ACQUIRED CYSTIC BRONCHIECTASIS IN THE DOG: A CASE HISTORY REPORT

A 9-year-old neutered female mixed breed dog was examined for productive coughing, gagging, increased respiratory effort and restlessness. In survey chest radiographs a soft tissue opacity was present in the right middle lung lobe. In horizontal-beam radiographs, it was apparent that the opacity was a thin-walled cyst containing air and fluid. Peribronchial infiltration and bronchial dilation were present in all lung lobes. At necropsy, a diagnosis of chronic bronchitis and bronchiolitis and cylindrical and cystic bronchiectasis was made. Acquired bronchiectasis may result from any disease process which weakens the bronchial wall or obstructs drainage. Three forms of bronchiectasis have been described in man: cylindrical, saccular and cystic. Cylindrical bronchiectasis is tubular distention of larger, thick-walled bronchi; saccular bronchiectasis is circumscribed outpocketing of intermediate-sized bronchi and cystic bronchiectasis is a more pronounced manifestation of saccular bronchiectasis in terminal bronchi. Cylindrical and saccular bronchiectasis have been described in the dog; cystic bronchiectasis has not been described in the dog. Generalized bronchiectasis is an incurable condition due to the irreversible bronchial pathologic changes. Focal bronchiectasis can be surgically corrected by lobectomy and the prognosis is good. Aggressive antibiotic therapy should be used to treat chronic bronchitis in an effort to prevent bronchial destruction and development of bronchiectasis.     

Pulmonary lipoma in a dog

An eight‐year‐old, neutered, male German short‐haired pointer was presented for a chronic cough and an intrathoracic mass. Computed tomography revealed a mass with low attenuation in the right caudal lung lobe that invaded the principal bronchi. The mass was removed by right caudal and accessory lung lobectomy. The histopathological diagnosis was pulmonary lipoma. The clinical signs resolved following surgery. There was no evidence of recurrence or de novo lesions on computed tomography performed 12 months post‐surgery. To the authors’ knowledge, this is the first report of a pulmonary lipoma in a dog.     

Pulmonary and hepatic eosinophilic granulomas and epistaxis in a horse suggestive of multi‐systemic eosinophilic epitheliotropic disease

Multi‐systemic eosinophilic epitheliotropic disease (MEED) is a relatively uncommon disease characterised by eosinophilic infiltration of more than one organ system, with the skin and gastrointestinal tract most commonly affected. This case report describes a gelding that presented for weight loss, increased respiratory rate and effort and chronic intermittent epistaxis. During post mortem examination diffuse eosinophilic granulomatous lesions were identified in the lung and liver, leading to a diagnosis of MEED. Veno‐occlusive pulmonary remodelling was also discovered, believed to be the cause of the chronic epistaxis and a result of the pulmonary fibrosis and eosinophilic granulomas.     

Chronic idiopathic pulmonary fibrosis in five dogs

Five dogs presented with chronic and progressive pulmonary illness characterized by progressive dyspnea, exercise intolerance, and significant inspiratory crackles on auscultation. Radiographically, there was a widespread and diffuse interstitial lung pattern with varying degrees of bronchial involvement. Histopathological changes included thickened alveolar septa, interstitial fibrosis, and pneumocyte hyperplasia. Based on the clinical, radiographic, and histopathological changes, a diagnosis of idiopathic pulmonary fibrosis was made. Idiopathic pulmonary fibrosis is a chronic disease characterized by inflammation and fibrosis of the pulmonary interstitium and peripheral airspaces, which has been poorly characterized in the dog.     

COMPARISON BETWEEN SEDATION AND GENERAL ANESTHESIA FOR HIGH RESOLUTION COMPUTED TOMOGRAPHIC CHARACTERIZATION OF CANINE IDIOPATHIC PULMONARY FIBROSIS IN WEST HIGHLAND WHITE TERRIERS

Canine idiopathic pulmonary fibrosis is a progressive interstitial lung disease mainly affecting West Highland white terriers. Thoracic high‐resolution computed tomographic (T‐HRCT) findings for Canine idiopathic pulmonary fibrosis acquired under general anesthesia have been described previously. However, the use of general anesthesia may be contraindicated for some affected dogs. Sedation may allow improved speed and safety, but it is unknown whether sedation would yield similar results in identification and grading of Canine idiopathic pulmonary fibrosis lesions. The aim of this prospective, observational, method‐comparison, case‐control study was to compare findings from T‐HRCT images acquired under sedation versus general anesthesia for West Highland white terriers affected with Canine idiopathic pulmonary fibrosis (n = 11) and age‐matched controls (n = 9), using the glossary of terms of the Fleischner Society and a scoring system. Ground‐glass opacity was identified in all affected West Highland white terriers for both sedation and general anesthesia acquisitions, although the Ground‐glass opacity extent varied significantly between the two acquisitions (P < 0.001). Ground‐glass opacity was the sole lesion observed in control dogs (n = 6), but was less extensive compared with affected West Highland white terriers. Identification and grading of a mosaic attenuation pattern differed significantly between acquisitions (P < 0.001). Identification of lesions such as consolidations, nodules, parenchymal and subpleural bands, bronchial wall thickening, and bronchiectasis did not differ between acquisitions. The present study demonstrated that T‐HRCT obtained under sedation may provide different information than T‐HRCT obtained under general anesthesia for identification and grading of some Canine idiopathic pulmonary fibrosis lesions, but not all of them. These differences should be taken into consideration when general anesthesia is contraindicated and sedation is necessary for evaluating West Highland white terriers with Canine idiopathic pulmonary fibrosis.     

COMPUTED TOMOGRAPHIC APPEARANCE OF PRIMARY LUNG TUMORS IN DOGS

Canine primary lung tumors typically appear radiographically as a well‐circumscribed solitary mass in the periphery of a caudal lung lobe. Consolidated and diffuse forms of primary lung tumors have also been described. Nineteen dogs with computed tomographic (CT) images of the thorax and a histological diagnosis of primary lung tumor (17 primary carcinomas and two primary sarcomas) were evaluated retrospectively to characterize the CT findings. All primary lung tumors were bronchocentric in origin with internal air bronchograms. The bronchi were typically narrowed, displaced, and often obstructed by the tumor. Eighteen of 19 (95%) of the tumors were solitary and there was one pneumonic/alveolar form. Most solitary tumors were well circumscribed (17/18), located in the central to periphery of the lung (14/18), and in a cranial or caudal lobe (16/19). Most primary lung tumors (11/17) had mild to moderate heterogeneous contrast enhancement. Five of 19 dogs (26%) had evidence of pulmonary metastasis. Internal mineralization (3/19) and tracheobronchial lymphadenopathy (4/19) were also identified. On CT examination, solitary, well circumscribed, bronchocentric masses with internal air bronchograms are consistent with a primary pulmonary tumor in dogs.     

COMPUTED TOMOGRAPHY BRONCHIAL LUMEN TO PULMONARY ARTERY DIAMETER RATIO IN DOGS WITHOUT CLINICAL PULMONARY DISEASE

Bronchiectasis is diagnosed in humans using multiple computed tomography (CT) criteria, the most important being dilatation of the bronchi. The most widely used criterion for detection of bronchial dilatation is a bronchial lumen to pulmonary artery diameter (bronchoarterial [BA]) ratio >1.0. No studies have been performed to determine the BA ratio in normal dogs. Thoracic CT images of 24 dogs without clinical pulmonary disease were reviewed. The BA ratio of the lobar bronchi of the left cranial (cranial and caudal parts), right cranial, right middle, left caudal, and right caudal lung lobes was measured. The mean of the mean BA ratio for all dogs was 1.45±0.21 (99% confidence interval [CI]=1.34–1.56). The mean of the mean BA ratio as determined by lung lobe was 1.45±0.04 (99% CI=1.41–1.49). The range of individual BA ratios was 0.8–2.0. There was no significant difference in mean BA ratios as a function of lung lobe ( P =0.60). The BA ratio in these clinically normal dogs was consistent and may be a useful tool in evaluating for bronchiectasis on CT images. BA ratios >2.0 were not identified in this population, suggesting a threshold to differentiate normal from abnormal bronchi.     

Pulmonary fibrosis after high cumulative dose nitrosourea chemotherapy in a cat

Small to intermediate cell alimentary lymphoma was diagnosed in a cat after abdominal exploratory surgery with no prior history of pulmonary disease. Initial response to several chemotherapy regimens was poor, but a long‐term remission was achieved with CCNU (lomustine) and corticosteroid therapy. After receiving a total cumulative CCNU dose of 552 mg m^?2 over 12 months, an acute episode of respiratory distress occurred and the cat died. Necropsy identified severe diffuse pulmonary fibrosis and no signs of lymphoma. This is the first report of pulmonary fibrosis following high cumulative dose nitrosourea chemotherapy in a cat.     

Diffuse cylindrical bronchiectasis due to eosinophilic bronchopneumopathy in a dog

A miniature pinscher-cross was evaluated for chronic coughing. Computed tomography and bronchoscopy revealed severe, diffuse, cylindrical bronchiectasis secondary to eosinophilic bronchopneumopathy. Computed tomography is the gold standard for diagnosis of bronchiectasis in humans, and should be further investigated in dogs as a means of characterizing severity and pattern of disease.     

QUANTITATIVE AND QUALITATIVE COMPUTED TOMOGRAPHIC CHARACTERISTICS OF BRONCHIECTASIS IN 12 DOGS

Bronchiectasis is an irreversible dilatation of the bronchi resulting from chronic airway inflammation. In people, computed tomography (CT) has been described as the noninvasive gold standard for diagnosing bronchiectasis. In dogs, normal CT bronchoarterial ratios have been described as <2.0. The purpose of this retrospective study was to describe quantitative and qualitative CT characteristics of bronchiectasis in a cohort of dogs with confirmed disease. Inclusion criteria for the study were thoracic radiography, thoracic CT, and a diagnosis of bronchiectasis based on bronchoscopy and/or histopathology. For each included dog, a single observer measured CT bronchoarterial ratios at 6 lobar locations. Qualitative thoracic radiography and CT characteristics were recorded by consensus opinion of two board‐certified veterinary radiologists. Twelve dogs met inclusion criteria. The mean bronchoarterial ratio from 28 bronchiectatic lung lobes was 2.71 ± 0.80 (range 1.4 to 4.33), and 23/28 measurements were >2.0. Averaged bronchoarterial ratios from bronchiectatic lung lobes were significantly larger (P < 0.01) than averaged ratios from nonbronchiectatic lung lobes. Qualitative CT characteristics of bronchiectasis included lack of peripheral airway tapering (12/12), lobar consolidation (11/12), bronchial wall thickening (7/12), and bronchial lumen occlusion (4/12). Radiographs detected lack of airway tapering in 7/12 dogs. In conclusion, the most common CT characteristics of bronchiectasis were dilatation, a lack of peripheral airway tapering, and lobar consolidation. Lack of peripheral airway tapering was not visible in thoracic radiographs for some dogs. For some affected dogs, bronchoarterial ratios were less than published normal values.     

Clinical, bronchoscopic, histopathologic, diagnostic imaging, and arterial oxygenation findings in West Highland White Terriers with idiopathic pulmonary fibrosis

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic, interstitial lung disease primarily affecting West Highland White Terriers (WHWTs). Objective: To describe the clinicopathological and diagnostic imaging features in WHWTs with IPF. Animals: Twelve WHWTs with IPF and 14 healthy control WHWTs. Method: Prospective study. Clinical signs and findings of physical examination, blood and arterial blood gas analyses, radiography, high‐resolution computed tomography (HRCT), bronchoscopy and bronchoalveolar lavage (BAL) of IPF dogs were obtained and compared with controls. Histopathologic changes in IPF dogs were evaluated. Results: Mean partial pressure of oxygen was significantly lower in IPF (mean ± SD, 65.5 ± 15.4 mmHg) than in controls (99.1 ± 7.8 mmHg, P<.001). The alveolar‐arterial oxygen gradient was significantly higher in IPF (50.1 ± 17.3 mmHg) than in controls (17.5 ± 4.9 mmHg, P<.001). In HRCT, ground glass opacity (GGO) was detected in all IPF dogs, traction bronchiectasis in 4, and honeycombing in 1. Bronchoscopic airway changes were noted in all IPF dogs. On BAL fluid (BALF) cytology, the total cell count (TCC) was higher in IPF dogs, and the numbers but not the percentages of macrophages, neutrophils, and mast cells were increased. On histopathology, multifocal or diffuse interstitial fibrosis, type II pneumocyte hyperplasia, prominent intraalveolar macrophages, distortion of alveolar architecture, and emphysematous change were detected. Conclusion and Clinical Importance: IPF causes substantial hypoxemia. In HRCT, GGO is a consistent finding. IPF dogs have concurrent airway changes and an increase in BALF TCC.     

RADIOGRAPHIC APPEARANCE OF BRONCHOALVEOLAR CARCINOMA IN NINE CATS

Thoracic radiographs of nine cats with confirmed bronchoalveolar carcinoma (BAC) were reviewed retrospectively. Radiographic appearance of BAC was divided into three categories: mixed bronchoalveolar pattern, ill-defined alveolar mass, or mass with cavitation. In addition to these radiographic signs, all nine cats had evidence of some form of bronchial disease. Cavitary lesions were the most common finding (n = 5). In addition, three cats in this category had diffuse bronchointerstitial opacity and one cat had focal peribronchial cuffing. Five cats had either a mixed bronchoalveolar pattern with bronchiectasis (n = 3) or an ill-defined alveolar mass with peribronchial cuffing (n = 2). One cat had both a mixed bronchoalveolar pattern and a cavitary mass. Each of these nine cats had some form of bronchial disease (bronchointerstitial pattern, peribronchial cuffing, or bronchiectasis), which aids in the radiographic diagnosis of bronchoalveolar carcinoma and may represent airway metastasis.     

RADIATION PNEUMONITIS IN THREE DOGS

Radiation pneumonitis developed within the radiation treatment field in three dogs with soft tissue sarcomas located on or adjacent to the thoracic wall. Radiographic signs compatible with a diagnosis of radiation pneumonitis developed from one (n = 2 dogs) to two (n = 1 dog) months after completion of therapy. The initial radiographic sign was an alveolar infiltrate in all three dogs. At subsequent examinations at variable time periods after treatment, radiographic findings included: bronchiectasis (n = 3 dogs), alveolar infiltrate (n = 2 dogs), decreased lung volume (n = 2 dogs), and unstructured interstitial opacification (n = 1 dog). Necropsy examination of one dog at fourteen months after the completion of radiotherapy showed evidence of pulmonary fibrosis within the irradiated lung. Necropsy examination of the second dog did not show any evidence of radiation induced changes. It is possible that histopathologic examination did not include irradiated lung. No clinical signs that could be attributed to the radiation pneumonitis were observed in any dog. It appears that approximately 25% of the lung can be safely irradiated to high doses, if indicated, in order to deliver an adequate dose of radiation to a primary tumor site.     

Computed tomographic findings in three dogs naturally infected with Crenosoma vulpis

Crenosoma vulpis is a nematode lungworm found in wild and domestic canids in some parts of North America and Europe. Reported radiographic findings are nonspecific and consist of a combination of bronchial and interstitial changes of variable severity. This retrospective, case series study aimed to describe thoracic computed tomographic (CT) findings for a group of dogs with confirmed crenosomosis. Selection criteria were presentation with a chronic cough during the period of January 2016 to February 2017, evaluation by thoracic CT, and final diagnosis of C. vulpis infection based on bronchoscopic findings, bronchoalveolar lavage fluid analysis, and quantitative polymerase chain reaction. Medical records and CT images were retrieved and reviewed by a board‐certified veterinary internist, a veterinary internal medicine resident, two board‐certified veterinary radiologists, and a veterinary radiology intern, and findings were recorded. Three dogs met inclusion criteria. Thoracic CT findings for all dogs included the following: diffuse bronchial wall thickening, multifocal peribronchial ground glass attenuation, consolidation of the pulmonary parenchyma, and cylindrical bronchiectasis. In two dogs, the bronchial wall thickening was irregular to nodular, which was consistent with the bronchoscopic findings. Two dogs showed pulmonary parenchymal bands. Thoracic computed tomographic changes in dogs with C. vulpis are consistent with those seen on thoracic radiographs and crenosomosis should be considered in dogs with these findings.     

High-resolution computed tomography bronchial lumen to pulmonary artery diameter ratio in anesthetized ventilated cats with normal lungs

High-resolution computed tomography (CT) is the preferred noninvasive tool for diagnosing bronchiectasis in people. A criterion for evaluating dilation of the bronchus is the bronchial lumen to pulmonary artery diameter (bronchoarterial ratio [BA ratio]). A ratio of > 1.0 in humans or > 2.0 in dogs has been suggested as a threshold for identifying bronchiectasis. The purpose of this study was to establish the BA ratio in normal cats. Fourteen specific pathogen-free cats were selected for analysis of thoracic CT images. The BA ratios of the lobar bronchi of the left cranial (cranial and caudal parts), right cranial, right middle, left caudal, and right caudal lung lobes were measured. The mean of the mean BA ratio of all lung lobes was 0.71 +/- 0.05. Individual BA ratios ranged from 0.5 to 1.11. Comparing individual lobes for each cat, there was no significant difference (P = 0.145) in mean BA ratio between lung lobes. A mean BA ratio for these normal cats was 0.71 +/- 0.1, which suggests an upper cut-off normal value > 0.91 (mean +/- 2 standard deviations) between normal and abnormal cats.     

A RETROSPECTIVE STUDY OF THE RELATIONSHIP BETWEEN TRACHEAL COLLAPSE AND BRONCHIECTASIS IN DOGS

Tracheal collapse is common in middle age toy and miniature breed dogs. Cartilaginous defects have been identified histologically and are considered a form of chondromalacia. In addition to tracheal cartilaginous changes, concurrent lower airway histologic changes indicative of inflammation have been noted in dogs with tracheal collapse and these changes may lead t o concurrent bronchiectasis. The purpose of this study was to investigate the prevalence of bronchiectasis in dogs with a previous radiographic diagnosis of tracheal collapse. The thoracic radiographs of 60 dogs with tracheal collapse were evaluated for evidence of concurrent bronchiectasis. Eighteen of 60 (30%) dogs had evidence of bronchiectasis, and all were cylindrical in morphology. The signalment of affected dogs was similar to that previously reported. The occurrence of bronchiectasis in this group of dogs with tracheal collapse (18 dogs) was six times higher (P < 0.05) than the expected prevalence within a random sample population (three dogs). The results of this study provide evidence of a link between tracheal collapse and bronchiectasis. A finding of bronchiectasis with tracheal collapse should encourage further evaluation for chronic lower airway disease in these patients.     

Pulmonary fibrosis and gammaherpesvirus infection in horses

Pulmonary fibrosis is a devastating and often progressive condition leading to exercise intolerance and frequently the demise of the animal. Although uncommonly encountered in horses, the condition is intensely researched both in human medicine and animal models. Viral infections have long been suspected to play a part in the development of pulmonary fibrosis and neoplastic conditions in other species. In 2007, an association between equine herpesvirus 5 (EHV‐5) infection and nodular pulmonary fibrosis in horses was suggested and the name equine multinodular pulmonary fibrosis (EMPF) was introduced. Recently, the presence of EHV‐5 in equine lymphoma has also emerged. The case report by Schwarz et al. in this issue describes a horse suffering from concurrent T cell leukaemia and EMPF in association with EHV‐5. This article summarises current knowledge about EMPF and EHV‐5 infections in horses, recent developments in the understanding of pulmonary fibrosis in man and the proposed contribution of viral infections to pulmonary fibrosis and neoplastic conditions.     

RETROSPECTIVE ASSESSMENT OF THORACIC RADIOGRAPHIC FINDINGS IN METASTATIC CANINE HEMANGIOSARCOMA

Twenty-one dogs with histopathologically confirmed hemangiosarcoma were evaluated by thoracic radiography for metastatic disease. All dogs had histopathologic examinations of the lungs within two weeks of thoracic radiography. Fourteen dogs had histopathologic evidence of pulmonary hemangiosarcoma; metastatic disease was detected radiographically in eleven of these dogs. The most common radiographic pattern was that of poorly defined small coalescing nodules (8 dogs); other radiographic patterns included well-circumscribed nodules (3 dogs) and alveolar infiltrates secondary to hemorrhage (2 dogs). Differential diagnoses for diffuse, poorly defined, coalescing pulmonary opacities should include hemangiosarcoma in addition to edema, lymphoma, systemic mycoses, fibrosis, allergy, toxicosis, and carcinomas.     

MULTIDETECTOR‐ROW COMPUTED TOMOGRAPHY PATTERNS OF BRONCHOESPHAGEAL ARTERY HYPERTROPHY AND SYSTEMIC‐TO‐PULMONARY FISTULA IN DOGS

Anomalies involving arterial branches in the lungs are one of the causes of hemoptysis in humans and dogs. Congenital and acquired patterns of bronchoesophageal artery hypertrophy have been reported in humans based on CT characteristics. The purpose of this retrospective study was to describe clinical, echocardiographic, and multidetector computed tomography features of bronchoesophageal artery hypertrophy and systemic‐to‐pulmonary arterial communications in a sample of 14 dogs. Two main vascular patterns were identified in dogs that resembled congenital and acquired conditions reported in humans. Pattern 1 appeared as an aberrant origin of the right bronchoesophageal artery, normal origin of the left one, and enlargement of both the bronchial and esophageal branches that formed a dense network terminating in a pulmonary artery through an orifice. Pattern 2 appeared as a normal origin of both right and left bronchoesophageal arteries, with an enlarged and tortuous course along the bronchi to the periphery of the lung, where they communicated with subsegmental pulmonary arteries. Dogs having Pattern 1 also had paraesophageal and esophageal varices, with the latter being confirmed by videoendoscopy examination. Authors conclude that dogs with Pattern 1 should be differentiated from dogs with other congenital vascular systemic‐to‐pulmonary connections. Dogs having Pattern 2 should be evaluated for underlying pleural or pulmonary diseases. Bronchoesophageal artery hypertrophy can be accompanied by esophageal venous engorgement and should be included in the differential diagnosis for esophageal and paraesophageal varices in dogs.