The interstitium – the tissue and space around the air sacs of the lungs – can be affected by a group of pathological processes known as interstitial lung disease (ILD). These diseases commonly affect the regeneration of lung tissue, creating too much and producing thick, scarred masses that can make it difficult for oxygen to pass into the bloodstream.
It was estimated that ILD affected 595,000 people globally in 2013([FOOTNOTE=1. Global Burden of Disease Study 2013, Collaborators (22 August 2015). "Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013". Lancet. 386 (9995): 743–800. doi:10.1016/s0140-6736(15)60692-4.],[ANCHOR=],[LINK=]), resulting in 471,000 deaths.([FOOTNOTE=GBD 2013 Mortality and Causes of Death, Collaborators (10 January 2015). "Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013". Lancet. 385 (9963): 117–71. doi: 10.1016/s0140-6736(14)61682-2.],[ANCHOR=],[LINK=])
The breadth of causes is great and may aid in the classification of a patient’s ILD([FOOTNOTE=Bourke SJ (August 2006). "Interstitial lung disease: progress and problems". Postgrad Med J. 82 (970): 494–9. doi: 10.1136/pgmj.2006.046417.],[ANCHOR=],[LINK=]). Causes include:
The nonspecific nature of these symptoms compels clinicians to be reliant on other means of diagnosis.Risk factors making people more vulnerable to intestitial lung disease are age, smoking, occupational and environmental toxins exposure, gastroesophageal reflux and radiation and chemotherapy.([FOOTNOTE=https://www.mayoclinic.org/diseases-conditions/interstitial-lung-disease/symptoms-causes/syc-20353108],[ANCHOR=],[LINK=])
Defining the specific cause of interstitial lung disease is paramount to its effective treatment. Diagnosis rests on a clinician ruling out a broad spectrum of lung diseases which can mimic ILD, then identifying causal factors. Investigation will primarily focus on symptoms, searching for links between the patient’s condition and the known causes listed above.
The following tests may be utilised in concert with investigation to diagnose ILD:
Once the cause of ILD is found, treatment begins by removing contributing factors. If environmental, occupational or medication causes are suspected, patient contact with these triggers must be avoided.
Medications may be prescribed with the aim to slow the progress of ILD, or even entirely stabilise its progression. Corticosteriods may be used in combination with other drugs that suppress the immune system, while medications for idiopathic pulmonary fibrosis and gastroesophageal reflux disease may also help to slow progression.
With an aim to improve daily lung function and limit the impact of ILD on a patient’s life, pulmonary rehabilitation has proved beneficial to many patients([FOOTNOTE=Dowman L, Hill CJ, Holland AE. Pulmonary rehabilitation for interstitial lung disease. The Cochrane Database of Systematic Reviews.],[ANCHOR=],[LINK=]). While not treating the underlying problem, oxygen therapy can make ILD patients far more comfortable, and is often used for physical activity or while sleeping. Lung transplantation is a last resort for patients who don’t respond to the above treatments.