Sjogren's syndrome

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In rheumatology, Sjogren's syndrome is a "chronic inflammatory and autoimmune connective tissue disease in which the salivary and lacrimal glands undergo progressive destruction by lymphocytes and plasma cells resulting in decreased production of saliva and tears."[1]

Etiology

The mechanism of disease is the action of lymphocytes (white blood cells) target and attack two kinds of exocrine gland: lacrimal and salivary glands. Both tears and saliva will diminish in quantity and quality after the attack.

There could be a combination of genetic and environmental factors. Researchers believe different genes may affect different ethnic groups. Having this gene does not guarantee developing Sjogren’s Syndrome as there has to be a disease trigger to activate the immune system. It is not known whether this trigger is viral or bacterial.

“Scientists think that the trigger may be a viral or bacterial infection. It might work like this: a person who has a Sjogren’s-associated gene gets a viral infection. The virus stimulates the immune system to act, but the gene alters the attack, sending fighter cells (lymphocytes) to the glands of the eyes and mouth. Once there, the lymphocytes attack healthy cells, causing the inflammation that damages the glands and keeps them from working properly. This is an example of auotoimmunity. These fighter cells are supposed to die after their attack in a natural process called apoptosis, but in people with Sjögren’s syndrome, they continue to attack, causing further damage. Scientists think that resistance to apoptosis may be genetic. The possibility that the endocrine and nervous systems play a role in the disease is also under investigation,” according to NIAMS.

History

Sjogren’s Syndrome was discovered by Swedish ophthalmologist Dr. Henrik Sjogren (1899-1986) In his 1933 thesis, he reported 19 female patients exhibited some of the best known symptoms of Sjogren’s syndrome. Of those 19 women studied, 13 of them were diagnosed with chronic arthritis along with eye and mouth dryness,[2]

Symptoms

A wide range of symptoms is reported in Sjogren’s Syndrome. Some symptoms can include dry eyes, dry mouth, joint and muscle pain, prolonged dry skin, skin rashes on the extremities, chronic dry cough and vaginal dryness.

The eyes may burn or itch. Some patients may have problems with blurry vision or bright lights such as fluorescent lighting.

Patients may report their mouth feels like dry cotton or may feel chalky. There could be problems with swallowing, speaking and taste. Dental cavities (caries) and mouth infections may occur due to the lack of saliva.

Primary Sjogren’s Syndrome patients may more keenly feel the effects of Sjogren’s Syndrome. Secondary patients may have less Sjogren’s symptoms, but they may have to contend with other associated symptoms based on their primary autoimmune illness. Some of the diseases associated with Sjogren’s Syndrome include polymyositis, rheumatoid arthritis (RA), scleroderma and systemic lupus erythematosus (SLE).

Diagnosis

Examinations

  • Schirmer test. This test measures tears to see how the lacrimal (tear) glands are working. The doctor puts thin paper strips under the lower eyelids and measures the amount of wetness on the paper after 5 minutes. People with Sjogren's syndrome usually produce less than 8 millimeters of tears.
  • Slit lamp examination. This test, in which an ophthalmologist uses equipment to magnify and carefully examine the eye, shows how severe the dryness is and whether the outside of the eye is inflamed.
  • Staining with vital dyes (rose bengal or lissamine green). These tests show the extent to which dryness has damaged the surface of the eye. To perform one of these tests, the doctor puts a drop of a liquid containing a dye into the lower eyelid. The dye stains the surface of the eye, highlighting any areas of injury, thereby allowing the doctor to see with the slit lamp how much damage has occurred on the surface of the eye.
  • Mouth exam. The doctor will look outside the mouth for signs of major salivary gland swelling and inside the mouth for signs of dryness. Signs of dry mouth include a dry, sticky lining (called oral mucosa); dental caries (cavities) in characteristic locations; thick saliva, or none at all coming out of the major salivary ducts; redness of the mouth lining, often associated with a smooth, burning tongue; and sores at the corners of the lips. The doctor might also try to get a sample of saliva, to check its quality and see how much of it the glands are producing.
  1. Lip biopsy. This test is the best way to find out whether dry mouth is caused by Sjogren’s syndrome. To perform this test the doctor removes tiny minor salivary glands from the inside of the lower lip and examines them under the microscope. If the glands contain white blood cells in a particular pattern, the test is positive for the salivary component of Sjogren's syndrome. Because there are many causes of dry eyes and dry mouth (including many common medications, other diseases, or previous treatment such as radiation of the head or neck), the doctor needs a thorough history from the patient, and additional tests to see whether other parts of the body are affected.

Laboratory

Basic

Routine blood tests are useful in this diffuse disease, including a complete blood count, blood sugar, liver function and renal function tests.

  • Chest x ray. Sjogren’s syndrome can cause inflammation in the lungs, which will be visible on X-ray
  • Urinalysis. Urine tests contribute to the assessment of kidney function

Immunologic

Various blood tests may be performed to check for antibodies and other immunological substances often found in the blood of people with Sjogren’s syndrome. Immune substances that are normally present may be in unusual quantites or proportions, and antibodies not normally present may be demonstrable.

  • Immunoglobulins. The three main classes of immunoglobulins can be measured to see if there is a general increase in antibodies.
  • Antithyroid antibodies. Autoantibodies against the thyroid gland are created when lymphocytes migrate into the thyroid gland, causing thyroiditis (inflammation of the thyroid), a common problem in people with Sjögren’s syndrome.
  • Rheumatoid factor (RF). is often elevated in this disease
  • Anti-nuclear antibodies (ANAs). These are autoantibodies directed at the cells’ nuclei. The presence of ANAs in the blood can indicate an autoimmune disorder, including Sjogren's syndrome.
  • Sjögren’s antibodies, anti-SS-A antibodies (or Anti-Ro) and anti-SS-B (or Anti-La). These are specific antinuclear antibodies that occur commonly, but not always, in people with Sjogren’s syndrome.

References