Recognizing and Managing the Oral Clues That Point to Sjögren's Syndrome

, State University of New York at Buffalo

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In This Article

Editorial Comment: Diagnostic Confusion in Sjögren's Syndrome

Sjögren's syndrome (SS) is marked by several points of confusion, including what causes it and how to diagnose it.

There are no uniformly accepted criteria for diagnosis of SS. The San Diego or San Francisco criteria require objective evidence of decreased tear production that results in an ocular inflammatory condition called keratoconjuncitivitis sicca, decreased salivary flow rate, evidence of autoantibodies such as the antinuclear antibody (ANA), and often an abnormal minor salivary gland biopsy. In comparison, the European Community criteria permit the diagnosis of SS in the absence of abnormal autoantibodies or lip biopsy. As a result, many patients who are labeled "SS" using the European criteria would not be diagnosed with SS according to the San Diego or San Francisco criteria. Only about 15% of the patients diagnosed with SS using the European critera would be diagnosed with SS on the basis of the San Diego criteria. Using San Diego criteria, about 0.5% of adult women have SS, whereas the incidence is about 7-fold higher if the European criteria are used.

In today's world of managed care and multiple specialists, treatment options are closely tied to the diagnostic code, so it is important to precisely make the correct diagnosis. If the term SS is used to indicate an "autoimmune disease," then the physician's attention and therapeutic approach is directed toward the immune system. However, many patients classified as having SS by the European system do not show evidence of a systemic autoimmune disorder, and they should be reassured about the "intactness" of their immune system, rather than subjected to therapy that may have side effects. Also, the label of SS may divert the physician from looking for other treatable causes of dryness, such as medications that cause dryness, or infections (such as hepatitis C) that may contribute to symptoms.

Among the majority of SS patients diagnosed with the San Diego criteria, the symptoms remain limited to dry eyes, dry mouth, and, often, dry upper airways. The symptoms are managed by artificial tears, a program of active oral hygiene, and often the use of medications to stimulate the secretion of saliva and tears. Frequently, the biggest challenge is treating the next most common complaint in SS patients--fatigue associated with flu-like symptoms. Fatigue may be due to an active autoimmune process, as indicated by lab tests such as a high erythrocyte sedimentation rate (ESR), a high C-reactive protein (CRP), or high immunoglobulin levels. On the other hand, fatigue may be due to nonimmune processes such as disrupted sleep patterns (often secondary to getting up at night to urinate or experiencing nocturnal leg cramps) or other problems such as a low thyroid hormone level. Among patients with an active "autoimmune process," manifestations may include disorders of the skin, lungs, kidneys, and nervous system. Medications similar to those used in SLE patients are often required to treat these manifestations or prevent complications such as vasculitis. Although the risk of lymphoma is statistically increased among SS patients in comparison to age-matched controls, the actual incidence remains low, and SS patients need to be reassured of this.

The cause of SS remains unknown, but this is also true of most autoimmune diseases. From studies of identical twins, we know that genetic and environmental factors play a role. At least 4 or 5 different genes serve in "co-accelerator" roles. Owing to the multigene requirements, it is unlikely (less than 10% probability) that a child or sibling will develop SS. Some of the genes that predispose to SS (called HLA-DR genes) play a role in stimulation of the immune system; others play a role in terminating the immune response through a process of cell death termed apoptosis. The environmental factors important in SS also remain unknown. Indirect evidence has pointed to members of the herpes virus family (including Epstein Barr virus, EBV) as possible candidates, since these viruses have "latency" in the salivary glands of all normal individuals. For example, it has long been known that infectious mononucleosis (caused by EBV) is transmitted as the "kissing disease" due to passage of saliva containing the virus. However, it needs to be stressed that SS is not the same thing as "chronic EBV" disease, which refers to a vague series of symptoms including chronic fatigue.

Robert I. Fox, MD, PhD
Division of Rheumatology
Scripps Clinic and Research Foundation
La Jolla, Calif.

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