Isolated Unilateral Ptosis Caused by Idiopathic Orbital Myositis / 대한신경근육질환학회지

ABSTRACT

Idiopathic orbital myositis is considered as a subgroup of idiopathic orbital inflammatory disease. It is a non-infectious inflammatory disorder primarily affecting the extraocular muscles and causes various eye symptoms including pain, diplopia and limitation of extraocular movement. Cases of isolated ptosis by idiopathic orbital myositis have been very rarely described in the literature. We report a patient who developed unilateral painless ptosis caused by idiopathic orbital myositis. A 52-year-old man presented with drooping of the right eyelid for 3 days. There was no history of headache, double vision or any other complaints. Neurological examination revealed right ptosis without pupil and extraocular muscles involvement. Repetitive nerve stimulation test was normal. Ptosis did not improve after the neostigmine injection. Magnetic resonance imaging scan showed asymmetric enlargement of right superior rectus/levator palpebrae superioris muscle complex and medial rectus muscle. Ptosis resolved dramatically after oral corticosteroid therapy. Isolated unilateral ptosis can be caused by various etiologies. Idiopathic orbital myositis should be considered in the differential diagnosis of ptosis.