Background The diagnosis of primary Sjögren’s Syndrome (pSS) relies on invasive or non-specific tests, such as salivary gland biopsy, sialometry, sialography or scintygraphy. Ultrasonography (US) has become widely available for rheumatologists and parotid gland evaluation is easy to learn, rapidly performed, repeatable, non-invasive and non-radiating.
Objectives Pilot study to explore the diagnostic utility of parotid gland US and its potential to identify patients with high disease activity or risk for systemic disease complications.
Methods US of parotid glands was performed scoring parenchymal inhomogeneity as 0 = completely normal, 1 = slight abnormalities/few hypoechogenic areas, 2 = multiple hypoechogenic areas or 3 = many or confluent hypoechogenic lesions 1. Assessment of EULAR SS Disease Activity Index (ESSDAI), presence of autoantibodies and immunoglobulin levels were assessed in pSS patients. PSS patients, disease controls and healthy persons completed the EULAR SS Patient Reported Index (ESSPRI) VAS scale for dryness simultaneously. Salivary gland biopsies were assessed with regard to focal sialadenitis and Germinal Centre (GC)-like structures by routine staining and light microscopy, when available.
Results Parotid glands of 77 pSS patients fulfilling the American European Consensus Criteria and of 28 controls (healthy n=7, sicca syndrome n=9, chronic arthritis n=7, systemic vasculitis or connective tissue disease n=5) were studied. 51% of the pSS patients and none of the controls showed the characteristic pattern of multiple or confluent hypoechogenic rounded lesions typical for pSS, (p<0.001).
Patients with SS-typical US pattern (score 2-3) had significantly higher ESSDAI score (9.1 vs. 3.4) and IgG levels (23.0 vs. 15.3g/l) (both p<0.001), significantly more often a history of systemic disease (80% vs. 50%, p=0.007), autoantibodies to Ro and La (95% vs. 53%, p<0.001) and GC-like structures in the salivary gland biopsy (53% vs. 18%, p=0.022). Trends were seen towards lower levels of complement factor C3 and C4. No difference was found in the presence of focal sialadenitis and in dryness severity.
Conclusions US of the parotid gland is a non-radiating, easy to perform and rapid bedside investigation. The typical pattern of multiple hypoechogenic lesions has high specificity for pSS and might be suitable as substitute for the more invasive parotid sialography or less specific scintygraphy within the classification criteria. Furthermore patients with these lesions have higher disease activity and more severe histological aberrations and may be at risk for lymphoma development.
Hocevar A, Ambrozic A, Rozman B, Kveder T, Tomsic M. Ultrasonographic changes of major salivary glands in primary Sjogren’s syndrome. Diagnostic value of a novel scoring system. Rheumatology (Oxford) 2005;44:768-72.
Disclosure of Interest None Declared
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