Spotlight on the diagnosis of extrinsic allergic alveolitis (hypersensitivity pneumonitis)

Röntgenbefunde bei diffusen parenchymatösen Lungenerkrankungen

Klinisches Problem

Empfehlungen für die Praxis

[Chest radiography findings in diffuse parenchymal lung diseases]

CLINICAL ISSUE

Diffuse parenchymal lung diseases include a heterogeneous group of diseases of the lung parenchyma, the alveolar spaces, the vessels and the airways, which can be triggered by various pathomechanisms, such as inflammation and fibrotic changes. Since the therapeutic approaches and prognoses differ significantly between the diseases, the correct diagnosis is of fundamental importance. In routine clinical practice, next to the patients' history, the clinical presentation, the laboratory findings and the bronchoscopy, imaging plays a central role in establishing a diagnosis.

PRACTICAL RECOMMENDATIONS

The diagnosis of diffuse parenchymal lung diseases is an enormous challenge for clinicians, radiologists as well as pathologists and should therefore preferably be carried out in a multidisciplinary setting. Since patients often present with unspecific, respiratory symptoms, chest radiographs are the first imaging method used. Many patterns of diffuse parenchymal lung diseases (e.g., ground-glass opacities and consolidations), their distribution (e.g., cranial-caudal) and the presence of additional findings (e.g., mediastinal lymphadenopathy) are often already detectable on chest X‑rays. However, the imaging reference standard and thus, an integral part of the assessment of diffuse parenchymal lung disease, is the chest HR-CT. In some cases, the pattern of the HR-CT is pathognomonic, in others it is unspecific for a disease, so that further diagnostic steps are necessary.

Sooty bark disease of maples: the risk for hypersensitivity pneumonitis by fungal spores not only for woodman

In the middle of the twentieth century, the from North America sooty bark disease (SBD) of maples was first discovered in England and has spread in the last decades in Central Europe, in particular. The trigger of SBD is the mould fungus Cryptostroma (C.) corticale. The most common infested maple is the sycamore, Acer pseudoplatanus, a common tree in woods and parks. The disease is characterised by peeling of the outer layer of the bark and brownish-black spores under the peeled off bark. These spores can cause maple bark disease (MBD) in humans, a hypersensitivity pneumonitis (HP) with similar symptoms like COPD, allergic asthma, influenza or flu-like infections and interstitial pneumonia. Persons who have intensive respectively occupational contact with infested trees or wood, e.g., woodman, foresters, sawyers or paper mill workers, are at risk in particular. Since C. corticale favours hot summers and host trees weakened by drought, SBD will increasingly spread in the future due to ongoing climate change. Consequently, the risk of developing MBD will increase, too. As with all HPs, e.g., farmer's lung and pigeon breeder's disease, the diagnosis of MBD is intricate because it has no clear distinguishing characteristics compared to other interstitial lung diseases. Therefore, the establishment of consistent diagnosis guidelines is required. For correct diagnosis and successful therapy, multidisciplinary expertise including pulmonologists, radiologists, pathologists and occupational physicians is recommended. If MBD is diagnosed in time, the removal of the triggering fungus or the infested maple wood leads to complete recovery in most cases. Chronic HP can lead to lung fibrosis and a total loss of lung function culminating in death. HP and, thus, MBD, is a disease with a very high occupational amount. To avoid contact with spores of C. corticale, persons working on infested wood or trees have to wear personal protective equipment. To protect the public, areas with infested maples have to be cordoned off, and the trees should be removed. This is also for impeding further spreading of the spores.

Medical devices in allergy practice

Medical devices provide people with some health benefits in terms of diagnosis, prevention, treatment, and monitoring of disease processes. Different medical specialties use varieties of medical devices more or less specific for them. Allergology is an interdisciplinary field of medical science and teaches that allergic reactions are of systemic nature but can express themselves at the level of different organs across the life cycle of an individual. Subsequently, medical devices used in allergology could be regarded as: 1) general, servicing the integral diagnostic and management principles and features of allergology, and 2) organ specific, which are shared by organ specific disciplines like pulmonology, otorhinolaryngology, dermatology, and others. The present position paper of the World Allergy Organization (WAO) is meant to be the first integral document providing structured information on medical devices in allergology used in daily routine but also needed for sophisticated diagnostic purposes and modern disease management. It is supposed to contribute to the transformation of the health care system into integrated care pathways for interrelated comorbidities.

Sertraline-induced hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is a granulomatous, non-IgE-mediated hypersensitivity reaction of the alveoli and distal bronchioles presenting as an acute, subacute or chronic condition. It is most commonly associated with exposure to extrinsic allergens (eg, avian dust, mould and tobacco) and medications including antiarrhythmics (eg, amiodarone), cytotoxics (eg, methotrexate) and antiepileptics (eg, carbamazepine). Individuals diagnosed with this condition can present with severe hypoxia and respiratory failure. The fundamental principle of management is to remove the causative allergen. Evidence implicating selective serotonin reuptake inhibitors as a causative agent is limited, and this case report describes a rare clinical presentation of HP associated with sertraline, how it was diagnosed and subsequently treated. It is anticipated that raising awareness of this interaction will assist multidisciplinary teams, managing patients diagnosed with HP, to be more cognisant of sertraline as being an aetiological factor for this condition.

Intra- and inter-individual variability of Aspergillus fumigatus reactive T-cell frequencies in healthy volunteers in dependency of mould exposure in residential and working environment

Invasive aspergillosis remains a deadly disease in immunocompromised patients, whereas the combination of an exaggerated immune response and continuous exposure lead to various hyperinflammatory diseases. This pilot study aimed to gain an overview of the intra- and inter-individual variability in Aspergillus fumigatus reactive T-helper cells in healthy adults and the correlation with environmental mould exposure. In this flow cytometric study, the frequencies of CD154⁺ A. fumigatus reactive T cells were evaluated in 70 healthy volunteers. All subjects completed a standardised questionnaire addressing their mould exposure. Subjects with intensive mould exposure in their professional or residential surrounding demonstrated considerably higher mean frequencies of A. fumigatus reactive T-helper and T-memory cells. Comparative evaluation of multiple measurements over time demonstrated relatively conserved reactive T-cell frequencies in the absence of major changes to the exposure profile, whereas those frequently exposed in professional environment or with changes to their risk score demonstrated a marked dependency of antigen reactive T-cell frequencies on recent mould exposure. This pilot study was the first to provide data on the intra-individual variability in A. fumigatus reactive T-cell frequencies and its linkage to mould encounter. Fungus reactive T cells are to be considered a valued tool for the assessment of environmental mould exposure.

Imaging of nontraumatic thoracic emergencies

PURPOSE OF REVIEW

Acute chest symptoms form an important incentive for imaging in the emergency setting. This review discusses the radiologic features of various vascular and pulmonary diseases leading to acute respiratory distress and recent developments on important emergency radiologic examinations.

RECENT FINDINGS

Recently, triple-rule-out computed tomography protocol was introduced in diagnosis of chest pain, and advancing computed tomography technology and knowledge have led to discussion on treatment of pulmonary embolism. Diffuse pulmonary opacities remain a diagnostic dilemma in the emergency setting and although imaging findings can often be nonspecific, they help in guiding toward accurate diagnosis and timely management.

SUMMARY

Though promising, triple-rule-out is not yet justified because of low incidence of additional findings compared with conventional computed tomography angiography in chest pain, but it might be suited for clinical practice in the near future. Relevance of isolated subsegmental pulmonary embolism is unknown and research on this topic is needed and on its way. We provided some key findings in differentiating diffuse pulmonary opacities and describe the additional value of chest ultrasound in this clinical dilemma. A brief sidestep to pneumothorax is made, as this is also a frequent finding in the acute dyspneic patient, as well as in patients with acute chest pain.

Occupational Allergies: A Brief Review

Occupational allergies are groups of work-related disorders that are accompanied by immunologic reaction to workplace allergens and include occupational asthma, rhinitis, hypersensitivity pneumonitis, dermatitis, and anaphylaxis. This mini review presents a brief analysis of the more important aspects of occupational allergic disorders.