Mixed connective tissue disease (MCTD) is a chronic inflammatory autoimmune disease characterized by joint pain, muscle weakness, cardiac, lung, and skin manifestations, kidney disease, and dysfunction of the esophagus. MCTD describes a collection of symptoms that may have similarities to lupus, scleroderma, and other connective tissue diseases but is not strictly diagnosable as one of those conditions because signs and symptoms overlap.
Diagnosis of MCTD can be difficult, as it may feature simultaneous symptoms of lupus, scleroderma, and rheumatoid arthritis. Sometimes, MCTD is a precursor to a later diagnosis of one of these conditions. In other cases, it’s considered a condition on its own and never progresses to full lupus, scleroderma, or rheumatoid arthritis.
MCTD can occur at any age, with the average age of onset in the teens to 30s. Eight out of ten patients are women. The disease occurs in all races and is found worldwide. The prevalence is not known, but it’s thought to be somewhat less than lupus, which affects 15 to 50 people in 100,000.
Symptoms of MCTD usually include:
- Raynaud’s phenomenon, causing increased sensitivity of the fingers and toes to the cold, changes in skin color, pain, and occasionally ulcers of the fingertips or toes
- Arthritic pain and aches in joints, and weakness and pain in muscles, especially in the shoulders and hips
- Swollen hands, sausage-like fingers, swollen or red patches over the knuckles
- Lung disease, including pleuritis, shortness of breath on exertion, or, more rarely, pulmonary hypertension
- Lupus-like rashes, including a butterfly-shaped, purple-colored rash on the cheeks and nose bridge
- Spider veins on the face and hands
- Small patches of hair loss or thinning hair
- Shortness of breath
- Swollen lymph nodes
- Abdominal pain, heartburn
- Hoarseness, difficulty swallowing
- Dry eyes and dry mouth
In a small percentage of patients, kidneys can be affected, butdamage is usually mild.
MCTD is diagnosed when lupus, scleroderma, and rheumatoid arthritis symptoms overlap. Bloodwork in MCTD patients may reveal
- High levels (often greater than 1:1,000) of antinuclear antibodies (ANAs)
- Positive rheumatoid factor
- High levels of anti-Ul-RNP antibodies
- Presence of anti-RNP antibodies
- Presence of anti-Ul-70 kD
- Antiphospholipid antibodies (including anticardiolipin antibodies and lupus anticoagulant)
- Moderate anemia
In the long term, as symptoms evolve, eventually lupus, scleroderma, or rheumatoid arthritis may be diagnosed.
A rheumatologist experienced in the diagnosis and treatment of MCTD should be involved in treatment of this condition. Other specialists, such as a pulmonologist, may be called in to help coordinate treatment, especially in the case of lung-related complications.
Treatment for MCTD is similar to lupus. Nonsteroidal anti-inflammatory agents (NSAIDs) are given to help reduce pain and inflammation, and may be the only drugs needed in mild MCTD. Low-dose oral corticosteroids or low-dose methotrexate is reserved for more serious and debilitating joint inflammation.
- Naproxen (Naprosyn, Naprelan, Aleve, Anaprox) can be used for inflammation and swelling.
- Celecoxib (Celebrex) and rofecoxib (Vioxx) are frequently used to treat muscle and joint pain related to MCTD.
- Calcium channel blockers such as nifedipine (Adalat, Procardia XL) may be recommended for Raynaud’s phenomenon.
- Omeprazole (Prilosec) is used for esophageal reflux.
- Antimalarial drugs such as hydroxychloroquine (Plaquenil) can be prescribed to help prevent disease flares.
- Corticosteroids such as prednisone (Deltasone) are used for active or severe disease.
- Cytotoxic agents such as cyclophosphamide (Cytoxan) are prescribed for major organ involvement.
Things to Know
With MCTD, symptom-free periods can last for years. In around 13 percent of people, MCTD can progress and become more serious or life-threatening. Secondary Sjogren’s syndrome occurs in 25 percent of patients with MCTD and may cause eye symptoms and dry mouth.