Connective tissue diseases are autoimmune diseases that cause inflammation of collagen and elastin fibers.Connective tissue is found throughout the body. A connective tissue disease affects not only blood vessels, tendons, ligaments, bones and skin, but also the surrounding organs.
Examples of common connective tissue diseases are:
- Rheumatoid arthritis
About 25% of patients with one of the above conditions (or another connective tissue disorder such as dermatomyositis or Sjögren's syndrome) develop a secondary connective tissue disorder over time. Health professionals refer to this as overlap syndrome.
Types of connective tissue diseases
There are over 200 types of connective tissue diseases. Some of the most common conditions are:
- Churg-Strauss Syndrome: Inflammation in the blood vessels of the digestive system, skin, nerves or lungs
- DermatomiositeorPolymyositis: Inflammation and breakdown of muscle tissue, which can eventually affect the skin as well
- Granulomatose com Polyangiitis: Inflammation of blood vessels in organs such as the nose, kidneys or lungs
- microscopic polyangiitis: A rare autoimmune disease that affects blood vessels in various organs
- Rheumatoid arthritis: Inflammation of the membranes surrounding the joints (a common autoimmune disease that affects women more than men)
- scleroderma: autoimmune disease that causes scarring of the skin, internal organs, or small blood vessels and disproportionately affects women of reproductive age
- Systemic lupus erythematosus: Inflammation of connective tissue throughout the body
Some individuals have symptoms of the above conditions but do not meet the criteria for a specific diagnosis. When this happens, it is referred to asundifferentiated connective tissue disease.
What is MTD?
Mixed connective tissue disease (MCTD) is an overlapping syndrome that includes symptoms of lupus, polymyositis, and scleroderma. As the symptoms are varied and similar to other illnesses,it may take several yearsfor a correct diagnosis.
A rheumatologist is trained to officially diagnose autoimmune diseases, but many patients notice the following symptoms before contacting their doctor:
- don't feel good
- Ankle discoloration (red or brown spots)
- joint pain
- Muscle aches
- numb fingers in cold weather
- shortness of breathe
- swollen fingers
- difficulties in swallowing
- inexplicable tiredness
While it's important to be aware of when your body feels "off", you should never try to diagnose yourself based on information you read online or hear from others. Don't worry about a possible diagnosis and see your doctor for an evaluation.
Your doctor will look for signs of dry eyes or mouth, swollen hands and joints, and limited range of motion between joints. Typical for patients with connective tissue diseases is Raynaud's syndrome, in which individual parts of the fingers become noticeably pale and numb from cold or emotional stress.
Tight skin on the fingers can be a sign of sclerosis. Your doctor will look for rashes characteristic of lupus, as well as hair loss.
Joint swelling and arthritis pain are some of the most common symptoms. Your doctor may ask you to perform basic movements, such as lifting your arms over your shoulders, walking up stairs or sitting on a chair, or standing up to see if you have difficulty doing these tasks.
Classic Signs of MCTD
MCTD typically leads to inflamed joints and muscles. Swollen fingers with hard skin and discoloration (known as Raynaud's syndrome) is a telltale sign of MCTD.Your doctor will also examine your lungs for signs of pulmonary hypertension.
You will be checked for fatigue, high blood pressure, fever, abdominal pain, swollen lymph nodes and kidney function (via blood tests) to look for other common signs of connective tissue disease. A questionnaire to check family history is also helpful, as many autoimmune diseases run in families.
Laboratories and Tests
A variety of tests will help identify the cause of your symptoms and make the correct diagnosis. Blood and urine tests, tissue biopsies, magnetic resonance imaging (MRI), X-rays, and tests for eyes or dry mouth are some of the ways you can be screened for connective tissue disorders.
Sometimes the lack of specific symptoms is more telling. For example, severe central nervous system and kidney problems are common in patients with lupus but not with mixed collagen disease.
Initial testing can help your doctor make the correct diagnosis, but ongoing monitoring is essential to watch for new symptoms. Connective tissue diseases are chronic and require ongoing care as they progress and change over time.
Genetic testing is not recommended for most connective tissue disorders because the role of heredity has not been established.A general review of family history can provide some information about how likely you are to develop an autoimmune disease, but there are no specific genetic markers to diagnose the disease.
Blood count and inflammatory markers
Patients with connective tissue disease may show signs of mild anemia (low levels of red blood cells that carry oxygen), thrombocytopenia (low levels of platelets that help the blood to clot), and leukopenia (low levels of white blood cells that fight infection). , which can be recognized with acomplete blood count (CBC).
Elevated inflammatory markers such as erythrocyte sedimentation rate (ESR) orC-reactive protein (CRP), are common in any autoimmune disease.
Protein and Antibody Tests
Specific antibodies are primary markers for connective tissue diseases. Your blood will be tested for antinuclear antibodies (ANA), antibodies to ribonucleoprotein U1, anti-DNA antibodies, and Smith antibodies.
Different types of immunoassays can be used for ANA testing, each with its own advantages and disadvantages. Examples include:
- WHEN ONE: Preferred method as it is very sensitive but requires experience to interpret
- ELISA: results are easier to interpret and the test is more widely available but not as sensitive
- CLIA: more sensitive than ELISA, but not as sensitive as IFA; can be automated
- Multiplex-Assay (LIA, MBA): can analyze groups of antibodies
Measuring muscle enzymes such as creatine kinase, aminotransferases, and lactic acid dehydrogenase can help detect symptoms of myositis.
A urinalysis is useful for patients with connective tissue diseases and kidney diseases. Elevated protein, red blood cell or white blood cell count can be found in the urine.
Tissue biopsies can be helpful in diagnosing a number of connective tissue diseases, including lupus and myositis. Skin lesions occur in 80% of patients with lupus, and specific features can be attributed to certain variants of lupus subtypes.
With inflammatory myositis, muscle biopsies are required. Microscopic observations, such as the thickness and arrangement of collagen fibers, edema in vessel walls, or the presence of certain immune cells, help make a clearer diagnosis and provide information about the stage and course of the disease.
Common liquid analysis
A synovial fluid analysis examines the synovial fluid for microorganisms, immune cells (such as white blood cells), amyloid fragments, fat globules, and other biomarkers to indicate a specific diagnosis.A closer examination of the fluid in the joints helps to distinguish between inflammatory arthritis such as gout or rheumatoid arthritis, osteoarthritis or septic arthritis due to infection.
Various imaging methods, such asfunctional magnetic resonance imaging (fMRI),Positron Emission Tomography (PET Scans),Computed tomography (CAT scans), orX raymay examine the tissues under the skin to check for more serious signs of connective tissue disease, such as B. Fluid around the lungs or problems with brain function.
For example, duplex color ultrasound can provide healthcare professionals with a more detailed view of the soft tissues of the neck, including cervical lymph nodes and salivary glands.
Your doctor may use imaging to look for scleroderma (characterized by excessive collagen deposits in the skin, blood vessels, or other organs) or thyroid changes and muscle weakness caused by myositis.
Are imaging procedures necessary?
In general, imaging procedures are not necessary for the initial diagnosis of connective tissue disorders. However, when problems related to disease progression arise (such as tumor growth, lung disease, or cognitive problems), imaging is helpful in detecting problems early and treating them.
In pediatric patients, imaging is more critical because connective tissue disease can lead to long-term developmental delays. Pediatric specialists may use chest x-rays to examine the lungs, barium swallow tests to examine the esophagus, echocardiography to estimate blood pressure in the lungs, and renal ultrasound to assess kidney function.
Many of the features associated with connective tissue disorders are also found in injuries or other physical and mental health conditions.
For example, just because you have pain, fatigue, skin changes, swelling, or memory problems doesn't necessarily mean you have an autoimmune disease. It's possible that fibromyalgia, allergies, stress injuries, or even depression could be causing your symptoms.
To diagnose connective tissue disease, your doctor needs to review a variety of factors. You should never assume the worst when trying to figure out why you're not feeling well. Instead, seek the help of a qualified professional to guide you towards a proper diagnosis and treatment plan to regain control of your health.