How is Lung Involvement Diagnosed?

Annual tests are an essential aspect of managing systemic sclerosis and monitoring disease progression. You are entitled to have these tests routinely, however if you notice any changes in-between appointments, such as breathlessness or a persistent cough, it is important to tell your doctor straightaway. 

Lung function testing, repeated every six-to-twelve months, is used to detect the presence of ILD and to check for any progression. This encompasses a variety of tests to check how well the lungs work. A steady decline in lung function test results may indicate that fibrosis is getting worse, and that treatment may be required. 

• Spirometry is the basic lung function test. It measures the amount of air that the patient can breathe out, as well as how forcefully air can be emptied from the lungs.
• Lung volume testing is more precise than spirometry. This measures the volume of air in the lungs, including how much remains at the end of a normal breath.
• Diffusing capacity tests (also called DLCO) measure how easily oxygen enters the bloodstream. This is an important measure as it is very sensitive.
• Exercise testing helps to evaluate causes of shortness of breath.  The six-minute walk is frequently used, and consists of walking up and down a set distance (usually in a corridor), to measure the total distance you are able to walk and whether there is a fall in oxygen levels. If you are asked to perform this test, you do not need to prepare for it in advance. Exercise tests may also be performed on a bike or treadmill, and you will be given additional instructions about how to prepare for this before your appointment.
• CT (computed tomography) is a scan of the chest, that can detect even mild degrees of lung involvement. The lung function tests and the CT scan are used together to estimate whether interstitial lung disease is mild or extensive. If the results of lung function tests are declining, a CT scan may be repeated to help assess any progression.
• Echocardiogram forms part of the initial assessment for someone diagnosed with SSc. It is an ultrasound scan that examines the heart and nearby blood vessels. The scan uses a small probe to send out high-frequency sound waves, that create echoes when they bounce off different parts of the body. These echoes are picked up by the probe and displayed as a moving image on a monitor during the scan. 
• Cardiac catheterisation (also known as coronary angiography) is carried out if pulmonary arterial hypertension is already suspected. This will accurately measure the pressure in your pulmonary artery and is performed under local anaesthetic.
  Bronchoscopy may occasionally be considered. This involves passing a flexible fibreoptic camera into the airways to check for any problems and obtain samples of the inflammatory cells within the lungs if necessary. One reason to do this would be to check for possible infection.
  
• Biomarkers are classed as a medical sign of illness rather than as a symptom. These can be any biological difference that may indicate or predict the outcome of disease. Examples of biomarkers that could possible relate to a number of conditions include:

• Blood pressure
• Pulse rate
  
• Molecule (protein, enzyme, antibodies etc)
  
• Genes

Testing for biomarkers will often involve a blood test. In the case of scleroderma, the presence of anti-SCL-20 antibodies can indicate diffuse scleroderma, anti-centromere antibodies are more closely associated with the diagnosis of limited scleroderma.