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A 70-year-old man, a non-smoker, presented with diplopia in upgaze for the past 4 months. There was no history of trauma, fever, nasal congestion, discharge or thyroid-related 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. Non-contrast 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, blow-out 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.1
‘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 sino-inflammatory disease.2 Kass et al reported 22 cases of the syndrome, of which 5 had ocular signs.3 Babar-Craig et al reported 16 patients, of which diplopia was present in 32% and hypoglobus in 44%.4 These ocular features are attributed to long-term ongoing inflammation in the sinus that blocks the osteomeatal complex creating a negative pressure, leading to the collapse of the orbital floor.5 Diplopia, if present, is often associated with enophthalmos or hypoglobus. It is more commonly seen in middle-aged population with a mean age of presentation of 38.3 years.3 The occurrence in children is rarely encountered as seen in few case reports.4 6 Management involves endoscopic sinus surgery to establish free ventilation to the sinus along with orbital reconstruction with implants. Some cases also have spontaneous resolution of ocular symptoms after sinus surgery.4 Our patient presented early in the disease process with diplopia due to inferior sagging of the orbital floor along with inferior rectus and its sheath without hypoglobus or enophthalmos.
All cases of diplopia might not be explained by nerve palsy or extraocular muscle abnormalities.
Imaging plays an important role in diagnosing certain unusual cases of diplopia.
Contributors PR contributed to the acquisition of data, drafting the manuscript and has agreed to be accountable for the article. RD contributed to drafting the manuscript, revising it critically for intellectual content and agreed to be accountable for the article. SS contributed to analysis and interpretation of data and agreed to be accountable for the article. RS contributed to the conception, design, interpretation of data, final approval of the version sent for publication and agreed to be accountable for the article.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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