AB0464 ULTRASONOGRAPHIC FEATURES OF THE PAROTID AND SUBMANDIBULAR SALIVARY GLANDS IN SJÖGREN’S SYNDROME

Abstract

BackgroundPrimary Sjögren’s syndrome (pSS) is a systemic autoimmune disease characterized by the presence of “sicca syndrome”, secondary to the involvement of the exocrine glands. Different studies have been published and have shown that salivary gland ultrasound (SGUS) could be used as a tool for the diagnosis of pSS, especially the score of parenchymal inhomogeneity of salivary glands (SG) [1].ObjectivesTo identify relevant ultrasonographic features associated with glandular involvement in patients with pSS, such as size measurements, vascularization, and the characteristics of adjacent lymph nodes of parotid and submandibular SG, and their association with the score of parenchymal inhomogeneity.MethodsWe enrolled patients with pSS (n=53), based on the 2002 American–European Consensus Group (AECG) pSS classification criteria, and non-Sjögren’s sicca subjects (n=25), who exhibited sicca symptoms but did not fulfill the AECG pSS classification criteria. We considered SGUS score based on parenchymal homogeneity, presence of hypoechogenic areas, and clearness of posterior glandular border of SG. The score of the highest graded gland was considered and a score ≥2 was defined as a positive SGUS, according to OMERACT US-SG scoring [1]. The size measurements of the SG were the diameters in anterior-posterior, medio-lateral, and vertical directions during dental occlusion, and length and width of anterior prolongation of parotid glands. The vascularization was ranked according to the color doppler ultrasonography pattern without salivary stimulation. For the lymph nodes examination we considered the shape, number, and size of submandibular, superficial parotid (preauricular), and intraparotid lymph nodes, and the jugulodigastric lymph node, considering also that lymph nodes may not be detected. Categorical variables were compared using the Chi-square test and continuous variables were compared using Student’s t-test with Welch’s correction. p-values <0.05 were considered significant.ResultsSGUS was positive in a higher proportion of patients with pSS, in comparison to non-Sjögren’s sicca subjects (60% vs. 24%, p=0.003). The size measurements showed a smaller antero-posterior diameter of both the right (mean 31.3 mm vs. 35.4 mm, p=0.037) and left (mean 30.1 mm vs. 34.2 mm, p=0.004) submandibular glands in pSS patients. A smaller antero-posterior diameter of the left parotid gland was also observed (mean 30.2 mm vs. 34.2 mm, p=0.046) in pSS patients. The lymph nodes evaluation showed that superficial parotid lymph nodes were detected in a lower proportion in pSS patients (45% vs. 72%, p=0.027). No significant differences were found between pSS patients and non-Sjögren’s sicca subjects regarding the rest of the size measurements, the vascularization pattern, nor the shape, number, nor size of lymph nodes when they were detected. In addition, positive SGUS in pSS patients was also associated with smaller antero-posterior diameter of both the right (mean 29.9 mm vs. 35.4 mm, p=0.009) and left (mean 32.8 mm vs. 34.2 mm, p=0.008) submandibular glands, and a smaller antero-posterior diameter of the left parotid gland (mean 27.5 mm vs. 34.2 mm, p=0.044).ConclusionUltrasonographic features are a valuable resource for the evaluation of pSS. The score of parenchymal inhomogeneity is associated with clinical diagnosis, and other indices such as the antero-posterior diameter of the submandibular glands and a lower detection of the superficial parotid lymph nodes may be used to assist the evaluation. However, no other macrostructural features of the parotid and submandibular SG, and the adjacent lymph nodes, seem to be different between pSS patients and non-Sjögren’s sicca subjects.