Section 5. Bone, Joint, and Muscle Disorders

Chapter 68. Autoimmune Disorders of Connective Tissue

Topics: Introduction | Systemic Lupus Erythematosus | Scleroderma | Sjögren's Syndrome | Polymyositis and Dermatomyositis | Mixed Connective Tissue Disease | Relapsing Polychondritis | Eosinophilic Fasciitis

Sjögren's Syndrome

Sjögren's syndrome is characterized by excessive dryness of the eyes, mouth, and other mucous membranes.

Sjögren's syndrome is thought to be an autoimmune disorder, but its cause is not known. It is more common in women than in men.

White blood cells infiltrate the glands that secrete fluids, such as the salivary glands in the mouth and the tear glands in the eyes. The white blood cells injure the glands, resulting in a dry mouth and dry eyes--the hallmark symptoms of this syndrome.

Symptoms

In some people, only the mouth or eyes are dry (a condition called sicca complex or sicca syndrome). Dryness of the eyes may severely damage the cornea, resulting in a scratchy or irritated sensation, and a lack of tears can cause permanent eye damage. Insufficient saliva in the mouth can dull taste and smell, make eating and swallowing painful, and cause cavities. The salivary glands in the cheeks (parotids) become enlarged and slightly tender in about one third of people. The mouth may also burn, which may sometimes indicate a complicating yeast infection.

In other people, many organs are affected. Sjögren's syndrome can dry out the mucous membranes lining the digestive tract, windpipe (trachea), vulva, and vagina. Dryness of the trachea and lungs can make these organs more susceptible to infection, leading to pneumonia. Dryness of the vulva and vagina can make sexual intercourse difficult. The protective sac surrounding the heart (pericardium) may be inflamed--a condition called pericarditis. Nerve, lung tissue, and other tissues may be damaged by the inflammation.

Joint inflammation (arthritis) occurs in about one third of people, affecting the same joints that rheumatoid arthritis affects, but the joint inflammation of Sjögren's syndrome tends to be milder and is usually not destructive. Some people also have severe rheumatoid arthritis or systemic lupus erythematosus.

Lymphoma, a cancer of the lymphatic system, is much more common in people who have Sjögren's syndrome than in the general population.

Diagnosis

Although a sensation of dry mouth or dry eyes is fairly common, a sensation of dry mouth and dry eyes accompanied by joint inflammation probably indicates that the person has Sjögren's syndrome. Various tests can help a doctor diagnose this disorder and differentiate it from other connective tissue disorders that can produce similar symptoms.

The amount of tears produced can be estimated by placing a filter paper strip under each lower eyelid and observing how much of the strip is moistened (Schirmer test). A person who has Sjögren's syndrome may produce less than one third of the normal amount. An ophthalmologist can test for damage to the eye's surface. More sophisticated tests to evaluate salivary gland secretion may be performed, and a doctor may order scans or a biopsy of the salivary glands.

Blood tests can detect abnormal antibodies, including SS-B, an antibody that is highly specific for Sjögren's syndrome. Often, people with Sjögren's syndrome also have antibodies that are more characteristic of rheumatoid arthritis or lupus. The erythrocyte sedimentation rate (ESR), a test that measures the rate at which red blood cells settle to the bottom of a test tube containing blood, is elevated in about 7 of 10 people. About 1 of 3 people has a decreased number of red blood cells (anemia) or of certain types of white blood cells (leukopenia).

Prognosis and Treatment

The prognosis is generally good. However, if the lungs, kidneys, or lymph nodes are damaged by the antibodies, pneumonia, kidney failure, or lymphoma may result.

No cure for Sjögren's syndrome is available, but symptoms can be relieved. Dry eyes can be treated with artificial tear drops. A dry mouth can be moistened by continuously sipping liquids, chewing sugarless gum, or using a mouth rinse. Drugs that reduce the amount of saliva, such as decongestants, antidepressants, and antihistamines, should be avoided because they can worsen the dryness. The drug pilocarpine may help stimulate the production of saliva if the salivary glands are not too severely damaged.

Fastidious dental hygiene and frequent dental visits can minimize tooth decay and loss. Painful, swollen salivary glands can be treated with analgesics. Because joint symptoms are usually mild, treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) and rest is often sufficient. When symptoms resulting from damage to internal organs are severe, corticosteroids such as prednisone given by mouth can be useful.