Bronchiolitis: Classification, Computed Tomographic and Histopathologic Features, and Radiologic Approach

Analysis of Risk Factors of Bronchiolitis Obliterans in Children with Mycoplasma pneumoniae Bronchiolitis

Objective

To investigate the related risk factors for bronchiolitis obliterans (BO) in children with mycoplasma pneumonia (MP) bronchiolitis.

Method

The clinical data of 227 children with MP bronchiolitis who were admitted to the II Department of Respiratory of Children's Hospital of Hebei Province from January 2018 to June 2020 were retrospectively analyzed. According to the sequelae of BO, they were divided into 32 cases in the BO group and 195 cases in the non-BO group. The univariate analysis was performed on the clinical and laboratory parameters of the two groups, and the multifactor logistic regression was performed further to determine the independent risk factors for the occurrence of BO in MP bronchiolitis, and then, the cut-off value with the maximum diagnostic value of indicators was found through the ROC curve analysis.

Results

The results of univariate and multivariate logistic regression analysis showed that the independent risk factors for the occurrence of BO in MP bronchioles were longer duration of moist rales (OR = 1.203, P = 0.003), higher levels of serum lactate dehydrogenase (LDH) (OR = 1.005, P = 0.036), hypoxemia (OR = 7.442, P = 0.035), and pleural effusion (OR = 4.437, P = 0.004). The area under the ROC curve was 78.2%, 72.0%, 68.2%, and 71.0%, respectively (P < 0.001). The cut-off value of duration of moist rales and levels of serum LDH are 7.5 d and 330 U/L, respectively.

Conclusion

Children with MP bronchiolitis with high serum LDH level (≥330 U/L), combined with hypoxemia, pleural effusion, and lung wet rale duration (≥7.5 d), may be more prone to BO, in which lung wet rale duration prediction value is the largest. Among them, duration of pulmonary moist rales has the highest predictive value.

Cryobiopsy in the diagnosis of bronchiolitis: a retrospective analysis of twenty-three consecutive patients

Bronchiolitis manifests as a variety of histological features that explain the complex clinical profiles and imaging aspects. In the period between January 2011 and June 2015, patients with a cryobiopsy diagnosis of bronchiolitis were retrospectively retrieved from the database of our institution. Clinical profiles, imaging features and histologic diagnoses were analysed to identify the role of cryobiopsy in the diagnostic process. Twenty-three patients with a multidisciplinary diagnosis of small airway disease were retrieved (14 females, 9 males; age range 31-74 years old; mean age 54.2 years old). The final MDT diagnoses were post-infectious bronchiolitis (n = 5), constrictive bronchiolitis (n = 3), DIPNECH (n = 1), idiopathic follicular bronchiolitis (n = 3), Sjogren's disease (n = 1), GLILD (n = 1), smoking-related interstitial lung disease (n = 6), sarcoid with granulomatous bronchiolar disorder (n = 1), and subacute hypersensitivity pneumonitis (n = 2). Complications reported after the cryobiopsy procedure consisted of two cases of pneumothorax soon after the biopsy (8.7%), which were successfully managed with the insertion of a chest tube. Transbronchial cryobiopsy represents a robust and mini-invasive method in the characterization of small airway diseases, allowing a low percentage of complications and good diagnostic confidence.

Perspectives in veterinary medicine: Description and classification of bronchiolar disorders in cats

This Perspectives in Veterinary Medicine article seeks to define, describe putative causes, and discuss key diagnostic tests for primary and secondary bronchiolar disorders to propose a classification scheme in cats with support from a literature review and case examples. The small airways (bronchioles with inner diameters <2 mm), located at the transitional zone between larger conducting airways and the pulmonary acinus, have been overlooked as major contributors to clinical syndromes of respiratory disease in cats. Because the trigger for many bronchiolar disorders is environmental and humans live in a shared environment with similar susceptibility, understanding these diseases in pet cats has relevance to One Health. Thoracic radiography, the major imaging modality used in the diagnostic evaluation of respiratory disease in cats, has low utility in detection of bronchiolar disease. Computed tomography (CT) with paired inspiratory and expiratory scans can detect pathology centered on small airways. In humans, treatment of bronchiolar disorders is not well established because of heterogeneous presentations and often late definitive diagnosis. A review of the human and veterinary medical literature will serve as the basis for a proposed classification scheme in cats. A case series of cats with CT or histopathologic evidence of bronchiolar lesions or both, either as a primary disorder or secondary to extension from large airway disease or interstitial lung disease, will be presented. Future multi‐institutional and multidisciplinary discussions among clinicians, radiologists, and pathologists will help refine and develop this classification scheme to promote early and specific recognition and optimize treatment.

Constrictive Bronchiolitis Obliterans in a Dog

A 2 yr old, neutered male rottweiler was evaluated for a chronic cough that had acutely worsened. Computed tomographic examination revealed a diffuse alveolar pattern in the right, middle, and left cranial lung lobes. Aerated parenchymal tissue was not observed in the left cranial lung lobe, and both lobes were markedly decreased in volume. Lobectomy of the right middle and left cranial lung lobes was performed. Histopathologic examination of both lungs identified alveolar collapse associated with marked chronic bronchial and bronchiolar luminal concentric fibrosis leading to reduced airway lumen diameter and bronchiolar destruction. The clinical signs and airway pathology were consistent with constrictive bronchiolitis obliterans. The dog remained stable for over 2 yr with glucocorticoid therapy and intermittent antimicrobics. Although the polypoid form of bronchiolitis obliterans has been described in cattle and occasionally in dogs, constrictive bronchiolitis obliterans has not been reported previously in veterinary species.

Imaging of small airways and emphysema

High-resolution chest computed tomography (CT) is one of the most useful techniques available for imaging bronchiolitis because it shows highly specific direct and indirect imaging signs. The distribution and combination of these various signs can further classify bronchiolitis as either cellular/inflammatory or fibrotic/constrictive. Emphysema is characterized by destruction of the airspaces, and a brief discussion of imaging findings of this class of disease is also included. Typical CT findings include destruction of airspace, attenuated vasculatures, and hyperlucent as well as hyperinflated lungs.

Bronchiolitis

Bronchiolitis is a disease of the small airways accompanied by progressive and often irreversible airflow obstruction. Bronchiolitis can have several causes such as infection, toxic exposure, collagen vascular disease, post lung and stem cell transplant, and idiopathic etiology. Symptoms of cough and sputum production are often mistaken for chronic obstructive pulmonary disease or asthma, leading to a delay in diagnosis. Unfortunately, many types of bronchiolitis do not improve with therapy. Bronchiolitis following lung and stem cell transplant are the most common types seen in adults, and provide important insights into its pathogenesis.