Posters

Atypical paediatric thyroid orbital myositis

Poster Details

First Author: H. Morfeq FRANCE

Co Author(s):    S. Milazzo   B. Jany                 

Abstract Details

Purpose:

Reporting an atypical unilateral thyroid orbital myositis (TOM) in a pediatric patient and to highlight the importance of age-adjusted interpretation of serum thyroid hormones level.

Setting:

9-year-old girl without medical history was referred to our clinic for right eyelid swelling, right eye (OD) ptosis, proptosis, painful ophthalmoplegia, and binocular horizontal diplopia since 1 week. She was afebrile with visual acuity of 20/20 OU and normal intraocular pressure. Pupillary, slit lamp and fundus examinations were normal

Methods:

On oculomotor examination:she had hypotropia associated with marked limitation of abduction,adduction and elevation OD.The were no other signs of Thyroid- associated orbitopathy(TAO).Lancaster red-green test showed a restrictive pattern.Thyroid ultrasound was normal.MRI of the orbit with short tau inversion recovery sequences (STIR) showed enlargement of the muscle bellies that spare the tendinous insertion on the globe of the superior, medial and lateral recti muscles OD sparing the inferior rectus.There was no infiltration of orbital fat, bones nor sinuses. Thyroid-stimulating hormone (TSH) level was normal but at lower normal range 0.46 mUI/L and Free thyroxine (fT4) was higher than normal 1,64 ng/dL.

Results:

After reviewing the literature we found 3 studies which analyzed pediatric reference intervals (R.I) for thyroid hormone levels. Concerning our patient's age (9-10 years), she was in subclinical hyperthyroid status according to R.I of Zurakowski et al and Elmlinger et al. Differently, she was in hyperthyroid status by using Djemli et al R.I. Accordingly, The patient was treated with systemic corticosteroids 2mg/kg/day for 2 weeks then taper dosage over 12 weeks. Progressive clinical improvement was noted starting from the fourth day of medical treatment with complete remission after 1 month with normalization of TSH of 3.05 mUI/L and fT of 41.49 mUI/L.

Conclusions:

Pediatric Graves' orbitopathy is a rare disease and commonly lacks significant inflammatory features. Atypical findings of pediatric TOM were found in our case report. The physicians should be aware of these atypical features to avoid late diagnosis of Graves' disease and unnecessary biopsy or unwarranted antibiotic use. Other differential diagnosis most be ruled out including infections, inflammations and tumors. Nonspecific orbital inflammation still a diagnosis of exclusion. More studies are needed to evaluate and standardized the pediatric normal range of thyroid hormones.

Financial Disclosure:

NONE