g., methimazole, propylthiouracil) are the mainstay
Radioactive iodine therapy and thyroidectomy are generally deferred in active TED, especially with optic nerve compromise, due to potential exacerbation
Smoking cessation is critical if the child is exposed to smoke
Selenium supplementation may be considered in mild cases.
Medical Management:
For active inflammatory TED: Corticosteroids (oral or intravenous) are the first-line treatment for moderate to severe active disease, especially with optic nerve compression
Intravenous methylprednisolone pulses are often preferred
Lubricating eye drops and ointments for dry eyes
Prism correction for diplopia
Management of underlying hyperthyroidism with antithyroid drugs to achieve euthyroid state
Immunosuppressive agents (e.g., azathioprine, mycophenolate mofetil) may be used for refractory cases or steroid-sparing
Benzodiazepines can help with anxiety.
Surgical Management:
Surgical intervention is reserved for inactive, stable TED and is usually performed in a staged manner after the thyroid status is controlled and eye inflammation has subsided
Surgical options include: Orbital decompression (to relieve proptosis and optic nerve compression), strabismus surgery (to correct diplopia), and eyelid surgery (to correct retraction).
Supportive Care:
Psychosocial support for the child and family
Regular ophthalmological and endocrinological follow-up
Education regarding the chronic nature of the disease and adherence to treatment
Head elevation at night may reduce periorbital edema
Avoidance of irritants like dust and smoke
Protective eyewear.
Complications
Early Complications:
Optic nerve compression leading to vision loss
Corneal ulceration and infection due to exposure keratitis
Severe diplopia impacting daily activities
Rapidly progressive inflammation.
Late Complications:
Fibrosis of extraocular muscles causing permanent strabismus
Persistent proptosis and eyelid retraction leading to disfigurement
Dry eye syndrome and recurrent corneal abrasions
Reduced visual acuity and field defects
Thyroid-associated orbitopathy progression even after thyroid normalization.
Prevention Strategies:
Early diagnosis and treatment of underlying Graves' disease
Aggressive management of active TED with corticosteroids
Strict control of thyroid hormone levels
Smoking cessation for the patient and household members
Judicious use of radioactive iodine therapy in the presence of active TED
Prompt surgical intervention for optic nerve compression.
Prognosis
Factors Affecting Prognosis:
Severity and activity of TED at diagnosis
Presence of optic nerve involvement
Age of onset (earlier onset may have better prognosis for thyroid normalization but worse orbital outcomes)
Adherence to treatment
Smoking status
Control of thyroid status.
Outcomes:
With appropriate management, visual acuity can be preserved in most children
However, cosmetic deformities and some degree of motility impairment may persist
Complete resolution of symptoms is not always achieved, and long-term management may be required
Pediatric TED can have a more aggressive orbital course compared to adult cases.
Follow Up:
Regular follow-up with pediatric endocrinology and ophthalmology is essential
Monitoring of thyroid function tests, ocular motility, visual acuity, and orbital status
Patients require lifelong monitoring for recurrence or progression of thyroid disease and its ocular manifestations.
Key Points
Exam Focus:
Pediatric TED is rare, often associated with Graves' disease
Key features: proptosis, eyelid retraction, diplopia
Management targets both thyroid status and orbital inflammation
Corticosteroids are first-line for active disease
Surgery is for stable, inactive disease.
Clinical Pearls:
Always consider thyroid dysfunction in children presenting with proptosis or diplopia
Differentiate TED from other orbital pathologies
Aggressive management in children is crucial to prevent long-term visual sequelae
Recognize that even after achieving euthyroid status, orbital symptoms can persist or worsen.
Common Mistakes:
Delaying diagnosis due to rarity
Underestimating the severity of TED in children
Inappropriately using radioactive iodine therapy in active TED
Failing to manage both thyroid dysfunction and orbital inflammation concurrently
Not performing a thorough ophthalmological examination.