"The presentation varies; intermittent high-level exposure can precipitate flu-like episodes within 4-8 hours. This is most common in farmers' lung (bacteria and mould) and bird-fanciers (avian proteins). Symptoms include fever, chills, malaise, myalgias, nonproductive cough and dyspnoea tailing off after 12- 48 hours."
"most commonly, nitrofurantoin, amiodarone, methotrexate, penicillins, cephalosporins, minocycline, sirolimus/everolimus 8,15,14"
"The true incidence is unknown and varies widely based on climate, geography, occupational and environmental exposures, age and genetic susceptibility. Flooding events can increase the incidence of mould-related HP. Prevalence is estimated at 1-2 cases per 100,000 population in Europe and North America, and most presentations occur after the age of 40 20; increasing age is associated with an increasing incidence of fibrotic disease. Studies suggest that fewer individuals present with non-fibrotic disease 19."
"Cigarette smoking affects the incidence and severity of HP in the following ways:"
"nicotine and other components of cigarette smoke suppress the innate and adaptive immune responses, thereby reducing the incidence of HP 25"
"cigarette smoke injures the alveolar epithelium, and chronic exposure results in persistent activation of fibrogenic pathways, exacerbating fibrotic HP 26"
"BAL - lymphocytosis >20% is more common in non-fibrotic HP and levels"
"BAL - lymphocytosis >20% is more common in non-fibrotic HP and levels"
"BAL - lymphocytosis >20% is more common in non-fibrotic HP and levels"
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Fibrotic HP is insidious, presenting with progressive cough and dyspnoea, often without a relevant exposure history, and often in older individuals. Inspiratory crackles are more frequent, and digital clubbing is common 19."
"One or more of the following are required for the label ‘compatible with non-fibrotic HP’:"
"mosaic attenuation and lobular air-trapping that do not meet criteria for typical fibrotic HP"
"An ‘indeterminate’ label can be applied if there are signs of fibrosis only, and up to 25% closely resemble a UIP pattern 14:"
"variable distribution, however, a mid-lung predominance is suggestive, and an upper lobe predominance is much more common in fibrotic HP than in idiopathic pulmonary fibrosis 20"
"Mosaic attenuation is a geographic patchwork of sharply demarcated regions of differing attenuation on full inspiratory CT. The most specific variation for HP is the three-density sign, signifying a combination of lung lobules with preserved attenuation surrounded by patchy or lobular ground-glass attenuation, and interspersed with lobules of decreased attenuation and diminutive vessels due to gas-trapping, occurring within the same lobe 14. The decreased attenuation is accentuated on expiration. A similar pattern with only normal lung and gas-trapping is less specific."
"Bilateral mosaic attenuation affecting ≥3 lobes (>5 lobules in each lobe) distinguishes fibrotic HP from idiopathic pulmonary fibrosis, which may contain more limited areas of air-trapping 16."
"Drug-induced HP may present with ill-defined ground glass opacity, sometimes lower zone predominant, organising pneumonia. High attenuation areas indicate amiodarone deposition. Mosaic attenuation is less likely 27."
"Removal of precipitants is recommended for all patients with hypersensitivity pneumonitis; however, avian antigens can persist in an environment for many months after the source has been removed. Fibrotic HP may stabilise after antigen exposure ceases; however, in other cases, immune dysregulation persists, and fibrosis progresses. Prognosis is worse when the precipitant cannot be identified 14."
"Glucocorticoids can be helpful when symptoms persist despite removal of the precipitant, particularly in non-fibrotic HP 20."
"14.5 years for nonfibrotic HP with identified antigen"
"11.8 years for nonfibrotic HP with unidentified antigen"
"8.75 years for fibrotic HP with identified antigen"
"4.88 years for fibrotic HP with unidentified antigen"
"fungi/moulds, e.g. mushrooms, Aspergillus, Cryptococcus"
"yeasts, e.g. Candida"
"bacteria, e.g. Pseudomonas"
"protozoa, e.g. Amoebae"
"mites, e.g. Acarus siro"
"Typical"
"Compatible"
"Typical"
"Compatible"
Expected headings
"Subtypes"
"Non-fibrotic hypersensitivity pneumonitis"
"Fibrotic hypersensitivity pneumonitis"
"Indeterminate"
"A proposed update to the classification of interstitial pneumonias introduces a new category of bronchiolocentric interstitial pneumonia (BIP), which includes hypersensitivity pneumonitis, CTD, aspiration and medication-induced pulmonary injury 22. The CT appearance and disease distribution are sometimes helpful in suggesting the underlying diagnosis."
"The true incidence is unknown and varies widely based on climate, geography, occupational and environmental exposures, age and genetic susceptibility. Flooding events can increase the incidence of mould-related HP. Prevalence is estimated at 1-2 cases per 100,000 population in Europe and North America, and most presentations occur after the age of 40 20; increasing age is associated with an increasing incidence of fibrotic disease. Studies suggest that fewer individuals present with non-fibrotic disease 19."
"The true incidence is unknown and varies widely based on climate, geography, occupational and environmental exposures, age and genetic susceptibility. Flooding events can increase the incidence of mould-related HP. Prevalence is estimated at 1-2 cases per 100,000 population in Europe and North America, and most presentations occur after the age of 40 20; increasing age is associated with an increasing incidence of fibrotic disease. Studies suggest that fewer individuals present with non-fibrotic disease 19."
"poorly circumscribed interstitial non-necrotising (non-caseating) granulomas: consisting of lymphocytes, plasma cells, and epithelioid histiocytes, with or without giant cells"
"For a ‘compatible’ with fibrotic hypersensitivity pneumonitis label, one or more of the following are required:"
"The true incidence is unknown and varies widely based on climate, geography, occupational and environmental exposures, age and genetic susceptibility. Flooding events can increase the incidence of mould-related HP. Prevalence is estimated at 1-2 cases per 100,000 population in Europe and North America, and most presentations occur after the age of 40 20; increasing age is associated with an increasing incidence of fibrotic disease. Studies suggest that fewer individuals present with non-fibrotic disease 19."
"The presentation varies; intermittent high-level exposure can precipitate flu-like episodes within 4-8 hours. This is most common in farmers' lung (bacteria and mould) and bird-fanciers (avian proteins). Symptoms include fever, chills, malaise, myalgias, nonproductive cough and dyspnoea tailing off after 12- 48 hours."
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Non-fibrotic hypersensitivity pneumonitis individuals sometimes have a clear exposure history; this is usually absent in fibrotic HP. For most cases, diagnosis is based on probabilities, starting with the history, detailed occupational and environmental exposure analysis and CT, resorting to invasive tests (BAL and histology) to help resolve uncertainty. BAL is helpful in non-fibrotic HP if the lymphocyte count is high; however, histology may be unhelpful and can demonstrate features of NSIP or UIP. Multidisciplinary evaluation is ideal and is the current standard to aim for 20."
"Drug-induced hypersensitivity pneumonitis can demonstrate lymphocytic infiltration, foamy macrophages and organising pneumonia; granulomas are rare and may be associated with foreign material 14."
"Removal of precipitants is recommended for all patients with hypersensitivity pneumonitis; however, avian antigens can persist in an environment for many months after the source has been removed. Fibrotic HP may stabilise after antigen exposure ceases; however, in other cases, immune dysregulation persists, and fibrosis progresses. Prognosis is worse when the precipitant cannot be identified 14."
"Removal of precipitants is recommended for all patients with hypersensitivity pneumonitis; however, avian antigens can persist in an environment for many months after the source has been removed. Fibrotic HP may stabilise after antigen exposure ceases; however, in other cases, immune dysregulation persists, and fibrosis progresses. Prognosis is worse when the precipitant cannot be identified 14."
"mosaic attenuation: gas-trapping of limited extent is seen in normal individuals; however, it is often more widespread in small airways disease and organising pneumonia; in CTEPH, the demarcation is typically indistinct 24"
"mosaic attenuation: gas-trapping of limited extent is seen in normal individuals; however, it is often more widespread in small airways disease and organising pneumonia; in CTEPH, the demarcation is typically indistinct 24"
"most commonly, nitrofurantoin, amiodarone, methotrexate, penicillins, cephalosporins, minocycline, sirolimus/everolimus 8,15,14"