Spontaneous midlobar lung lobe torsion in a 2-year-old Newfoundland

A 2-year-old, intact male Newfoundland was presented for evaluation of a 1- to 2-day history of coughing, retching, and progressive lethargy. Thoracic radiographs demonstrated right-sided pleural effusion and lobar vesicular emphysema. An exploratory thoracotomy revealed midlobar torsion of the right caudal lung lobe. A partial lung lobectomy was performed, and following surgery, the dog recovered without complications. Lung lobe torsions in dogs typically occur at the hilus of the affected lung lobe. This report documents that midlobar lung lobe torsions occur in dogs and should be considered as a differential diagnosis in cases of lobar vesicular emphysema and pleural effusion.     

IMAGING DIAGNOSIS—CANINE THORACIC MESOTHELIOMA

A 12-year-old neutered female Pembroke Welsh Corgi had a 2-month history of a progressive, productive cough nonresponsive to therapy. Mild pleural effusion, right middle lung lobe collapse, and multiple subpleural nodular lesions were detected in thoracic radiographs and computed tomography (CT) images. Histopathologic diagnosis of the pleural nodules was mesothelioma. Mesothelioma should be considered in patients where pleural masses are detected in radiographs or CT images.     

Use of computed tomography and minimum intensity projection in the detection of lobar pneumonia mimicking lung lobe torsion in a dog

A 10‐year‐old female spayed Dachshund was referred with progressive coughing for 1 month. The dog was tentatively diagnosed with right middle lung torsion based on pleural effusion, vesicular emphysema, abruptly ending bronchus in consolidated right middle lung, and no contrast enhancement of the affected lobe on radiography and computed tomography (CT). There was no evidence of torsion upon thoracotomy, and histological examination confirmed lobar pneumonia. The CT images were reevaluated using minimum intensity projection and revealed normal bronchial courses. The minimum intensity projection technique can be to assist in evaluation of the bronchial tree for dogs with suspected lung lobe torsion and other pulmonary diseases.     

Isolation and identification of Mycobacterium kansasii from pleural fluid of a dog with persistent pleural effusion

A 3-year-old spayed female Whippet was examined for cough and respiratory distress. Lung lobe torsion with pleural effusion was diagnosed, and lung lobectomy was performed. Pleural effusion recurred during the following 27 months; conventional bacteriologic cultures of pleural effusion did not result in bacterial growth. A second lung lobectomy, pleuroperitoneal shunt placement. and pericardectomy were subsequently performed. Mycobacterium kansasii was eventually isolated from pleural fluid and identified by polymerase chain reaction amplification and DNA sequencing. The dog was euthanatized before therapeutic response could be evaluated. To our knowledge, this is the first report of M. kansasii infection in a dog. Additionally, this is the first report of mycobacterial isolation from pleural fluid, and one of few reports of antemortem mycobacterial isolation from a body fluid, as opposed to identification in specimens during histologic examination. Routine bacteriologic culture methods are insufficient to isolate mycobacterial agents, and special methods are indicated in dogs with persistent pleural effusion.     

Radiographic, computed tomographic, and ultrasonographic findings with migrating intrathoracic grass awns in dogs and cats.

The purpose of this study was to describe the clinical, radiographic, and computed tomographic findings in dogs and cats with migrating intrathoracic grass awns. Thirty-five dogs and five cats with visual confirmation of a grass awn following surgery, endoscopy or necropsy, and histology were assessed. The medical records and all diagnostic imaging studies were reviewed retrospectively. Labrador Retrievers or English Pointers < 5 years of age, with a history of coughing and hyperthermia, were the most common presentations. Seventeen animals had an inflammatory leukogram of which 14 had a left shift or toxic neutrophils. Radiographs were performed in 38 animals and computed tomography (CT) in 14. Thoracic radiographs were characterized by focal pulmonary interstitial to alveolar opacities (n = 26) that occurred most commonly in the caudal (n = 19) or accessory lobes (n = 8). Additional findings included pneumothorax (n = 9), pleural effusion (n = 8), and pleural thickening (n = 7). Pulmonary opacities identified on radiographs correlated to areas of pneumonia and foreign body location. CT findings included focal interstitial to alveolar pulmonary opacities (n = 12) most commonly in the right caudal lung lobe (n = 9), pleural thickening (n = 11), mildly enlarged intrathoracic lymph nodes (n = 10), soft tissue tracking (n = 7) with enhancing margins (n = 4), pneumothorax (n = 6), pleural effusion (n = 4), and foreign body visualization (n = 4). Histologic diagnoses included pulmonary and mediastinal granulomas or abscesses, bronchopneumonia, and pleuritis. Migrating intrathoracic grass awns should be considered as a differential diagnosis in coughing, febrile animals with focal interstitial to alveolar pulmonary opacities, pleural effusion, pleural thickening, and/or pneumothorax on radiographs or CT.     

COMPUTED TOMOGRAPHIC FEATURES OF LUNG LOBE TORSION

The imaging features of lung lobe torsion in 10 dogs (nine complete, one partial torsion) acquired with a helical single‐slice computed tomography (CT) unit are described. Attenuation values of normal, rotated, and adjacent collapsed lung lobes before and after intravenous contrast medium administration were compared. Affected lung lobes were: left cranial (5), right middle (3), right cranial (1), and left caudal (1). CT findings in nine dogs with complete lung lobe torsion included pleural effusion and an abruptly ending bronchus. In eight of these dogs, enlargement, consolidation, emphysema of the affected lung lobe, and mediastinal shift to the contralateral side were present. Rotated lung lobes did not enhance, whereas adjacent collapsed and aerated lung lobes did (P<0.05). Apnea induced with hyperventilation or breath‐hold is essential to reduce motion artefacts and obtain a diagnostic study.     

Lung lobe torsion in association with a chronic diaphragmatic hernia and haemorrhagic pleural effusion in a cat

CLINICAL SUMMARY: This report describes torsion of the right cranial lung lobe in a cat with haemorrhagic pleural effusion and a chronic diaphragmatic hernia. Surgical treatment comprising lung lobectomy without de-rotation, and repair of the diaphragmatic defect, led to an uneventful recovery. PRACTICAL RELEVANCE: Lung lobe torsion is a rare condition in cats. While spontaneous lung lobe torsions may occur, a frequent association with underlying thoracic disease has been recognised in cats. However, neither haemorrhagic pleural effusion nor diaphragmatic hernia have been previously described in cats with lung lobe torsions, although they have been documented in dogs and humans. In a cat with suspected lung lobe torsion, a thorough search for an underlying disease should be undertaken.     

Characterization of primary pulmonary adenosquamous carcinoma‐associated pleural effusion

A 10‐year‐old, female spayed Shih Tzu was presented due to weight loss, increased respiratory effort and lethargy, determined to be secondary to a congenital para‐esophageal diaphragmatic defect with partial herniation of the stomach and spleen. Four days following reduction surgery of the displaced abdominal organs thoracic effusion developed. Thoracic fluid evaluation revealed a cell‐rich, protein‐poor modified transudate with neutrophils, reactive mesothelial cells, and atypical epitheloid cells which occasionally appeared to be keratinizing, consistent with neoplastic exfoliation. Thoracic effusion recurred 2 days later, with similar characteristics as the initial sample. Computed tomography (CT) indicated consolidation and displacement of the right middle and accessory lung lobes. Exploratory thoracic surgery demonstrated a thickened, hyperemic right middle lung lobe, and thickened pericardial diaphragmatic ligament. Histologic evaluation of these tissues identified a primary pulmonary adenosquamous carcinoma with intravascular and pleural invasion. Based on these cytologic, histologic, and clinical findings, we conclude that primary pulmonary carcinomas may involve superficial thoracic structures and exfoliate into a thoracic effusion.     

RADIOGRAPHIC DIAGNOSIS OF LUNG LOBE TORSION

Clinical data, thoracic radiographs, ultrasonographic exams, and histopathologic reports in 13 dogs and two cats with confirmed lung lobe torsion were reviewed. Age of dogs ranged from 4 months to 11.5 years, (mean of 6.4 years) and several breeds of large and small dogs were represented. Right middle lobe torsion was predominant in large dogs (five of eight large breed dogs) and left cranial lobe torsion was more commonly seen in small dogs (three of five small-breed dogs). Two domestic short-hair cats, 10 and 14 years of age, had right cranial and right middle lobe torsion, respectively. Underlying thoracic disease was found in only five of 15 patients. On thoracic radiographs, increased lobar opacity and pleural effusion were found in all patients (100%). Small dispersed air bubbles were found within the affected lobe of 13 patients (87%). This pattern, which was the result of vesicular emphysema, was variably extensive, and became more evident on follow-up radiographs in five of six dogs. The lobar bronchi could be seen in only eight of 15 patients (54%), and appeared irregular, focally narrowed or blunted in six of the eight patients, and displaced in five of the eight. Other common radiographic findings included mediastinal shift (nine), curved and dorsally displaced trachea (seven), and axial rotation of the carina (seven). Ultrasonography was used in seven patients and considered generally useful, although variable signs were observed.     

Torsion of a lung lobe in the dog

A 3-year-old Whippet in severe respiratory distress was found to have an extensive pleural effusion associated with a 180^o torsion of the cardiac lobe of the right lung. The possible cause of torsion and diagnostic indications of this lesion are discussed.     

Medical and surgical management of esophageal foreign body in a ferret

A ferret was examined because of anorexia, repeated episodes of regurgitation, and subsequent dehydration. Radiography had revealed a radiodense midesophageal foreign body. Results of endoscopy of the esophagus, however, could not confirm the diagnosis. Contrast radiography revealed esophageal perforation, with subsequent penetration of the foreign body into the right pleural space, causing pleural effusion. Surgical repair of the esophagus was performed, and a gastrostomy feeding tube was inserted to provide adequate nutrition during esophageal healing. Nine days after surgery, radiography revealed a severe stricture at the esophageal surgical site. Surgery was repeated; the esophagus was transected, the stricture was removed, and esophageal tissues were closed in 2 layers. Systemically administered antibiotics and gastrostomy tube feedings were continued throughout the post-operative healing period. The esophagus healed with a mild stricture that diminished over time in response to corticosteroid administration.     

IMAGING CHARACTERISTICS OF INTRATHORACIC HISTIOCYTIC SARCOMA IN DOGS

In this retrospective study, two observers independently reviewed thoracic imaging studies of 39 dogs with confirmed histiocytic sarcoma. The most common findings were intrathoracic lymphadenopathy, identified by the first and second observers in 82.1% and 87.2% of dogs, respectively, and pulmonary masses (74.4% and 82.1%). Right middle lung lobe masses were significantly more common than masses in any other lung lobe (P<0.0013), with the majority having a ventral distribution. Sternal and tracheobronchial lymphadenopathy were significantly more common than cranial mediastinal lymphadenopathy (P‐values of 0.0002 and 0.012, respectively). Interobserver agreement regarding distribution of lymphadenopathy and pulmonary masses was good (κ=0.64 and 0.75, respectively). Other findings included pulmonary nodules, pleural effusion, and abnormal pulmonary patterns. In patients with CT examinations, the majority of masses were mildly to moderately enhancing and heterogeneous, poorly marginated, and bronchocentric. Lymphadenopathy and pulmonary masses are the most common intrathoracic findings in dogs with histiocytic sarcoma, and the strong predilection for the ventral aspect of the right middle lung lube may help to differentiate it from other types of neoplasia.     

Recurrent pneumothorax associated with a pulmonary emphysematous bulla in a dog: surgical correction and proposed pathogenesis

A three year old dog was affected with recurrent dyspnea for two months, due to a recurrent pneumothorax. This followed an episode of mild blunt trauma to the thorax and transient strangulation. Conservative therapy of aspiration of air by repeated thoracentesis gave only temporary relief. Thoracic radiographs indicated the presence of a bulla in the right middle lung lobe. An exploratory thoracotomy confirmed the diagnosis, and a lobectomy was successfully performed. The pathogenesis of acquired pulmonary bullae is postulated. Reasons for the predisposition of the right middle lung lobe are outlined. These are related to the anatomy of the right middle bronchus, and include its position between the right pulmonary artery and vein, its oval shape, and the absence of cartilagenous support at its origin.     

Congenital lobar emphysema and tension pneumothorax in a dog.

Congenital lobar emphysema (CLE) and tension pneumothorax (TPT) are rarely reported in dogs. A case of CLE of the right middle lung lobe predisposing to air trapping, alveolar hyperinflation, and pleural rupture resulting in fatal spontaneous TPT in a 6-month-old mixed breed dog is described. The unique alteration of "bloat line" was observed in this case in addition to compressive atelectasis of all other lung lobes and lack of negative pressure within the thoracic cavity, signifying markedly elevated intrathoracic pressure. Bronchial cartilage hypoplasia and bronchiectasis were confirmed microscopically, which likely led to abnormal dynamic collapse of bronchi during expiration, consequentially leading to increased intrapulmonary pressure, bullous emphysema, and pleural rupture resulting in TPT. TPT consequent to CLE may therefore be considered one of the potential causes of sudden death in young dogs without overt clinical illness.     

Idiopathic pleural effusion and pulmonary thromboembolism in a dog with autoimmune hemolytic anemia

Pleural effusion and pulmonary thromboembolism were diagnosed in a dog with autoimmune hemolytic anemia. Clinical signs of tachypnea, then dyspnea in association with pleural effusion, developed after 10 days of immunosuppressive corticosteroid therapy (greater than 2 mg/kg of body weight/d, PO). The diagnosis of pulmonary thromboembolism was made tentatively on the basis of results of a radionuclide lung perfusion scan and was confirmed by exploratory thoracotomy and lung biopsy. Tachypnea and pleural effusion gradually resolved without specific treatment, and additional episodes of anemia or dyspnea have not been observed. The pathogenesis of these findings was suspected to be related to corticosteroid-induced thrombotic tendencies, persistent thrombocytosis (greater than 800,000 cells/microliters), and vascular injury caused by repeated jugular venous catheterization. Pulmonary thromboembolism should be considered in dogs that develop clinical signs of tachypnea and/or pleural effusion during administration of immunosuppressive dosages of corticosteroids.     

Unusual congenital pulmonary anomaly with presumed left lung hypoplasia in a young dog

A seven‐month‐old, entire, male miniature schnauzer dog was referred with acute vomiting, inappetence and depression primarily as a result of a gastric foreign body (pine cones). During investigations, thoracic radiographs revealed increased volume of the right lung lobes, deviated cardiomediastinal structures and elevation of the heart from the sternum. Thoracic computed tomography revealed left cranial lung lobe hypoplasia and extension of the right cranial lung parenchyma across the midline to the left hemithorax. Branches of the right pulmonary vessels and bronchi also crossed the midline and extended to the left caudal lung lobe. These findings suggested that the right and left lungs were fused. In humans this finding is consistent with horseshoe lung, which is an uncommon congenital malformation. To the authors’ knowledge, this case represents the first report of such a pulmonary anomaly in a dog.     

Broncho-oesophageal fistula in two dogs

Two clinical cases of broncho-oesophageal fistula in the dog are presented. While both cases illustrate the value of oesophagoscopy as a diagnostic tool, one case depicts the complications which may be associated with positive contrast oesophagography. These two cases support previous observations that broncho-oesophageal fistulae are frequently of foreign body aetiology and usually extend from the caudal oesophagus, via the pleural space, to the caudal or middle right lung lobes.     

Pneumopericardium associated with a pulmonary-pericardial communication in a dog

A 6-year-old 18-kg (39-lb) spayed female Standard Poodle was referred for treatment of pneumopericardium. The dog did not have severe clinical signs relating to the pneumopericardium, and the diagnosis was made incidentally while investigating the cause of a cough. Computed tomography revealed an air-filled structure consistent with a bulla to the right of the heart base that appeared to communicate with the pericardial cavity Because spontaneous resolution of the pneumopericardium seemed unlikely and cardiac tamponade was a possibility, exploratory thoracotomy was performed. A lobulated bulla was found at the hilus of the right middle lung lobe adhered to the underlying pericardial sac, and a 4-cm-diameter communication from the pericardium to the pulmonary bulla was found. Right middle lung lobectomy was performed, and the pericardiotomy and pericardial opening were sutured. The dog recovered without complications. In previously reported cases of pneumopericardium involving a cat and a dog, the condition resolved spontaneously. In this dog, in contrast, surgical resection of the affected lung lobe with pericardial reconstruction was required for resolution of the pneumopericardium.     

Use of computed tomography and silicon endocasts to identify pulmonary veins with echocardiography

The pulmonary veins were identified from the silicone endocast heart models of 19 dogs. Although variation in the number of the more peripheral veins on each specimen existed, all of the casts had a consistency with regards to the most proximal coalescence of the pulmonary veins as they entered the body of the left atrium. That is, the confluence of the veins formed three ostia at the atrial entry point that consisted of 1) right cranial and right middle pulmonary lobe veins; 2) right caudal, accessory, and left caudal pulmonary lobe veins; and 3) both the left cranial and left caudal pulmonary lobe veins of the left cranial lung lobe. The location of these structures identified by the 3-dimensional endocasts were then used to assist in the identification of the pulmonary veins using computed tomography of 2 dogs. Slices were made that approximated those commonly performed during echocardiographic examination. Understanding which pulmonary veins are seen by echocardiography in the different imaging planes will permit prospective evaluations of pulmonary vein size and abnormal flow patterns.     

Radiographic aspects of exercise-induced pulmonary hemorrhage in racing horses

Abnormal pulmonary radiopacities were identified in 13 racing horses in which a diagnosis of exercise-induced pulmonary hemorrhage (EIPH) had been confirmed. The lesions were in the caudal lung lobe in all horses; seven were on the right and three on the left, and the laterality for three could not be determined. In ten horses the opacities, which were large and peripherally located, obliterated the thoracophrenic angle. They merged with the silhouette of the diaphragm and had a circular or ovoid surface directed toward the hilum. The intensity of opacification of the consolidated areas varied, and they often were not sharply marginated. Dorsal displacement of the pulmonary arteries was noted in the region of the radiopacity in seven horses. Varying volumes of pleural effusion were observed in nine horses. Serial radiographic examinations were performed in seven horses. The pulmonary radiopacities cleared within ten days in two horses. In the remaining five horses, gradual resolution, characterized by a reduction in lesion size with improved margination, occurred during several months. The central region of the radiopaque lesion commonly had a patchy appearance, suggesting cavitation. Normal pulmonary vascular and interstitial markings were evident following complete resolution of these lesions. The cause of these abnormal pulmonary opacities has not been determined. Pathologic-radiologic correlations will be required to improve understanding of the pathophysiology of EIPH in the racing horse.