Clinical and serologic follow-up of four children and five adults with bird-fancier's lung

Antigen avoidance in people with hypersensitivity pneumonitis: A scoping review

BACKGROUND

Antigen avoidance (AA) is essential for people with hypersensitivity pneumonitis (HP). An intervention programme to promote continuous AA in people with HP will be the focus of future research.

OBJECTIVES

We systematically analysed the AA behaviour of people with HP, interventions of health-care providers to promote AA behaviour, clinical outcomes after AA, and evaluation methods after AA.

METHODS

We conducted a scoping review using six online databases and manual searches. Papers written in English or Japanese that reported cases on AA were selected. The extracted data were classified qualitatively.

RESULTS

In total 205 cases included in 109 eligible papers were examined.

CONCLUSIONS

This review clarified the fundamental evidence of AA in people with HP. These people required the continuous support of health-care providers to continue appropriate AA. This review highlighted four aspects that require further research to design interventions for promoting effective and continuous AA in people with HP.

[Hypersensitivity pneumonitis in children]

Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by an immune response to a variety of antigens to which patients have been previously sensitised. It can occur at any age. In children, it is a rare disease, probably under-diagnosed, with an estimated prevalence of 4 per million. The paediatric forms are not really different from those of adults but present some particularities. Avian exposure is by far the most frequent cause of HP, accounting for nearly two-thirds of cases. Although there is no current recommendation for the diagnosis of HP, it is commonly considered that the diagnosis can be made with confidence on the combination of (1) compatible respiratory symptoms, (2) exposure to a known offending antigen, (3) lymphocytic alveolitis, (4) decreased transfer factor for carbon monoxide or hypoxia on exertion and (5) compatible radiologic features. The treatment is based on antigen avoidance that must be complete and definitive. Corticosteroids can be necessary in severe forms. The prognosis of HP in children is better than in adults, with a full clinical and functional recovery in the majority of cases after complete antigenic withdrawal.

Diagnostic implications of positive avian serology in suspected hypersensitivity pneumonitis

BACKGROUND

The diagnostic evaluation of patients with interstitial lung disease (ILD) often involves serologic assessment for identifiable causes such as hypersensitivity pneumonitis (HP). While not on its own defining of HP, precipitin serologies are often obtained to support clinical suspicion if other findings are inconclusive. We studied the clinical relevance of positive avian serology in patients undergoing ILD evaluation.

MATERIAL AND METHODS

We identified individuals with positive avian serology (>53.3 mg/L) and undifferentiated ILD seen at our institution over a three-year period. Clinical, laboratory, pathologic, and radiologic findings were evaluated for consensus HP diagnosis by two expert pulmonologists, blinded to presenting serology levels.

RESULTS

Ninety-one ILD subjects with positive avian serology were identified; mean age was 62.7 ± 15.3 years with a slight male predominance (56%). Forty-nine (54%) received a consensus HP diagnosis. Those with HP had higher mean avian serology titer (95.0 ± 38.7 mg/L vs. 68.3 ± 16.7, (P < 0.0001). Never-smokers also had higher titers compared to prior or active smokers (P = 0.0008). Positive avian protein exposure (P < 0.0001, OR 21.3 (6.4-87)), DLCO% (P = 0.04, unit OR 0.96 (0.92-0.99)), and increasing serology titer (P < 0.015, unit OR 1.03 [1.01-1.06]) were independent predictors of HP diagnosis.

CONCLUSION

Among patients with positive avian serology, those with higher titers were more likely to have HP diagnosis. Nonsmokers also manifested higher titers compared to those with smoking history. These results may guide the usage and interpretation of avian serology screening in the initial assessment of suspected HP.

Fibrotic Hypersensitivity Pneumonitis: Key Issues in Diagnosis and Management

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 in children: clinical features, diagnosis, and treatment

Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, is a form of immune-mediated inflammatory lung disease involving the distal portions of the lungs associated with intense or repeated exposure to a variety of finely dispersed environmental antigens. Although once believed to be a disease of adults because of its frequent association with the occupational setting, HP exists in the pediatric population and often goes unrecognized. Childhood HP is often associated with exposure to antigens in the home environment as well as with certain hobbies. Patients present in any one of the three disease stages: acute, subacute, and chronic, all with unique clinical presentations. Histopathologic findings depend on the disease stage at the time of evaluation. The immuno-pathogenesis is complex, but immune-complex (type III hypersensitivity) and cell-mediated (type IV hypersensitivity) immune responses appear to be the primary immune mechanisms involved in the pathogenesis of HP. Diagnosis can be very challenging. Although no single diagnostic or clinical laboratory test is available to diagnose HP, the most significant diagnostic tool is a detailed environmental exposure history. Avoidance of the inciting antigen is the most important form of treatment. Acute HP is responsive to antigen removal alone. However, a short course of prednisone for 2-3 weeks can be useful in patients with severe attacks. Subacute and chronic HP may require higher doses of corticosteroids for a longer duration (i.e. months); however, the long-term efficacy of using corticosteroids is still not well defined. As with most hypersensitivity diseases, early diagnosis provides the best prognosis.

Use of co-immunoelectrodiffusion to detect presumed disease-associated precipitating antibodies, and time-course value of specific isotypes in bird-breeder's disease

BACKGROUND AND OBJECTIVE

The practical value of immunological diagnosis of bird-breeder's disease (BBD) is controversial, because of difficulties in distinguishing active disease patients from simple contact subjects. The aim of this study was to determine the diagnostic and prognostic value of (a) presumed disease-associated antibodies precipitating pigeon antigens (immunoglobulin A (IgAp) and P2 component), (b) characterization of specific isotypes (IgG, IgM, and IgA), and (c) antibody kinetics after antigen eradication.

METHODS

405 subjects (775 sera) in contact with birds were studied [by means of co-immunoelectrodiffusion (Co-IED) and enzyme-linked immunofiltration (ELIFA)] with soluble extracts of pigeon droppings and squab crop milk. These patients were divided into two groups based on the final clinical evaluation of the patients' physicians, which was taken as the gold standard (positive in 90 and negative in 315 cases).

RESULTS

On the basis of this gold standard, the detection of presumed disease-associated precipitating antibodies by Co-IED had a specificity of 95.5%, a sensitivity of 98.7%, an accuracy of 98%, and positive and negative predictive values of 95.5% and 98.7%, respectively. Most of the patients with a final positive diagnosis of BBD had specific IgG, IgM, and IgA antibodies by ELIFA. After antigen eradication, anti IgAp and/or P2 antibodies disappeared more rapidly than other precipitating systems.

CONCLUSION

Identification by Co-IED of precipitating immune complexes IgAp and/or P2 significantly reinforces the intrinsic credibility of immunological diagnosis of BBD. Compared to these presumed disease-associated precipitating antibodies, detection and time course of specific IgM, IgA antibodies, provided no additional diagnostic value or prognostic arguments to judge disease activity after antigen eradication.

Clinicopathological features of chronic hypersensitivity pneumonitis

OBJECTIVE

Only limited information exists concerning the clinical and pathological features of chronic hypersensitivity pneumonitis (HP) in Japan and elsewhere. We present data on clinicopathological features of chronic HP obtained through a Japanese nationwide survey.

METHODOLOGY

We studied the clinical and pathological findings in 10 patients with chronic HP who underwent surgical lung biopsy or postmortem examination.

RESULTS

There were three types of clinical course: six of the 10 patients had persistent symptoms followed by repeated acute episodes; two showed a subacute onset with persistent symptoms; and two exhibited an insidious onset. Five patients made no attempt to avoid antigen exposure and they all had progressive disease. Pathological findings indicated that lesions were mainly centrilobular with or without epithelioid cell granulomas in specimens obtained during the acute or subacute stage. In contrast, most patients in the chronic stage predominantly showed interstitial fibrosis with a usual interstitial pneumonia pattern.

CONCLUSIONS

The pathological findings of chronic HP depend on the stage of the disease at tissue sampling.

Hypersensitivity pneumonitis in children

Hypersensitivity pneumonitis in children is an underrecognized form of immune-mediated interstitial lung disease that results from repeated exposure to the inhalation of organic antigens. Because overt disease develops in only a small percentage of exposed individuals, complex interactions between the nature of the antigen, the intensity and duration of the exposure, and the host response in susceptible individuals are most likely involved. In most reported pediatric cases, hypersensitivity pneumonitis results from exposure to avian antigens, but it has also been seen with exposure to molds and methotrexate. The diagnosis is established by documented exposure, compatible clinical presentation, and consistent radiologic features; it is supported by positive precipitating antibodies, lymphocytosis in bronchoalveolar lavage fluid, and characteristic histologic changes on lung biopsy. Treatment consists of antigen avoidance in all cases, and corticosteroids in severe cases. The prognosis is excellent when prompt recognition and treatment are initiated.

The long-term outcome in acute, subacute, and chronic forms of pigeon breeder's disease hypersensitivity pneumonitis

BACKGROUND

Pigeon breeder's disease (PBD) is an avian-induced hypersensitivity pneumonitis. The limited data that exist on the long-term outcome for the disease are conflicting.

OBJECTIVE

We sought to determine the long-term outcome of patients with PBD to evaluate the course of the disease.

METHODS

Review a case series of 18 pigeon breeders that were followed from 4 to 26 years after initial diagnosis.

RESULTS

Fourteen breeders reduced their bird contact significantly; four kept their birds. In eight patients with the acute form of the disease, pulmonary function either did not change from normal or improved to normal. Of five patients with subacute disease, four had persistent symptoms. All had mildly abnormal spirometry with either restrictive or obstructive changes which persisted. Five patients with chronic disease exhibited daily dyspnea. They had severe abnormalities of lung function at diagnosis. Of these patients, three improved and two deteriorated. Chest radiographs were of little value in predicting outcome.

CONCLUSIONS

Patients with the acute form of PBD have the best prognosis, compared with those with subacute and chronic forms. Although some improvement could be seen in most individuals, recovery may still not be complete. Those with the chronic form are at particular risk for morbidity.

Pigeon breeder's lung in childhood: varied clinical picture at presentation

Extrinsic allergic alveolitis occurs rarely in childhood. We present 5 cases and briefly review the literature regarding this condition in the pediatric population. This report includes all cases (n = 5) of extrinsic allergic alveolitis known to have occurred in childhood on Malta. All cases were males, and were initially misdiagnosed as having other respiratory illnesses or mental disturbances. The diagnosis was based on a history of exposure to birds, clinical findings, positive avian precipitins, a restrictive defect on pulmonary function tests, and a suggestive chest X-ray appearance. All were treated with high-dose oral steroids for 3-4 weeks, with excellent response. Although these patients appear to have suffered no long-term sequelae, delayed diagnosis can lead to irreversible pulmonary fibrosis. The diagnosis of extrinsic allergic alveolitis should be entertained early in the differential diagnosis of children presenting with unusual respiratory symptoms and signs.

A family with extrinsic allergic alveolitis caused by wild city pigeons: A case report

We describe a family in which the mother died of unresolved lung disease and whose 5 children, some of whom had previous signs of asthma, were subsequently affected by extrinsic allergic alveolitis caused by contact with wild city pigeon antigens. The children received systemic corticosteroids for 1 month and inhaled steroids for 24 months, while antigen exposure was reduced as much as feasible. This was followed by a quick clinical recovery and a slow normalization of chest radiographs and pulmonary function indices, especially of diffusion capacity, during a follow-up of 24 months. Because pigeon-breeder's lung caused by free-roaming city pigeons has not been previously described, it remains unclear whether this family developed the disease because of high antigen exposure or because of increased susceptibility. None of the supposedly high-risk human leukocyte antigen types were found in the children. Whether human leukocyte antigen B7 in 1 child played a role in the course of the illness remains speculative. It is unknown to what extent pigeon-breeder's lung caused by nondomestic birds remains undetected and misdiagnosed as difficult or steroid-resistant asthma. The question remains whether free-roaming city pigeons are indeed a public health risk. We suggest that atypical outdoor antigens be considered in all patients with nonresolving chest disease or therapy-resistant asthma.

Occupational allergic alveolitis

Hypersensitivity pneumonitis is an important occupational pulmonary disease. A variety of antigens including foreign proteins and low molecular weight chemicals have been described as etiologic agents. The immunopathogenesis appears to involve activated CD8+ cells as well as activated macrophages. The clinical disease may be acute, subacute or chronic depending upon the nature and level of exposure. Reducing exposure to known antigens is a strategy that appears promising in terms of prevention of irreversible disease.

Shortness of breath secondary to a pet cockatiel

A case of hypersensitivity pneumonitis in a 40-year-old patient secondary to a pet bird is presented. The clinical presentation, diagnosis, and management of hypersensitivity pneumonitis are reviewed.

Pet birds as an independent risk factor for lung cancer: case-control study

OBJECTIVE

To test the hypothesis that exposure to pet birds increases risk of developing lung cancer.

DESIGN

Case-control study. Computerised interviews were used to assess previous exposure to pets and other risk factors for lung cancer.

SETTING

Three major hospitals treating respiratory disease in former West Berlin.

SUBJECTS

All people newly diagnosed as having primary malignant neoplasm of the trachea, bronchi, or lung who were 65 or younger and control subjects matched for age and sex from the general population of former West Berlin. 279 cases and 635 controls qualified for the study; 239 cases and 429 controls participated.

MAIN OUTCOME MEASURES

Odds ratio of developing lung cancer according to whether or not pet birds were kept and the duration of keeping pet birds.

RESULTS

In addition to the risk of lung cancer imposed by smoking, passive smoking, and occupational exposure to carcinogens, an increased relative risk of 2.14 (95% confidence interval 1.35 to 3.40) was found among people exposed to pet birds. The adjusted odds ratio for exposures longer than 10 years was 3.19 (1.48 to 8.21).

CONCLUSIONS

Avian exposure seems to carry a risk of lung cancer. Until the pathogenesis is understood, long term exposure to pet birds in living areas should be avoided, especially among people at high risk of developing lung cancer.