What is mixed connective tissue disease?

Mixed connective tissue disease (MCTD) is a rare autoimmune disorder. It’s sometimes called an overlap disease because many of its symptoms overlap with those of other connective tissue disorders, such as lupus, scleroderma, and polymyositis. Some cases of MCTD also share symptoms with rheumatoid arthritis.

There’s no cure for MCTD, but it can usually be managed with medication and lifestyle changes. It shouldn’t have much of an impact on your life expectancy. According to the National Institutes of Health, the 10-year survival rate of people MCTD is about 80 percent. That means 80 percent of people with MCTD are still alive 10 years after being diagnosed.

What are the symptoms?

The symptoms of MCTD usually show up in sequence over a number of years, not all at once.

About 90 percent of people with MCTD have Raynaud’s phenomenon. This is a condition characterized by severe attacks of cold, numb fingers that become blue, white, or purple. It sometimes occurs months or years before other symptoms.

Additional symptoms of MCTD vary from person to person, but some of the most common include:

Other possible symptoms include:

  • chest pain
  • stomach inflammation
  • acid reflux
  • trouble breathing
  • hardening or tightening patches of skin
  • swollen hands

What causes it?

The exact cause of MCTD is unknown. It’s an autoimmune disorder, meaning it involves your immune system mistakenly attacking healthy tissue. MCTD occurs when your immune system attacks the fibers that provide the framework for your body.

Are there any risk factors?

Some people with MCTD have a family history of it, but researchers haven’t found a clear genetic link.

According to the Mayo Clinic, it seems to be most common among women under 30, but it can strike at any age.

How is it diagnosed?

MCTD can be difficult to diagnose because it can resemble several conditions. It may look like scleroderma one year and rheumatoid arthritis the next.

To make a diagnosis, your doctor will give you a physical exam. They’ll also ask you for a detailed history of your symptoms. If possible, keep a log of your symptoms, noting when they happen and how long they last. This information will be helpful for your doctor.

If your doctor recognizes signs of MCTD, such as swelling around the joints, they may perform a blood test to check for certain antibodies associated with MCTD, such as anti-RNP, as well as the presence of inflammatory markers. They may also test blood for the presence of antibodies more closely associated with other autoimmune diseases to ensure an accurate diagnosis.

How is it treated?

Medication can help manage the symptoms of MCTD. Some people only require treatment when their disease flares up, but others may need long-term treatment.

Medications used to treat MCTD include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs). Over-the-counter NSAIDs, such as ibuprofen (Advil, Motrin) and naproxen (Aleve), can treat joint pain and inflammation.
  • Corticosteroids. Steroid medications, such as prednisone, can treat inflammation and help to stop your immune system from attacking healthy tissues. Because they can result in many side effects, such as high blood pressure, cataracts, mood swings, and weight gain, they’re usually used only for brief periods of time to avoid long-term risks.
  • Antimalarial drugs. Hydroxychloroquine (Plaquenil) can help with mild MCTD and probably prevent flare-ups.
  • Calcium channel blockers. Medications such as nifedipine (Procardia) and amlodipine (Norvasc) help manage Raynaud’s phenomenon.
  • Immunosuppressants. People with severe MCTD may require long-term treatment with immunosuppressants, which are drugs that suppress your immune system. Common examples include azathioprine (Imuran, Azasan) and mycophenolate mofetil (CellCept). These drugs may be limited during pregnancy due to the potential for fetal malformations or toxicity.
  • Pulmonary hypertension drugs. Pulmonary hypertension is the leading cause of death among people with MCTD. Doctors may prescribe drugs like bosentan (Tracleer) or sildenafil (Revatio, Viagra) to prevent pulmonary hypertension from getting worse.

In addition to medication, several lifestyle changes can also help:

  • Get regular exercise. A moderate level of physical activity four to five times per week will help improve muscle strength, reduce blood pressure, and decrease your risk of heart disease.
  • Quit smoking. Smoking causes your blood vessels to narrow, which can make the symptoms of Raynaud’s phenomenon worse. It also raises blood pressure.
  • Get enough iron. About 75 percent of people with MCTD have iron deficiency anemia.
  • Eat a high-fiber diet. Eating a healthy diet rich in whole grains, fruits, and vegetables can help keep your digestive tract healthy.
  • Protect your hands. Protecting your hands from the cold can reduce your chances of having a Raynaud’s phenomenon flare-up.
  • Limit salt intake. Salt can contribute to high blood pressure, which is risky for people with MCTD.

What’s the outlook?

Despite its complex range of symptoms, MCTD generally isn’t too serious. Most people are able to manage their symptoms with a combination of medication and lifestyle changes. Talk to your doctor about establishing a long-term treatment plan that works best for your symptoms.