Distinct histopathology of acute onset or abrupt exacerbation of hypersensitivity pneumonitis (original) (raw)

Fibrotic hypersensitivity pneumonitis

Journal of Advanced Lung Health, 2023

Hypersensitivity pneumonitis (HP), which is otherwise known as extrinsic allergic alveolitis, is a clinical syndrome characterized by diffuse interstitial involvement secondary to exposure to organic antigens. The diagnosis of HP relies on the clinical evaluation of a number of features, including a history of significant exposure to potentially causative antigens, physical examination, chest computed tomography (CT) scan appearances, bronchoalveolar lavage (BAL) lymphocytosis, and, in selected cases, histology. Now the entity is classified as nonfibrotic HP and fibrotic HP. Here we review the recent literature to highlight the new classification.

Fibrotic Hypersensitivity Pneumonitis: Key Issues in Diagnosis and Management

Journal of clinical medicine, 2017

The diagnosis of hypersensitivity pneumonitis (HP) relies on the clinical evaluation of a number of features, including a history of significant exposure to potentially causative antigens, physical examination, chest CT scan appearances, bronchoalveolar lavage lymphocytosis, and, in selected cases, histology. The presence of fibrosis is associated with higher morbidity and mortality. Differentiating fibrotic HP from the idiopathic interstitial pneumonias can be a challenge. Furthermore, even in the context of a clear diagnosis of fibrotic HP, the disease behaviour can parallel that of idiopathic pulmonary fibrosis in a subgroup, with inexorable progression despite treatment. We review the current knowledge on the diagnosis, management, and prognosis of HP with particular focus on the fibrotic phenotype.

Hypersensitivity Pneumonitis: Perspectives in Diagnosis and Management

American journal of respiratory and critical care medicine, 2017

Hypersensitivity pneumonitis (HP) is an immune-mediated interstitial lung disease caused by recurrent exposure to one or more offending inducers in genetically susceptible individuals. It mimics other acute and chronic pulmonary diseases and is often misdiagnosed as idiopathic pulmonary fibrosis (IPF) or another idiopathic interstitial pneumonia if the history of exposure to the inducer is not elicited. We propose a new classification of HP based not only on clinical data but also radiologic and histopathologic findings which might have potential to serve as predictors of disease behaviour and therefore guide management. Two primary clinical manifestations of HP, acute and chronic HP, correspond to the 2 primary histopathologic patterns, inflammatory and fibrotic. We place particular emphasis on cryptogenic HP, where the underlying inducer/s remain occult despite thorough investigation. The need for identification of the offending antigen is crucial not only for diagnosis and manage...

Early Neutrophil Alveolitis after Antigen Inhalation in Hypersensitivity Pneumonitis

Chest, 1985

ronchoalveolar lavage (BAL) was carried out before and after antigen inhalation in ten hypersensitivity pneumonitis (HP) and fivecontrol subjects. Control subjects did not show any significant variation in BAL cells after challenge with diluted pigeon serum. In UP patients, the total number of BAL cells increased from (41.5±16.8)XI()4 cells/mi before challenge to (84.0 ± !8.9) X1()4 cellslml after challenge. Of greater interest, the values of polymorphonuclear neutrophils in patients increased from 8.3 ± 9.7 percent before

Chronic hypersensitivity pneumonitis

Journal of Asthma and Allergy, 2016

Hypersensitivity pneumonitis (HSP) is a common interstitial lung disease resulting from inhalation of a large variety of antigens by susceptible individuals. The disease is best classified as acute and chronic. Chronic HSP can be fibrosing or not. Fibrotic HSP has a large differential diagnosis and has a worse prognosis. The most common etiologies for HSP are reviewed. Diagnostic criteria are proposed for both chronic forms based on exposure, lung auscultation, lung function tests, HRCT findings, bronchoalveolar lavage, and biopsies. Treatment options are limited, but lung transplantation results in greater survival in comparison to idiopathic pulmonary fibrosis. Randomized trials with new antifibrotic agents are necessary.

Hypersensitivity pneumonitis in man. Light- and electron-microscopic studies of 18 lung biopsies

American Journal Of Pathology

Light-and electron-microscopic changes produced by hypersensitivity pneumonitis were analyzed in open lung biopsies taken from 18 patients with chronic forms of the disease. The main changes observed were: alveolitis (both luminal and mural), granulomas, intraalveolar buds, and interstitial fibrosis. The cells infiltrating the alveolar walls were mainly lymphocytes. Occasionally these lymphocytes presented irregularities in the contours of the nuclear membranes and resembled Sezary cells. In one patient, a few lymphocytes were found that resembled "hand-mirror" cells. Intraalveolar macrophages often had a foamy appearance. Granulomas, present in two-thirds of the patients, differed in several respects from those in sarcoidosis: they were smaller, more loosely arranged, and poorly limited; they had a higher content of lymphocytes; and they were located more frequently in HYPERSENSITIVITY PNEUMONITIS is an interstitial lung disorder resulting from a reaction of predisposed individuals to repeated inhalation of organic particulates.1`7 Although the pathogenesis of this disorder is not completely understood, it clearly results from the immunologic reaction to antigens associated with the organic particulate. In this regard, patients with hypersensitivity pneumonitis characteristically have both cellular and humoral immune processes directed against the organic particulate. However, even though many different substances are known to induce hypersensitivity pneumonitis, the resulting changes within the lung parenchyma are thought to be similar.3

Induced sputum and bronchoalveolar lavage from patients with hypersensitivity pneumonitis

Respiratory Medicine, 2004

Background and Aim: Hypersensitivity pneumonitis (HP) is an immunologically induced inflammation of the lung parenchyma, though bronchial airways may be also involved. The aim of this study was to compare the cellular profiles of induced sputum (IS) in patients with newly diagnosed HP to that of healthy subjects, and to examine the relationship between inflammatory cells from IS and BAL.

Hypersensitivity Pneumonitis: A Clinical Case

Journal of Medical Cases, 2012

The hypersensitivity pneumonitis (HP) or extrinsic allergic alveolitis (EAA) is the paradigm of lung response to inhaled organic and inorganic. It is a relatively rare disease, constituting 2% of cases of interstitial lung diseases.The authors describe a case of a 50 years old man, with occupational exposure to metals and paints, who presented with weakness, easy fatigability on small and medium exertion, nonproductive cough, dyspnea and not quantified weight loss. Physical examination revealed bilateral crackles. The study pointed to the initial diagnosis of sarcoidosis with severe restrictive syndrome, but further study revealed that it was of hypersensitivity pneumonitis by lipid inhalation (paint-related products and lead). The patient underwent treatment with prednisone with poor response, showing improvement only after introduction of azathioprine.The authors present this case to emphasize the importance of history of exposure to any toxic substances, a lack of specificity of clinical manifestations, the need for invasive diagnostic methods and, sometimes, poor response to therapy.