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Case of the week 110  ( April 2013 )
Extraocular muscle enlargement


35 years old man complains of downward deviation of the left eye. The condition started since 4 months as painless progressive condition. Free T3 & T4 were done and they are within normal values. MRI showed enlargement of the inferior rectus muscle with tendon affection, he was diagnosed as myositis of the extraocular muscles, a megadose of corticosteroid therapy was administrated with no improvement of the case. Ocular motility and forced duction test are illustrated in the following photos and videos 


 See video of this patient

 See Forced Duction Test of this patient
 


 DIFFERENTIAL DIAGNOSIS OF ENLARGED EXTRAOCULAR MUSCLES

  1. Graves’ disease

  2. Vascular (carotid-cavernous fistula or arteriovenous

  3. malformation): enlarged superior ophthalmic vein

  4. Acute orbital myositis: irregular muscle enlargement

  5. Orbital pseudotumor

  6. Malignant lymphoid tumor

  7. Metastatic breast carcinoma

  8. Metastatic cutaneous melanoma

  9. Metastatic neuroblastoma

  10. Metastatic lung carcinoma

  11. Metastatic carcinoid

  12. Metastatic pancreatic carcinoma

  13. Metastatic seminoma

  14. Leukemia

  15. Cysticercosis

  16. Wegener’s granulomatosis

  17. Eosinophilic granuloma of soft tissue

  18. Angioma

  19. Rhabdomyosarcoma

  20. Acromegaly

  21. Malignant nonchromaffin paraganglioma

  22. Mesodermal dysplasia

  23. Trichinosis

Extraocular muscle enlargement is most often due to idiopathic inflammation, thyroid myopathy, or metastases, although a number of other entities can producenextraocular muscle enlargement

An idiopathic orbital myositis is most common in patients in the first three decades of life. The clinical presentation is the rapid onset of discomfort and/or pain on extraocular movement. Usually, a single, unilateral muscle is involved. Limitation of movement is most common in the field of action of the involved muscle. Most commonly, single or multiple recti muscles are involved, although in about 20 percent of cases, the oblique muscles are infiltrated by lymphocytes. Patients show a dramatic response to 80 mg of oral prednisone given for 7 to 10 days; in about 80 percent of cases, there is a complete resolution of symptoms with no recurrence.

In approximately 80 percent of patients with thyroid orbitopathy, there is a history of systemic Graves’ disease. Although bilateral proptosis with scleral show is almost pathognomonic for thyroid-related eye disease.

SEQUENTIAL LABORATORY EVALUATION TO DIAGNOSE THYROID ORBITOPATHY

1. Serum thyroid stimulating hormone (TSH), thyrotropin

2. Serum thyroid stimulating immunoglobulin antibodies (TSI)

3. Antimicrosomal and antithyroglobulin antibodies

Patients with metastatic tumors to the extraocular muscles usually presented with a known history of widespread disease.  In metastatic tumors to the extraocular muscles, three clinical and imaging patterns are common :

  1. A single muscle may be involved by metastasis.

  2. Muscle enlargement is more uniform in thyroid orbitopathy and more patchy in metastases.

  3. Metastases can involve both the extraocular muscle and contiguous structures.

الموقع المصري للحول وامراض الجهاز الحركي للعين

The Egyptian Site of Strabismus & Oculomotor Disorders