Sinonasal abnormalities in patients with graves' orbitopathy

Abstract

To compare radiographic sinus mucosal thickening in patients with Graves' orbitopathy versus controls and determine whether target autoantigens thought to underlie systemic manifestations of Graves' disease are present within paranasal sinus mucosa. Case-control study. Sinus computed tomography (CT) scans from patients with Graves' orbitopathy scheduled for orbital decompression surgery (n = 50) were compared with maxillofacial CT scans from control patients (n = 50). Scans were rated for sinus mucosal disease by two independent reviewers using the Lund-MacKay and Harvard staging systems. Gene expression for thyrotropin receptor and type 1 insulin-like growth factor receptor (IGF-1R) was assessed in ethmoid mucosal samples using real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC). Increased sinus mucosal thickening was found in patients with Graves' orbitopathy compared with controls for both the Lund-MacKay (6.2 vs. 2.7; P < .01) and Harvard (2.1 vs. 1.3; P < .01) systems. Compared with control scans, the Graves' orbitopathy group exhibited greater mucosal thickening in the ethmoid, frontal, and sphenoid sinuses (P < .05 for all). RT-qPCR and IHC demonstrated gene expression for both the thyrotropin receptor and the IGF-1R in ethmoid mucosa. Patients with Graves' orbitopathy who present for orbital decompression exhibit a higher prevalence of sinus mucosal thickening on CT scan. These findings may be explained by circulating autoantibodies to target antigens, thyrotropin receptor and IGF-1R, associated with Graves' disease and found to be expressed in sinus mucosa.