Bronchoalveolar lavage fluid lymphocytosis in 104 dogs (2006-2016)

Quantifiable features of a tidal breathing phenotype in dogs with severe bronchomalacia diagnosed by bronchoscopy

Dynamic lower airway obstruction is the primary component of canine bronchomalacia, but the ventilatory function remains underinvestigated. This prospective study analyzed tidal breathing characteristics in 28 dogs, comprising 14 with severe bronchomalacia diagnosed by bronchoscopy versus 14 without respiratory disease. Spirometry was conducted in all dogs. Bronchoscopy with bronchoalveolar lavage or brush under anesthesia was performed in 14 dogs with cough and expiratory effort. Severe bronchomalacia was defined by the severity of collapse and total number of bronchi affected. Ventilatory characteristics were compared between groups. Results revealed that dogs with severe bronchomalacia had lower minute volume (218 vs 338 mL/kg, p = .039) and greater expiratory-to-inspiratory time ratio (1.55 vs 1.35, p = .01) compared to control dogs. The tidal breathing pattern of dogs with bronchomalacia was different from that of normal dogs, and the pattern differed from the concave or flat expiratory curves typical of lower airway obstruction. Compared to control dogs, dogs with severe bronchomalacia had a significantly prolonged low-flow expiratory phase (p < .001) on the flow-time plot and a more exponential shape of the expiratory curve (p < .001) on the volume-time plot. Flow-time index ExpLF/Te (>0.14) and volume-time index Vt-AUCexp (≤31%) had a high ROC-AUC (1.00, 95% confidence interval 0.88 to 1.00) in predicting severe bronchomalacia. In conclusion, the tidal breathing pattern identified here indicates abnormal and complicated ventilatory mechanics in dogs with severe bronchomalacia. The role of this pulmonary functional phenotype should be investigated for disease progression and therapeutic monitoring in canine bronchomalacia.

Differentiating airway inflammation in calves based on cluster analysis of bronchoalveolar lavage fluid cytology

BACKGROUND

Nonbronchoscopic bronchoalveolar lavage (nBAL) is routinely performed in calves, and airway cytology has great potential in airway disease diagnostics. A good reference framework for nBAL cytology is lacking.

OBJECTIVES

To distinguish different cytological profiles in nBAL from grouped housed calves using cluster analysis, and characterize these profiles on individual and herd levels.

ANIMALS

Three hundred thirty-eight group-housed calves from 60 herds (mainly dairy and beef ).

METHODS

Cross-sectional study. Differential counts of white blood cells were determined on nBAL fluid, followed by differentiation of cytological profiles by K-means-based cluster analysis. These profiles were characterized by reference values, decision tree analysis, and associations with clinical, ultrasonographic, bacteriological, and cytological features.

RESULTS

A normal (55.9%), a neutrophilic (41.1%), and an eosinophilic profile (3.0%) were identified. The normal profile was characterized by reference values of 2.3% to 47.4% neutrophils, 35.1% to 95.1% macrophages, 0.4 to 22.9% lymphocytes, and 0.0% to 0.9% eosinophils. The neutrophilic profile was characterized by ≥44.5% neutrophils, <1.6% eosinophils, and <11.5% lymphocytes. This profile was associated with the isolation of Pasteurella multocida, the presence of neutrophils with toxic granulation, and the presence of phagocytosed bacteria in neutrophils. The eosinophilic profile was characterized by eosinophils ≥1.6% (neutrophilia present) or ≥2.4% (neutrophilia absent), and associated with the presence of mast cells. On herd level, the neutrophilic and eosinophilic profiles were present in 85.0% and 15.0% of the herds, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study provides a first step in the development of cytological guidelines, aiding the assessment of airway health and inflammation in calves through nBAL fluid cytology.

Prospective evaluation of the efficacy of inhaled steroids administered via the AeroDawg spacing chamber in management of dogs with chronic cough

BACKGROUND

Glucocorticoids are frequently required for management of cough because of inflammatory airway disease (IAD) and airway collapse (AWC).

OBJECTIVES/HYPOTHESIS

To determine the efficacy and feasibility of inhaled administration of corticosteroids in controlling cough in dogs with noninfectious airway disease.

ANIMALS

Thirty-six client-owned dogs.

METHODS

Dogs were prospectively recruited for this placebo-controlled cross-over study. Inflammatory airway disease was diagnosed through bronchoalveolar lavage cytology. Airway collapse was diagnosed through bronchoscopy, or if dogs were unsuitable anesthetic candidates, by crackles on auscultation, radiographic changes in airway diameter, or fluoroscopy. Dogs were randomly assigned to receive placebo or fluticasone propionate for the first 2 weeks of the trial then crossed over to fluticasone. A quality of life (QOL) survey (best score 0, worst score 85) was completed at 0 and 6 weeks. A visual-analog cough survey was submitted at 0, 2, 4, and 6 weeks to assess cough, feasibility, and adverse effects of treatment.

RESULTS

For 32 dogs, QOL score at study end (mean 28.1 ± 14.1) was significantly lower (P < .0001) compared to entry (mean 11.3 ± 9.7), with a median change of 69% in QOL score, indicating improved quality of life. Cough frequency, duration, and severity were significantly (P < .0001) decreased at study end. Feasibility of aerosolized delivery improved with continued use (P = .05) with only 1 dog unable to accept inhaled medication.

CONCLUSION AND CLINICAL IMPORTANCE

This study supports the utility of fluticasone propionate by inhalation in management of cough in dogs with IAD and AWC.

Presence of bronchial nodules, younger age, and heavier body weight are associated with a diagnosis of eosinophilic lung disease in dogs with cough

OBJECTIVE

To describe the association between a diagnosis of eosinophilic lung disease (ELD) in dogs with signalment and bronchoscopic features and evaluate the accuracy of visualization of nodules for the diagnosis of ELD.

ANIMALS

781 dogs with cough that underwent bronchoscopy between 2014 and 2016.

PROCEDURES

Data were extracted from the medical records of each included dog. Multivariable logistic regression was performed to investigate associations between ELD and patient characteristics.

RESULTS

ELD was diagnosed in 113 (14.5%) dogs. More than 3 nodular lesions of the bronchial mucosa were detected in 64 (8.2%) dogs. The odds of having ELD were greater in dogs with nodules (adjusted OR [aOR], 26.0; 95% CI, 13.0 to 52.0) and static bronchial collapse (aOR, 2.3; 95% CI, 1.1 to 4.6), and lower in dogs having focal versus diffuse inflammation (aOR, 0.05; 95% CI, 0.01 to 0.37). The odds of having ELD decreased for each 1-year increase in age (aOR, 0.86; 95% CI, 0.80 to 0.92), and increased for each 1-kg increase in weight (aOR, 1.04; 95% CI, 1.01 to 1.06). Visualization of nodules during bronchoscopy had a overall accuracy of 89.4% (95% CI, 87.0% to 91.4%), sensitivity of 41.6% (32.4% to 51.2%), and specificity of 97.5% (96.0% to 98.5%) for a diagnosis of ELD.

CLINICAL RELEVANCE

On the basis of high specificity and negative predictive value, lack of visualization of bronchial nodules during bronchoscopy can be used to preliminarily rule out ELD. However, visualization of bronchial nodules does not imply presence of ELD. This could be especially relevant when results of BAL cytology are available several days after the actual bronchoscopy.

Bronchoalveolar lavage affects thorax computed tomography of healthy and SARS-CoV-2 infected rhesus macaques (Macaca mulatta)

Medical imaging as method to assess the longitudinal process of a SARS-CoV-2 infection in non-human primates is commonly used in research settings. Bronchoalveolar lavage (BAL) is regularly used to determine the local virus production and immune effects of SARS-CoV-2 in the lower respiratory tract. However, the potential interference of those two diagnostic modalities is unknown in non-human primates. The current study investigated the effect and duration of BAL on computed tomography (CT) in both healthy and experimentally SARS-CoV-2-infected female rhesus macaques (Macaca mulatta). In addition, the effect of subsequent BALs was reviewed. Thorax CTs and BALs were obtained from four healthy animals and 11 experimentally SARS-CoV-2-infected animals. From all animals, CTs were obtained just before BAL, and 24 hours post-BAL. Additionally, from the healthy animals, CTs immediately after, and four hours post-BAL were obtained. Thorax CTs were evaluated for alterations in lung density, measured in Hounsfield units, and a visual semi-quantitative scoring system. An increase in the lung density was observed on the immediately post-BAL CT but resolved within 24 hours in the healthy animals. In the infected animals, a significant difference in both the lung density and CT score was still found 24 hours after BAL. Furthermore, the differences between time points in CT score were increased for the second BAL. These results indicate that the effect of BAL on infected lungs is not resolved within the first 24 hours. Therefore, it is important to acknowledge the interference between BAL and CT in rhesus macaques.

Lower airway collapse: Revisiting the definition and clinicopathologic features of canine bronchomalacia

Bronchomalacia (BM) is an inconsistently defined term in dogs, impairing understanding of clinical presentation, therapeutic response and prognosis. Herein the authors propose to clarify the definition of canine bronchomalacia (CBM) as regional to diffuse dynamic airway collapse of segmental and/or subsegmental bronchi with associated clinical signs due to airflow limitation. In contrast to tracheal collapse, mainstem bronchial collapse, and in some cases lobar collapse, CBM requires advanced imaging. Common co-morbid conditions (e.g., chronic bronchitis, mitral valve degenerative disease, etc.) should be identified during a comprehensive diagnostic evaluation. Current empiric treatments advocated in absence of clinical trials documenting efficacy in the dog warrant evaluation, as some (e.g., bronchodilators) may have detrimental effects in certain types of airway collapse in humans. There is no direct treatment for CBM, as defined above, but non-specific therapies and targeted treatment of co-morbid disease may improve clinical signs and quality of life. In this manuscript, the authors provide a review of the different types of airway collapse focusing on CBM, reviewing their definition and etiology, proposing a classification scheme, and discussing clinical signs, diagnostic testing, and treatment. Future studies should focus on both improving understanding of the etiology and natural disease progression of CBM and treatment trials.

Bronchoalveolar lavage fluid lymphocytosis in 104 dogs (2006-2016)

BACKGROUND

Bronchoalveolar lavage (BAL) fluid cytology and culture are used to characterize respiratory diseases in dogs. Little is known about disorders associated with increased numbers of lymphocytes in BAL fluid.

OBJECTIVE

To evaluate duration of clinical signs and detection of specific respiratory diagnoses in dogs with BAL lymphocytosis.

ANIMALS

One-hundred four client-owned dogs evaluated for respiratory signs.

METHODS

Medical records of dogs that had >300 cells/μL and >20% lymphocytes on a differential cell count of BAL fluid between January 1, 2006, and January 1, 2016, were reviewed retrospectively. Cases were evaluated for the duration of clinical signs and respiratory diagnoses, including aspiration injury, infectious or inflammatory respiratory disease, and airway collapse.

RESULTS

Dogs ranged in age from 0.5 to 16 years (median, 7.9 years) and had a median body weight of 11.4 kg (range, 2.0-42.7 kg). Eosinophilic lung disease was documented in 13 of 104 dogs (Group 1) and airway neutrophilia associated with infectious or inflammatory disease was found in 59 of 104 dogs (Group 2). Lymphocytosis alone in BAL fluid was described in 32 dogs (Group 3). Duration of cough did not differ among groups, but airway collapse was significantly more common in dogs with solitary lymphocytosis than in those with other types of inflammation.

CONCLUSIONS AND CLINICAL IMPORTANCE

Lymphocytosis in BAL fluid is common in dogs and, in many cases, likely represents a common response to airway injury, independent of the type or duration of insult. It is unknown whether airway collapse leads to lymphocytosis or if the inflammatory process causes airway collapse.