Mixed connective tissue disease is a rheumatic disease that has features shared by lupus, scleroderma, polymyosistis or dermatomyositis and rheumatoid arthritis.
When symptoms first appear, they may suggest that the person affected has any one of several rheumatic diseases. However, when a person has mixed connective tissue disorder, the symptoms aren't as severe or as widespread as they would be if the person has lupus, scleroderma, rheumatoid arthritis or other rheumatic disorder.
This condition has many symptoms, including:
- Pain in two or more joints. Almost all persons with mixed connective tissue disease have this symptom. Three out of four persons with the condition have arthritis and may have the swollen, deformed joints of rheumatoid arthritis.
- Raynaud's phenomenon. This symptom may appear years before any other.
- Skin changes. These can be like those of lupus or red patches over the knuckles, violet discolorations of the eyelids, loss of hair over the body and abnormal opening up (dilation) of the capillaries of the hands and face that may form a tumor
- Swollen hands. This is the most common symptom. With time, the fingers look more and more like sausages.
- Muscle weakness. There may sometimes also be tenderness.
- Difficulty swallowing and keeping food in the stomach.
- Loss of sensation in the nerves of the face and head.
- Lung disorders. Nearly 80% of the people with mixed connective tissue disease have some involvement of the lungs. Symptoms can include inflammation of the lining that covers the lungs and the inside of the chest, difficulty breathing or pulmonary hypertension.
- Kidney disease. Only about one out of every 10 patients has this symptom, which is often mild. In some cases, however, it can become life threatening.
It isn't yet known what causes this disease. In some cases, it gets worse and develops into scleroderma or lupus. Several factors, however, suggest that mixed connective tissue disease is a distinct disorder in its own right. These include symptoms shared by several rheumatic conditions, the presence of certain antibodies, abnormalities in the system that regulates the body's immune response and frequent pulmonary hypertension.
A rheumatologist may suspect mixed connective tissue disease if a patient appears to have lupus, scleroderma, vasculitis, polymyositis, Sjögren's syndrome, lymphoma or viral pericarditis but also has symptoms of the other conditions as well.
Your doctor may order:
- Blood tests to measure antibodies or the presence of the rheumatoid factor, among other things
- Electromyogram. This is a type of image that is made by recording the electrical activity of the muscles. It helps measure how well the nerves and muscles are communicating with each other.
- Muscle biopsies. This involves taking a sample of muscle tissue to exam under a microscope. If a person has mixed connective tissue disease, there will be signs of damage to the muscle fibers.
This condition is treated much like lupus. Corticosteroids, especially when given early in the course of the disease, can be helpful in managing the symptoms.
Mild forms of the condition can be controlled with nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, antimalarial drugs or very low doses of corticosteroids. In some patients, the symptoms disappear for many years (go into remission) and don't require ongoing corticosteroids.
Mixed connective tissue disease can cause life-threatening complications such as pulmonary hypertension, kidney failure, heart attack, infections, stroke or the development of holes in the colon (the lower part of the large intestine). In these cases, patients need stronger treatment. This usually includes larger doses of corticosteroids.
