Unusual case of elevator deficit: looking beyond the extraocular muscles

Abstract

© BMJ Publishing Group Limited 2021. No commercial reuse. See rights and permissions. Published by BMJ. DESCRIPTION A 70yearold man, a nonsmoker, presented with diplopia in upgaze for the past 4 months. There was no history of trauma, fever, nasal congestion, discharge or thyroidrelated symptoms or no history of sinus surgery. On examination, anterior and posterior segment including pupillary reaction and visual acuity were normal. Slight limitation of upgaze was noted in the right eye with associated vertical diplopia (figures 1 and 2). Hirschberg test showed 5–10 degrees of hypotropia in upgaze, and diplopia charting documented the diplopia (figure 1G). There was no enophthalmos or hypoglobus. The thyroid profile was normal. Noncontrast CT of the orbit and paranasal sinuses revealed right chronic maxillary sinusitis with blockage of the ostium, deviation of the nasal septum and atelectasis of maxillary sinus leading to sagging of the inferior orbital wall. These findings were suggestive of ‘silent sinus syndrome’ (figures 3 and 4), causing sagging of the inferior rectus and the surrounding soft tissue, thus causing upgaze limitation and diplopia. The patient was referred to the Otorhinolaryngology department where he was managed conservatively. Vertical diplopia occurs due to an abnormality in either the extraocular muscles or the nerve supplying it. Common differentials are thyroid ophthalmopathy, blowout fracture with inferior rectus entrapment, neurological causes like superior oblique palsy, neuromuscular junction abnormalities like myasthenia gravis or, in some cases, cysticercosis of the extraocular muscles. ‘Silent sinus syndrome’ is a rare condition where chronic maxillary sinusitis presents with progressive enophthalmos and hypoglobus in the absence of any symptoms of a sinoinflammatory disease. Kass et al reported 22 cases of the syndrome, of which 5 had ocular signs. BabarCraig et al reported 16 patients, of which diplopia was present in 32% and hypoglobus in 44%. These ocular features are attributed to longterm ongoing inflammation in the sinus that blocks the osteomeatal complex creating a negative pressure, leading to the collapse of the orbital floor. Diplopia, if present, is often associated with enophthalmos or hypoglobus. It is