SarcoidosisSarcoidosis is a disease in which abnormal collections of inflammatory cells (granulomas) form in many organs of the body. These collections of cells are most often found in the lungs, but granulomas may also form in the lymph nodes, lungs, liver, eyes and skin. More rarely, they can form in the spleen, bones, joints, skeletal muscles, kidneys, heart and nervous system. Eventually, the granulomas may disappear completely or become scars.
Many people with sarcoidosis only discover that they have the disease during a chest X-ray that is ordered for another reason. Other people may have minor symptoms that do not worsen. It is rare that sarcoidosis causes serious symptoms.
Sarcoidosis can cause calcium to collect in the blood and urine because the granulomas produce activated vitamin D, which causes the intestines to absorb more calcium. High blood calcium levels lead to a loss of appetite, nausea, vomiting, thirst and excessive urine production. After a long time, high blood calcium levels may lead to kidney stones or calcium deposits in the kidney and, eventually, to kidney failure.
The signs of sarcoidosis vary widely. They can include:
- Aching joints
- Chest pain
- Enlarged lymph nodes that usually do not cause symptoms
- Feeling tired
- Feeling unwell generally
- Fever and night sweats
- Losing weight
- Eyes. In some people with sarcoidosis, parts of the inside of the eye become inflamed (swollen and tender), causing redness and difficulty seeing. If the inflammation continues for a long time, it may keep fluid from draining from the eye, causing glaucoma or eventual blindness. In some cases the granulomas may form in the membrane that covers the eyeball and the inside of the eyelids (the conjunctiva). Sometimes people with sarcoidosis have dry, sore and red eyes due to sluggish tear glands that are affected by the disease.
- Heart. Granulomas in the heart may cause chest pain (angina) or heartfailure.
- Joints. The swelling and tenderness can cause achy joints, especially in the hands and feet. Cysts that form in the bones can inflame nearby joints.
- Liver. Almost three out of four people with sarcoidosis have it in the liver. These often produce no symptoms or apparent changes in how the liver functions
- Nerves of the head. Sarcoidosis that affects the nerves of the head can cause double vision and make one side of the face droop. If the pituitary gland or the bones surrounding it are affected, diabetes insipidus may result. The pituitary gland stops producing vasopressin, a hormone needed by the kidneys to concentrate urine, causing frequent urination and excessive amounts of urine
- Skin. Over a long period of time, sarcoidosis may cause flat patches, raised patches or lumps just under the skin along with discoloration of the nose, cheeks, lips and ears.
Causes and Risk Factors
The cause of sarcoidosis is not yet known. Some factors may be infections, an abnormal response of the immune system or genetics. It usually develops between the ages of 20 and 40. It is most common among Swedes and African American, although it can occur in anyone
To diagnose sarcoidosis, a doctor conducts a physical exam and take note of symptoms. A doctor bases a diagnosis on the distinctive changes that sarcoidosis produces, as well as information gained from:
- Blood tests to check for a low number of white blood cells or platelets, high immunoglobulin levels and liver enzyme levels, especially alkaline phosphatase. The level of angiotensin-converting enzyme (ACE) in the blood may be measured. In many people with sarcoidosis, ACE in the blood is high.
- Chest X-rays or computed tomography (CT) scans in which the lung tissue appears hazy like ground glass
- Examination of a sample of tissue that shows inflammation and granulomas. For most people, the best way to do this is with bronchoscopy and a biopsy of lung tissue taken from the bronchi. Tissue samples may also be taken from skin abnormalities, swollen lymph nodes that are close to the skin or the conjunctiva.
- Examining lung fluid to see if it contains a large number of lymphocytes
- Lung function tests may show whether the amount of air the lung can hold is less than normal
- The presence of enlarged lymph nodes
- A tuberculin test may be performed to rule out the presence of tuberculosis, which can cause many of the same types of changes as sarcoidosis
- A whole-body gallium scan is sometimes done when the diagnosis is not clear. A gallium scan shows abnormal patterns in the lungs or lymph nodes.
- The usefulness of these tests depend on the organs most affected by the sarcoidosis or in some cases how advanced it is.
Almost two out of three people with lung sarcoidosis improve without treatment. Even enlarged lymph nodes in the chest and extensive lung inflammation may disappear in a few months or years. If there are severe symptoms (such as shortness of breath, joint pain or fever), corticosteroids may be given. These drugs are also given if:
- Tests show high levels of calcium in the blood
- The heart, liver or nervous system are affected
- Disfiguring skin lesions are present
- The eyes are affected and not responding to eye drops with corticosteroids
- The lung condition continues to worsen
People who have sarcoidosis that has not spread beyond the chest do better than those who also have sarcoidosis other places in the body. People with enlarged lymph nodes in the chest but no sign of lung disease have a very good prognosis. Almost half the people who once had sarcoidosis have relapses.
The success of treatment can be monitored with chest X-rays, CT scans, pulmonary function tests and measurements of calcium or angiotensin-converting enzyme levels in the blood. These tests are repeated regularly to detect relapses after treatment stops.