Where is the problem
Lungs are made up millions of air sacs which supply oxygen to the neighbouring thin blood vessels. In addition, there are air tubes, which supply air to the air sacs and in between the air sacs sit a netlike mesh of tissue called interstitium. Lung fibrosis/ interstitial lung disease affects this and the result is thicked of the borders of the air sacs causing difficulty in transport of oxygen from within the air sacs to the blood.
What are the symptoms
Breathlessness and dry cough are the usual symptoms. A group of patients could have flu-like symptoms as well as weight loss. However, one must remember that these could be symptoms of multiple diseases and therefore appropriate diagnostic tests should be performed to make the diagnosis.
What causes it
In the most common form (Usual Interstitial Pneumonia or Idiopathic pulmonary Fibrosis), the cause is unknown. However, there are other forms of fibrosis which are associated with rheumatoid disorders, drug or occupational exposures to various dusts or chemicals. Certain forms could also be due to body’s allergic reaction to various inhaled particles
Role of Precise diagnosis: It is very important to come to the correct diagnosis, which is a challenging job for the doctors as there are around 200 different varieties of interstitial lung disease. There are newer effective treatments for a handful of diseases (described below) while in many other forms of this disease, the best course of action is to wait and watch as treatment in these forms are entirely ineffective
A precise diagnosis also helps doctors to advise the patient to avoid certain occupation and drugs, exposure to which will make the disease even worse.
We are providing some basic information about brad categories of interstitial lung disease. It may be difficult to grasp this table for readers not exposed to medical terms and therefore may be only helpful for patients or relatives who have been affected by any one form of the disease. The list is in no way comprehensive and there are many other forms not covered by this table.
How do you diagnose
Chest X ray – Often shows a special netlike pattern.
Breathing tests- Typically this shows a restrictive defect (A reduced amount of air can be breathed in and out). Additionally, less amount of inhaled gas can pass through the lung membranes into blood causing reduced “transfer factor”.
CT scan - This is most diagnostic. CT scan can precisely detect the scarring process within the lungs and often an experienced physician is able to figure out the type of ling fibrosis affecting the lungs from CT scan abnormalities.
Blood tests - If one wants to know whether there is another underlying disease causing the scarring with the lung tissue, the doctor may want to do a few blood tests (ANA, ANCA, ACE etc)
Bronchoscopy – It sometimes helps to put a scope inside the lungs and to take samples from within the lungs to see which cell types are predominant and this gives the doctors some clues about the underlying cause.
Surgical lung biopsy – if all of the above fail to explain the nature of lung fibrosis, an open lung biopsy can be helpful. It is associated with more complications, but often is immensely helpful
What are the treatments
Treatment depends strictly on the type of lung fibrosis, and as mentioned before, a precise diagnosis of the precise form is of utmost importance. Some have steroid as standard treatment for variable length of time, some have recently developed drugs and in some others there is no drug treatment at all (treating these types with medication is a waste of resource and raises false hope amongst patients).
Steroid: This is effective in lung fibrosis caused by allergy/ hypersensitivity. Also effective if a diagnosis of “non-specific interstitial pneumonia” is made and in fibrosis caused by sarcoidosis in some cases.
Azathioprine: In a patient who needs long term steroid to achieve clinical stability, Azathioprine can be used to spare him/ her from side effects of steroid. However, Azathioprine can cause reduced blood count and liver dysfunction. The doctor needs to ensure that the patient is capable of handling Azathioprine in their body. For this, the doctor should test for thiopurine methyltransferase (TPMT) level before prescribing to avoid unwanted severe side effects of Azathioprine. It is also important to check certain blood tests at regular intervals when someone is on Azathioprine (blood counts and liver function test).
Pirfenidone There has been considerable interest on this new drug after 2011 following publication of multiple studies showing benefit in Idiopathic pulmonary fibrosis, for which no effective drug treatment existed. This drug stops the formation of fibrous tissue within lungs and thereby reduces progression of scar tissue formation. The result is a reduction of decline in lung function in patients.
The dose needs to be gradually increased and there has to be monitoring with blood tests that the patient does not get any undesirable side effect Common side effect include rash, nausea diarrhoea, abdominal discomfort, photosensitivity among others, but usually limited to 20-40% pf patients taking the drug.
Nintedanib This slows the progression of disease by reducing the formation of scar tissue within the lungs. Side effects include diarrhoea and liver related problems. This is also a relatively new drug being used in idiopathic pulmonary fibrosis and along with Pirfenidone, offers some hope for patients to halt unrelenting progression of disease. This also needs regular liver function monitoring by blood test.
Avoidance of exposure of causative agent: If the disease is caused by an offending drug, unless the patient stops it, the disease will progress relentlessly. Same is true for occupational exposure to dust, fumes and smoke. Sometimes appropriate avoidance of exposure almost completely reverse the disease process and the patient feels back to normal.
Oxygen therapy: Long term oxygen therapy (LTOT) - In patients in whom the disease has progressed considerabley, continuous oxygen use of more than 16 hours a day (if their resting oxygen level is low), can halt the ill effect of the disease on the blood vessels within the lung and this can prolong the life span of the patient.
Ambulatory oxygen use – In patients who are able to mobilise and go out their house, and in who exercise is shown to reduce the oxygen content of their blood, having a small source of oxygen during mobility can increase their ability to wlak longer distances and to able to do more in their regular day-to-day life
Pulmonary rehabilitation When the lungs cannot supply enough oxygen to the tissues, another way to increase the exercise capacity is to make the muscles more efficient in utilising whatever amount of oxygen is supplied to them. Pulmonary rehabilitation is done through a few week long programme (usually 23 times a week) where the patient is taught various exercises to achieve better fitness. They are also shown various breathing techniques to cope with breathlessness and to be able to clear their chest to reduce the chance of infection. In these courses, they are also routinely given basic information about the disease process along with smoking cessation support. This has been shown to improve quality of life, sense of breathlessness and helps in being able to walk longer distances.
Vaccination In pulmonary fibrosis, it is dangerous and often fatal to have chest infections. Therefore anything that prevents infection is beneficial. Currently Pneumococcal vaccination and seasonal influenza vaccination is recommended for these patients.