Pathologic Predictors of Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a disease of the respiratory system characterized by the thickening and scarring (fibrosis) of the lung tissue. People with PF experience symptoms such as shortness of breath and a dry cough.

Environmental pollutants, certain medications, or connective tissue diseases and interstitial lung diseases are some of the causes of PF. But in most cases, the cause is unknown, in which case the disease is called idiopathic pulmonary fibrosis (IPF; idiopathic means of unknown cause).

Research has shown that there are many clinical variables that can predict survival in IPF. These are clinical predictors obtained using the medical history and a physical exam of the patient, along with radiographic, physiologic, pathologic, and biomarker predictors.

This page focuses on the pathologic predictors in pulmonary fibrosis.

What are pathologic predictors?

The term pathologic refers to pathology, which is the science that studies the causes, nature, and effects of a disease.

Usual interstitial pneumonia (UIP) is a specific histopathologic pattern of fibrosis seen in the lungs of most people with IPF. In this sense, UIP and IPF are considered synonymous.

In 2001, the American Thoracic Society (ATS) and the European Respiratory Society (ERS) jointly wrote an International Consensus Statement defining the clinical symptoms, pathology, and radiologic features of patients with idiopathic interstitial pneumonias (IIP), in which IPF is included.

The pathological classifications were developed from data obtained from surgical lung biopsies and examinations of lung tissue obtained after the death of patients. The international group recommended that surgical lung biopsy obtained from more than one lobe of the lung, through its less invasive form of video-assisted thoracoscopic surgery, is the best method to diagnose IPF when computed tomography (CT) scans do not show classic features of UIP.

UIP features and prediction of survival

UIP is characterized by a number of histopathologic features of heterogeneous appearance with alternating areas of normal lung tissue, interstitial inflammation, fibrotic zones (known as fibroblast foci), and areas of honeycombing change (honeycombing refers to the CT manifestation of diffuse pulmonary fibrosis).

These features affect certain areas of the lower lungs known as the peripheral subpleural parenchyma. The presence of UIP features is important in predicting IPF prognosis, especially because UIP is considered to have a very poor prognosis with high mortality rates.

The extent of fibroblastic foci  — areas of fibroblasts, myofibroblasts, and newly formed collagen, characteristic of UIP — present in lung biopsies can be used to predict survival in IPF: Survival is longer in people who have a lower degree of fibroblastic foci.

In advance stages of IPF, the proliferation of fibroblast foci is thought to play a key role in the destruction of a large number of alveoli, which are tiny air sacs at the end of bronchioles in the lungs that are responsible for the exchange of carbon dioxide and oxygen. Therefore, controlling the fibroblast proliferation may be a successful approach in preventing the progression of IPF.

Note: Pulmonary Fibrosis News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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