<b>Objective:</b> Hypersensitivity pneumonitis (HP) may be a complex syndrome rather than a single, uniform disease entity. The problems associated with HP treatment include a lack of awareness of primary care procedures and scarcity of recent information regarding HP. The main objective of this study was to investigate the problems in the interaction between primary care physicians and chest specialists. <b>Data source:</b> All available clinical records of cases at the Fukujuji Chest Hospital, Tokyo, between 1994 and 2005, supervised by specialists of a university hospital. <b>Study selection:</b> All cases suspected of HP during the period. <b>Results:</b> Nine cases were excluded because of insufficient records or because they did not satisfy the clinical criteria. Twenty-eight enrolled patients (14 men and 14 women; mean age, 53.0 years) were initially treated for respiratory infections by primary care physicians. The final HP types were summer-type (n = 18), bird fancier’s lung (n = 2), ventilation-related (n = 3), or undetectable antigen (n = 5). On the basis of the interval between the onset of initial symptoms and the time of referral to our hospital, the cases can be categorized into 3 groups, which may represent acute, subacute, and chronic HP. <b>Conclusion:</b> All patients initially received treatment on the basis of a different diagnosis at primary evaluation. We concluded that interaction between primary care physicians and chest specialists is essential for solving problems associated with the early diagnosis and adequate treatment of HP.
Hypersensitivity pneumonitis (HP) is a complex syndrome of varying intensity, clinical presentation, and natural history rather than a single, uniform disease entity [1-3]. On the basis of a nationwide epidemiological study, the Japanese Research Committee on Diffuse Pulmonary Disease for Hypersensitivity Pneumonitis has proposed diagnostic criteria for HP [4-6]. The survey, which was sponsored by the Japanese Ministry of Health, Labor and Welfare, revealed that summer-type HP (S-HP) is the most common type of HP in Japan. Of the 835 surveyed patients, 621 (74.4%) were diagnosed with S-HP [
In this study, we studied these issues in HP diagnosis in patients who were diagnosed with HP over a 10-year period. Furthermore, we investigated the role of interactive communication between primary care physicians and specialists and revisited the diagnostic criteria for HP in Japan.
All patients who were suspected of having HP on the basis of clinical diagnosis and were hospitalized at the Fukujuji Chest Hospital, Tokyo, between January 1994 and November 2005 were included in this study. The diagnosis of HP was made on the basis of exposure history and the results of clinical assessments, including blood analysis and determination of KL-6 levels, which served as a specific biomarker for interstitial lung disease [
The diagnosis of HP in this study was essentially based on the diagnostic criteria of the Japanese Research Committee on Diffuse Pulmonary Disease for Hypersensitivity Pneumonitis, [
Patients who showed respiratory and/or constitutional symptoms and signs such as crackles on chest auscultation, cough, breathlessness, febrile episodes, wheezing, and fatigue were enrolled as possible cases of HP. Particular attention was paid to the assessment of each clinical course in terms of acute, subacute, or chronic illness described above.
Reticular, nodular, or ground-glass opacity on chest radiographs or HRCT images comparable with the opacities reported in a previous study on HP were assessed [
Lymphocytosis in bronchoalveolar lavage fluid (BALF) and the CD4/CD8 ratio [
The findings of these tests are especially suggestive if they are present, appearing, or worsening several hours after antigen exposure [
Data were analyzed using the Statistical Package for the Social Sciences (SPSS) Version 11.1 for Windows (SPSS Inc., Chicago, Illinois, U.S.A.). We used Student’s t test or analysis of variance for continuous variables and the chi-square test or Fisher’s exact test for categorical variables. Data are expressed as mean ± 1SD; all reported P-values are 2-sided, and P values less than 0.05 were considered significant.
Over 10 consecutive years, a total of 37 patients received a clinical diagnosis of HP. Among these, 3 patients were excluded from our study because of insufficient data, and 6 patients whose data did not satisfy the clinical criteria were also excluded. Thus, a total of 28 cases were assessed in the study.
All 28 patients were treated by primary care physicians before admission to our hospital. The initial diagnoses made by the primary care physicians were as follows: acute upper respiratory infection (n = 4), bronchitis (n = 11), pneumonia caused by Mycoplasma infection (n = 1), bacterial pneumonia (n = 3), interstitial pneumonia (n = 5), HP (n = 1), bronchial asthma (n = 1), and undetermined diagnosis (n = 2). The mean interval between the initial clinical symptoms and referral to our hospital was 10.5 ± 8.3 wk. The distribution of this interval is shown in
The subjects included 14 men and 14 women with a mean age of 53.0 years (range: 22 - 74 years). The subjective symptoms at the initial visit to the institute were cough (17.9%), fever (46.4%), and dyspnea either at rest or on exertion (21.4%). Information on the place of work just before the onset of symptoms was available in 22 patients, including householders (n = 9), company employees (n = 7), and office workers (n = 6), but 6 patients did not show an obvious or known exposure to specific agents. Eleven patients smoked or had a history of smoking. Three patients had underlying lung diseases, including bronchial asthma (n = 2) and chronic obstructive pulmonary disease (COPD; n = 1). In 2 cases, one each in the shortand the long-interval groups, an initial diagnosis of interstitial pulmonary fibrosis (IPF) was made on the basis of the HRCT images (see below). All chest radiographs were evaluated by both radiologists and chest specialist. Each radiograph was carefully re-assessed by 3 authors.
The percentages of eosinophils and lymphocytes in the peripheral blood were 4.6% ± 4.7% and 19.5% ± 9.9%, respectively. Cell populations in the peripheral blood showed significant differences among the various types of HP, e.g., the number of white blood cells in the ventilator-related type was greater than those in the bird fancier’s lung type (p = 0.033) and undetectable antigen type (p = 0.003). However, such differences were not observed in the number of neutrophils or lymphocytes. Furthermore, the proportion of neutrophils was greater in the cases of acute HP (acute vs. chronic, p = 0.028), while the proportion of lymphocytes was smaller in the same disease group (acute vs. subacute, p = 0.010; acute vs. chronic, p = 0.003).
Serum-specific antibodies (precipitins) were detected
in 13 patients; this included antibodies for antigens of T. cutaneum (n = 9; 32.1%), T. asahii (n = 6; 21.4%), T. domesticum (n = 4; 14.3%), and Cryptococcus (n = 8; 28.6%).
Data on KL-6 levels were available for 17 patients. The mean KL-6 concentration was 2386 U/ml (range: 215 - 8580 U/ml; normal range: less than 499 U/ml). As shown in
A summary of the HRCT findings is shown in