Silent sinus syndrome-In the eye of a Radiologist

Silent sinus syndrome-Radiological point of view

1. Silent Sinus Syndrome Dr.Santosh Atreya Phase-B Resident-Department of Radiology & Imaging Bangabandhu Sheikh Mujib Medical University

2. Clinical photo of the patients frontal view -showing “Typical facial asymmetry seen in silent sinus syndrome”. Right globe is displaced downward ( hypoglobus ) with associated upper lid retraction and deepening of upper lid sulcus

3. EVIDENCE. (1) 32-year-old woman was referred for Radiologist for evaluation of an acquired right upper eyelid ptosis . ( 2A) Coronal CT image shows thinning and retraction of the right orbital floor; ( 2B) coronal CT image (posterior cut) shows right maxillary sinus hypoplasia and opacification with lateralization of the uncinate process (arrow). The axial CT image shows inward bowing and retraction of the posterolateral and medial walls of the right maxillary sinus.

4. Introduction Silent sinus syndrome (SSS) is a rare clinical condition that can pose a diagnostic challenge for a Radiologist.

5. History The first two reported cases were reported in 1964, but the term “silent sinus syndrome” was coined 30 years later by Dr.Soparkar and colleagues . Since that time, several case series have been published.

6. EPIDEMIOLOGY Third to fifth decade of life. No gender predilection. May be idiopathic. In a small number of patients, trauma to the lateral nasal wall and ostiomeatal complex may be the cause, e.g. endonasal intubation 

7. Clinical Presentation Painless,relatively long-standing facial asymmetry, Enophthalmos and hypoglobus   . Symptoms of sinusitis are not always present  . Significant deformity of the orbital floor-May develop  diplopia . Extraocular movements are usually normal 

8. Clinical Presentation of my Patient My patient 30-year-old male with chief complain of orbital asymmetry & headache. Visual acuity was 6/6 and was normal. All routine lab. Investigations were normal.

9. Pathogenesis Chronic occlusion of the maxillary sinus ostium / ostia results in gradual resorption of the air. Subsequently , negative pressure is generated within the sinus  . This, in turn, results in gradual inward bowing of all four of the maxillary walls.   Orbital  volume increases with resultant enophthalmos and variable flattening of the malar eminence  . Other hypotheses - inflammatory erosion and softening of walls due to chronic sinusitis.

10. Radiographic features Imaging of the sinuses confirms the findings. Additionally , the diagnosis may be made incidentally by a Radiologist on imaging of the region for other reasons.

11. Plain radiograph Plain radiographs are no longer considered sufficiently sensitive or specific for the assessment of paranasal sinus disease by Radiologist . However , they are still not infrequently performed. The findings are the same as those seen on CT .

12. CT inferior bowing of the orbital floor: increased orbital volume and  enophthalmos lateral bowing of the medial wall: lateral displacement of the middle and inferior turbinate The   uncinate process is usually superiorly and laterally displaced, in direct contact with the inferomedial wall of the orbit, and the  ostiomeatal complex is occluded 

13. MRI Radiologist do not prefer MRI for diagnosis of this disease. If performed, will demonstrate a fully opacified sinus with thickening and enhancement of the mucosa. The secretions are of variable intensity. Axial T2-weighted MRI image showing fluid level in right maxillary sinus with reduction in its volume

14. Treatment and prognosis The condition is benign but may result in diplopia . Treatment involves the creation of a drainage route for the sinus. This can be with a nasal antral window or maxillary antrostomy . Once drainage is established, no further volume loss will develop.

15. Differential diagnosis congenital maxillary sinus hypoplasia post traumatic maxillary sinus deformity Orbital trauma Mucocele chronic sinusitis  with mucoperiosteal thickening

16. Take Home Messages A n acquired condition,occurs in adults with unilateral, progressive, spontaneous enophthalmos and hypoglobus secondary to maxillary sinus hypoventilation caused by blockage of the ostiomeatal complex. P atient often presents with a droopy eyelid and a deep superior sulcus . Important to have orbitofacial with PNS imaging Radiological Consultation