Sarcoidosis is characterized by the appearance of small nodular swellings called “granulomas” that develop in the tissues of an organ. This disease can affect different parts of the body (lungs, eyes, skin, bones, liver, spleen, muscles, nervous system, etc.). There are a few reported cases of sarcoidosis also affecting the glands (thyroid, parathyroid, pancreas and suprarenals), the pleura (protective lining of the lungs) and certain blood vessels. Granulomas can also show up as skin lesions.
In most cases granulomas are found in the lungs, which suggests that the respiratory system might be the route of entry of the causing agent. This same agent then travels through the bloodstream to affect other parts of the body.
Most of the time, sarcoidosis is asymptomatic, produces no serious effect and clears up after a few years. However, it can occasionally cause irreversible damage to certain organs and lead to respiratory or cardiac complications that will seriously limit the person’s quality of life.
Despite the numerous studies that have been performed so far, causes remain unknown. An allergen is believed to be the cause of an inflammatory reaction of the immune system, in people with a genetic predisposition.
It does not appear to be an infectious agent, but several cases of sarcoidosis have been reported among health professionals working closely with patients with sarcoidosis.
Also, there may be a link between the disease and certain environmental factors currently being examined, i.e. fir trees, beryllium (used to manufacture aircraft) and allergens.
Persons at risk
This relatively rare disease affects approximately 20 people out of 100 000 world wide. Young adults, especially women, are most affected. For reasons that remain unknown, people of African descent appear to be especially prone to this disease.
Signs and symptoms
- General feeling of discomfort
- Chronic fatigue
- Loss of appetite and/or weight
- Fever, on occasion
- Night sweats
Symptoms linked to a specific part of the body
- Dry, persistent cough
- Shortness of breath
- Lesions on the limbs, and scaly skin
- Uveitis (bloodshot eyes)
- Visual problems (if granulomas are close to the optic nerve)
- Lumps in the neck area
The diagnosis is based on:
- medical history and clinical examination
- medical imaging (X-ray and chest scan)
- lab tests (sampling and analysis of the affected tissue – biopsy)
A TB test is often performed to eliminate tuberculosis as a potential diagnosis, given the resemblance between its clinical profile and that of sarcoidosis.
A diagnosis of lung sarcoidosis is generally based on the discovery of opacities (thick shadows) and/or the presence of enlarged nodes in the pulmonary hila (area of the lung where vessels and nerves pass) visible on a lung X-ray. It is sometimes necessary to perform a pulmonary biopsy by means of a bronchoscopy (an internal examination of the bronchial tubes), in addition to the thoracic scanner and pulmonary function tests.
In the early stage of the disease the results of the pulmonary function tests often indicate an obstructive syndrome. However, in the advanced stage, tests are more indicative of a restrictive syndrome, given the pulmonary fibrosis that develops.
It is therefore important to quickly assess the spread to other organs, using the following tests:
- cardiac examination and electrocardiogram (heart examination)
- ophthalmological examination (eye examination)
- renal assessment (kidney examination)
- neurological examination (nervous system examination)
In most people with sarcoidosis, healing occurs naturally. If indicated, treatment is determined based on the progression of the disease and the risks to the affected organ. The treatment is designed to slow down, or even halt, the development of granulomas and to relieve the various ailments depending on the symptoms.
The various drugs used for this purpose belong to several classes:
- corticosteroids (cortisone-based anti-inflammatories)
- cytotoxic agents
- immunomodulators (a treatment that stimulates or slows down the immune system’s reactions)
- certain antibiotics
Cortisone medications are the initial treatment of choice because of their powerful anti-inflammatory properties. In more severe or persistent cases, the physician may add a different class of drug to the existing corticosteroid therapy. Because of the numerous side effects associated with these drugs, the risks and benefits should be weighed before adding them to the initial treatment. The physician may recommend frequent follow-ups of the patient. In very severe cases of pulmonary or cardiac illness, a lung or heart transplant , although very rare, may be considered.
During pregnancy, corticosteroid therapy may be maintained, which is not the case for all the other drugs. Alleviation of the symptoms is often observed during pregnancy, but for some reason the symptoms may recur after the delivery.
Tips and prevention
- NO SMOKING (to avoid causing further damage to the respiratory system)
- Avoid chemical dust and other agents likely to irritate the lungs
- Eat well
- Remain active but not to the point of exhaustion
- Minimize direct exposure to the sun, as this may cause an accumulation of calcium in the blood and lead to renal damage.
Did you know that
The Quebec Lung Association offers direct services to the population. For more information, visit our Patient Resources section.