Definition
Sjögren's syndrome is a chronic autoimmune disease caused by the immune system mistakenly attacking the body's own cells and tissues. Named after the Swedish ophthalmologist Henrik Sjögren, who first described the disease in the 1930s, the syndrome is best known for its effect on the glands responsible for the production of tears and saliva. However, the disease can extend far beyond these glands and affect many different organs and systems in the body.
Primary and secondary Sjögren's syndrome
- Primary Sjögren's syndrome: This occurs when the disease occurs on its own, without the presence of another disease, particularly another autoimmune disease.
- Secondary Sjögren's syndrome: This is a form of the syndrome that occurs in conjunction with other autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus or systemic sclerosis.
Pathogenesis: How does Sjögren's syndrome develop?
The exact cause of Sjögren's syndrome is not yet fully understood, but it is thought that a combination of genetic, environmental and hormonal factors play a role.
- Genetic factors: There is evidence that genetic predisposition plays a role, as Sjögren's syndrome is more common in some families. Certain genetic markers, such as HLA-DR and HLA-DQ, have been associated with an increased risk of developing the disease.
- Environmental factors: Environmental factors such as viral infections could act as triggers for Sjögren's syndrome. Some studies have identified viruses such as the Epstein-Barr virus and hepatitis C virus as possible triggers that could activate the immune system and trigger an autoimmune reaction.
- Hormonal factors: The fact that women are more frequently affected by Sjögren's syndrome than men (ratio about 9:1) suggests a hormonal influence. Oestrogen, a female sex hormone, could influence the immune system and contribute to the development of the disease.
Symptoms: How does Sjögren's syndrome manifest itself?
The symptoms of Sjögren's syndrome are diverse and can vary greatly from person to person. The most common and characteristic symptoms affect the lacrimal and salivary glands.
Dry eyes (keratoconjunctivitis sicca)
Symptoms: Burning eyes, itching, a feeling of grains of sand in the eyes, sensitivity to light and blurred vision.
Consequences: Increased risk of eye infections and damage to the cornea.
Dry mouth (xerostomia)
Symptoms: difficulty speaking and swallowing, frequent thirst, cracked lips, bad breath and changes in taste.
Consequences: Increased risk of tooth decay, gum disease and oral infections.
Systemic symptoms
Sjögren's syndrome can also affect other organ systems and cause systemic symptoms, such as
- Joint pain and inflammation
- Muscle pain
- Chronic fatigue
- Skin dryness and rashes
- Swelling of the salivary glands
- Problems with other mucous membranes (nose, vagina)
- Gastrointestinal complaints
- In severe cases, Sjögren's syndrome can also affect internal organs such as the lungs, kidneys, liver, blood vessels and the nervous system.
Diagnosis: How is Sjögren's syndrome diagnosed?
The diagnosis of Sjögren's syndrome is complex and requires careful evaluation by a rheumatologist. The diagnosis is based on a combination of clinical symptoms, laboratory tests and special diagnostic tests.
- Medical history and physical examination: The doctor will take a detailed medical history and perform a thorough physical examination to detect signs of dryness and other symptoms.
- Blood tests:
- Autoantibodies: Tests for the presence of specific autoantibodies such as anti-Ro/SSA and anti-La/SSB, which are detectable in many patients with Sjögren's syndrome.
- Inflammation markers: determination of inflammation parameters such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) as well as organ-specific parameters
- Special tests:
- Schirmer test: Measures tear production by placing a strip of filter paper under the lower eyelid and measuring the amount of tear fluid after 5 minutes.
- Sialometry: Measures saliva production by collecting and measuring the amount of saliva produced within a certain time.
- Salivary gland biopsy: A small tissue sample is taken from the salivary glands (usually from the lower lip) and examined for inflammatory changes.
Diagnostic criteria: ACR/EULAR 2016 classification criteria for Sjögren's syndrome
A point system is used to make a diagnosis. A patient is classified as suffering from Sjögren's syndrome if they score a total of at least 4 points and report at least one typical symptom of dryness of the eyes or mouth.
Core criteria and scoring:
- Positive biopsy of the salivary glands (focus score ≥1) (3 points): A focus score of ≥1 means that at least one focus of ≥50 lymphocytic cells was found in a 4 mm² tissue area in a biopsy of the minor salivary glands.
- Anti-Ro/SSA antibody positive (3 points): The presence of anti-Ro/SSA antibodies in the blood is a strong indication of Sjögren's syndrome.
- Objective evidence of eye dryness (2 points): Positive results in at least one of the following tests:
- Schirmer test (without anesthetic): ≤5 mm in 5 minutes.
- Eye coloration according to van Bijsterveld: score ≥4.
- Objective evidence of dry mouth (1 point): Positive results in at least one of the following tests:
- Non-stimulated salivary flow rate: ≤0.1 ml/min.
- Positive salivary gland scintigraphy.
- Positive parotissialography.
Further diagnostic indications:
While the above criteria are mainly used for classification, the following additional tests and observations can support the diagnosis and influence disease severity and management:
- Blood tests:
- Rheumatoid factor (RF)
- Antinuclear antibodies (ANA)
- Other imaging techniques:
- Ultrasound of the salivary glands to assess the structure of the glands.
Other symptoms and concomitant diseases: Concomitant symptoms such as joint pain, muscle pain and fatigue should also be taken into account.
Therapy: How is Sjögren's syndrome treated?
The treatment of Sjögren's syndrome aims to alleviate the symptoms and prevent complications, as there is currently no cure for the disease.
Symptomatic treatment
- Tear substitutes and eye gel: To relieve dry eyes.
- Saliva substitutes and frequent drinking: to combat dry mouth.
- Good oral hygiene and regular dental check-ups: To avoid dental problems.
Medication
- Cholinergics: Drugs such as pilocarpine and cevimeline can stimulate the production of saliva and tears.
- Immunosuppressants: Drugs such as hydroxychloroquine, methotrexate and corticosteroids can help to dampen the immune response in more severe cases.
New therapy options
- Research into Sjögren's syndrome is progressing and there are promising new therapeutic approaches that focus on specific mechanisms of the disease.
- Biologics: In addition to Rituximab, other monoclonal antibodies that block certain target molecules in the immune system are being researched.
- Janus kinase (JAK) inhibitors: These new drugs block specific enzymes involved in the immune response and are showing promising results in early studies.
- B-cell therapy: Since B cells play a key role in autoimmunity, some new therapies aim to influence these cells and reduce their activity.
Lifestyle and home remedies
- Avoid dry air and smoking: To relieve symptoms.
- Diet: A balanced diet can improve overall health and alleviate symptoms.
- Regular exercise: Can help reduce joint and muscle pain and combat general fatigue.
