Mixed Connective Tissue Disease

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Mixed Connective Tissue Disease

Mixed connective tissue disease is a term used by some experts to describe a

collection of symptoms similar to those of systemic lupus erythematosus,

scleroderma, polymyositis, and dermatomyositis.

About 80% of people who have this disease are women. Mixed connective tissue

disease affects people from ages 5 to 80. Its cause is unknown, but it

appears to be an autoimmune disorder.

Symptoms

The typical symptoms are Raynaud's phenomenon (in which the fingers suddenly

become very pale and tingle or become numb in response to cold or emotional

upset (see Section 3, Chapter 34)), joint inflammation (arthritis), swollen

hands, muscle weakness, difficulty in swallowing, heartburn, and shortness

of breath. Raynaud's phenomenon may precede other symptoms by many years.

Regardless of how mixed connective tissue disease starts, it tends to

worsen, and symptoms spread to several parts of the body.

The hands are frequently so swollen that the fingers look like sausages. A

purplish butterfly-shaped rash on the cheeks and bridge of the nose, red

patches on the knuckles, a violet discoloration of the eyelids, and red

spider veins on the face and hands all may appear. Skin changes similar to

those in scleroderma also may occur. The hair may thin.

Almost everyone with mixed connective tissue disease has aching joints;

about 75% develop the swelling and pain typical of joint inflammation

(arthritis). Mixed connective tissue disease damages the muscle fibers, so

the muscles may feel weak and sore, especially in the shoulders and hips.

Although the esophagus is often affected, it seldom causes difficulty in

swallowing and is not painful. Fluid may collect in or around the lungs. In

some people, abnormal lung function is the most serious problem, causing

shortness of breath during exertion.

Occasionally, the heart is weakened, leading to heart failure (see Section

3, Chapter 25). Symptoms of heart failure may include fluid retention,

shortness of breath, and fatigue. The kidneys and nerves are affected in

only 10% of people, and the damage is usually mild compared to the damage

caused by lupus. Other symptoms may include a fever, swollen lymph nodes,

abdominal pain, and persistent hoarseness. Sjögren's syndrome may develop.

Over time, most people develop symptoms that are more typical of lupus or

scleroderma.

Diagnosis and Treatment

Doctors suspect mixed connective tissue disease when some symptoms from

lupus, scleroderma, polymyositis, or rheumatoid arthritis overlap.

Blood tests are performed to detect an antibody to ribonucleoprotein, which

is present in almost all people who have mixed connective tissue disease. A

high level of this antibody without the other antibodies present in lupus is

reasonably specific for mixed connective tissue disease.

The treatment is similar to that of lupus. Corticosteroids are usually

effective, especially when the disease is diagnosed early. Mild cases can be

treated with aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs),

quinacrine or similar drugs, or very low doses of corticosteroids. The more

severe the disease, the higher the dose of corticosteroid needed. In severe

cases, immunosuppressive drugs may also be needed.

In general, the more advanced the disease and the greater the organ damage,

the less effective the treatment. Scleroderma-like damage to the skin and

esophagus is least likely to respond to treatment. Symptom-free periods can

last for many years with little or no continuing treatment with a

corticosteroid. Despite treatment, mixed connective tissue disease

progresses in about 13% of the people, producing potentially fatal

complications in 6 to 12 years.