Sarcoidosis Diagnosis

  • Diagnosis

    Sarcoidosis is a chronic inflammatory disease characterized by small bumps, known as granulomas, that can appear almost anywhere inside or outside the body. These granulomas are small areas of inflamed cells.

    Symptoms depend on what part of the body is affected. Shortness of breath, irritation of the eyes, raised pinkish lumps on the skin, weight loss, and fatigue are some possible symptoms of sarcoidosis. However, sarcoidosis can occur without symptoms. Because there is no known cause, and because symptoms can be absent or due to other disorders, sarcoidosis is difficult to diagnose.

    The disease usually begins in the lungs and lymph nodes, although other commonly affected organs and systems include the skin, eyes, liver, heart, nervous system, and kidneys.

    The disease can appear and then disappear quite suddenly, never to return. In some people, however, sarcoidosis is a chronic disease, with symptoms coming and going for years. These symptoms can be controlled with medication. Much about sarcoidosis remains unknown. Although there is no "cure," sarcoidosis may disappear on its own with or without treatment, sometimes within a year or two. Even when sarcoidosis lasts longer, it is likely that you will be able to lead a normal life. Sarcoidosis is fatal in only 1% to 5% of cases, usually as a result of respiratory failure. It is not a contagious disease.

    Although sarcoidosis can develop at any age, it most commonly occurs for the first time in people between the ages of 20 and 40. Sarcoidosis affects people throughout the world. Yet sarcoidosis often goes undiagnosed or is mistaken for another illness, making it difficult to estimate how many people have it. Current estimates place the number of people in the U.S. with the disease at about 25,000.

    The cause of sarcoidosis is unknown. Research suggests, however, that it is an autoimmune disease—one in which the immune system mistakenly attacks the cells, tissues, and organs of a person's own body.

    Because certain racial groups such as African-Americans are more likely than others to develop sarcoidosis, genetic factors are suspected of playing a role in the disease.

    Given that transplant recipients have acquired sarcoidosis after receiving organs from donors with the disease, many researchers believe that an infectious agent may be involved.

    Many people with sarcoidosis never develop symptoms. In these people, the disease is usually discovered when a chest x-ray is taken for an unrelated reason.

    When symptoms do develop, they may occur over one to two weeks, and usually involve the lungs, skin, and eyes. They may also develop more gradually.

    The most common symptoms are a dry cough, a vague feeling of chest discomfort, and shortness of breath (dyspnea), especially when exercising. Some people develop rashes, nodules (small bumps), or other skin problems. Table 01

    Others may experience:

    • eye problems (usually dry eyes)
    • enlarged lymph nodes
    • muscle weakness
    • joint pain
    • abnormal heartbeat.

    The number and kinds of symptoms vary from individual to individual, depending on which part of the body is affected.

    Table 1.  Symptoms of Sarcoidosis

    Part of body affected Estimated percentage of people who develop the symptom Symptoms
    Lungs More than 90% Dry cough, chest discomfort or pain, shortness of breath
    Lymph glands 30% Enlarged lymph nodes, sometimes causing discomfort or pain
    Heart 5% Chest pain, shortness of breath, abnormal heartbeat, fainting
    Liver 50% to 80% Pain, jaundice, nausea, vomiting
    Skin 25% Rashes, nodules (small bumps), pain, itching
    Eyes 11% to 83% Dry eyes, tearing, difficulty seeing
    Nervous system Less than 10% Muscle weakness or paralysis, tremors, poor coordination
    Musculoskeletal system (muscles and bones) 25% to 39% Joint pain, muscle pain or weakness

    Sarcoidosis affects men and women of all races and ages, although people in Sweden, people in Denmark, and African-Americans appear to be at highest risk. In addition, women are slightly more likely than men to develop the disease.

    Age is also a risk factor. People between the ages of 20 and 40 are at highest risk, although in Sweden and Japan a second peak in incidence of the disease occurs in women over the age of 50.

    Your doctor will ask you questions about your symptoms and medical history. He or she will ask you about when your symptoms began, how severe they are, and how long you have had them. To rule out other possible causes for your symptoms, your doctor will also ask you about any medications you may have taken recently, including herbal or other alternative supplements. You'll also be asked about the possibility of having been exposed to various chemicals at work or elsewhere, or if you have had certain infections that could cause similar symptoms.

    You will be given a thorough physical examination. Your doctor will examine your skin for rashes or nodules, which sometimes accompany the illness. In addition, the doctor will examine your eyes for signs of inflammation or other problems, which can indicate sarcoidosis. Your doctor will also examine the lymph glands in your neck, groin, and armpits for swelling.

    Part of the exam will include using a stethoscope to listen to your lungs. The lungs are affected in 90% of sarcoidosis cases, and the doctor will be listening for unusual “crackling” sounds when you take a breath. The doctor will also “percuss” your lungs, which involves placing one hand on your chest and thumping it with the fingers of the other hand. The ensuing vibration helps the doctor determine the condition of your lungs.

    You will also be given a chest x-ray. People with sarcoidosis quite commonly have enlarged lymph nodes, particularly between the two lungs. These swollen lymph nodes may not be noticeable except on a chest x-ray. Your doctor will also look for small round spots in your lungs; such spots indicate clusters of inflammation. An x-ray can also help your doctor determine how much of your lungs have been affected by the disease. Using the findings from your chest x-ray, your doctor will “stage” your illness from I to IV, with IV being the most severe.

    Samples of your blood and urine will be taken and analyzed. Both will be examined for increases in calcium levels. People with sarcoidosis are sometimes sensitive to vitamin D, which can cause too much calcium to be absorbed through the intestines—and a subsequent high level of calcium in the blood and urine. This can lead to a condition known as hypercalcemia, which, if left untreated, can be life-threatening.

    Your blood may also be analyzed for a substance called angiotensin-converting enzyme (ACE). The cells that make up granulomas tend to secrete large amounts of ACE; high levels of these enzymes, therefore, may indicate the presence of sarcoidosis, though you can still have the disease with normal ACE levels. You will also undergo and EKG to look for abnormalities in your heart.

    To further help with the diagnosis, your doctor may recommend other tests.

    • Bronchoalveolar lavage. This procedure, which is usually done in a hospital under local anesthesia, uses a bronchoscope—a long, narrow, lighted instrument that is inserted through the nose or mouth into the lower air passages to wash out (lavage) cells from inside the lungs. The cells in the fluid are then examined for signs of inflammation.
    • Tissue biopsy. This test takes a tissue sample for microscopic evaluation from one or more areas of your body—most likely from your lungs, skin, lymph nodes, or liver. The procedure is often done by withdrawing cells through a fine needle (needle aspiration). To acquire specimens of lung tissue for a biopsy, a bronchoscope may be used.
    • Gallium scan. For this test, a small amount of radioactive material (gallium-67) will be injected into one of your veins. Two days later you will have your body scanned by a special machine that can detect gamma rays emitted by the gallium. By then, the gallium will have collected at areas of your body that are inflamed by either sarcoidosis or some other inflammatory condition.
    • CT (computed tomography) scan. This painless radiologic procedure may enable your doctor to see swollen lymph nodes and lung scars that a regular chest x-ray may not pick up. The procedure involves lying still while a doughnut-shaped CT scanner takes cross-sectioned pictures of your body.
    • Pulmonary function tests. These tests measure how well the lungs can receive, hold, and use air—and can therefore help determine if and how much your lungs are damaged by sarcoidosis. To take these tests, you exhale into a special mouthpiece attached to monitoring equipment.
    • Slit-lamp eye examination. This special eye exam uses a high-intensity lamp that can be focused into a narrow slit of light that enables the inside of your eyes to be examined for signs of sarcoidosis-related abnormalities.

    Because the causes of sarcoidosis are not yet clearly understood, methods of preventing the disease also remain a mystery. There is no screening test for sarcoidosis, although the disease often can be detected on a routine chest x-ray.

  • Prevention and Screening

    Because the causes of sarcoidosis are not yet clearly understood, methods of preventing the disease also remain a mystery. There is no screening test for sarcoidosis, although the disease often can be detected on a routine chest x-ray.

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