Sjogren's syndrome is a chronic illness caused by autoimmune phenomena, manifesting primarily in dryness of the eyes and the mouth.
First described by Henrik Sjogren in the beginning of this century, it affects between 400,000 and 3 million people in the world, and is primarily diagnosed in persons aged 45-55 years. About nine times as many females are affected as males.
Apart from these symptoms, the illness may also affect the lungs, kidneys, gut, and brain.
Sjogren's syndrome is caused when autoantibodies attack the salivary and lacrimal glands, resulting in xerostomia and keratoconjunctivitis sicca respectively. Parotid swelling may occur on one or both sides in over a third of patients, and may be mistaken for non-Hodgkin’s lymphoma which has a higher incidence in this group.
What illnesses are associated with Sjogren's syndrome?
Both primary and secondary forms of the disorder exist. In the primary form, there is no underlying illness, either at the time of the initial diagnosis or later.
In secondary Sjogren's syndrome, which accounts for over 50% of the cases diagnosed, other autoimmune diseases are present, including rheumatoid arthritis (20-30%), systemic lupus erythematosus (15-35%), systemic sclerosis (10-25%), and psoriatic arthritis.
Many people who are diagnosed with Sjogren's syndrome later find that they also have rheumatoid arthritis, or systemic lupus erythematosus, and vice versa. Other autoimmune diseases are also associated with this condition, and thus approximately one in two individuals has both Sjogren's syndrome and another autoimmune disorder.
Symptoms of Sjogren's syndrome may also mimic a number of other disorders, such as dry eyes due to radiation, for instance.
However, in most cases, Sjogren's syndrome does not seriously affect the quality of life or cause other illnesses.
Nevertheless, it is well to be aware of possible extraglandular involvement and disease complications so that they may be recognized and treated as early as possible.
Joint and muscle conditions
Muscle aches and joint pain, or whole body pain, may feel like the pain of fibromyalgia, which is also associated with dry eyes and mouth. This is because the autoimmune reaction may affect connective tissue via inflammation, throughout the whole body. Typically, a non-erosive polyarthritis occurs in about half of all patients.
Nervous system involvement
Manifestations in the nervous system include peripheral neuropathy affecting the limbs; numbness or other sensory phenomena of the nerves in 10-25% of patients; and sometimes brain lesions, appearing similar to multiple sclerosis.
Drying and itchiness of skin, sometimes with rashes, is seen in 10% of patients, usually as a vasculitis of the small and medium-sized vessels of the lower extremities. Other manifestations in the skin include annular erythema, urticarial rashes, and purpura due to the deposition of gamma globulins resulting from hypergammaglobulinemia.
Nephritis occurs in 5% of patients because of damage to the tubulointerstitial tissue of the kidney, often accompanied by distal renal tubular acidosis and causes muscular hypotonia due to low potassium levels.
Inflamed lungs may accompany this condition, causing pneumonia or bronchitis, hoarseness and chronic cough; normally, after years, the patient develops interstitial lung disease or follicular bronchiolitis.
Sjogren's syndrome may cause multiple other problems, including:
- Thyroid abnormalities, typically hypothyroidism
- Debilitating fatigue and cognitive problems
- Gut issues including bloating, diarrhea or abdominal pain
- Hepatitis or pancreatitis
- Dental caries are twice as common, with many patients losing their teeth early, because of the loss of saliva with its protective effect on the teeth
- Candida infections of the mouth are ten times more frequent in this group because of dryness of the mouth
- Visual problems due to dry eyes, with increased sensitivity to light, blurring of vision and damage to the cornea
Non B-cell Hodgkin’s lymphoma develops in 5% of all individuals with primary Sjogren's syndrome. Markers of this change include reduced complement levels, cryoglobulinemia, lymph node enlargement, permanent parotid swelling, and vasculitis of the skin. If a biopsy is done, it will show tissue masses which resemble ectopic germinal centers.
Such patients are at high risk and should be followed up by close monitoring, with appropriate tests like chest X-rays and abdominal ultrasound.
About 1.7% of women with Sjogren's syndrome who are pregnant and have anti-Ro/SSA and anti-La/SSB antibodies may experience pregnancy complications due to the ability of these molecules to cross the placenta. In the fetal circulation, they cause inflammation of the developing fetal heart, leading to congenital heart block.
Complete heart block and death may occur in the fetus. Pregnant patients require weekly monitoring of fetal cardiac function by ultrasound during the second trimester.