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

[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.

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A Rare Pediatric Case of Severe Bird Fancier's Lung Presented with Viral Pneumonitis-Like Picture

Bird Fancier's Lung (BFL) is a rare, nonatopic immunologic response to repeated or intense inhalation of avian (bird) proteins/antigens found in the feathers or droppings of many species of birds, which leads to an immune-mediated inflammatory reaction in the respiratory system. Although this is the most common type of hypersensitivity pneumonitis (HP) reported in adults, it is one of the classifications of a rare subtype of interstitial lung disease that occurs in the pediatric age group of which few case reports are available in the literature. The pathophysiology of HP is complex; numerous organic and inorganic antigens can cause immune dysregulation, leading to an immune-related antigen⁻antibody response (immunoglobulin G-IgG- against the offending antigen). Diagnosing BFL in the pediatric age group is challenging due to the history of exposure usually being missed by health care providers, symptoms and clinical findings in such cases being nonspecific and often misdiagnosed during the acute illness with other common diseases such asthma or acute viral lower respiratory tract infection, and the lack of standardization of criteria for diagnosing such a condition or sensitive radiological or laboratory tests. Treatment, on the other hand, is also controversial. Avoidance of the offending antigen could be the sole or most important part of treatment, particularly in acute mild and moderate cases. Untreated cases can result in irreversible lung fibrosis. In this case report, we highlight how children presenting with an acute viral lower respiratory tract infection can overlap with the acute/subacute phase of HP. Early intervention with pulse steroids markedly improves the patient's clinical course.

Risk of hypersensitivity pneumonitis and interstitial lung diseases among pigeon breeders

We studied the risk of hypersensitivity pneumonitis and other interstitial lung diseases (ILDs) among pigeon breeders.This is a retrospective follow-up study from 1980 to 2013 of 6920 pigeon breeders identified in the records of the Danish Racing Pigeon Association. They were compared with 276 800 individually matched referents randomly drawn from the Danish population. Hospital based diagnoses of hypersensitivity pneumonitis and other ILDs were identified in the National Patient Registry 1977-2013. Stratified Cox regression analyses estimated the hazard ratios (HR) of hypersensitivity pneumonitis and other ILDs adjusted for occupation, residence and redeemed prescription of medication with ILDs as a possible side-effect. Subjects were censored at death, emigration or a diagnosis of connective tissue disease.The overall incidence rate of ILD was 77.4 per 100 000 person-years among the pigeon breeders and 50.0 among the referents. This difference corresponded to an adjusted HR of 1.56 (95% CI 1.26-1.94). The adjusted HRs of hypersensitivity pneumonitis and other ILDs for pigeon breeders were 14.36 (95% CI 8.10-25.44) and 1.33 (95% CI 1.05-1.69), respectively.This study shows an increased risk of ILD among pigeon breeders compared with the referent population. Protective measures are recommended even though ILD leading to hospital contact remains rare among pigeon breeders.

Hypersensitivity pneumonitis : a broader perspective

Hypersensitivity pneumonitis (HP) represents a group of lung disorders caused by the inhalation of a wide variety of organic particles by susceptible individuals. HP occurs mainly in nonsmokers, but smoking may promote an insidious and chronic disease. The prevalence of HP is difficult to estimate accurately since several antigens can produce the disease, but the range spans infancy to old age. Regardless of the causative antigen or its environmental setting, the clinical manifestations are essentially the same. Three different clinical presentations have been recognized: acute, subacute, and chronic. In the acute form, patients show flu-like symptomatology, followed by dyspnea and dry cough. Symptoms subside a few hours or days later. The subacute and chronic forms result from recurrent low-level antigen exposure and are characterized by progressive dyspnea and dry cough. Other constitutional symptoms such as fatigue, anorexia, and weight loss can be apparent. Fever may occur in the subacute form. Importantly, chronic HP may evolve insidiously or may result from repeated acute/subacute episodes. Recurrent acute, subacute, and chronic HP may progress to irreversible lung fibrosis or provoke emphysematous changes.HP can be difficult to identify, and precise diagnosis requires a history of exposure and a constellation of clinical, imaging, laboratory, bronchoalveolar lavage and pathologic findings. General laboratory tests show an increase of acute phase reactants. Specific precipitating antibodies, when present, are evidence of antigen exposure, and are a hallmark for diagnosis. Chest radiograph usually reveals widespread ground-glass attenuation, and nodular or reticulonodular shadowing. High-resolution CT features include diffuse or patchy ground-glass opacities with small poorly defined nodules and air trapping. Pulmonary function tests are characterized by a predominantly restrictive ventilatory defect with loss of lung volume and hypoxemia at rest that worsens with exercise. Bronchoalveolar lavage reveals a significant increase in lymphocytes, mostly over 40%. In the acute form there is also an increase in neutrophils. Antigen-induced lymphocyte proliferation, and environmental or laboratory-controlled inhalation challenge, may be used for diagnostic purposes and can help to establish a diagnosis of insidious forms of HP. In subacute or chronic cases, lung biopsy may be necessary. Typical findings include bronchiolitis, lymphocytic alveolitis, and loosely formed granulomas, although occasionally other morphologic patterns such as nonspecific interstitial pneumonia may exist. Treatment focuses on avoiding further exposure to the offending antigen(s). Corticosteroids are recommended in subacute and chronic forms. The usual regimen consists of initial high doses of systemic corticosteroid (e.g. prednisone 0.5-1.0 mg/kg/day), followed by gradual tapering.

Hypersensitivity pneumonitis

Clinical manifestations of hypersensitivity pneumonitis may closely mimic other interstitial lung diseases, and the disease onset is usually insidious. High-resolution computed tomography and bronchoalveolar lavage are the sensitive and characteristic diagnostic tests for hypersensitivity pneumonitis. The relevant antigen to hypersensitivity pneumonitis cannot be identified in up to 20% to 30% of patients. Clinicians should be aware that hypersensitivity pneumonitis must be considered in all cases of interstitial lung disease, and a detailed environmental exposure history is mandatory.

Chronic hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is a complex syndrome caused by the inhalation of environmental antigens. Chronic HP may mimic other fibrotic lung diseases, such as idiopathic pulmonary fibrosis. Recognition of the antigen is important for diagnosis; avoidance of further exposure is critical for treatment. Fibrosis on biopsy or high-resolution computed tomography is a predictor of increased mortality. Additional research is needed to understand why the disease develops only in a minority of exposed individuals and why cases of chronic HP may progress without further antigen exposure.

Pet birds and risks of respiratory disease in Australia: a review

OBJECTIVE

Exposure to birds has long been associated with disease in humans. Three respiratory diseases (psittacosis, allergic alveolitis and asthma) were reviewed in association with pet bird ownership with the aim to clarify the spectrum of avian-related respiratory illnesses.

APPROACH

Nineteen studies were selected for review based on recreational bird exposure in relation to psittacosis, allergic alveolitis and asthma.

CONCLUSION

Literature reveals little consensus on the relationship between pet bird ownership and respiratory illness.

IMPLICATIONS

Future studies should aim to clarify the spectrum of avian-related illnesses, and to direct the dissemination of public health information to clinicians and members of the public who keep birds as pets.

[Pigeon breeder's lung]

Bird fancier's or breeder's lung is an unusual hypersensitivity pneumonitis found in pediatric patients, due to avian antigen inhalation. A case of pigeon breeder's lung in a 12 years old child is presented. Clinical symptoms were dry cough for 15 days, dyspnea and weight loss. Physical examination of the patient showed cyanosis, chest tightness, tachypnea, inspiratory crackles and oxygen saturation of 91% in room air. Laboratory data revealed hypergammaglobulinemia and elevated LDH. Pulmonary function testing showed a mixed ventilatory pattern and a decreased carbon monoxide diffusion (DLCO) capacity. Radiological findings were compatible with hypersensitivity pneumonitis, and pigeon IgG antibodies (ELISA) and skin tests with pigeon serum were positive. The child improved with corticoid therapy and antigen avoidance.

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Quantification of IgG antibodies to Aspergillus fumigatus and pigeon antigens by ImmunoCAP technology: an alternative to the precipitation technique?

BACKGROUND

We evaluated the ImmunoCAP technique for measurement of IgG specific to Aspergillus fumigatus and pigeon antigens.

METHODS

We used ImmunoCAP and precipitation technique to measure concentrations of IgG to A. fumigatus or pigeon antigens in sera from 265 patients and 42 controls. We also evaluated linearity, interference, imprecision, concordance, and diagnostic accuracy of the measuring techniques.

RESULTS

The precipitation and ImmunoCAP technique showed moderate concordance (kappa, 0.46 for both A. fumigatus and pigeon antibodies). Specific IgG results for A. fumigatus and pigeon were linear (r = 0.98 and 0.97, respectively), with interrun reproducibility rates of 23% and 14% and maximal interference of 36.5% and 8% by lipid and 24% and 21% by hemolysis, respectively. A. fumigatus antibody concentrations were higher in patients with aspergillosis and allergic bronchopulmonary aspergillosis (ABPA) (median, 103 and 70.1 mgA/L, respectively) than in patients with other pulmonary diseases (median, 18.15-33.40 mgA/L). Antibodies to pigeon antigens were high in patients with hypersensitivity pneumonitis (median, 1024 mgA/L) but also in patients with other pulmonary diseases (median, 445 mgA/L). Antibody titers were substantially higher in patients with other pulmonary diseases and contact with pigeons (median, 1060 mgA/L) than in patients without antigen contact (median, 27.35 mgA/L) (P <0.004).

CONCLUSIONS

Agreement between the precipitation and ImmunoCAP technique was 86% for A. fumigatus and 70% for pigeon antigens. Highest concentrations of specific IgG to A. fumigatus were found in patients with aspergillosis and ABPA. Our results suggest that antigen contact was the most important variable affecting the presence of antibodies to pigeon antigen.

Pigeon breeder's lung in childhood: is family screening necessary?

In this paper, we report on clinical and laboratory findings of pigeon breeder's lung (PBL) in a mother and her 2 children: 2 with the chronic recurrent form, and 1 with the chronic insidious form without any symptoms or signs, who was diagnosed during family screening. The index case was diagnosed as having primary pulmonary hypertension on admission. However, on evaluation, the diagnosis was of pigeon breeder's lung in the index case and her symptomatic mother. High-resolution computerized tomography (HRCT) revealed interstitial lung disease in an asymptomatic sister of the index case. All cases responded to steroid treatment, and at the end of the third month, HRCT findings disappeared. In conclusion, in patients with acute respiratory symptoms and rapidly recovering pulmonary hypertension after hospitalization, PBL should be remembered. All family members of the index case should be screened by HRCT in terms of interstitial lung disease, even if they are asymptomatic.

Bird breeder's disease: a rare diagnosis in young children

Bird breeder's lung disease is the most common form of hypersensitivity pneumonitis and is a rare entity in young children. We report three cases of children under 7 years of age in whom this diagnosis was confirmed early in the course of the disease. Three children aged 4.4 to 6.5 years presented with dry cough lasting for more than 1 month, dyspnoea, variable loss of appetite, weight loss, fatigue, fever and mild signs of respiratory distress. Chest X-ray films and CT scans showed a bilateral micronodular infiltrate. All three patients had strongly suggestive bronchoalveolar lavage fluid findings with lymphocytosis; two had elevated cell counts and decreased CD4/CD8 ratios. Lung biopsy confirmed the diagnosis in all children. Contact with allergens was identified in all children: two had spent holidays close to a farm in the previous month and one was living next to a pigeon house. In all children, avian precipitins were positive. The symptoms rapidly resolved after allergen avoidance and treatment with oral prednisone. Corticoid treatment was given between 11 and 15 weeks. One child relapsed and required long-term low-dose corticotherapy for 1 year. Lung function tests were normal in all three patients, 3.9 to 5.7 years after diagnosis.

CONCLUSION

Bird breeder's lung disease is a rare entity but should be considered in young children presenting long lasting cough. While rapid allergen exclusion and start of treatment can avoid the evolution into irreversible lung fibrosis, clinical and biological evolution should be monitored carefully even after stopping corticoid treatment because of the possibility of relapse.

Treatment of interstitial lung disease in children

The treatment of interstitial lung disease in children depends on the nature of the underlying pathology. In approximately 50% of cases a specific aetiology can be found such as: chronic viral infection, an auto-immune process, sarcoidosis or alveolar proteinosis. In the remainder, the process is idiopathic and the pathological findings are based on the descriptive morphological features seen in the diagnostic lung biopsy. If a specific cause is found then targeted treatment with antivirals, steroids or other immunosuppressive agents is available. Alveolar proteinosis can be treated by bronchial lavage and GM-CSF. Idiopathic cases are treated primarily with intravenous pulsed methylprednisolone or oral prednisolone backed up hydroxychloroquine. Other immunosuppressive agents such as azathioprine, methotrexate or ciclosporin have been used successfully in individual patients. The prognosis is very variable and includes no response to any therapy, partial response with chronic long term morbidity, to virtually complete recovery. The overall mortality rate is 15%. There are no controlled therapeutic trials available because of the rarity of these conditions in childhood. Unlike in adult practice, no correlation has as yet been demonstrated between the initial pattern of chest x-ray change or the degree of pathological change on the lung biopsy and the clinical outcome. The recurrence rate within families is 1 in 8.

Toxic and other non-IgE-mediated effects of fungal exposures

There are more than 100000 recognized species of fungi, comprising 25% of the biomass of the earth. Allergic, IgE-induced, manifestations of airborne fungi are common, whereas non-IgE manifestations are rare. Recently, much focus has been placed on the non-IgE-mediated effects of various molds, including hypersensitivity pneumonitis, infectious disease, and mycotoxicoses. Hypersensitivity pneumonitis is a clinical syndrome associated with systemic and interstitial lung disease that occurs in susceptible individuals following fungal inhalation. Most fungi are not pathogenic to man; however, certain fungi are capable of infecting immunocompetent individuals. Although mycotoxins and exposure to mycotoxins ("toxic mold syndrome") are implicated in causing numerous, nonspecific, systemic symptoms, currently, there is no scientific evidence to support the allegation that human health is affected by inhaled mycotoxins. However, if mold is discovered in a home, school, or office setting, the source should be investigated and appropriate remediation undertaken to minimize structural damage and potential allergic sensitization.

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.