Successive torsion of the right middle and left cranial lung lobes in a dog

This case report describes the torsion of two lung lobes in a dog. The animal was first presented for a torsion of the right middle lung lobe. Following the surgical resection of that lobe, the dog suffered another torsion of the left cranial lung lobe (cranial and caudal segments).     

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.     

Segmental lung lobe torsion in a 7-week-old Pug

Case summary: A 7‐week‐old, intact female Pug was referred with an acute history of expiratory dyspnea, tachypnea, and pyrexia. Radiologic evaluation revealed bilateral pleural effusion and a poorly demarcated area of soft tissue opacity cranial to the heart. The presence of air bronchograms in the cranial lung lobes suggested alveolar parenchymal pathology consistent with pulmonary edema, congestion, or cellular infiltration. Exploratory thoracotomy revealed a segmental torsion of the left cranial lung lobe. The affected lobe was removed and the puppy recovered uneventfully. Unique information: Lung lobe torsion tends to occur more frequently in mature large breed dogs at a mean age of 3 years. The age, breed, and segmental nature of the torsion in the reported case are contrary to most of the previously documented cases of lung lobe torsion. To the authors' knowledge, this is the first report of lung lobe torsion in a 7‐week‐old dog.     

Bronchial cartilage dysplasia with multifocal lobar bullous emphysema and lung torsions in a pup.

Bronchial cartilage dysplasia is believed to have caused lobar bullous emphysema in a 5-month-old Chow Chow that had exercise intolerance, progressive dyspnea, and episodic cough. Radiography of the thorax revealed hyperlucency of the left hemithorax, displacement of the mediastinum and heart to the right, and flattening of the diaphragm. The pup died shortly after the radiographs were obtained. Necropsy revealed massive hyperinflation with 180 degrees torsion of the cranial portion of the left cranial lung lobe, and hyperinflation with less than 180 degrees torsion of the right accessory lung lobe. Histologic examination of the affected lung lobes revealed a lack of bronchial cartilage, loss and displacement of alveolar walls, and bulla formation that resembled congenital (infantile) lobar emphysema of human beings. In this pup, lung lobe torsions may have been predisposed by bronchial cartilage dysplasia.     

Lung lobe torsion associated with chylothorax in a cat

A 10.5-year-old domestic shorthair presented with a history of progressive inappetence, lethargy and elevated respiratory rate. Clinical and diagnostic findings confirmed the presence of a chylothorax with evidence of a mass or collapsed lung within the right cranial thorax. Computed tomography, sternotomy and histopathology confirmed the presence of a right middle lung lobe torsion associated with a chylothorax. The torsion was successfully managed with surgical removal of the affected lung lobe, and the patient continues to be asymptomatic 6 months postoperatively.     

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.     

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.     

Spontaneous lung lobe torsion in two pugs

Two, young adult, male pugs presented for spontaneous left-cranial lung lobe torsions. Clinical signs associated with these two cases included increased weakness, increased respiratory effort, tachypnea, acute collapse, lethargy, anorexia, and cyanosis. The torsed lung lobes were excised using a thoracoabdominal stapling device without detorsing the lobes. Both dogs recovered uneventfully, and at least one year postoperatively, no clinical abnormalities were noted by their owners. Results of this report suggest that spontaneous lung lobe torsion in pugs occurs and should be a differential diagnosis for pugs with increased respiratory effort, tachypnea, nonproductive cough, acute collapse, cyanosis, and lethargy. Surgical excision may be curative.     

Study of lobation and vascularization of the lungs of wild boar (Sus scrofa)

The purpose of this study was to describe the anatomy of the lungs of wild boars for comparison with those of domestic swine. It was found that the right lung of the wild boar is divided into four lobes: cranial, median, caudal and accessory, whereas the left lung is divided into two lobes: cranial and caudal. In 93.4% of the cases, right pulmonary artery separates into the ascendant, descendant, median, accessory and caudal branches. In 73.3% of the cases, left pulmonary artery separates most frequently to form three branches to the cranial lobe, whereas the median lobe is generally supplied by only one arterial branch. There is a single pattern of bronchial distribution: in the right lung a tracheal bronchus leads to the cranial lobe, where it separates into the cranial and caudal bronchi and there are also bronchi to the median, caudal and accessory lobes. In the left lung, the large bronchus separates to form two branches, one of which further separates to form two branches to the cranial lobe whereas the other forms a single branch to the caudal lobe.     

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.     

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.     

Macroscopic Anatomy of the Lower Respiratory System in Mole rats (Spalax leucodon)

The morphologic and morphometric features of the lower respiratory system in mole rats were examined. It was seen that the low respiratory system of this species leading a special life under highly hypoxic/hypercapnic conditions underground is structurally similar to other mammals living on land in terms of the parts examined; trachea was formed by 29.5 ± 4 oval‐formed cartilaginous tracheals arranged backwards and became gradually more stenotic diameter from cranial to the caudal of the neck. The trachea was separated in two principal bronchus at the fourth thoracal intercostal spatium level. The angle between the two main principal bronchi was 60.5 ± 2.35°. The lung constituted 1.29 ± 0.03% of the body weight and the right lung was heavier than the left lung. Fissura inter‐lobaris was deep and separated the lung lobes wholly, and the right lung was separated in four lobes, whereas the left lung was not separated into the lobes. Also, the medial lobe of the left lung was the lightest lobe.     

Thoracoscopic foreign body removal and right middle lung lobectomy to treat pyothorax in a dog

A three-year-old, 30-kg, spayed female German wirehaired pointer was presented for coughing, pyrexia and lethargy. Thoracic radiographs showed mild right-sided pleural effusion, moderate pneumothorax and a pulmonary lesion in the right middle or caudal lung lobe. A diagnosis of pyothorax was established by fine needle aspiration of the pleural effusion. Thoracoscopic exploration was performed using one-lung ventilation. A vegetal foreign body (grass awn) and an abscess were observed in the distal part of the right middle lung lobe. The foreign body was removed and a right middle lung lobectomy was performed, both thoracoscopically. No complications were noted. The dog was discharged 48 hours after surgery, and no recurrence of the clinical signs was observed during the follow-up time period (three years and three months). Thoracoscopy is a minimally invasive alternative to thoracotomy to explore and successfully treat some non-chronic pyothoraces in dogs, including lesions affecting the right middle lung lobe.     

Usefulness of CT imaging for segmental lung lobe torsion without typical radiographic imaging in a Pomeranian

A 3-year-old, intact female Pomeranian presented with a 1-month history of coughing. Thoracic radiography showed focal infiltration of the left cranial lung lobe and widening of the cranial mediastinum. Subsequent computed tomography revealed torsion of the caudal segment of the left cranial lung lobe, which was confirmed by exploratory thoracotomy. There was no apparent underlying etiology for the condition. To the authors’ knowledge, this is the first report of lung lobe torsion in this breed and the first detailed CT imaging report for segmental lung lobe torsion.     

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.     

Right cranial lung lobe torsion after a diaphragmatic rupture repair in a Jack Russell terrier

A seven-year-old male Jack Russell terrier was presented with a history of coughing, generalised weakness and lethargy 10 days after an abdominal coeliotomy to repair a large diaphragmatic rupture. Thoracic radiographs demonstrated a soft tissue mass in the midcaudal right thoracic cavity. Ultrasonographic studies, bronchoscopy and subsequent exploratory thoracotomy confirmed a diagnosis of a right cranial lung lobe torsion (LLT), with an anomalous caudodorsal displacement of the affected lobe. LLT should be considered as a differential diagnosis for respiratory tract disease following diaphragmatic rupture repair.     

Asymptomatic anomalous pulmonary veins in a Siberian Husky

A 2-year-old, neutered male Siberian Husky presented with depression, weight loss and an inability to prehend food and water. Cerebrospinal fluid was collected under general anaesthesia prior to euthanasia. The elevated white cell count comprised mostly mononuclear cells. Histological changes within the brain were variable and multifocal. Non-suppurative meningitis secondary to lymphoma was diagnosed. At necropsy, abnormal venous drainage of the right cranial and middle lung lobes was found. A dilated major pulmonary vein from these lobes passed across the lateral aspect of the right caudal lung lobe prior to entering the heart, and subpleural veins from the affected lobes were enlarged and tortuous. These vascular abnormalities were considered incidental. There were no apparent congenital abnormalities of the heart and the animal's clinical signs were related to lymphoma of the brain.     

Radiographic and computed tomographic evaluation of experimentally induced lung aspiration sites in dogs

This study was performed to radiographically examine the prevalence of aspiration sites and to evaluate their atomical correlation with the bronchial pattens. Ten healthy beagle dogs were repeatedly radiographed, at weekly intervals, in the left and right lateral, ventrodorsal (VD) and dorsoventral (DV) positions. Three mililiters of iohexol distilled with same volume of saline was infused into the tracheal inlet. Which lung lobe was aspirated was decided upon by the presence of a significant alveolar pattern due to the contrast medium. Alveolar patterns were identified at the left (100%) and right cranial lung lobes (77%) with the dogs in dependant lateral recumbency, at the right caudal lung lobe (71%) with the dogs in VD recumbency and at the right middle lung lobe (59%) with the dogs in DV recumbency, respectively. The anatomical correlation was evaluated by performing computed tomography. The right principal bronchus (165.8 ± 1.6°) was more straightly bifurcated than was the left principal bronchus (142.7 ± 1.8°, p < 0.01). In VD position, the right side lung had a greater opertunity to become aspirated. The ventrally positioned right middle lobar bronchial origin was more easily to be aspirated the other laterally positioned ones. We think that these anatomical characteristics can be one of the causes for aspiration pneumonia to occur more frequently in the right side lung.     

EFFECT OF DEPENDENCY VERSUS NONDEPENDENCY ON LUNG LESION VISUALIZATION

Paraffin blocks and mineral oil were used as a model to determine the effect of dependency versus nondependency on radiographic visualization of lung lesions in lateral thoracic radiographs. It was concluded that the increased opacity of the material surrounding the lesion, not contact between the heart and the lesion, was responsible for the inability to detect lung disease in the dependent lung. The results were tested in dogs with pneumonia in the right middle lung lobe. When the dog was in right lateral recumbency, the dependent right lung was increased in opacity and decreased in volume and the pulmonary lesion was difficult to detect. When the dog was in left lateral recumbency, the nondependent right lung was increased in volume and decreased in opacity and the pulmonary disease was clearly visible. A single recumbent lateral radiograph must not be used to assess a dog with suspected lung disease because lesions in the dependent lung lobes may not be detected.