Introduction

What are autoimmune diseases?

Autoimmune diseases occur when the immune system, which normally protects the body from pathogens and infections, mistakenly attacks the body’s own healthy tissues.¹ There are over 80 autoimmune diseases known by medicine, which can affect nearly any organ or system in the body. The symptoms and severity vary widely, but approximately 75% of patients who suffer from autoimmune diseases are women, especially those of childbearing age.² 

What is mixed connective tissue disease (MCTD)?

Mixed Connective Tissue Disease (MCTD) is a rare autoimmune disorder that combines features of several other connective tissue diseases, mainly: systemic lupus erythematosus (SLE), systemic sclerosis (scleroderma), and polymyositis. Since it shares symptoms with these conditions, MCTD is sometimes called an “overlap” disease”. People with MCTD may also show signs of rheumatoid arthritis or Sjögren’s syndrome.

The term “mixed” is used because MCTD presents with a blend of symptoms from different autoimmune diseases.³ It can cause a wide range of symptoms, from joint pain and skin changes to muscle weakness and fatigue. Since these symptoms are very common in other illnesses, MCTD can be tricky to diagnose. Some people may be told by their doctors that they have lupus or scleroderma, until more symptoms appear over time that point to MCTD.

Who does it affect?

MTCD can affect people of any age, but it is most commonly seen in women under 30.⁴ Similar to other autoimmune diseases, the exact cause is unknown, but it is thought to involve a combination of genetic and environmental factors. 

Why is it hard to diagnose?

Diagnosing MCTD is challenging because its symptoms develop gradually and overlap with other autoimmune diseases. Signs such as inflammation, tissue destruction and scarring, may be mistaken for other conditions. Although it can be complex, understanding what MCTD is and how it combines different aspects of multiple autoimmune conditions, may prepare patients and caregivers on how to better manage it.

Key overlapping features

From lupus (SLE)

• Skin rashes: A distinctive butterfly-shaped rash across the cheeks and nose
• Joint Pain: Swelling and stiffness around the joints
• Sun sensitivity: Skin reactions (rashes, redness) triggered by sunlight

From scleroderma 

• Raynaud’s phenomenon: Fingers and toes turn white when cold or stressed due to blood flow issues
• Digestive issues: Acid reflux of trouble swallowing due to esophageal stiffening
• Telangiectasia (Broken Capillaries): Visible small linear red blood vessels

From polymyositis

• Muscle weakness: Difficulty lifting arms, climbing stairs or standing due to inflammation
• Muscle pain: Tenderness in shoulders, hips or thighs
• Fatigue: Constant tiredness that limits daily activities

In MCTD, people do not usually have just one disease - they may experience a mix of symptoms from all three diseases. Therefore, it is known as a “mixed” connective tissue disease. Understanding each symptom from different autoimmune diseases helps patients and families recognise the signs and seek care early.

How MCTD progresses

Early stage:

MCTD often begins with symptoms such as: 

• Raynaud’s phenomenon 
• swollen or puffy hands
• joint pain or stiffness⁵ 

These early signs are usually mild, and may come and go, making them easy to overlook. 

Later stage:

As the disease progresses, symptoms can shift or become severe. Some people may develop skin thickening and tightness, similar to scleroderma, while others may experience lupus-like symptoms, such as rashes or inflammation of organs. Muscle weakness and pain, which are characteristic of polymyositis may also become more noticeable in the later stage.⁶

Organ risks:

In more advanced cases, MCTD can affect major organs. Complications may include lung problems, such as pulmonary hypertension (high blood pressure in the arteries)⁷, scarring (thickening and stiffening of lung tissue, reducing oxygen intake), heart inflammation, and kidney disease. Monitoring and early intervention are important to reduce the risk of severe organ damage.

Diagnosing and monitoring

Diagnosing MCTD is like solving a puzzle because MCTD does not look exactly the same in everyone. Its symptoms often overlap with other autoimmune conditions like lupus, scleroderma, and polymyositis. Some diagnosis methods for MCTD include:

Blood Tests:

Doctors look for specific antibodies in the blood, especially the anti-U1 RNP⁸, which is commonly found in people with MCTD. Additional blood tests may check for signs of inflammation and rule out other autoimmune diseases.

Symptom tracking:

Doctors and clinicians carefully monitor the patient’s symptoms over time, looking for patterns or new features that suggest MCTD, such as joint, muscle or heart symptoms. Keeping a log of symptoms (e.g. fatigue, swallowing issues) may help identify progression.

Regular check-ups:

Medical check-ups are important to catch complications as early as possible. These may include lung function tests, heart scans (echocardiograms, CT scans, etc) and kidney tests, to detect problems like scarring or hypertension before they become serious. 

The shifting symptoms found in MCTD require vigilant monitoring to prevent organ damage and tailor treatments. Early detection and intervention greatly improves long-term outcomes.

Management and support

Living with MCTD may feel overwhelming at first, but with the right care and support, many people are able to manage their symptoms and lead fulfilling lives. Managing MCTD involves a combination of medical treatments, lifestyle changes, and emotional support. Since the symptoms may vary from person to person, a flexible and comprehensive approach is important to help one maintain their quality of life. 

Treatment

Medications play a role in effectively managing the symptoms of MCTD and in preventing further complications. The type and dosage of medication depends on the severity and specific features of the disease in each individual. Doctors may prescribe medications such as:

• Anti-inflammatories: These medications help to reduce joint pain and swelling, making it easier to move and stay active
• Immunosuppressants: For more severe symptoms, these drugs calm the immune system to prevent further damage to organs and tissues

Lifestyle adjustment

Lifestyle adjustments are important in the management of MCTD. Taking care of your body and mind can make a big difference. Some helpful lifestyle changes include:

• Getting enough rest to help manage fatigue
• Gentle, regular exercise to keep muscles and joints moving
• Wearing warm clothing, especially for hands and feet, to help manage Raynaud’s phenomenon and reduce discomfort in cold environments
• Protecting your skin, especially if it’s sensitive or tight
• Reducing stress, since flare-ups can sometimes be triggered by emotional or physical strain

Emotional support

Emotional support is a vital part of living well with MCTD, such examples include:

• Counselling: Speaking with a counselor or therapist can help patients and families cope with the stress and emotional challenges of living with a chronic illness
• Support groups: Joining a support group allows patients and families to share experiences, gain practical advice and feel less alone

Coping with a chronic illness can be challenging, not just physically but also emotionally. Having access to the right support can make a big difference for both patients and their caregivers.

Summary

MCTD is a complex autoimmune condition that blends features of lupus, scleroderma and polymyositis. The symptoms of MCTD overlaps and changes over time, making it difficult to diagnose and manage. However, with the right care and support, many people live active and meaningful lives. Getting an early diagnosis and staying on top of regular checkups can make a big difference in managing symptoms and preventing complications.

Final Takeaways

• MCTD is an “overlap” disease, showing signs from several autoimmune conditions
• Diagnosis relies on specific blood tests and symptom tracking
• Treatment is tailored to each person and may include medications, physical therapy, and support for emotional well-being
• Ongoing check-ups are essential to catch complications early and adjust care as needed
• Support from healthcare professionals, families and caregivers makes a meaningful difference

Understanding MCTD is a crucial first step in managing the condition effectively. By learning about the symptoms, possible complications and available treatment options, it empowers both patients and caregivers to make informed decisions.