The usefulness of ultrasound in the diagnostics of Sjögrens's syndrome.

Sjögren's syndrome (SS) poses often a diagnostic challenge. Different clinical presentations can mimic the syndrome and although there exists no causal treatment, establishing or missing the diagnosis has serious socioeconomic consequences. By early diagnosis and prompt introduction of replacement therapies some of them may be delayed or avoided.

A number of diagnostic criteria sets have been proposed over the recent years(, the most accepted being the American-European Consensus Group criteria. They include also imaging methods, albeit only invasive ones.

Therefore, ultrasound can potentially fulfill the role, avoiding the invasiveness of the presently employed methods(.

The paper by Saied et al. published in 53rd issue of “Journal of Ultrasonography” is a thorough review of the potential role of ultrasound (US) in establishing the diagnosis of SS(. It shows in a systematic way that parenchymal heterogeneity of the parotid and submandibular glands is the most reliable US feature for classifying the patient as having SS.

The evidence provided in the review suggests that certainty of diagnosis may be strengthened by adding the US criterion to the already existing classifications.

It is difficult not to see the parallel between the classification criteria for rheumatoid arthritis (RA) as suggested by the American College of Rheumatology/European League Against Rheumatism and the potential new criteria for SS including US. Although the role of the imaging methods (magnetic resonance imaging – MRI and US) was only weakly mentioned and not satisfyingly characterized in the original publication, that was the first step towards accepting the modern techniques as potentially powerful tools in diagnosing RA(.

This path may now also open for US in bringing the diagnosis of SS closer.

Obviously, there still exist difficulties and unresolved issues in the extent of the role of US, especially the questions of the pace at which structural changes develop in the glands, function of the size of the glands, usefulness of Doppler modalities, differentiation between changes in primary and secondary SS, but the method's possible influence on establishing the diagnosis of SS cannot be rejected.

It should not be forgotten that US has also another and even more practical use in monitoring patients with already established diagnosis of SS. With its risk for developing lymphomas in the course of the disease in superficial structures such as the parotid or salivary glands, US is the most applicable method of follow-up of patients with SS. The suspicion may of course, in doubtful cases, lead to further investigations with MRI or computed tomography, but practical issues suggest that the primary follow-up method may be US.