In this critique, we concentrate on how to overcome an individual with ILD as well as the diagnostic process. strong course=”kwd-title” KEYWORDS: Cryoscopic lung biopsy, idiopathic pulmonary fibrosis, interstitial lung disease Introduction Interstitial lung disease (ILD) can be an umbrella term for more than 200 different diseases that display significant variation with regards to clinical course, prognosis and treatment. considerable variation with regards to clinical training course, treatment and prognosis. Generally speaking, they could be subdivided into people that have an identifiable trigger and the ones without; the latter getting known as idiopathic interstitial pneumonias. Clinical evaluation aims to recognize a possible trigger; screening for top features of systemic disease (eg connective tissues disease) or environmental sets off. Relevant exposures consist of pneumotoxic drugs, rays therapy, occupational exposures (eg asbestosis) or implicated things that trigger allergies (hypersensitivity pneumonitis). Distinguishing the many types of pulmonary fibrosis is crucial for determining correct management and for predicting prognosis; however, this is often obfuscated by the fact the lung has a limited repertoire in response to injury and, consequently, a finite number of disease patterns. In essence, all ILD is usually characterised by variable degrees of inflammation and fibrosis, not only between diseases, but also among individuals with the same disease (Fig?1). In inflammation dominant disease, the histology is usually that of organising pneumonia or non-specific interestitial pneumonitis, while in fibrosis dominant disease, one would expect to see usual interstitial pneumonitis (UIP) C characterised by fibroblastic foci and only moderate to moderate inflammation. These histological patterns are associated with specific radiological features, the recognition of which may abrogate the need for a formal biopsy and tissue diagnosis. Open in a G-418 disulfate separate ECT2 window Fig 1. Schematic classification of interstitial lung diseases according to aetiology. The obtaining of histological usual interstitial pneumonitis in a patient with an idiopathic interstitial pneumonia leads to the specific diagnosis of idiopathic pulmonary fibrosis. NSIP = non-specific interstitial pneumonitis. Idiopathic pulmonary fibrosis Idiopathic pulmonary fibrosis (IPF) is the most common of the idiopathic interstitial pneumonias, with an incidence of approximately 6,000 cases per year in the UK, affecting mainly older males. Median survival is usually worse than many cancers at just 3 years and the disease accounts for 5, 300 deaths each year in the UK.1 IPF is a growing problem, with an annual increase in incidence of 11% between 1991 and 2003, a rise that is only partly explained by an ageing population. 2 As already alluded to, distinguishing IPF from other ILDs, including other idiopathic forms, is usually important for multiple reasons. IPF does not respond to immunosuppressive therapy; in fact, immunomodulation may worsen outcomes.3 By contrast there is evidence, particularly in systemic sclerosis associated ILD,4 of benefit from cyclophosphamide and mutliple case reports suggest a potential role for rituximab5 as salvage therapy in connective tissue disease-ILD. In addition, there are now two drugs, pirfenidone and nintedanib, approved by the National Institute for Health and Care Excellence (NICE) for IPF; however, at an annual cost of around 26,000 per patient and the potential for significant side effects, accurate disease identification is essential. Finally, IPF has a worse prognosis than other ILD; therefore, a definitive diagnosis allows for timely involvement of palliative care physicians and consideration of lung transplantation. Pathogenesis of idiopathic pulmonary fibrosis The pathogenesis of IPF is usually complex and poorly understood, but involves aberrant wound healing in the context of repetitive alveolar injury. This results in abnormal fibroblast proliferation, differentiation and activation, which in turn drives expansion of the extracellular matrix with loss of normal lung architecture. Inflammation plays a less dominant role. This pathogenesis is usually illustrated schematically in Fig 2. Open in a separate window Fig 2. The pathogenesis of idiopathic pulmonary fibrosis. 1 C In an initiating phase, there is lung alveolar epithelial damage with loss of the normal lung architecture and disruption of the basement membrane across which gas exchange takes place. With further epithelial damage and apoptosis, comes upregulation of epithelial integrins, such as v6, and a phase of fibroproliferative repair dominates C driven by high levels of TGF-. Released in an inactive form, this cytokine requires an activation step facilitated by integrins that bind the Arg-Gly-Asp (arginine-glycine-aspartic acid; RGD) motif of pro-TGF and promote its cleavage G-418 disulfate and activation. 2 C Locally activated TGF- drives the recruitment of fibroblasts and a feed-forward cycle of further TGF- production. 3 C Under these conditions, fibroblasts differentiate into myofibroblasts that express high levels of integrin v6, are resistant to apoptosis and lay down a collagen matrix. 4 C Once collagen has been laid down in a lung, the architecture of G-418 disulfate which is usually already.