Primary or essential Sjögren's syndrome is an autoimmune disease characterized by chronic lymphocytic inflammation of exocrine glands and resulting glandular hypofunction and dryness of mucosa.
Its primary symptoms are dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia).
Presence of autoantibodies (rheumatoid factor, anti-nuclear antibodies, ENAAb) is typical for the disease. Their absence in patients suffering from dry eyes and dry mouth speaks strongly against the diagnosis.
Topical treatment is used for dryness of mucosa. Extraglandular symptoms and complicated disease may be treated with glucocorticoids, hydroxychloroquine and immunosuppressive medication.
Secondary Sjögren's syndrome may occur in patients with other autoimmune diseases.
Prevalence
Applying strict diagnostic criteria, the prevalence of Sjögren's syndrome in the adult population is approximately 0.1%.
The prevalence of mild or subclinical disease is not known precisely but it is probably many times that of the disease fulfilling the strict criteria.
In postmenopausal women, the prevalence may be as high as 1-2%.
The first symptoms usually occur at the age of 30-50 years. The majority of patients (> 90%) are women.
The average time from the first symptoms (usually dry eyes, dry mouth or recurrent parotitis) to diagnosis is 7 years.
Various degrees of hypofunction of exocrine glands also occur in patients with other autoimmune diseases. In the secondary form of the disease symptoms of dryness are milder than in primary disease.
Symptoms and findings
Glandular symptoms
Daily dryness, foreign body or gritty sensation in the eyes with sensitivity to light
Disturbing daily dryness of the mouth, which complicates eating and speaking and disturbs sleep
Recurrent or constant swelling of salivary glands
Increased caries rate and rapid dental cavity formation
Impaired sense of taste and smell. There may be ulceration in the corners of the mouth. The skin is dry.
Dry irritant cough may be present as a respiratory symptom.
Dryness of the vulva and vagina, dyspareunia.
Extraglandular symptoms and signs
There may be purpura on the lower limbs (leukocytoclastic vasculitis, picture 1). Raynaud's phenomenon Raynaud's Phenomenon (RP) or White Finger Disease is mild. Small vessel vasculitis and subacute cutaneous lupus erythematosus are potential skin manifestations. Some patients have abnormal skin reactions to sunlight.
Fatigue, myalgia and joint pain are common. Arthritis is mild and myositis rare.
There is an increased risk of lymphoma Lymphomas. Lymphoma may be suggested by solid enlargement of parotid glands or the appearance of enlarged lymph nodes, which warrant a biopsy. Because the incidence of lymphoma is low on the population level, lymphoma is rarely seen in patients with primary Sjögren's syndrome despite the increased risk (as high as more than 40-fold).
Maternal anti-SS-A and anti-SS-B antibodies are associated with a fetal risk of cardiac conduction disorder; see Pregnancy below.
Laboratory tests
ESR levels are usually elevated, CRP normal.
Anaemia in association with chronic disease is mild, and leukocyte (lymphopenia) and platelet levels may be low.
Anti-nuclear antibodies detected by immunofluorescence occur in more than 80% of patients, and about 70-80% are rheumatoid factor positive.
Grouping of antinuclear antibodies (ENAAb) shows anti-SS-A (70-90%) and anti-SS-B antibodies (50-70%).
Polyclonal hypergammaglobulinaemia (S-Prot-Fr)
Complement C3 and C4 levels may be low. Cryoglobulinaemia is seen in approximately 10% of patients.
Chemical screening of the urine may show mild proteinuria.
Autoantibody tests and other laboratory tests show signs of any associated organ-specific autoimmune diseases.
All patients should be screened for coeliac disease and have thyroid antibody tests (TPOAb) done. If these are positive, duodenal biopsy or TSH and T4V tests should be performed.
If ALT and ALP are permanently elevated, tests for smooth muscle and mitochondrial antibodies (MitoAb) should be performed in addition to other liver tests
The diagnosis should be made in specialized care using classification criteria of year 2017.
The diagnosis requires at least 1 extraglandular symptom or at least 1 positive answer to the questions listed below, and, additionally, a total score of at least 4 points using the criteria below.
Have you had daily, persistent, troublesome dry eyes formore than 3 months?
Do you have a recurrent sensation ofsand or gravel in the eyes?
Do you use tear substitutes morethan 3 times a day?
Have youhad a daily feeling of dry mouth for more than 3 months?
Do you frequently drink liquids to aid in swallowing dry food?
Criteria
Labial salivary gland biopsy with focal lymphosytic sialadenitis and focus score of at least 1 focus/4 mm2= 3 points
Anti-SS-A positive = 3 points
OSS (Ocular Staining Score) ≥ 5 or van Bijsterveld score at least 4 in at least 1 eye = 1 point
Schirmer's test ≤ 5 mm/5 minutes in at least one eye = 1 point
The criteria are fulfilled if the total score is at least 4 and none of the following exclusion criteria are present: history of head and neck radiation treatment, active hepatitis C infection, AIDS, sarcoidosis, amyloidosis, graft-versus-host disease, IgG4-related disease.
Invasive diagnostic examinations (salivary gland biopsy) should be avoided as far as possible.
In everyday clinical work, a clinical diagnosis can usually be made based on autoantibodies (SS-A/SS-B, rheumatoid factor and anti-nuclear antibodies) and sicca symptoms and, if so, all required criteria need not be fulfilled. Schirmer's test Dry Eye Syndrome and unstimulated salivary flow rate Dryness of the Mouth can be performed also at the doctor's office.
Other causes of dry eyes: ageing, the menopause, medication, many skin disorders, allergies, hypothyroidism
Other causes of dry mouth: ageing, medication, the menopause, radiotherapy of salivary glands, anorexia, depression, labile diabetes
In practice, absence of autoantibodies and normal results from other laboratory tests (ESR, basic blood count, platelets, no hypergammaglobulinaemia) in a patient reporting dry eyes and/or dry mouth will exclude primary Sjögren's syndrome.
In patients with parotid gland swelling, particularly if unilateral, the possibility of an IgG4-associated disease and bacterial infection should be considered.
Pilocarpine has been used for the treatment of dry mouth. The dosage is 5 mg four times daily. However, the drug has a lot of adverse effects and it is not reimbursable.
Hydroxychloroquine (usually 300 mg once daily) is used primarily for the treatment of mild systemic symptoms, joint and skin symptoms. Low dose prednisone (5-7.5 mg once daily) can be added to the regimen for a short period of time.
The use of biological drugs is not established. Rituximab has been used in special cases.
Follow-up
Mild and uncomplicated primary Sjögren's syndrome: no regular follow-up or follow-up every 1-2 years in primary health care
Primary symptoms and targeted clinical examination, home monitoring of blood pressure
Visits to a dentist and oral hygienist
ESR, CRP, basic blood count with platelet count, creatinine, ALT, ALP, chemical screening of urine, TSH and T4V (thyroid tests every 2-3 years if TPOAb is positive)
Disease with severe symptoms or complications: follow-up in specialized care
Pregnancy
The risk of pregnancy complications (miscarriage, premature childbirth, low foetal weight, preeclampsia) is not increased; antiphospholipid antibodies are very rare.
The risk of congenital atrioventricular heart block is 1-2% if anti-SS-A antibodies are positive and 2-4% if both anti-SS-A and anti-SS-B antibody levels are high.
If a previous child has had atrioventricular block, the risk of recurrence in following children is 16-20%.
Mother's use ofhydroxychloroquineduring pregnancy apparently decreases the risk of atrioventricular block in the child. Beginning of medication in early pregnancy needs to be considered with the pregnant patient.
Follow-up at a mother and child welfare clinic and central/university hospital
References
Ramos-Casals M, Tzioufas AG, Stone JH et al. Treatment of primary Sjögren syndrome: a systematic review. JAMA 2010;304(4):452-60. [PubMed]
Brito-Zerón P, Izmirly PM, Ramos-Casals M et al. The clinical spectrum of autoimmune congenital heart block. Nat Rev Rheumatol 2015;11(5):301-12. [PubMed]
Shiboski CH, Shiboski SC, Seror R ym. 2016 American College of Rheumatology/European League Against Rheumatism classification criteria for primary Sjögren's syndrome: A consensus and data-driven methodology involving three international patient cohorts. Ann Rheum Dis 2017;76(1):9-16. [PubMed]