Pulmonary fibrosis (PF) is a type of chronic lung disease that sees an irreversible decline in a patient’s lung function. The condition is characterised by scarring (fibrosis) of the lung tissue. This scarring gets progressively worse over time, and in advanced cases can see the patient being unable to take in enough oxygen through the lungs.
It is defined as an ‘interstitial’ lung disease, affecting only the lung tissue around the air sacs of the lungs (the interstitium). The blood vessels and airways of the lungs remain largely unaffected. In this way IPF is similar to many other types of interstitial lung disease, but can be treated very differently. Accurate diagnosis is crucial to minimising the effects of PF.
There are two main types of pulmonary fibrosis:
Idiopathic pulmonary fibrosis (IPF) is characterised by its causes being largely unknown (‘idiopathic’ literally meaning ‘of unknown cause’). There are, however, a range of common environmental and exposure risk factors that have been linked to increased instances of the disease, including:
It is a rare disease with an incidence estimated at 3.81 per 100,000 inhabitants in Europe.([FOOTNOTE=Orphanet. Prevalence and incidence of rare diseases: Bibilographic data [Internet]. Rare Diseases Collection; 2018 Available at: http://www.orpha.net/orphacom/cahiers/docs/GB/Prevalence_of_rare_diseases_by_alphabetical_list.pdf],[ANCHOR=],[LINK=])
There are many symptoms that could lead to a diagnosis of idiopathic pulmonary fibrosis, including:
Many of these symptoms aren’t unique to IPF and may simply point to hypoxemia (oxygen deficient blood). As an idiopathic disease, diagnosis necessitates first ruling out other, better understood causes.
Familial pulmonary fibrosis is defined by the presence of at least two cases of pulmonary fibrosis in the same family([FOOTNOTE=Steele MP, Speer MC, Loyd JE. Clinical and pathological features of familial interstitial pneumonia. Am J Respir Crit Med. 2005; 172:1146–1152],[ANCHOR=],[LINK=]),([FOOTNOTE=Borie R, Kannengiesser C, Nathan N, et al. Familial pulmonary fibrosis. Rev Mal Respir. 2015 ;32(4)413-34.],[ANCHOR=],[LINK=]). Up to one in five sufferers([FOOTNOTE=Lawson WE, Loyd JE. The genetic approach to pulmonary fibrosis. Can it provide clues to this complex disease? Proc Am Thorac Soc. 2006;(3)345–349.],[ANCHOR=],[LINK=]) of pulmonary fibrosis have a family history of the disease, meaning that the cause shifts from idiopathic (unknown) to familial. However treatment for both diseases remains largely the same.
The most common symptoms of pulmonary fibrosis – a dry cough, shortness of breath and acid reflux – can be eased through a variety of medications. Respiratory failure is the primary concern for IPF patients, but the disease can also lead to conditions such as heart failure, pulmonary hypertension, pneumonia and lung cancer, signs of which must be acted on quickly. Despite medical advances, PF still sees high in-hospital mortality.([FOOTNOTE=Brown AW, Fischer CP, Shlobin OA, et al. Outcomes after hospitalisation in idiopathic pulmonary fibrosis: a cohort study. Chest. 2015;147(1):173–9.],[ANCHOR=],[LINK=]) The vagaries of the disease can present a number of challenges to clinicians in a real-life setting.([FOOTNOTE=Kreuter, M., Kardos, P., Hoffstein, V. Management of idiopathic pulmonary fibrosis: selected case reports. European Respiratory Review 2014 23: 239-248],[ANCHOR=],[LINK=])
Since mechanical ventilation is associated with high mortality and poor outcoes reported in patients with pulmonary fibrosis([FOOTNOTE=Rush B, Wiskar K, Berger L et al. The use of mechanical ventilation in patients with idiopathic pulmonary fibrosis in the United States: A nationwide retrospective cohort analysis. Respiratory Medicine 2016; 111, 72–76.],[ANCHOR=],[LINK=]),([FOOTNOTE=Fumeaux ., Rothmeier C, Jolliet P. Outcome of mechanical ventilation for acute respiratory failure in patients with pulmonary fibrosis. Intensive Care Medicine 2001; 27(12), 1868–1874.],[ANCHOR=],[LINK=]), it is not always indicated for patients with acute exacerbation, and it is highly recommended to provide the information regarding the limitations and poor outcomes of mechanical ventilation to patients and their families.([FOOTNOTE=Schnapp, L and Whelan, T. Acute exacerbations of idiopathic pulmonary fibrosis. Up To Date 2018; accessed at: https://www.uptodate.com/contents/acute-exacerbations-of-idiopathic-pulmonary-fibrosis.],[ANCHOR=],[LINK=]),([FOOTNOTE=National Institute for Health and Care Excellence. Idiopathic pulmonary fibrosis in adults: diagnosis and management. 2013.],[ANCHOR=],[LINK=])
With a mean survival time of 3-5 years post-diagnosis,([FOOTNOTE=Panos R, Mortenson R, Niccoli S, et al. Clinical deterioration in patients with idiopathic pulmonary fibrosis: Causes and assessment. The American Journal of Medicine 1990; 88(4), 396–404.],[ANCHOR=],[LINK=]) lung transplatation represents the most promising option, but many critical care institution are simply not equipped for such a procedure, and indeed, the patient may not be a suitable candidate.
Dyspnoea, and the resultant hypoxia, is common in patients with PF. Oxygen supplementation is currently recommended by guidelines.18 Invasive mechanical ventilation should be considered only if used as bridge for preplanned lung transplantation.([FOOTNOTE=Stern J, Mal H, Groussard O et al. Prognosis of Patients With Advanced Idiopathic Pulmonary Fibrosis Requiring Mechanical Ventilation for Acute Respiratory Failure. Chest 2001; 120(1), 213–219.],[ANCHOR=],[LINK=]),([FOOTNOTE=Dellgren G, Riiseb G, Swärde K. Extracorporeal membrane oxygenation as a bridge to lung transplantation: a long-term study. Eur J Cardiothorac Surg 2015; 47: 95–100],[ANCHOR=],[LINK=])
Noninvasive ventilation is the preferred option for acute exacerbation and acute respiratory failure in IPF patients.([FOOTNOTE=Vianello A, Arcaro G, Battistella L, Pipitone E, Vio S, Concas A, et al. Noninvasive ventilation in the event of acute respiratory failure in patients with idiopathic pulmonary fibrosis. J Crit Care. 2014;29(4):562–7.],[ANCHOR=],[LINK=]),([FOOTNOTE=Yokoyama T, Kondoh Y, Taniguchi H, et al. Noninvasive ventilation in acute exacerbation of idiopathic pulmonary fibrosis. Intern Med. 2010;49(15):1509–14.],[ANCHOR=],[LINK=])