Diagnosis Of Hypersensitivity Pneumonitis Research Articles

Diagnosis and Treatment of Hypersensitivity Pneumonitis - S2k Guideline of the German Respiratory Society and the German Society for Allergology and Clinical Immunology

Hypersensitivity pneumonitis (HP) is an immune-mediated interstitial lung disease (ILD) in sensitized individuals caused by a large variety of inhaled antigens. The clinical form of acute HP is often misdiagnosed, while the chronic form, especially the chronic fibrotic HP, is difficult to differentiate from other fibrotic ILDs. The present guideline for the diagnosis and treatment of HP replaces the former German recommendations for the diagnosis of HP from 2007 and is amended explicitly by the issue of the chronic fibrotic form, as well as by treatment recommendations for the first time. The evidence was discussed by a multidisciplinary committee of experts. Then, recommendations were formulated for twelve questions on important issues of diagnosis and treatment strategies. Recently published national and international guidelines for ILDs and HP were considered. Detailed background information on HP is useful for a deeper insight into HP and the handling of the guideline.

The Role of Serum IgG Precipitins against Six Typical Organic Antigens Involved in Hypersensitivity Pneumonitis: A 10-Year Retrospective Study of a Referral Interstitial Lung Disease Centre

Hypersensitivity pneumonitis (HP) represents the third common interstitial lung disease caused by an exaggerated immune response following the inhalation of organic and/or chemical environmental antigens. The aim of this study was to determine the cut-off values of specific IgG antibodies (named precipitins) and their association with clinical data in the diagnosis of HP. In this 10-year retrospective study, the IgG concentrations against six antigens, Penicillium chrysogenum/notatum, Aspergillus fumigatus, Alternaria alternata, Aspergillus niger, Micropolyspora faeni, and pigeon droppings, were retrieved. The controlled group was made of 1516 healthy subjects without diagnosis of lung pathologies, while the case group consisted of 54 individuals affected by HP. Considering all six IgG antibodies together and the 97.5% percentiles determined in the control group, 30 of 54 subjects (56%) had one or more positive precipitins. In these patients, the major frequencies found were IgG antibodies against pigeon droppings, followed by Penicillium chrysogenum/notatum and Aspergillus niger. Although the sensitivity of serum precipitins depends on the population enrolled and the method used, the cut-off values determined in this study can be a valuable tool for clinicians in the diagnosis of HP, in eliminating the antigens responsible from the environment, and in establishing more specific IgG panels.

Hypersensitivity pneumonitis: application of a new diagnostic algorithm to a time series of the disease

ABSTRACT Background The diagnostic criteria for Hypersensitivity pneumonitis (HP) have changed over time. Our aim is to apply a recent diagnostic algorithm to a historical series of patients diagnosed with HP to assess its distribution according to current diagnostic criteria and the diagnostic confidence achieved. Research design and methods Application to each patient the algorithm criteria. The diagnosis was HP (≥90%), provisional high (70–89%) or low confidence (51–69%) or non-HP (unlikely) (≤50%); or HP, provisional or non-HP, if they had lung biopsy. Results 129 patients [mean age 64 ± 12 years; 79 (61.2%) women] were included of which 16 (12.4%) were diagnosed on the basis of high clinical suspicion. After applying the algorithm, 106 patients (82.2%) could be evaluated and 83 (78.3%) had a diagnosis of HP or high confidence. Lung biopsy was able to establish a diagnosis of certainty in another 21 patients and a provisional diagnosis in 9 more [total, 113 (87.6%)]. The 16 patients without strict diagnostic criteria for HP had a low confidence diagnosis. A total of 56 lung biopsies (64.4%) could have been avoided according to the new guidelines. Conclusions The application of this algorithm achieves a high diagnostic yield in HP, significantly reducing the number of lung biopsies required.

Relative incidence of interstitial lung diseases in Brazil.

To assess the relative frequency of incident cases of interstitial lung diseases (ILDs) in Brazil. This was a retrospective survey of new cases of ILD in six referral centers between January of 2013 and January of 2020. The diagnosis of ILD followed the criteria suggested by international bodies or was made through multidisciplinary discussion (MDD). The condition was characterized as unclassifiable ILD when there was no specific final diagnosis following MDD or when there was disagreement between clinical, radiological, or histological data. The sample comprised 1,406 patients (mean age = 61 ± 14 years), and 764 (54%) were female. Of the 747 cases exposed to hypersensitivity pneumonitis (HP)-related antigens, 327 (44%) had a final diagnosis of HP. A family history of ILD was reported in 8% of cases. HRCT findings were indicative of fibrosis in 74% of cases, including honeycombing, in 21%. Relevant autoantibodies were detected in 33% of cases. Transbronchial biopsy was performed in 23% of patients, and surgical lung biopsy, in 17%. The final diagnoses were: connective tissue disease-associated ILD (in 27%), HP (in 23%), idiopathic pulmonary fibrosis (in 14%), unclassifiable ILD (in 10%), and sarcoidosis (in 6%). Diagnoses varied significantly among centers (c2 = 312.4; p < 0.001). Our findings show that connective tissue disease-associated ILD is the most common ILD in Brazil, followed by HP. These results highlight the need for close collaboration between pulmonologists and rheumatologists, the importance of detailed questioning of patients in regard with potential exposure to antigens, and the need for public health campaigns to stress the importance of avoiding such exposure.

Assessment of clinical relevance of antigen improves diagnostic accuracy of hypersensitivity pneumonitis

BackgroundExposure assessment is integral to the diagnosis of hypersensitivity pneumonitis (HP). Although the clinical relevance of exposed antigens is essential for the assessment, many of the previous guidelines or reports have only evaluated simple exposure histories or immunological tests. To overcome this problem, the Exposure Assessment Form (EAF) was developed as an assessment tool for classifying the exposure grade from G0 to G4. The EAF was modified from the description in the Japanese clinical practice guide 2022 for HP published by the Japanese Respiratory Society.MethodsOne hundred and seventy-two consecutive patients with interstitial lung disease who underwent multidisciplinary discussion (MDD) at our hospital were retrospectively examined. We assessed whether the use of the EAF improved the diagnostic performance of the international guideline of HP. We also evaluated whether the exposure grade affected the prognosis of HP.ResultsEven when a HP diagnosis was made with a confidence of 70% or higher according to the international guideline, less than half of these cases resulted in a final diagnosis of HP when the exposure grades were lower than G3. When the result of the EAF was integrated into the exposure definition of the international guideline, the specificity of the diagnostic performance improved, while sensitivity was maintained. Furthermore, HP patients with an exposure grade of G3 or higher showed a tendency to take a longer time to initiate medication.ConclusionsThis is the first study to evaluate the clinical relevance of possible antigens using the EAF. Assessing the exposure grade prevents overdiagnosis and improves the diagnostic performance of the international guideline.

Pulmonary Function and Diffusing Capacity of Carbon Monoxide in Hypersensitivity Pneumonitis: An Observational Study of 152 Patients.

Hypersensitivity pneumonitis (HP) is an inflammatory and/or fibrotic lung disease. The restrictive lung function with low diffusing capacity of carbon monoxide (DLCO) is common in interstitial lung diseases (ILD). There are limited data on pulmonary function test (PFT) in HP and its role for diagnosis is questionable. We analyzed the data of 152 HP patients for type of defect, lung volume, and DLCO. The present study is a retrospective analysis of 152 patients at one of the tertiary chest institutes in India. All diagnosed cases with at least spirometry were included. PFT findings were classified and graded as obstructive, restrictive, and mixed patterns. The correlation of PFT was calculated with disease duration and 6MWT distance. The majority were female [106 (70%)], with a mean age of 47.8 ± 12.3 years. Spirometry with lung volume data were available for 97% patients. PFT was abnormal in 118 (80%) cases. Among the patterns of abnormality, the most common type was restrictive (74%) followed by mixed (15%) and obstructive (11%) with the majority in the severe to very severe grade. The mean total lung capacity (TLC) and residual volume (RV) were reduced, with the grade more severe when the pattern of abnormality was restrictive while the RV/ TLC was higher suggestive of air tapping. DLCO data were available for 132 (87%) cases, with levels decreased in 67%. The severity of DLCO was highest when the pattern of abnormality was restrictive. One of the PFT parameters was abnormal in 137 (90%) cases, with isolated decreased DLCO levels seen in 16 (10%) cases. Forced vital capacity (FVC), TLC, and DLCO showed positive correlation with 6MWT distance (FVC r = .22, P = .02; TLC r = .28, P = .003; DLCO r = .30, P = .002). The PFT abnormality is seen in >80% of HP patients. All types of abnormality were seen, with the restrictive pattern being the most common. Isolated decreased DLCO levels were seen in 10% of cases. We advised to do full PFT for diagnosis and followup of HP.

Nationwide Study of the Epidemiology, Diagnosis, and Treatment of Hypersensitivity Pneumonitis in Korea.

Hypersensitivity pneumonitis (HP) is a condition with an uncertain global incidence, and information on its diagnosis and management is limited. This study aimed to address these knowledge gaps. This study utilized customized claims data from the Health Insurance Review and Assessment Service (HIRA) in South Korea from January 2010, to December 2021. Patients with HP were identified based on the diagnosis code (International Classification of Diseases, 10th Revision, J67) between 2011 and 2020. Incident HP cases were defined as new HP claims, excluding those with claims in the previous year. The study examined various factors such as age, sex, comorbidities, diagnostic methods, and treatment patterns. Additionally, multivariate logistic regression analysis was performed to identify risk factors associated with treatment initiation. A total of 8,678 HP incident cases were confirmed, with age- and sex-adjusted annual incidence rates ranging from 1.14/100,000 in 2020 to 2.16/100,000 in 2012. The mean age of patients with incident HP was 52 years, with a higher incidence observed among males. Additionally, the most common comorbidity was asthma. Bronchoscopy was performed on 16.9% of patients, and 25.4% of patients did not receive treatment within 1 year of diagnosis. Among those who received treatment, prednisone was the most used systemic steroid, and azathioprine was the most commonly used second-line immunosuppressant. Factors associated with treatment initiation included the female sex, having asthma or gastroesophageal reflux disease (GERD), and undergoing bronchoscopy. This study provides valuable insights into the incidence, diagnosis, and treatment patterns of HP in South Korea using nationwide medical claims data.

Differential Diagnosis of Fibrotic Hypersensitivity Pneumonitis with Its Non-Fibrotic Phenotype and Usual Interstitial Pneumonia During High-Resolution Computed Tomography

Background. Diagnosis of hypersensitivity pneumonitis (HP) using high-resolution computed tomography (HRCT) is not an easy task. The most difficult aspects of the disease include differential diagnosis of its fibrotic (fHP) and non-fibrotic (nfHP) phenotypes, as well as their differentiation from usual interstitial pneumonia (UIP) in idiopathic pulmonary fibrosis. The determination of fibrous changes at an early stage of development can significantly accelerate the beginning of antifibrotic therapy and improve the prognosis.Objective: to identify key HRCT signs for reliable differentiation of fHP and nfHP, to carry out differential diagnostics between fHP and UIP.Material and methods. The data of 73 patients with morphologically verified HP, in whom HRCT had been performed, were retrospectively analysed. In 21 patients, nfHP was determined, and in 52 patients fHP was identified. The comparison group consisted of 24 patients with a typical radiological UIP pattern. The analysis of the changes detected during HRCT was carried out by qualitative and semi-quantitative methods. The significance of qualitative differences in a sign manifestation was assessed by Fisher’s exact test, semi-quantitative differences were evaluated using Mann–Whitney test.Results. The results of the study allow to assume, that the presence and degree of manifestation of certain HRCT signs significantly differ between the selected groups of patients in qualitative and/or semi-quantitative terms. In cases of НP, the distribution of changes was mostly uniform and diffuse, with no clear predominance in certain lobes. In UIP, diffuse craniocaudal distribution took place, and in the axial plane, the changes were mainly subpleural in nature.Conclusion. Based on the results of the study, it can be assumed that fHP significantly differs from nfHP in such features as the presence and degree of manifestation of ground glass and honeycombing symptoms, reticular changes and traction bronchiectases. When comparing the fHP and UIP groups, the distinctive signs of fHP were centrilobular nodules, mosaic pattern, as well as diffuse axial sign distribution.

MicroRNAs as fibrosis markers in patients with hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is a complex interstitial pulmonary syndrome. This clinical entity is characterized by sensitization to a specific antigen. Early detection of this antigen is associated with an increased likelihood of a favorable outcome. Increased mortality in hypersensitivity pneumonitis is associated with the development of lung fibrosis. At the same time, clinical interventions do not significantly improve the prognosis of the disease due to a lack of understanding the mechanisms underlying the development of this type of fibrosis. Using reliable biomarkers that objectively reflect biological processes in lung fibrosis may improve clinical decisionmaking. Various biomarkers are now beginning to play a critical role in diagnosing and treating a variety of human diseases. Unfortunately, hypersensitivity pneumonitis is an exception to this general trend. There is still a great deal of research to be done in this area in the search for diagnostic biomarkers. The aim of this study was to identify biomarkers of lung fibrosis development in patients with hypersensitivity pneumonitis. We used mature serum microRNAs, which may regulate inflammation and fibrosis, as such diagnostic markers. Patients with a diagnosis of hypersensitivity pneumonitis (with and without lung fibrosis) as well as healthy individuals without chronic diseases (control group) were included into the study. Clinical and laboratory parameters were assessed in all patients. The miScript miRNA PCR Array Kit (QIAGEN) was used for gene expression profiling of mature serum miRNAs. The data obtained were verified using real-time PCR. Our research has identified a number of mature microRNAs that are likely to be involved in lung fibrosis and inflammation (miR-22, miR-150 and miR-106b). Following an extended study, including monitoring of disease progression over time, the applied diagnostic kit may be used in clinical practice to determine disease activity and development of fibrosis formation in lung tissue in patients with different variants of hypersensitivity pneumonitis.

Evaluation of high-resolution computed tomography findings and associated factors in hypersensitivity pneumonitis

Background/Aim: Hypersensitivity pneumonitis (HP) is a lung disease from inhaling diverse environmental and occupational organic substances, such as fungi, bacteria, birds, and occasionally nonorganic materials. An immune response triggers this condition. A high-resolution chest computed tomography (HRCT) scan is typically performed as part of the initial diagnostic assessment. This study assesses HRCT findings in HP patients and examines associated factors between fibrotic and non-fibrotic patient groups. Methods: This retrospective cross-sectional study encompassed all HP patients monitored between 2010 and 2022. The analysis included data from 117 patients. HRCT findings from the patients were categorized based on fibrosis presence, leading to the division of patients into fibrotic and non-fibrotic groups. Comparative analyses were conducted between these groups. Results: Among the 117 subjects analyzed, 59 (50.4%) were male, and 58 (49.6%) were female. The mean age at diagnosis was 52.1 (13.6) years, ranging from 20 to 81. The non-fibrotic HP group comprised 70 (59.8%) patients, while the fibrotic HP group comprised 47 (40.2%). The most prevalent HRCT findings were ground-glass opacity (90.6%), mosaic attenuation (87.2%), and traction bronchiectasis (50.4%). Statistically significant disparities were observed between non-fibrotic and fibrotic HP groups in terms of HRCT findings: ground-glass opacity, irregular linear opacities, reticulation, traction bronchiectasis, honeycombing, and fibrosis (P=0.024, P&lt;0.001). In contrast, the lymphocyte ratio in bronchoalveolar lavage fluid was 28.78 (16.2) in the non-fibrotic HP group and 14.66 (10.3) in the fibrotic HP group. The fibrotic HP group exhibited a statistically significant lower lymphocyte ratio in bronchoalveolar lavage fluid (P&lt;0.001). Conclusion: HRCT findings are pivotal in HP diagnosis and classification. Computed tomography also assists in delineating the HP classification. This study identified ground-glass opacity and mosaic attenuation as the most prevalent HRCT findings in HP patients. Investigating the connection between fibrosis and prognosis is vital for determining patient outcomes, as fibrosis appears to be the principal determinant.

Hypersensitivity pneumonitis due to metal working fluids: Detection of specific IgG antibodies to microbial antigens

Occupational exposure to microbially contaminated metal working fluids (MWF) can cause hypersensitivity pneumonitis (HP). An important step in the diagnosis of HP is to identify the triggering antigen by detection of corresponding specific IgG antibodies (sIgG). As commercial sIgG tests are currently not available, protein antigens were prepared from MWF-workplace samples and from MWF-typical bacterial isolates. In 57 % of suspected HP-cases (n = 30) elevated sIgG concentrations were measured to at least one MWF-relevant antigen, of which Mycobacterium immunogenum was most prominent (88 %), followed by Pseudomonas oleovorans and Pseudomonas spec (82 % each), MWF-antigen mix and Pseudomonas alcaliphila (65 % each). Elevated sIgG concentrations to other microorganisms were measured to Micropolyspora faeni (82 %) and Aureobasidium pullulans (77 %). Correlation of sIgG values of all tested microbial antigens showed a significant relationship of MWF-antigen mixture to Pseudomonas antigens, but a low correlation to moulds. These newly prepared MWF-antigens are useful tools for the diagnosis of patients with suspected MWF-HP and are available for further investigations.

Real-Life Diagnostic Performance of the Hypersensitivity Pneumonitis Guidelines: A Multicenter Cohort Study.

Hypersensitivity pneumonitis (HP) is a heterogeneous interstitial lung disease (ILD) that may be difficult to confidently diagnose. Recently, the 2020 ATS/JRS/ALAT HP diagnostic guidelines were published, yet data validating their performance in real-life settings are scarce. We aimed to assess the diagnostic performance of the HP guidelines compared to the gold-standard multidisciplinary discussion (MDD). For this purpose, we included consecutive ILD patients that underwent diagnostic bronchoscopy between 2017 and 2020 in three large medical centers. Four diagnostic factors (antigen exposure history, chest computed tomography pattern, bronchoalveolar lavage lymphocyte count, and histology results) were used to assign guidelines-based HP diagnostic confidence levels for each patient. A sensitivity analysis was performed, with MDD diagnosis as the reference standard. Overall, 213 ILD patients were included, 45 (21%) with an MDD diagnosis of HP. The guidelines' moderate (≥70%) confidence threshold produced optimal performance with 73% sensitivity for HP, 89% specificity, and a J-index of 0.62. The area under the receiver operating characteristic curve (AUC) for a correct guidelines-based diagnosis was 0.86. The guidelines had better performance for non-fibrotic than fibrotic HP (AUC 0.92 vs. 0.82). All diagnostic factors, except bronchoalveolar lavage lymphocyte count, were independent predictors for MDD diagnosis of HP in a multivariate analysis. In conclusion, the HP guidelines exhibited a good diagnostic performance compared to MDD diagnosis in real-life setting.

Impact of radiographic honeycombing on transplant free survival and efficacy of immunosuppression in fibrotic hypersensitivity pneumonitis

BackgroundThe distinction between hypersensitivity pneumonitis (HP) and idiopathic pulmonary fibrosis (IPF) was thought to be important due to the difference in mortality between the conditions as well as the response to treatment. However, recent work suggests that the clinical diagnosis may matter less than certain radiographic features, namely usual interstitial pneumonia (UIP) pattern. The purpose of this study is to evaluate whether radiographic honeycombing is more predictive of transplant-free survival (TFS) than other clinical, radiographic, or histologic findings that distinguish HP from IPF in the current guidelines and to evaluate the impact of radiographic honeycombing on the efficacy of immunosuppression in fibrotic HP.MethodsWe retrospectively identified IPF and fibrotic HP patients evaluated between 2003 and 2019. Univariable and multivariable logistic regression was performed for patients with fibrotic HP and IPF to evaluate TFS. To assess the impact of treatment with immunosuppression on TFS in fibrotic HP, a cox proportional hazard model adjusted for known predictors of survival in HP including age, gender, and baseline pulmonary function testing results was constructed, and p-interaction for the presence of honeycombing on high resolution computed tomography and use of immunosuppression was calculated.ResultsOur cohort included 178 with IPF and 198 with fibrotic HP. In a multivariable analysis, the presence of honeycombing had a greater impact on the TFS than the diagnosis of HP vs. IPF. Among the criteria used in the HP diagnostic guidelines, only typical HP scan impacted survival in a multivariable model, while identification of antigen and surgical lung biopsy findings had no impact on survival. We identified a trend toward worse survival on immunosuppression in those with HP with radiographic honeycombing.ConclusionOur data suggests that honeycombing and baseline pulmonary function testing have a greater impact on TFS than the clinical diagnosis of IPF vs. fibrotic HP and that radiographic honeycombing is a predictor of poor TFS in fibrotic HP. We suggest that invasive diagnostic testing including surgical lung biopsy may not be useful in predicting mortality in HP patients with honeycombing and may potentially increase risk of immunosuppression.

Predictors of Pulmonary Hypertension and Right Ventricular Dysfunction in Patients with Hypersensitivity Pneumonitis.

Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) that occurs in susceptible individuals in response to various inhaled antigens. The fibrotic phenotype of HP is characterized by disease progression and can lead to pulmonary hypertension (PH). The aim of this study was to estimate the prevalence of PH and to identify predictors of PH in patients with chronic HP. We conducted an observational longitudinal study that included 85 patients with an established diagnosis of HP. Clinical examination, quality of life questionnaires, high-resolution computed tomography (HRCT) of the chest, arterial blood gases analyses, six-minute walking test (6-MWT), pulmonary function tests, and echocardiography were performed. Patients were divided into groups with fibrotic (71.8%) and nonfibrotic phenotype (28.2%). PH was detected in 41 (48.2%) patients. Patients with PH had the predominant fibrotic phenotype of HP, were older, more symptomatic, and had a higher FVC/DLco ratio. The most significant predictors of PH were CT signs of fibrosis, finger clubbing, FVC/DLco, decreased distance, and SpO2 at the end of 6-MWT, as well as the presence of cardiovascular diseases. PH is a common condition in patients with chronic HP, especially with the fibrotic phenotype. Early detection of the PH predictors is necessary for the timely diagnosis of this complication of HP.

The Characteristic of Transbronchial Lung Cryobiopsy in the Pathological Diagnosis of Hypersensitivity Pneumonitis.

Transbronchial lung cryobiopsy (TBLC) has widely used for the diagnosis of diffuse lung disease. However, it remains unclear whether TBLC is useful for the diagnosis in hypersensitivity pneumonitis (HP). We investigated 18 patients who underwent TBLC and were diagnosed with HP based on pathology or multidisciplinary discussion (MDD). Of the 18 patients, 12 had fibrotic HP (fHP), 2 had non-fibrotic HP (non-fHP) diagnosed with MDD. The remaining 4 patients were diagnosed with fHP by pathology but not by MDD because of clinical features. The radiology and pathology of these cases were compared. All patients with fHP showed radiological findings of inflammation, fibrosis, and airway disease. Conversely, pathology showed fibrosis and inflammation in 11 of 12 cases (92%), but airway disease was significantly less common with 5 cases (42%) (p = 0.014). Non-fHP showed inflammatory cell infiltration mainly in the centrilobule on pathology, which was consistent with radiology. Granulomas were found in 5 patients with HP (36%). In the non-HP group, airway-centered interstitial fibrosis was observed in 3 patients (75%) with pathology. The pathology with TBLC is difficult to evaluate airway disease of HP. We need to understand this characteristic of TBLC to make a MDD diagnosis of HP.

Characteristics of a diagnostic bronchoscopy in hypersensitivity pneumonitis.

Bronchoalveolar lavage and transbronchial biopsy can increase diagnostic confidence in the diagnosis of hypersensitivity pneumonitis (HP). Improving the yield of bronchoscopy may help to improve diagnostic confidence while decreasing the risk of potential adverse outcomes associated with more invasive procedures such as surgical lung biopsy. The purpose of this study is to identify factors that were associated with a diagnostic BAL or TBBx in HP. We conducted a retrospective cohort study of HP patients at a single center who underwent bronchoscopy during the diagnostic evaluation. Imaging characteristics, clinical characteristics including use of immunosuppressive medications and presence of active antigen exposure at the time of bronchoscopy, and procedural characteristics were collected. Univariable and multivariable analysis was performed. 88 patients were included in the study. 75 patients underwent BAL and 79 patients underwent TBBx. Patients who had an active fibrogenic exposure at the time of bronchoscopy had a higher BAL yield than those who were out of exposure at the time of bronchoscopy. TBBx yield was higher when more than 1 lobe was biopsied, with a trend toward higher yield of TBBx when nonfibrotic lung was biopsied compared to fibrotic lung. Our study suggests characteristics that may improve yield of BAL and TBBx in patients with HP. We suggest that bronchoscopy be performed when patients are in the antigen exposure and that TBBx samples are taken from more than 1 lobe in order to improve diagnostic yield of the procedure.

Hypersensitivity pneumonitis: Principles in diagnosis and management.

Hypersensitivity pneumonitis: Principles in diagnosis and management.

Impact of diagnostic guidelines on the diagnosis of hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is an immune-mediated interstitial lung disease from exposure to environmental antigens. Diagnosing HP could be challenging. The American College of Chest Physicians (CHEST) and American Thoracic Society/Japanese Respiratory Society/and Asociación Latinoamericana del Tórax (ATS/JRS/ALAT) have published diagnostic guidelines in 2021 and 2020 respectively. The CHEST guideline uses four grades of confidence: confident (>90%), provisional high (70-89%), provisional low (51-69%), and unlikely (≤50%). The ATS/JRS/ALAT guideline uses five grades of confidence: definite (>90%), high (80-89%), moderate (70-79%), low (51-69%) and not excluded (≤50%). In this study, we determined how these two guidelines could have affected the diagnosis of HP made before the guidelines. Two hundred and fifty-nine adult patients from a previous cohort with HP (ICD-9:495) made between Jan. 1, 2008, and Dec. 31, 2013, at Duke University Medical Center were included. We simplified the diagnostic confidence into three categories so we could compare the guidelines: high (≥90%), intermediate (51-89%), and low (≤50%). There were 156 female and 103 male. Mean age was 58 (range: 20-90). 68.8% of the patients had restrictive defects (FVC < 80% pred) and 48.6% had lung biopsy. The CHEST guideline classified 33.6% of the patients into high, 59.5% into intermediate and 6.9% into low confidence categories. The ATS/JRS/ALAT guideline classified 29.7% of the patients into high, 21.2% into intermediate and 49.0% into low confidence categories (p < 0.0001 vs. CHEST). Cohen's kappa was 0.331. In patients with identifiable inciting agents (IAs) (N = 168), the CHEST guideline classified 32.1% of the patients into high, 64.3% into intermediate and 3.6% into low confidence categories. The ATS/JRS/ALAT guideline classified 29.2% of the patients into high, 20.8% into intermediate, and 50.0% into low confidence categories. Cohen's kappa was 0.314. In our HP cohort with two-thirds of the patients with restrictive defects, we found the two guidelines had fair agreement in diagnosing HP with or without identifiable IAs. They agreed more when the diagnostic confidence was high. When the diagnostic confidence was lower, however, the ATS/JRS/ALAT guideline was more stringent. Clinicians should be aware of the differences between the two guidelines when evaluating patients suspicious of HP.

Hipersensitivite pnömonisi hastalarında sistemik kortikosteroid tedavi yanıtı: bir tek merkez deneyimi

Aim: Hypersensitivity pneumonitis (HP) is defined as an inflammatory and/or fibrotic immune reaction provoked by an inhalational exposure in susceptible individuals. Initial management of HP patients includes remediation of exposure and treatment with immunosuppressive agents. In this study we aimed to define clinical features and treatment modalities and to evaluate response to corticosteroids in HP patients followed in a single tertiary care setting. Materials and Methods: The patients with HP diagnosis followed between 1 January 2019 and 31 December 2020 were included in this retrospective study. Firstly, the candidate factors related with treatment response were evaluated by univariate analysis and then the possible factors with p values below 0.15 were evaluated by multiple linear regression model to identify independent predictors of systemic corticosteroid response. Results: The study population consisted of 50 HP patients and 20 of them (40%) had fibrotic HP. Forty-one (82.0%) patients were followed with a medical treatment for longer than 3 months. Within follow-up period 15 (36.5%) patients didn’t show clinical or radiological response to systemic corticosteroids. Patients without treatment response were presented as fibrotic HP (66.6% vs 26%, p=0.02), had radiological features of fibrosis (86.6% vs 30.7%, p=0.002) and had loss of pulmonary functions (60.0% vs 34.6%, p=0.03) more frequently. Uni-variable analysis revealed that radiological features of fibrosis (OR: 0.07 [95%CI: 0.01-0.42], p=0.003) and mosaic attenuation (OR: 7.0 [95%CI: 0.30-10.07], p=0.08) in HRCT related with corticosteroid treatment response. Conclusion: Our study suggests radiological features of fibrosis relate with worse clinical and radiological response to corticosteroid treatment. Prospective clinical trials are needed to clarify the role of immunosuppressive therapy in HP patients.

Hypersensitivity Pneumonitis: A Pictorial Review Based on the New ATS/JRS/ALAT Clinical Practice Guideline for Radiologists and Pulmonologists.

Hypersensitivity pneumonitis (HP) is a complicated and heterogeneous interstitial lung disease (ILD) caused by an excessive immune response to an inhaled antigen in susceptible individuals. Accurate diagnosis of HP is difficult and necessitates a detailed exposure history, as well as a multidisciplinary discussion of clinical, histopathologic, and radiologic data. We provide a pictorial review based on the latest American Thoracic Society (ATS)/Japanese Respiratory Society (JRS)/Asociación Latinoamericana del Tórax (ALAT) guidelines for diagnosing HP through demonstrating new radiologic terms, features, and a new classification of HP which will benefit radiologists and pulmonologists.