Introduction
Sjögren's syndrome is a chronic systemic autoimmune disease characterized by dysfunction of the exocrine glands and is often accompanied by systemic manifestations. The lacrimal and salivary glands are most commonly affected, resulting in distressing symptoms such as xerostomia and dry keratoconjunctivitis. Primary Sjögren's syndrome (when there are no other signs of autoimmune disease) and secondary Sjögren's syndrome (developing in patients with other autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, etc.) are distinguished. Women are affected by this disease nine times more often than men, particularly during the postmenopausal period. The average age of patients is 50-60 years, although people of various ages and both sexes may be affected (1, 2).
In this article, we will review the epidemiology, clinical features, and main aspects of the diagnosis and treatment of Sjögren's syndrome.
Epidemiology and Pathogenesis of Sjögren's Syndrome
The prevalence of the disease varies depending on the classification criteria used, the study design, the population studied, and the sample size. According to a study conducted in Norway, the overall prevalence of the disease in the 40-44 age group was 0.22%, while in the 71-74 age group it was six times higher. The disease was diagnosed according to refined European criteria. Primary Sjögren's syndrome is diagnosed in 1-3% of the general population, whereas secondary Sjögren's syndrome affects as many as 10-20% of patients with rheumatoid arthritis, scleroderma, or systemic lupus erythematosus (2, 5).
The causes of Sjögren's syndrome continue to be investigated, and the precise pathogenetic mechanisms remain unclear. It is believed that environmental factors trigger inflammatory processes in the glands of individuals with a genetic predisposition to the disease. Primary Sjögren's syndrome is an autoimmune disorder in which lymphocytes accumulate in the salivary and lacrimal glands, leading to glandular destruction and the production of autoantibodies against the ribonucleoproteins SS-A/Ro and SS-B/La. Glandular epithelial cells become activated, cytokines and chemokines are stimulated, B-lymphocyte proliferation and differentiation are promoted, and autoantibodies are produced. These processes lead to local glandular inflammation. Over time, the inflamed glandular tissue undergoes atrophy, fibrotic changes develop, and signs of gland hypofunction appear. Glomerulonephritis and vasculitis develop as a result of immune complex deposition (2, 3, 5).
Clinical Features of the Disease
The main symptoms of Sjögren's syndrome are dryness of the eyes and mouth. Damage to the lacrimal glands manifests as dry keratoconjunctivitis. Patients complain of:
- itching, stinging, burning, or a scratching sensation in the eyes;
- a feeling of a foreign body or sand in the eyes;
- eye grittiness, redness, tearing, and eyelid swelling;
- sensitivity to light;
- sticky mucus in or around the eyes in the morning;
- blurred or foggy vision.
Symptoms often worsen in smoky or dusty environments, in dry, hot air, in air-conditioned rooms, or in drafts. In severe cases, complications of dry keratoconjunctivitis may occur, including corneal thinning and scarring, bacterial keratitis, blepharitis, and worsening vision.
The main sign of salivary gland dysfunction is xerostomia, or simply dry mouth, which is manifested by:
- food, especially dry food, sticking in the mouth or throat;
- changes in the tongue, which becomes smooth, with cracks and atrophy of the taste buds;
- the need to constantly drink water while eating in order to swallow food;
- difficulty chewing due to food particles sticking to the teeth;
- burning and dryness in the mouth, as if it were full of sand;
- increased thirst and changes in taste;
- hoarseness and difficulty breathing and speaking through the mouth;
- cracking and peeling at the corners of the lips;
- occasional enlargement of the major salivary glands (parotid, submandibular, and sublingual).
Some patients experience itching and dryness of the vaginal mucosa, leading to painful sexual intercourse. Sjögren's syndrome may also manifest with systemic symptoms such as chronic fatigue, arthralgia, myalgia, myositis, intermittent low-grade fever, non-erosive symmetrical polyarthritis, Raynaud's syndrome, and palpable purpura (cutaneous vasculitis). Kidney involvement occurs in 2-67% of patients diagnosed with Sjögren's syndrome and is manifested as chronic interstitial nephritis and, less commonly, glomerulonephritis. Gastrointestinal tract involvement is less common and may include dysphagia, nausea, and possible atrophic gastritis (1-5).
With the onset of the above symptoms, patients' quality of life and ability to adapt to daily activities deteriorate.
Dr. Elvyra Vasilevskaja
Vilnius City Clinical Hospital
Continuation in the "Internist" magazine No. 1, 2019.
