Sarcoidosis is a disease that results from a specific type of inflammation of tissues of the body. It can appear in almost any body organ, but it starts most often in the lungs or lymph nodes. The cause of sarcoidosis is unknown. The disease can appear suddenly and disappear. Or it can develop gradually and go on to produce symptoms that come and go, sometimes for a lifetime.
As sarcoidosis progresses, microscopic lumps of a specific form of inflammation, called granulomas, appear in the affected tissues. In the majority of cases, these granulomas clear up, either with or without treatment. In the few cases where the granulomas do not heal and disappear, the tissues tend to remain inflamed and become scarred (fibrotic).
Types of Sarcoidosis
Sarcoidosis can affect almost any part of the body, and depending on where it occurs, patients can experience very different symptoms and require different treatment methods. Additionally, a patient may experience more than one type of sarcoidosis at once. Some of the common types are discussed here.
Pulmonary sarcoidosis refers to sarcoidosis affecting the lungs. This is the most common form since the majority of sarcoidosis patients experience some level of lung involvement.
Ocular sarcoidosis refers to sarcoidosis affecting the eyes or the surrounding structures. It occurs in about 50 percent of sarcoidosis patients. The symptoms can vary depending on which parts of the eye are affected, with the most common complication being uveitis.
When granulomas develop in and around the nervous system, the disease is referred to as neurosarcoidosis. Depending on the nerves affected, it can have a wide variety of symptoms. Neurosarcoidosis most commonly affects hormone-producing regions of the brain, the hypothalamus, and the pituitary gland. This can disrupt many systems, such as menstrual cycles in female patients.
Neurosarcoidosis can also affect the peripheral nerves and lead to problems with motor function, such as muscle weakness or numbness. Granulomas around the optic nerve can lead to vision loss.
When sarcoidosis affects the heart, the condition is referred to as cardiac sarcoidosis. While cardiac sarcoidosis occurs in a third of sarcoidosis patients, only around 5 percent will experience symptoms. These include irregular heartbeat, or arrhythmia, as the granulomas disrupt the electrical signals that trigger the contraction of the heart muscle.
Musculoskeletal sarcoidosis refers to sarcoidosis affecting the bones, muscles, or joints. Sarcoidosis can cause inflammation in the bones, but this normally does not cause symptoms. Some sarcoidosis medications, such as prednisone, can also cause the bones to become more fragile and prone to breaking (osteoporosis).
Sarcoidosis can cause several skin complications, occurring in about 20-35 percent of patients. Examples include:
- Erythema nodosum, or acute painful red lumps on the lower legs or arms
- Lupus pernio, associated with chronic, painful blue lesions or discoloration on the face, ears, fingers, or toes
- Lesions, on the extremities, face, scalp, back, and buttocks, which can vary in severity from relatively painless lumps and rashes to more severe plaques where multiple lesions have occurred together in the same location.
Sarcoidosis can lead to kidney stone formation, kidney damage, or kidney failure. This can be due to sarcoidosis causing changes in calcium metabolism, resulting in too much calcium in the blood (hypercalcemia). Inflammation, caused by granulomas in the kidneys, can cause scarring and permanent kidney damage.
Liver involvement, called hepatic sarcoidosis, is common. However, this rarely affects organ function. In rare cases, it can cause cirrhosis (liver disease), or portal hypertension (high blood pressure in the liver).
Sarcoidosis of the spleen and bone marrow
Sarcoidosis of the spleen and bone marrow can result in cytopenia — or low blood cell counts. Bone marrow is involved in the production of blood cells, so when sarcoidosis affects the bone marrow, this can lead to abnormalities such as anemia, or low red blood cells. The spleen is involved in filtering out blood cells, and if is not functioning correctly, too many, or the wrong type of blood cells, can be removed.
How Sarcoidosis is progressed?
The unknown antigen triggers a cell-mediated immune response that is characterized by the accumulation of T cells and macrophages, the release of cytokines and chemokines, and organization of responding cells into granulomas. Clusters of disease in families and communities suggest a genetic predisposition, shared exposures, or, less likely, person-to-person transmission.
The inflammatory process leads to the formation of non-caseating granulomas, the pathologic hallmark of sarcoidosis. Granulomas are collections of mononuclear cells and macrophages that differentiate into epithelioid and multinucleated giant cells and are surrounded by lymphocytes, plasma cells, fibroblasts, and collagen. Granulomas occur most commonly in the lungs and lymph nodes but can involve any organ and cause significant dysfunction. Granulomas in the lungs are distributed along lymphatics, with most occurring in peribronchiolar, subpleural, and perilobular regions.
Hypercalcemia may occur because of increased conversion of vitamin D to the activated form by activated macrophages. Hypercalciuria may be present, even in patients with normal serum calcium levels. Nephrolithiasis and nephrocalcinosis may occur, sometimes leading to chronic kidney disease.
What are the Symptoms of Sarcoidosis?
Many people with sarcoidosis think they have the flu or a respiratory infection before they’re diagnosed. Sarcoidosis can affect many different organs, but it most commonly affects your lungs.
Common symptoms of sarcoidosis include:
- Shortness of breath
- Chest pain
- Night Sweats
- Wheezing or abnormal breathing
- Feeling congested
Sarcoidosis also can cause the following:
- Skin rashes or raised bumps on the skin
- Joint pain or stiffness
- Eye irritation, dryness of the eyes and sometimes blurry vision
- Fast heart rate or lightheadedness
- Kidney stones
- Increased levels of calcium in the bloodstream
- Abnormal liver function
Causes of sarcoidosis
The body’s immune system normally fights off infections by releasing white blood cells into the blood to isolate and destroy the germs. This results in inflammation (swelling and redness) of the body tissues in that area. The immune system responds like this to anything in the blood it doesn’t recognize and dies down when the infection has been cleared.
It’s thought that sarcoidosis happens because the immune system has gone into “overdrive”, where the body starts to attack its own tissues and organs. The resulting inflammation then causes granulomas to develop in the organs.
There are many similar conditions, such as rheumatoid arthritis and lupus that are caused by the body attacking its own tissues. These are collectively known as autoimmune conditions.
It’s not known why the immune system behaves like this.
It’s possible that some environmental factor triggers the condition in people who are already genetically susceptible to it.
Sarcoidosis can occasionally occur in more than one family member, but there’s no evidence that the condition is inherited. The condition isn’t infectious, so it can’t be passed from person to person.
Risk factors for Sarcoidosis
You may have an increased risk for sarcoidosis because of your age, your family history, and genetics, or your race. Some risk factors, such as occupation, can be changed. Most risk factors, such as age, family history and genetics, race and ethnicity, and sex, cannot be changed.
- Age: You can be diagnosed with sarcoidosis at any age, but sarcoidosis is most commonly diagnosed in people age 55 and older.
- Environment or occupation: Your risk for sarcoidosis may be higher if you have repeated exposure to environmental substances that cause inflammation, such as insecticides or mold, or if you work in health care or as a firefighter. Working in these occupations may expose you to substances that trigger the formation of granulomas.
- Family history and genetics: You have a higher risk of sarcoidosis if you have a close relative with sarcoidosis.
- Other medical conditions: Sarcoidosis sometimes occurs after lymphoma, a type of blood cancer.
- Race or ethnicity: People of any race can get sarcoidosis, but it is more common in people of African or Scandinavian descent.
- Sex: Both men and women can develop sarcoidosis, but it is more common in women.
Complications during Sarcoidosis
If sarcoidosis is untreated or if the treatment does not work, inflammation can continue and scarring may develop. Sarcoidosis can cause serious and life-threatening damage to the organs it affects, including:
- Blood and bone marrow problems, including lower-than-usual numbers of red or white blood cells
- Endocrine conditions, including hypercalcemia external link, diabetes insipidus, and amenorrhea
- Heart complications, including arrhythmia, heart failure, sudden cardiac arrest, cardiomyopathy
- Kidney conditions, such as kidney stones or kidney failure
- Lung diseases, such as pulmonary hypertension and pulmonary fibrosis
- Problems with the nervous system, including brain tumors, meningitis, hydrocephalus, psychiatric problems, and nerve pain
How is Sarcoidosis Diagnosed?
There is no single way to diagnose sarcoidosis since all the symptoms and laboratory results can occur in other diseases. For this reason, your doctor will carefully review your medical history and examine you to determine if you have sarcoidosis. The main tools your doctor will use to diagnose sarcoidosis include:
Chest X-rays to look for cloudiness (pulmonary infiltrates) or swollen lymph nodes (lymphadenopathy).
HRCT scan (high-resolution CT) to provide an even more detailed look at the lungs and lymph nodes than provided by a chest X-ray. CT findings in more advanced stages (II to IV) include
- Thickening of the bronchovascular bundles and bronchial walls
- Beading of the interlobular septa
- Ground-glass opacification
- Parenchymal nodules, cysts, or cavities
- Traction bronchiectasis
Pulmonary function (breathing) tests to measure how well the lungs are working.
Bronchoscopy to inspect the bronchial tubes and to extract a biopsy (a small tissue sample) to look for granulomas and to obtain material to rule out infection. Bronchoscopy involves passing a small tube (bronchoscope) down the trachea (windpipe) and into the bronchial tubes (airways) of the lungs.
Mediastinoscopy is rarely needed if a bronchoscopy does not make a diagnosis. This procedure is done in a hospital where an anesthesia doctor puts you completely to sleep. A lung surgeon makes a small incision above your breastbone, a camera is used to look down into your chest, and lymph nodes may be removed and sent to a lab for testing.
Skin biopsy is a procedure done in a dermatologist’s office if you have skin rashes or bumps. The doctor numbs the skin near your rash with a needle and numbing medication. They then take a small sample of your skin and send it to the lab for testing.
Blood tests to check your lung and kidney functions, as well as ACE level, which is an enzyme that is sometimes a marker for active sarcoidosis.
The treatment and medications that cure Sarcoidosis
There’s no cure for sarcoidosis, but in many cases, it goes away on its own. You may not even need treatment if you have no symptoms or only mild symptoms of the condition. The severity and extent of your condition will determine whether and what type of treatment is needed.
If your symptoms are severe or organ function is threatened, you will likely be treated with medications. These may include:
- These powerful anti-inflammatory drugs are usually the first line treatment for sarcoidosis. In some cases, corticosteroids can be applied directly to an affected area – via a cream to a skin lesion or drops to the eyes.
- Medications that suppress the immune system. Medications such as methotrexate (Trexall) and azathioprine (Azasan, Imuran) reduce inflammation by suppressing the immune system.
- Hydroxychloroquine (Plaquenil) may be helpful for skin lesions and elevated blood-calcium levels.
- Tumor necrosis factor-alpha (TNF-alpha) inhibitors. These medications are commonly used to treat the inflammation associated with rheumatoid arthritis. They can also be helpful in treating sarcoidosis that hasn’t responded to other treatments.
An organ transplant may be considered if this disease has severely damaged your lungs, heart or liver.
Looking after yourself
If you currently smoke, the most important thing you can do to look after your health is to quit.
Getting regular exercise and enough sleep is very important.
It’s also important to eat well and maintain a healthy weight. Avoid sugar and processed foods where possible. Drink plenty of fluid to keep hydrated. Foods and fluids contain essential nutrients to help control your symptoms and keep you feeling as strong as possible.
If you have sarcoidosis, you might have a tendency to develop high levels of calcium in your urine or blood. Don’t take any calcium or vitamin D supplements unless they’re specifically recommended for you by your doctor. You should be able to get all the calcium and vitamin D you need from a balanced diet.
Is it possible to prevent sarcoidosis?
The cause of sarcoidosis still remains unknown, so there is at present no known way to prevent or cure this disease. However, doctors have had a great deal of experience in the management of the illness. It should be noted that most people with sarcoidosis lead normal lives.
If you have sarcoidosis, you can help yourself by following sensible health measures. You should not smoke. You should also avoid exposure to other substances such as dust and chemicals that can harm your lungs.
If you have any symptoms of sarcoidosis, see your doctor regularly so that the illness can be watched and, if necessary, treated. Regular checkups with the doctor are important even if there are no symptoms present. Eye examinations by an eye specialist can detect early eye inflammation from sarcoidosis.