SARCOIDOSIS AND THE LUNGS
Function of the Lungs and Sarcoidosis
As well as enlarged lymph nodes, there are also abnormalities in the lung parenchyma
The lymph nodes are enlarged in the central chest cavity, usually on both sides of the trachea
Your lungs transfer oxygen from the air to the blood. At the same time carbon dioxide leaves the blood through the lungs. This happens in lung tissue called lung parenchyma. In sarcoidosis of the lung the parenchyma becomes inflamed. The white blood cells which gather disrupt the oxygen uptake and carbon dioxide release. In addition, accumulations of white blood cells (also known as granulomas) may develop in the lymph system (the lymph system is an important part of the immune system) of the lungs. The granulomas adversely affect the operation of the lungs and can cause scarring. This inhibits the stretching, and therefore capacity, of the lungs. This in turn leads to a shortness of breath.
Common Symptoms of Lung Sarcoidosis
Shortness of breath, especially with exercise
Classifications of Sarcoidosis
Based on the chest X-ray, your consultant will classify the disease at one of several stages. They look especially for inflammation (granulomas) in the lungs: in the lymph system or the lung parenchyma.
The Stages of Sarcoidosis:
Stage 0: No visible abnormalities on chest radiography
Stage 1: The lymph nodes are enlarged in the central chest cavity, usually on both sides of the trachea
Stage 2: As well as enlarged lymph nodes, there are also abnormalities in the lung parenchyma
Stage 3: Only abnormalities of the lung parenchyma
Stage 4: Severe scarring of the lung parenchyma
Techniques to Understand your Condition
X-rays can give you a picture of lung abnormalities. If abnormalities are found, then generally additional tests are performed to confirm any diagnosis.
Lung Function Test: Spirometry tests how well you breathe in and out. Lung volume tests measure the total size of your lungs. Gas transfer tests measure the amount of oxygen that passes from your lungs into your blood.
CT scan (also called CAT scan or computed tomography) combines x-rays and computer technology to create detailed images of the inside of your body.
MRI scans use magnetic fields and radio waves. They show abnormal tissue clearer than CT scans. MRI is rarely used with the lungs but may be useful to check other organs.
Nuclear scans, for example PET scans and the octreotide scan. The patient swallows a radioactive tracer before images are taken with a special (gamma) camera. These techniques can sometimes be combined with CT scans or MRI scans to provide even more detailed images.
Bronchoscopy involves your consultant inserting a thin tubular viewing device to examine your lungs. Lavage is a technique sometimes used with bronchoscopy that uses salt water to extract cells for study under a microscope.
Biopsy: During bronchoscopy your consultant takes a piece of lung tissue (biopsy) to examine under the microscope. They may also take cells from an inflamed lymph node. In a few cases surgery is required to obtain a biopsy. This technique is often used when doctors want to confirm the disease as sarcoidosis. The most common technique for this is called VATS (video-assisted thoracoscopic surgery).
Course of the Disease
Sarcoidosis is a disease that affects people differently and follows an unpredictable course. The majority of people recover within a few years.
Treatment is designed to help relieve the symptoms as the disease runs its course. Most patients with lung sarcoidosis recover within a few years. Sometimes no treatment is needed. A consultant may prescribe drugs if, for example, the lungs malfunction or there is scarring in the lung tissue. There is no cure for sarcoidosis. The goal of the prescription is to suppress the lung inflammation (and scarring) whilst the disease is active.
Corticosteroids, for example prednisone, may be used for a year or more. Whilst being taken these may suppress the symptoms of the disease.
NSAIDS (Non-steroidal anti-inflammatory drugs) are aspirin-like anti-inflammatory drugs, which are also mild pain-killers.
Methotrexate is usually given in combination with corticosteroids; in tablet form, or administered by (repeated) injections.
New treatments: the treatments above suppress the inflammation and consequently the symptoms, but can have side effects. New drugs such as infliximab and adalimumab (so-called TNF inhibitors) are sometimes used to treat difficult and severe forms of sarcoidosis.