Salivary gland scintigraphy for the primary Sjögren syndrome
ACP J Club. 1993 Sept-Oct;119:51. doi:10.7326/ACPJC-1993-119-2-051
Markusse HM, Pillay M, Breedveld FC. The diagnostic value of salivary gland scintigraphy in patients suspected of primary Sjögren's syndrome. Br J Rheumatol. 1993 Mar;32:231-5.
To assess the diagnostic value of salivary gland scintigraphy in the primary Sjögren syndrome.
A blinded assessment of salivary gland scintigraphy used to diagnose the primary Sjögren syndrome.
A rheumatology clinic in the Netherlands.
149 consecutive patients (124 women) with arthralgias or myalgias, or both; oral or ocular dryness, or both; and abnormal Schirmer tests. 20 women with other soft tissue disease acted as control patients. Exclusion criteria were other connective tissue diseases and oral or ocular dryness associated with medications.
Description of test and diagnostic standard
The salivary glands were imaged serially after the administration of 120 MBq of 99mTc pertechnetate. Patients were supine with the gamma counter acquiring images anteriorly every minute for 1 hour. The salivary gland was stimulated with lemon juice at 45 minutes. An observer, blinded to the final diagnosis, read uptake and excretion values (1 point for each abnormality up to 8 points). Scintigrams were considered abnormal if at least both parotid or both submandibular glands showed a diminished uptake or excretion. The final diagnosis of the Sjögren syndrome was based on the California criteria (inclusion criteria based on keratoconjunctivitis sicca; xerostomia; objective evidence of salivary gland involvement; and laboratory evidence of systemic autoimmune disease; plus exclusion criteria based on the absence of other diseases).
Main outcome measures
Sensitivity, specificity, and positive predictive values of salivary gland scintigraphy.
26 patients (17%) had the primary Sjögren syndrome. This group differed from the remaining patients in erythrocyte sedimentation rate; presence of serum rheumatoid factor; antinuclear antibodies; antibodies to the soluble antigens SS-A and SS-B; number of patients with abnormal sialographic results; and presence of grade 4 histologic results of salivary gland tissue (P < 0.001 for each). The sensitivity and specificity for the primary Sjögren syndrome of scintigraphic scores of 2 or more abnormalities were 73% and 54%; for scores of ≥ 4, 62% and 66%; and for scores of ≥ 6, 23% and 88%. The positive predictive value of an abnormal scintigram was 25%, and the negative predictive value of a normal scintigram was 90%.
Salivary gland scintigraphy has limited diagnostic value for the primary Sjögren syndrome.
Source of funding: Not stated.
For article reprint: Dr. H. Markusse, Department of Rheumatology, Dr. Daniel Den Hoed Clinic, P.O. Box 5201, 3008 AE Rotterdam, Netherlands. FAX 31-10-486-1058.
Prototypical primary Sjögren syndrome poses little diagnostic challenge. Lacrimal function is inadequate to serve corneal viability, and salivary function is insufficient to avoid vicious carious and periodontal disease. Most patients are women; have the haplotype HLA-DR3; and have high titers of rheumatoid factor and precipitins to Ro(SS-A). Some have further immunodysregulation that manifests as monoclonal gammopathies; immune complex disorders; and lymphoproliferative disorders. This is a disease to be reckoned with (1); fortunately, it is rare.
Its specter weighs heavily, however, in the minds of diagnosticians and, thanks to the lay press, of many people with dry eyes or mouths. Consultants are asked to diagnose the sentinent stage of a disease. The literature is daunting; Dr. Markusse and colleagues offer no encouragement, but they do reinforce insights that need wider dissemination.
Only 26 of 149 patients with positive Schirmer tests reached Markusse's level of clinical confidence for a diagnosis of the Sjögren syndrome. The conclusion is that a positive Schirmer test is meaningless, and it should be removed from any diagnostic algorithm, as should tests of salivary flow rates.
Gross acinar destruction is an explicative salivary histopathologic result. It is also rare and usually confirms what is clinically obvious. Lymphorrhages are nonspecific and are variable in the tissue and over time. They are not diagnostically persuasive. This is also true for ductal distortion on sialography.
Precipitating antibodies to Ro(SS-A) were detected in 12 of the 26 patients thought to have the Sjögren syndrome and no others. Interesting? Yes, but with provisos. Precipitating antibodies may indicate a risk for any rheumatic disease, not just the Sjögren syndrome, which may remain subclinical. If the assay is rendered more sensitive, then its specificity for rheumatic disease is compromised; similar results occur after using the antinuclear antibodies.
Whether the patient with dry eyes or mouth and little else has subclinical Sjögren syndrome is indeterminate. This anxious person needs wise counsel, reassurance, and expectant observation
Nortin M. Hadler, MD
University of North Carolina Chapel Hill, North Carolina, USA