Pulmonologists, P.C., Pulmonary and Critical Care Specialists in Gaithersburg, Wheaton, and Bethesda, MD


What Is Sarcoidosis, and What Causes It?

Sarcoidosis was first described in the late 19th century as a skin disease. Because its appearance under the microscope resembled tuberculosis in some ways, it was originally thought to be a form of TB. It also had some similarities to cancer, hence the name "sarcoid" which means "sarcoma-like." We now know that sarcoidosis is neither a form of TB nor a form of cancer, but instead an inflammatory condition. Its cause remains unknown, despite more than 100 years of research. Investigators have looked at viruses, bacteria, dusts, plant products, and many other things. None of these has been proven as a cause.

Who Gets Sarcoidosis?

Most investigators believe that there is a genetic component to sarcoidosis, since it is seen more commonly in some ethnic groups (African-Americans, Northern Europeans, Japanese, and others) and rarely seen in other ethnic groups. The fact that some people present with an acute onset of sarcoidosis (so-called Lofgren type), along with the fact that more than 90% of sarcoidosis patients have lung problems, suggests that it is caused by some inhaled agent in the setting of a patient who has some genetic predisposition.

How Does Sarcoidosis Affect the Body?

Virtually every organ in the body has been described to be affected by sarcoidosis in some cases. But by far, the most common organ affected is the lung. More than 90% of patients with sarcoidosis have either symptoms, x-ray changes, or pulmonary function abnormalities affecting their lungs. Other organs fairly commonly affected include the eyes, the skin, the liver and spleen, and lymph nodes. In rare cases, the heart, central nervous system, kidneys, nervous system, and bone marrow may also be affected. One of the most unusual things about sarcoidosis is that it can be highly active in some areas of the body, and totally inactive in others. The reason for this, like the cause of sarcoidosis, remains unknown. Current research suggests that whatever initiates the disease makes the body's immune system "overactive" in parts of the body which are affected, and at the same time, "suppresses" the immune system in the same person in parts of the body which are not affected.

How Do We Diagnose Sarcoidosis?

Sarcoidosis can usually be suspected based on a patient's history, chest x-ray, and blood tests. However, confirmation of the diagnosis by obtaining a biopsy is important. The reason for this is that while many patients with sarcoidosis will not need treatment, or will respond to treatment fairly quickly, a small percentage will go on to require long term medication or go on to have significant disability as a result of this disease. There is also a small percentage of patients who, even though they appear to have sarcoidosis based on their symptoms and x-rays, may actually have an infection (such as tuberculosis or fungus) or lymphoma, which is a cancer affecting the lymph nodes. We do not want to find ourselves in a situation where we are watching or treating the wrong disease, or where we are using medication which may have significant side effects to treat the wrong disease.

The evaluation for suspected sarcoidosis, beyond the history, physical exam, and chest x-ray, most often involves additional testing. This will usually be a CT Scan of the chest (and sometimes the abdomen), pulmonary function testing to evaluate your lung capacity, and in most instances, a biopsy. If there are readily available sites to biopsy, such as a skin lesion or a superficial lymph node, we will sometimes recommend a biopsy from that area. Most often, however, the biopsy will be done of the lung or lymph nodes inside the chest. There are 3 different methods of performing a lung or thoracic lymph node biopsy. These include:

  • Bronchoscopy: This is a flexible endoscope, passed through the nose into the windpipe under local anesthesia with intravenous sedation. Your pulmonary physician will perform this procedure. Small pieces of lung tissue are removed for cultures and microscopic sections. The advantages of bronchoscopy are that it is done as an outpatient procedure, and requires only local anesthesia with sedation. The disadvantage is that about one quarter of the time, the small pieces of lung tissue we obtain are not sufficient to make a firm diagnosis. This will then necessitate a further biopsy.
  • Mediastinoscopy: This involves a thoracic surgeon making a small incision at the top of the breastbone at the bottom of the neck. A metal tube called a mediastinoscope is passed down behind the breastbone and pieces of lymph nodes are removed. This requires a general anesthetic, but can sometimes still be done as an outpatient. Occasionally, patients may need to stay one night in the hospital. It offers a very high yield diagnostically, but is more invasive than the bronchscopy.
  • Thoracoscopy: This is also done by the thoracic surgeon, and requires two small incisions on the side in between the ribs, along with general anesthesia. An operating scope and video camera are inserted into the chest cavity, and a small piece of lung is removed. This also has a very high yield for those patients whose lungs are involved by the disease process.

We will advise each patient which type of biopsy is most appropriate, based on the particular findings in that patient, and based on which procedure we feel offers the best balance of risk and diagnostic yield. For some patients who undergo bronchoscopy, a second procedure may be needed to confirm the diagnosis.

In addition, for those patients in whom we suspect involvement of other organs, such as the heart, brain, liver, eyes, or bone marrow, we may recommend additional testing to see whether, in fact, those organs are involved. This question may make a difference in the type and duration of treatment recommended.

How is Sarcoidosis Treated?

About two-thirds of patients with sarcoidosis will not need any treatment. This is because they have few or no symptoms, and no signs of lung dysfunction on their pulmonary function tests. For those patients who do require treatment, the most commonly used medication is prednisone. Prednisone is a steroid, usually given as a tablet, and results in marked improvement for most patients with sarcoidosis. We will generally start with a larger dose of prednisone, taken daily, which will then be tapered over several months, depending on the patient's response. Some patients respond rapidly, and can be tapered off prednisone in as little as 2-3 months. Others require up to 6-12 months of treatment in order to induce a remission of the disease. A small percentage of patients get sicker as the prednisone is tapered, and may require indefinite treatment. Your particular course of treatment (or observation) will depend on how quickly you respond, and upon what we see during clinical followup. Every patient with confirmed sarcoidosis (including those who do not need treatment when they are diagnosed) needs ongoing followup to detect and treat recurrences, which can sometimes occur months or years after treatment is stopped. The frequency of your followup will depend on how stable you are after you come off treatment.

What Can I Expect During Treatment?

Most patients with sarcoidosis respond very well to prednisone. Some will take longer than others to enter remission, and some will be tapered off steroids quicker than others. During treatment, and even after you are off prednisone, you will have periodic blood tests, x-rays, and pulmonary function studies. The frequency of these tests will depend on your response to treatment and your degree of symptoms.

Prednisone can cause a number of side effects, some of which are predictable and avoidable. The two most common are weight gain (due to increased appetite) and insomnia. Weight gain can be avoided if you are careful about not eating between meals and controlling portion size when you are eating. Weigh yourself daily and institute corrective measures (cutting down on calories) as soon as your weight goes up by as little as 2-3 pounds. If you have problems sleeping, we can add a mild sleeping medication. Stomach upset is also fairly common, so take your prednisone in the morning with food. You may also be advised to take acid-blocker medication, either over-the-counter or by prescription. With longer term use, prednisone can also raise blood pressure and blood sugar, cause bone loss leading to osteoporosis, and lead to cataracts in the eyes. We will make every effort to treat you with as small a dose of prednisone for as short a time as possible to help minimize or eliminate these potential harmful effects. Remember that the alternative to steroid therapy for many patients is progressive lung scarring and disability due to inability to breathe.

On occasion, we may recommend other medications as alternatives to or adjuncts to prednisone. These include Plaquenyl (hydroxychloroquine); Methotrexate; Imuran (azathioprine); or other agents. Patients with cough or wheezing often are given topical steroid inhalers. The risks and benefits of these alternative treatments will be reviewed with you if we feel these drugs are appropriate for your particular situation.

What is the Prognosis of Sarcoidosis?

The vast majority of patients with sarcoidosis do extremely well, and their life expectancy is not affected by this condition. Those patients who do not require any treatment (about one-third of the total) continue their normal activities, and return for periodic monitoring visits and tests. Those patients who do require drug treatment will usually be encouraged to remain as active as possible to minimize weight gain and preserve muscle conditioning. Once they enter remission, they can also usually resume normal daily activities. A small percentage (possibly 5-10% of the total) require long term treatment, and a small number of these patients experience progressive symptoms and progressive disability despite treatment. Thus, there are occasional patients with sarcoidosis who eventually become quite disabled, and may require chronic oxygen or, in rare instances, lung transplantation. Fortunately, this is a rare occurrence.

Reading about Sarcoidosis on the Internet

Please be careful about information you find concerning sarcoidosis on the Internet. As you know, this is a completely unfiltered and unedited medium, and there are many web sites containing stories about patients who have done very poorly with all types of diseases, including sarcoidosis. If you are interested in finding out more about this condition, please confine your searches to reputable institutions, such as the Mayo Clinic, NIH, the American Lung Association, etc. Information obtained from "advocacy" websites is often incorrect, misleading, and sometimes, harmful to patients.

Share your Questions With Your Doctor

Sarcoidosis requires careful monitoring and sometimes requires drug treatment which may lead to significant side effects. You will no doubt have questions about this complex disease, and about how it is progressing or improving in your particular situation. Please share questions with your doctor, who will help determine which symptoms are related to the disease, which are related to the treatment, and which may be unrelated and require separate evaluation. Also, be sure to tell your pulmonary specialist about other doctors who are treating you as well as all other medications you are taking. And, similarly, tell your other treating physicians about your diagnosis of sarcoidosis and what treatment you are taking. The best way to achieve the optimal outcome with this and all medical conditions is to establish a close and forthright working relationship with your physicians.