Surgical and nonsurgical management of and selected risk factors for spontaneous pneumothorax in dogs: 64 cases (1986-1999)

Significance of incidentally identified bullae and blebs on thoracic computed tomography and prevalence of subsequent pneumothorax in dogs

OBJECTIVE

To determine the prevalence of incidentally found pulmonary bullae and blebs (PBBs) in a population of dogs undergoing thoracic computed tomography (CT) for reasons other than presence of pneumothorax and to determine the prevalence of subsequent spontaneous pneumothorax (SP) development.

STUDY DESIGN

Retrospective study.

ANIMALS

A total of 30 dogs.

METHOD

A total of 2221 CT studies of the sample population were retrospectively assessed for the presence of incidental PBBs between April 2013 and April 2019. Inclusion criteria were complete thoracic CT studies from dogs obtained from the hospital database. Exclusion criteria were concurrent presence of a pneumothorax or severe pulmonary disease preventing assessment for PBBs, an air-filled space related to a pathological process, for example, neoplasm, incomplete CT studies, or no available follow-up. Long term outcome was evaluated using a questionnaire to determine the occurrence of SP post CT examination.

RESULTS

Incidental PBBs were identified in 30 out of 2178 (1.4%) CT studies that met the inclusion criteria. None of the dogs subsequently developed clinical evidence of SP (median follow-up time 1255 days, range: 147 to 2363 days). One dog died suddenly of unknown cause and as no post-mortem was performed SP could not be ruled out.

CONCLUSION

There was a low prevalence of incidentally found PBBs in dogs. None of the dogs followed over a long period subsequently developed SP.

CLINICAL SIGNIFICANCE

Based on this study, prophylactic removal of lung tissue containing incidentally found PPBs is not justified.

Successful resolution of a continuous pneumothorax using canine xeno-blood patch pleurodesis in a cat

Case summary

An 11-year-old male neutered cat was referred to The Ohio State University's Veterinary Teaching Hospital after being diagnosed with pleural effusion by a referral veterinarian. After thoracocentesis, analysis of the effusion was consistent with chyle. Echocardiography, radiographs and bloodwork were used to diagnose hypertrophic cardiomyopathy phenotype and left-sided congestive heart failure, suspected to be secondary to uncontrolled hyperthyroidism. While initiating medical therapy, repeated thoracocenteses were required. A severe pneumothorax developed, necessitating placement of bilateral thoracostomy tubes. A thoracic CT scan did not reveal a cause for the pneumothorax; therefore, it was suspected to have occurred secondarily to an iatrogenic laceration of the parenchyma during thoracocentesis. An autologous blood patch pleurodesis was considered contraindicated so instead the cat was administered a blood patch using blood from a canine blood donor. The cat's respiratory status remained stable without additional intervention. At 30 h after blood patch pleurodesis, the thoracostomy tubes were removed and thoracic radiographs revealed near resolution of the pleural effusion and pneumothorax. The cat remained subclinical and was discharged from the hospital 48 h after the blood patch pleurodesis. Upon follow-up at 4 and 8 weeks after discharge, the cat was alive and had no complications or adverse reactions from the blood patch pleurodesis.

Relevance and novel information

This case documents the first report of a xeno-blood patch pleurodesis performed in a cat using blood from a canine donor. The cat had a successful discharge from the hospital with no adverse reactions from the xeno-blood patch pleurodesis.

Improved detection of air-filled lesions using computed tomography in dogs with recurrent spontaneous pneumothorax through reduction of pulmonary atelectasis via positive pressure ventilation

Introduction

Spontaneous pneumothorax in dogs is predominantly caused by the rupture of air-filled lesions, such as bullae or blebs. The efficacy of Computed Tomography (CT) in detecting these lesions has been deemed limited due to its reportedly low sensitivity. This retrospective, cross-sectional study investigates the utility of CT in eight dogs diagnosed with recurrent pneumothorax, all of which had surgical confirmation of the cause of the pneumothorax.

Materials and methods

Thoracic radiographs were obtained before and the day following the CT studies. Initially, a CT study was conducted without positive pressure ventilation (pre-PPV CT). Subsequent CT studies were performed post-evacuation of pneumothorax and with positive pressure ventilation of 15 cmH2O until lung atelectasis was resolved (post-PPV CT). The pre-PPV CT and post-PPV CT images were anonymized and reviewed by two board-certified radiologists. The presence and morphology of air-filled lesions were evaluated on all images. Surgical findings were recorded and compared to the CT findings.

Results

Air-filled lesions were detected in 5 out of 8 dogs in the pre-PPV CT studies and in all 8 dogs in the post-PPV CT studies. The CT findings of air-filled lesions were consistent with surgical findings. None of the dogs showed increased severity of pneumothorax in radiographs taken the day following the CT studies.

Discussions

The study concludes that the resolution of lung atelectasis by evacuation of pneumothorax and positive pressure ventilation during CT studies is feasible and enhances the detection of air-filled lesions in dogs with recurrent spontaneous pneumothorax. This could potentially aid in improving surgical planning.

Thoracic CT incidental pulmonary bullae in dogs: Characterization, interobserver variability, and general anesthesia risks

Ruptures of pulmonary blebs and bullae are the most common cause of spontaneous pneumothorax in dogs. Incidental bullae/blebs have been documented in otherwise healthy people, however information for veterinary patients is currently lacking. Objectives of this retrospective, observer agreement, analytical study were to characterize incidental bullae in thoracic CT studies of dogs, assess interobserver variability for characterizing the bullae, and assess anesthesia risks. Inclusion criteria were dogs presenting for non-pneumothorax related reasons that had a thoracic CT at a single specialty and emergency hospital from 2012 to 2021 and had a bulla listed in the CT report. Medical records for dogs meeting inclusion criteria were reviewed to collect data on signalment, weight, total number of general anesthesia procedures 2 years prior and 2 years following the CT scan, and adverse anesthesia events. In addition, the CT images were reviewed by three American College of Veterinary Radiology-certified veterinary radiologists to collect data on the location, size, number of bullae and thickness of the bulla wall. A total of 1119 dogs met initial inclusion criteria and 74 dogs were included in analyses. There was no sex predilection for incidental pulmonary bullae. Bullae were more commonly found in older (median age 11.3 years), large breed dogs (median weight 20.7 kg). A solitary bulla of less than 1 cm was the most common finding with no apparent predilection for a particular lung lobe. There was strong correlation among the three radiologists for bulla location, size, and number, but weak correlations for bulla wall thickness. No adverse anesthesia events were found following CT anesthesia or following repetitive anesthesia procedures.

Allogenic blood patch pleurodesis for management of pneumothorax in a Cavalier King Charles Spaniel puppy with multiple pulmonary blebs and bullae

A 9‐week‐old male intact Cavalier King Charles Spaniel was presented for evaluation of acute onset dyspnea caused by left‐sided pneumothorax. Thoracic computed tomography (CT) identified multiple pulmonary bullae and blebs in multiple lung lobes. Rupture of ≥1 pulmonary blebs or bullae, precipitated by low impact trauma, was the suspected cause of pneumothorax. A volume of 7.5 mL/kg of fresh whole blood was collected from a type‐matched donor dog and administered into the left pleural space using a thoracostomy tube. The pneumothorax was successfully resolved and no adverse effects of blood patch pleurodesis were noted. The dog was clinically normal 12 months later.

Suspected Primary Spontaneous Asymptomatic Pneumothorax in a Cat

Spontaneous pneumothorax (SPT) is a documented emergency of the respiratory tract condition classified as either primary or secondary based on the presence of underlying pulmonary conditions. All reported SPT in the feline literature are evaluated for respiratory clinical signs. Primary SPT without underlying pathology or without clinical signs is not reported in cats. This case report describes a 10-year-old domestic longhair cat that was referred for evaluation of chronic lethargy with severe azotemia and placement of a subcutaneous ureteral bypass (SUB) system. Prior to presentation, the cat was diagnosed with renal insufficiency and treated medically with no resolution. Clinical examination under sedation revealed right-sided renomegaly. Thoracic radiographs revealed gas in the caudodorsal pleural space and concurrent pulmonary atelectasis. No respiratory clinical signs were present. Thoracic CT showed two pulmonary bullae, one located in the right caudal lung lobe and one in the cranial segment of the left cranial lung lobe. Abdominal ultrasound showed a right-sided ureteral obstruction. Medical management was elected for the spontaneous pneumothorax. A SUB was placed to address the ureteral obstruction; no complications were noted during recovery. The cat was free of clinical signs of respiratory disease after a follow-up time of nine months. This is the first reported case of a cat diagnosed with a nonclinical suspected primary spontaneous pneumothorax with no concurrent predisposing pulmonary pathology.

Spontaneous pneumothorax in German Shorthair Pointer due to penetration of a grass awn

This case report describes an incident of pneumothorax in 4-month old male German Shorthaired Pointer caused by a grass awn. The patient was brought to the Small Animal Clinic of the Faculty of Veterinary Medicine at Trakia University, Stara Zagora, Bulgaria with respiratory distress and anxiety. Tachypnea, cyanotic mucous membranes and tachycardia were observed during physical examination. Abnormal collection of air in the pleural space between the lung and the chest was observed radiographically. A diagnosis of primary spontaneous closed pneumothorax was made based on these findings. Later pathoanatomical findings showed the presence of the grass awn that had penetrated through the skin.

Spontaneous Pneumothorax: Management and Prognosis

This review article will review treatment and prognosis of spontaneous pneumothorax in dogs and cats. The advantages of surgical and medical management in dogs and cats, as well as current treatment practices, including autologous blood pleurodesis and small-bore chest tubes, will be discussed.

Spontaneous Pneumothorax: Pathophysiology, Clinical Presentation and Diagnosis

Spontaneous pneumothorax, which may have an acute or insidious onset in dogs and cats, results in respiratory difficulty and has the potential to be life threatening.^1-3 Dogs commonly develop spontaneous pneumothorax due to bullae or blebs, while cats typically have underlying inflammatory disease, like feline allergic airway disease. Urgent therapeutic intervention is essential in animals with respiratory distress. The recommended therapeutic strategies are typically different in each of these species due to underlying etiology. The first part of this review article will focus on physiology, clinical presentation, and diagnosis of spontaneous pneumothorax in dogs and cats. Advances in diagnostics, especially the recent utility of point of care ultrasound, will be discussed. The second part of the series will provide an overview of therapeutic options and management of patients with spontaneous pneumothorax, as well as information on prognosis.

Autologous blood patch pleurodesis treatment for persistent pneumothorax: A case series of five dogs (2016-2020)

Background

Autologous blood patch pleurodesis (ABP) has been described as a treatment for persistent pneumothorax in the dogs and among humans. Although the treatment of persistent or recurring spontaneous pneumothorax is classically surgical, it cannot always be performed due to medical or financial constraints. This case series describes the clinical course, etiology, and outcome of five dogs with persistent pneumothorax treated with ABP.

Case Description

Five client-owned dogs with persistent pneumothorax are presented. Two dogs had pneumothorax due to congenital pulmonary bullae, one due to thoracic trauma, another due to lungworm infection, and a fifth with unknown cause in the context of a relapsing subcutaneous haemangiosarcoma. Around 5 ml/kg of non-coagulated blood was aseptically collected from the jugular vein and injected via a thoracotomy tube immediately into the pleural cavity of dogs with persistent pneumothorax. The procedure was successful in four out of five dogs after one procedure, therefore a success rate of 80%. A repeat of the pleurodesis was attempted in the fifth dog, 12 hours after the first injection due to the recollection of the pneumothorax. Still, the dog died during anesthesia in preparation for the procedure. No complications that could be directly linked to ABP occurred.

Conclusion

ABP is a simple, rapid, inexpensive, effective, and safe procedure that can be useful for treating persistent pneumothorax that does not respond to conservative treatment and where surgical exploration cannot be carried out. Pneumothorax secondary due to trauma and congenital pulmonary bullae seem to respond well to ABP.

Treatment and outcome of spontaneous pneumothorax secondary to suspected migrating vegetal foreign body in 37 dogs

BACKGROUND

The aim of this study is to describe surgical findings, treatment and outcome of spontaneous pneumothorax (SP) secondary to suspected migrating vegetal foreign body (MVFB).

METHODS

This retrospective study included dogs with computed tomography (CT) consistent with SP suspected to be secondary to MVFB that underwent thoracic surgery. They were divided into two groups according to whether CT identified (group 1) or only suspected (group 2) an MVFB.

RESULTS

Thirty-seven dogs were included (twenty-one in group 1 and 16 in group 2). An MVFB was identified during surgery in 18 of 21 of cases of group 1 and in 10 of 16 of group 2. An agreement between lobes affected on CT and surgical findings was observed in 34 of 40 lobes. In nine of 37 of cases, a lung perforation was identified without evidence of MVFB. Thirty-nine lobectomies were performed: 15 complete and 24 partial. No recurrence of pneumothorax was observed. In four dogs, a second surgery was necessary to remove an MVFB 1.5 to 3 months after the initial surgery due to secondary draining tracts.

CONCLUSION

Surgical approach planed with CT resolved SP in all cases before discharge with excellent short-term outcome and no major complication. CT was reliable to assess perforated lung lobes in 85% of cases. Clinical signs of delayed draining tract developed in 33% of cases where surgery failed to find an MVFB identified on CT.

Surgical management and outcome of dogs with primary spontaneous pneumothorax: 110 cases (2009-2019)

OBJECTIVE

To describe surgical management and associated outcomes for dogs with primary spontaneous pneumothorax.

ANIMALS

110 client-owned dogs with primary spontaneous pneumothorax that underwent surgical management.

PROCEDURES

Medical records at 7 veterinary teaching hospitals were reviewed. Data collected included signalment, history, clinical signs, radiographic and CT findings, surgical methods, intraoperative and postoperative complications, outcomes, and histopathologic findings. Follow-up information was obtained by contacting the referring veterinarian or owner.

RESULTS

110 dogs were included, with a median follow-up time of 508 days (range, 3 to 2,377 days). Ninety-nine (90%) dogs underwent median sternotomy, 9 (8%) underwent intercostal thoracotomy, and 2 (2%) underwent thoracoscopy as the sole intervention. Bullous lesions were most commonly found in the left cranial lung lobe (51/156 [33%] lesions) and right cranial lung lobe (37/156 [24%] lesions). Of the 100 dogs followed up for > 30 days, 13 (13%) had a recurrence of pneumothorax, with median time between surgery and recurrence of 9 days. Recurrence was significantly more likely to occur ≤ 30 days after surgery, compared with > 30 days after surgery. Recurrence > 30 days after surgery was rare (3 [3%]). No risk factors for recurrence were identified.

CONCLUSIONS AND CLINICAL RELEVANCE

Lung lobectomy via median sternotomy resulted in resolution of pneumothorax in most dogs with primary spontaneous pneumothorax. Recurrence of pneumothorax was most common in the immediate postoperative period, which may have reflected failure to identify lesions during the initial thoracic exploration, rather than development of additional bullae.

Computed tomography in two recumbencies aides in the identification of pulmonary bullae in dogs with spontaneous pneumothorax

Spontaneous pneumothorax presents a unique diagnostic and therapeutic challenge in veterinary medicine, specifically with regard to accurate identification of bullous lesions. Positioning of dogs with spontaneous pneumothorax during CT has not previously been evaluated. This retrospective, diagnostic accuracy study was performed to evaluate the sensitivity, positive predictive value (PPV), and interobserver variability for detection of pulmonary bullae with dogs positioned in multiple recumbencies. Dogs underwent CT in sternal and dorsal recumbency followed by thoracic exploration via median sternotomy. Three American College of Veterinary Radiology-certified veterinary radiologists blinded to surgical findings reviewed dorsal and sternal images simultaneously. Severity of pneumothorax, degree of atelectasis, lesion location and size, and view in which lesions were most confidently identified were compared to surgical and histologic findings. Sensitivities and PPVs for bulla detection ranged from 57.7% to 69.2% and 62.1% to 78.9%, respectively. For two of the 3 radiologists, the location of bullae in the thorax was significantly associated with the recumbency in which the lesion was best identified. Degree of atelectasis was found to be associated with the ability to identify lesions (P ≤ .02). The interobserver variability for identification was good (κ = 0.670). The sensitivity of CT when performed in both sternal and dorsal recumbency is similar to that previously reported. Because the distribution of bullae is unknown prior to advanced imaging and bulla location affects which recumbency is most useful for identification, acquisition of CT images in both sternal and dorsal recumbency may improve detection of bullous lesions and aid surgical planning.

Long-term clinical outcomes following surgery for spontaneous pneumothorax caused by pulmonary blebs and bullae in dogs - a multicentre (AVSTS Research Cooperative) retrospective study

OBJECTIVES

To report the clinical characteristics and recurrence rate of spontaneous pneumothorax secondary to pulmonary blebs and bullae following surgical management in a large cohort of dogs. To explore potential risk factors for recurrence and describe outcome.

MATERIALS AND METHODS

Medical records were retrospectively reviewed for cases with spontaneous pneumothorax managed surgically between 2000 and 2017. Signalment, clinical presentation, diagnostic imaging, surgery, histopathology findings and patient outcomes were recorded. Follow-up was performed via patient records and telephone contact.

RESULTS

Records of 120 dogs with surgically treated pneumothorax were identified and reviewed, with 99 cases appropriate for exploratory statistical analysis. Median follow-up was 850 days (range: 9-5105 days). Two- and 5-year survival rates were 88.4% and 83.5%, respectively. There was recurrence in 14 of 99 dogs (14.1%) with adequate follow-up, with a median time to recurrence of 25 days (1-1719 days). Univariable Cox regression analysis suggested increased risk for recurrence in giant breeds (hazard ratio = 11.05, 95% confidence interval: 2.82-43.35) and with increasing bodyweight (HR = 1.04, 95% confidence interval: 1.00-1.09). Of 14 dogs with recurrence, six were euthanased, two died of causes related to pneumothorax and six underwent further treatment, of which five were resolved.

CLINICAL SIGNIFICANCE

Long-term survival for dogs with surgically managed spontaneous pneumothorax was good and associated with a low risk of recurrence. Giant breed dogs and increased bodyweight were the only variables identified as possible risk factors for recurrence. The outcome for dogs with recurrence undergoing a second intervention was also favourable.

CT is helpful for the detection and presurgical planning of lung perforation in dogs with spontaneous pneumothorax induced by grass awn migration: 22 cases

Spontaneous pneumothorax induced by grass awns accounts for 5% of spontaneous pneumothorax and 22.5% of thoracic grass awn cases. Previous studies report limited interest of CT for spontaneous pneumothorax. Aims of this retrospective case series were to describe CT features of this condition and determine if CT features can efficiently localize the perforation site. Dogs that had a spontaneous pneumothorax, CT examination, thoracic surgery, and confirmed lung perforation due to a grass awn were included. Computed tomography studies were reviewed and compared to the surgical findings.  In 19 of 22 (86.4%) dogs, the pneumothorax or its recurrence were ipsilateral to the perforation site. The perforation site was identified in 21 of 22 (95.5%) dogs and involved the caudal lobes in 20 of 22 (90.9%) cases. The lateralization and the involved lung lobe corresponded to surgical findings in 21 of 22(95.5%) dogs. The perforation site was characterized as a soft tissue attenuating focus lying against an extensive pleural thickening in 21 of 22(95.5%) dogs. An adjacent defect in the visceral pleura was seen in 13 of 22(59.1%) dogs. A grass awn was seen in 11 of 22(50%) dogs.  The pneumothorax distribution and grass awn position consistently indicated the perforation side in this sample of dogs. The comparison with surgical findings suggests CT might be helpful for future presurgical planning of this etiology for pneumothorax.

Concurrent pulmonary hypoplasia and congenital lobar emphysema in a young dog with tension pneumothorax: a rare congenital pulmonary anomaly

BACKGROUND

Pulmonary hypoplasia (PH) and congenital lobar emphysema (CLE) are very rare congenital pulmonary anomalies in veterinary medicine. PH refers to the incomplete pulmonary development due to embryologic imbalance of bronchial development between the lung buds, while CLE is defined as alveolar hyperinflation due to bronchial collapse during expiration caused by bronchial cartilage dysplasia, external bronchial compression, and idiopathic etiology. CLE may develop into pulmonary blebs or bullae that may rupture and induce a spontaneous pneumothorax. There are no reports on concurrent PH and CLE in animals.

CASE PRESENTATION

A 7-month-old castrated male Italian Greyhound weighing 5.5 kg presented with vomiting and acute onset of severe dyspnea without any previous history of disease. After emergency treatment including oxygen supplementation and thoracocentesis, plain radiology and computed tomography scanning were performed and lobar emphysema with multiple bullae in the left cranial lung lobe associated with tension pneumothorax was identified. Since the pneumothorax was not resolved despite continuous suction of intrathoracic air for 3 days, a complete lobectomy of the left cranial lung lobe was performed. The excised lobe was not grossly divided into cranial and caudal parts, but a tissue mass less than 1 cm in size was present at the hilum and cranial to the excised lobe. Postoperatively, the dog recovered rapidly without air retention in the thoracic cavity. Histopathologically, the mass was identified as a hypoplastic lung tissue with collapsed alveoli, bronchial dysplasia, and pulmonary arterial hypertrophy. Additionally, the excised lung lobe presented CLE with marked ectasia of alveoli, various blebs and bullae, and general bronchial cartilage dysplasia. According to gross and histopathologic findings, the dog was diagnosed with concurrent PH and CLE in the left cranial lung lobe. During 16 months of follow-up, the dog was well and without any respiratory problems.

CONCLUSIONS

This case report confirmed the clinical and histologic features of two different types of rare congenital pulmonary anomalies, PH and CLE, which occurred concurrently in a single lung lobe of a young dog. The condition was successfully managed with lobectomy.

Utility of bronchoscopy combined with surgery in the treatment and outcomes of dogs with intrathoracic disease secondary to plant awn migration

OBJECTIVE

To evaluate the diagnostic and therapeutic utility of bronchoscopy in dogs undergoing computed tomography (CT) and surgery for intrathoracic disease (pyothorax and pneumothorax) secondary to migrating plant awns (MPA) and to report outcomes in dogs that did and did not undergo bronchoscopy in addition to CT and surgery.

STUDY DESIGN

Retrospective case series.

ANIMALS

Thirty-seven client-owned dogs.

METHODS

Medical records from 2008 to 2017 were reviewed for dogs with documented MPA in the thoracic cavity treated with CT and surgery with or without bronchoscopy. Information regarding diagnostics, treatments, complications, and outcomes relating to hospitalization was evaluated.

RESULTS

At least one abnormal lung lobe was identified by CT in all dogs. Bronchial abnormalities were identified with bronchoscopy in 21 of 22 dogs (95.4%) with available reports. Agreement between CT and bronchoscopy findings ranged from 50% to 81.8%, depending on lung lobe. Thirty-six dogs had one or more lung lobes surgically removed. Thirty-seven MPA were retrieved via bronchoscopy in 10 of 27 (37%) dogs, and 39 MPA were retrieved at surgery in 26 of 37 (70.3%) dogs. Actinomyces spp. were cultured from surgical samples in 7 of 33 (21.2%) dogs. Thirty-five of 37 (94.6%) dogs survived to discharge.

CONCLUSION

Migrating plant awns were successfully retrieved via bronchoscopy. Agreement between CT findings and bronchoscopy was inconsistent, so there may be roles for both modalities. Short- and long-term survival was excellent in this cohort.

CLINICAL SIGNIFICANCE

Bronchoscopy may allow for diagnostic and therapeutic advantages compared with CT in dogs with endobronchial MPA. Actinomyces spp appear to be variably present in surgically acquired bacterial cultures in dogs with MPA.

Does the computed tomographic appearance of the lung differ between young and old dogs?

In computed tomographic (CT) images of humans, decreased lung attenuation, bronchial dilation, and/or thickening, air trapping, cysts, and thickened interlobular septa have been associated with increasing age. To determine if there are differences in the CT appearance of the lungs of young and old dogs that could affect interpretation of diagnostic studies, pulmonary CT images of dogs with conditions unrelated to the thorax were reviewed retrospectively in a case-control study. Computed tomography studies of 42 young dogs (range 0.3-4.8 years) and 47 old dogs (range 9-15.1 years) were jumbled and reviewed by an observer blinded to dog age. Computed tomography was performed under sedation in 62 (70%) dogs and under general anesthesia in 27 (30%). Heterotopic bone was more prevalent (62% vs. 14%) in old dogs. Lung collapse was significantly associated with old age, greater body weight, and anesthesia. There were no significant differences in median lung attenuation or occurrence of ground glass pattern, cysts, bronchial thickening, bronchial dilation, or degree of tracheal calcification. No examples of reticular pattern, emphysema, pleural thickening, or septal thickening were observed in any dog. Despite previous studies describing age-related changes in the radiographic appearance of the lungs of old dogs, it appears that there are minimal observable differences in CT images. Old dogs are more likely to have visible foci of heterotopic bone and may be more prone to lung lobe collapse than young dogs, but neither of these differences should contribute to misdiagnosis of pulmonary disease.

Preoperative and intraoperative ultrasound aids removal of migrating plant material causing iliopsoas myositis via ventral midline laparotomy: a study of 22 dogs

BACKGROUND

Migrating plant material is often suspected clinically to be the underlying cause of iliopsoas myositis in the dog, but cannot always be found pre- or intraoperatively. In most cases, recurrence of clinical signs is related to failure to remove the plant material. Preoperative ultrasonography can be useful to visualize migrating plant material and to determine anatomical landmarks that can assist in planning a surgical approach. The purpose of the present study was to report the role of intraoperative (intra-abdominal) ultrasonography for visualizing and removing the plant material from iliopsoas abscesses using a ventral midline laparotomy approach.

RESULTS

A retrospective case series of 22 dogs with iliopsoas muscle abnormalities and suspected plant material was reported. Preoperative visualization and subsequent retrieval of the plant material was performed during a single hospitalization. In all 22 dogs, the plant material (including complete grass awns, grass awn fragments and a bramble twig) was successfully removed via ventral midline laparotomy in which intraoperative ultrasonography was used to direct the grasping forceps tips to the foreign body and guide its removal. In 11 of these 22 dogs, the plant material was not completely removed during prior surgery performed by the referring veterinarians without pre- or intraoperative ultrasonography. Clinical signs resolved in all dogs and all dogs resumed normal activity after successful surgical removal of the plant material.

CONCLUSION

Intraoperative ultrasonography is a safe and readily available tool that improves success of surgical removal of plant material within the iliopsoas abscesses via ventral midline laparotomy. Moreover, ultrasonographic findings of unusual plant material can be useful in planning and guiding surgical removal, by providing information about the size and shape of the foreign body.

Treatment of a giant pulmonary emphysematous cyst with primary bronchoalveolar papillary carcinoma in a Shih Tzu dog

OBJECTIVE

To report the surgical treatment of a pulmonary emphysematous cyst concurrent with primary pulmonary bronchoalveolar papillary carcinoma in a dog.

STUDY DESIGN

Clinical case report.

ANIMALS

12-year-old 6.4 kg spayed female Shih Tzu dog.

METHODS

The dog presented for surgical treatment of pulmonary emphysema. Radiography revealed that more than half of the left caudal lung lobe was enlarged and hyperlucent and computed tomography (CT) confirmed the presence of an emphysematous space. Thoracoscopic lung lobectomy was attempted but was converted to an intercostal thoracotomy due to poor visualization and pleural adhesions. A left caudal total lung lobectomy was performed using a self-cutting endoscopic stapler.

RESULTS

The dog recovered uneventfully and a postoperative histopathologic diagnosis of pulmonary cystic bronchoalveolar papillary carcinoma was made. Re-evaluation using a CT scan with contrast study on postoperative days 27 and 177 revealed no evidence of residual, metastatic, or recurrent lesions. The dog has been doing well since surgery during the 11 month follow-up period.

CONCLUSION

This case report suggests a potential relationship between pulmonary emphysematous diseases and primary lung tumors in dogs.

Perianesthetic Mortality in Domestic Animals

Autopsy of animals that die in the perianesthetic period allows identification of anesthetic and surgical complications as well as preexisting disease conditions that may have contributed to mortality. In most studies to date investigating perianesthetic mortality in animals, inclusion of autopsy data is very limited. This retrospective study evaluated autopsy findings in 221 cases of perianesthetic death submitted to a veterinary diagnostic laboratory from primary care and referral hospitals. Canine ( n = 105; 48%) and feline ( n = 90; 41%) cases predominated in the study, involving elective (71%) and emergency (19%) procedures. The clinical history provided to the pathologist was considered incomplete in 42 of 221 cases (19%), but this history was considered essential for evaluating the circumstances of perianesthetic death. Disease had been recognized clinically in 69 of 221 animals (31%). Death occurred in the premedication or sedation ( n = 19; 9%), induction ( n = 22; 11%), or maintenance ( n = 73; 35%) phases or in the 24 hours postanesthesia ( n = 93 animals; 45%). Lesions indicative of significant natural disease were present in 130 of 221 animals (59%), mainly involving the heart, upper respiratory tract, or lungs. Surgical or anesthesia-associated complications were identified in 10 of 221 cases (5%). No lesions were evident in 80 of 221 animals (36%), the majority of which were young, healthy, and undergoing elective surgical procedures. Lesions resulting from cardiopulmonary resuscitation were identified in 75 of 221 animals (34%). Investigation of perianesthetic death cases should be done with knowledge of prior clinical findings and antemortem surgical and medical procedures; the autopsy should particularly focus on the cardiovascular and respiratory system, including techniques to identify pneumothorax and venous air embolism.

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.

Primary ciliary dyskinesia in two English Cocker Spaniels

BACKGROUND

Primary ciliary dyskinesia (PCD) is an inherited condition characterised by structural and functional defects of ciliated cells. Ciliated cells are present in several different anatomic locations and PCD can thus cause a variety of clinical signs; however, the predominant clinical signs in dogs are respiratory in nature, most commonly chronic nasal discharge and recurrent lower respiratory tract infections commencing in the neonatal period.

CASE REPORT AND CONCLUSION

This report describes two cases of PCD in English Cocker Spaniel puppies presenting with chronic nasal discharge and bronchopneumonia. We describe the use of a minimally invasive technique to collect samples suitable for cilial studies for its diagnosis.

Congenital lobar emphysema concurrent with pneumothorax and pneumomediastinum in a dog

A two-year-old castrated male Pomeranian dog was referred with the chief complaints of coughing and subcutaneous emphysema. On physical examination, the crepitant areas were palpable. When auscultated, the right chest was absent of respiratory sound, while the sound of the opposite side was enhanced. Radiographs presented pneumothorax and pneumomediastinum. On computed tomography, hypoattenuated bulla-like lesion at right middle lung lobe and trapped air in mediastinum were shown. After patient stabilization, surgery for excision of affected lobe was performed. During follow-up period, there were no recurrence and complication on radiographic examination. Based on clinical and pathological findings, the dog was diagnosed as congenital lobar emphysema.

Physical examination of the respiratory system

This article reviews the approach to a patient with respiratory distress, with a focus on clues obtained from the physical examination. Respiratory distress is a common reason for presentation of a companion animal to a veterinarian on an emergency basis, and thus the clinician should have a comfort level with the approach to these patients. Our discussion includes a basic review of respiratory pathophysiology and the differential diagnoses for hypoxemia. In the majority of cases, physical examination should allow localization of the cause of the respiratory problem to the upper airways, lower airways, pleural space, or pulmonary parenchyma. Such localization, coupled with signalment and historical clues, guides additional diagnostics and therapeutics based on the most likely differential diagnoses. Although managing a patient with respiratory distress can be challenging, a systematic approach such as the one presented here should ensure appropriate intervention in a timely fashion and maximize the chance of a good outcome.

Pleural Space Disease

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Abnormalities within the pleural space may include pleural effusion, pneumothorax, or space-occupying soft tissue structures (diaphragmatic hernia, neoplasia).

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A diagnostic thoracocentesis may also prove therapeutic in severely affected patients.

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Fluid analysis and cytologic evaluation should always be performed on aspirates from a patient with newly diagnosed pleural effusion of unconfirmed etiology.

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Aerobic and anaerobic culture and susceptibility testing of suppurative effusions are imperative.

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Comparison of pleural fluid and serum triglyceride levels and cholesterol concentrations are necessary to confirm the diagnosis of chylothorax.

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Clinical evidence of cardiovascular shock often precedes dyspnea in patients with hemothorax.

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Tension pneumothorax, regardless of its origin, rapidly may be fatal. Immediate drainage via thoracocentesis or thoracostomy tube placement is required before taking thoracic radiographs.

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Clinical signs of a traumatic diaphragmatic hernia may be delayed; however, early detection and correction are important because perioperative outcome is worse in chronically affected patients.

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Tools such as ultrasonography, computed tomography (CT), and thoracoscopy are becoming increasingly available to aid in the diagnostic evaluation and treatment of pleural space disease.

Retrospective evaluation of the use of autologous blood-patch treatment for persistent pneumothorax in 8 dogs (2009-2012)

OBJECTIVE

To describe the clinical course, outcome and success rate of 8 dogs with persistent pneumothorax treated with autologous blood-patch pleurodesis (ABP).

DESIGN

Retrospective case series.

SETTING

University teaching hospital

ANIMALS

Eight client-owned dogs.

INTERVENTION

Non-coagulated blood was aseptically collected from the jugular vein and injected immediately into the pleural cavity of dogs with persistent pneumothorax.

MEASUREMENTS AND MAIN RESULTS

The procedure was successful in 7 of 8 dogs. The median duration of pneumothorax until the ABP was performed was 4 days (range 2-6 days). Pneumothorax resolved immediately after 1 treatment in 4 dogs. Pleurodesis was repeated once in 3 dogs, and twice in 1 case after which it resolved in 3 of the 4 dogs. Out of a total of 13 ABP procedures performed in 8 dogs, 5 (62.5%) were successful after 1 procedure and the success rate increased to 87.5% after additional procedures. One dog failed ABP and was euthanized 3 days later due to continued deterioration and a hospital acquired pneumonia. Mild to moderate complications occurred in 2 other dogs and resolved in both.

CONCLUSIONS

ABP is a simple, inexpensive, and relatively safe procedure which can be considered in dogs with persistent pneumothorax that have failed conservative or surgical management. Infections following ABP were documented in 2 of the 8 dogs and resolved in 1 dog.

Evaluation of Video-Assisted Thoracic Surgery for Treatment of Spontaneous Pneumothorax and Pulmonary Bullae in Dogs

OBJECTIVE

To describe the operative findings and clinical outcome in dogs undergoing video-assisted thoracic surgery (VATS) for treatment of spontaneous pneumothorax and pulmonary bullae.

STUDY DESIGN

Multi-institutional retrospective case series.

ANIMALS

Dogs (n = 12) with spontaneous pneumothorax and/or pulmonary bullae.

METHODS

Medical records (2008-2013) were reviewed for signalment, clinical signs, diagnostic imaging, surgical and histopathologic findings, and outcome in 12 dogs that had VATS for treatment of spontaneous pneumothorax and pulmonary bullae. In particular, conversion to median sternotomy and surgical success were evaluated.

RESULTS

Twelve dogs had initial VATS for spontaneous pneumothorax and/or pulmonary bullae. Conversion to median sternotomy because of inability to identify a parenchymal lesion/leak was necessary in 7 (58%) dogs. VATS without conversion to median sternotomy was performed in 6 (50%) dogs. Successful surgical outcomes occurred in 5 (83%) dogs that had conversion to median sternotomy, and in 3 (50%) dogs that had VATS without conversion to median sternotomy.

CONCLUSIONS

Exploratory thoracoscopy was associated with a high rate of conversion to median sternotomy because of inability to identify leaking pulmonary lesions in dogs with spontaneous pneumothorax and pulmonary bullae. Failure to convert to a median sternotomy may be associated with recurrent or persistent pneumothorax.

Computed tomographic features of pneumothorax secondary to a bronchopleural fistula in two dogs

A bronchopleural fistula (BPF) can lead to continuous pneumothorax and is rarely reported clinically in dogs. This report describes computed tomographic (CT) findings in two dogs with BPFs and subsequent continuous pneumothoraces that necessitated thoracotomy. Both dogs had a peripheral BPF in the right caudal lung lobe. The fistula in one dog was secondary to a previous foreign body migration, and the fistula in the other was thought to be secondary to dirofilariasis. On both CT examinations, a dilated subsegmental bronchus was seen communicating with the pleural space at the center of a focal, concave region of parenchymal consolidation. Multiplanar reformatting aided in identification and characterization of the BPF. The pneumothoraces resolved after right caudal lobectomy in both dogs. CT has the potential to identify BPFs, such as secondary to foreign body migration or dirofilariasis.

Feline secondary spontaneous pneumothorax: a retrospective study of 16 cases (2000-2012)

OBJECTIVE

To describe the demographics, clinical characteristics, diagnostic findings, underlying etiologies, treatment, and outcome associated with secondary spontaneous pneumothorax (SSP) in cats; and to identify clinical feature differences among cats with asthma associated secondary spontaneous pneumothorax (AASSP) versus nonasthma-associated secondary spontaneous pneumothorax (NAASSP).

DESIGN

Retrospective case series.

SETTING

University teaching hospital.

ANIMALS

Sixteen client-owned cats with secondary spontaneous pneumothorax.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Domestic short hair was the predominant breed in this study (n = 15). The median age was 8 years old (range: 7 weeks to 17 years) with no sex predilection. Fourteen cats were affected by multi-lobar pulmonary pathology of infectious, inflammatory, or neoplastic causes. Asthma was the most common cause of spontaneous pneumothorax (25%). Ten of 12 treated cats survived the initial episode of spontaneous pneumothorax to discharge with medical management, including all 4 cats with AASSP. Reoccurrence was documented in 4 cats. Pulmonary lobectomy was curative for 1 cat with congenital accessory lung lobe emphysema. No difference in clinical presentation was identified between cats with AASSP and cats with NAASSP.

CONCLUSIONS

Feline SSP is frequently associated with extensive pulmonary pathology. Supportive medical management is most appropriate, except in rare cases with focal congenital abnormalities that may benefit from surgical intervention. AASSP appears to carry a good prognosis for short-term outcome (survival to discharge). Clinical assessment, imaging, and invasive diagnostics were required to differentiate between AASSP and NAASSP.

Spontaneous pneumothorax secondary to reactive bronchopneumopathy in a dog

CASE DESCRIPTION

An 8-year-old 38-kg (84-lb) castrated male German Shepherd Dog cross was evaluated because of respiratory distress secondary to pneumothorax (detected radio-graphically prior to referral).

CLINICAL FINDINGS

CT of the thorax confirmed the presence of pneumothorax and revealed pulmonary blebs without evidence of infiltrative pulmonary changes. A tentative diagnosis of primary spontaneous pneumothorax was made.

TREATMENT AND OUTCOME

Exploratory median sternotomy revealed emphysematous changes along the margins of all lung lobes, with the ventral margins of the left cranial, right cranial, and right middle lung lobes most affected. Partial lobectomies of the ventral aspects of these lobes were performed. Histologic examination of tissue samples from the lung lobes revealed diffuse smooth muscle hypertrophy of the terminal and respiratory bronchioles with moderate numbers of peribronchiolar eosinophils. Mucus plugs and mucous cell metaplasia within the airway epithelium were also evident. After surgery, clinical signs resolved and the dog was discharged from the hospital 2 days later. Eight months after surgery, the dog developed a mild cough, and treatment with prednisolone (tapering dosage starting at 0.5 mg/kg [0.023 mg/lb], PO, q 12 h) was initiated. Dosage reduction resulted in recurrence of coughing; however, with continued prednisolone treatment at a dosage of 0.5 mg/kg, PO, once daily, the dog was not coughing at 10 months after surgery.

CLINICAL RELEVANCE

Reactive bronchopneumopathy should be included as a differential diagnosis for spontaneous pneumothorax in dogs.

Imaging diagnosis--transesophageal ultrasound-guided removal of a migrating grass awn foreign body in a dog

A 3-year-old English Setter dog was presented for an acute onset of coughing. Tracheobronchoscopic examination allowed localization and removal of one grass awn foreign body. A second migrated grass awn was suspected to be present in the left caudal lung lobe. Transesophageal ultrasound revealed an area of pulmonary consolidation in the dorsomedial portion of left caudal lobe and a linear hyperechoic structure consistent with a grass awn foreign body within the area of consolidation. Transesophageal ultrasonography was also used to provide anatomical landmarks that facilitated successful thoracoscopic removal of the foreign body.

Use of pleural access ports for treatment of recurrent pneumothorax in two dogs

CASE DESCRIPTION

An 8-year-old castrated male mixed-breed dog (dog 1) and a 13-year-old spayed female mixed-breed dog (dog 2) were evaluated because of spontaneous pneumothorax.

CLINICAL FINDINGS

Both dogs had decreased bronchovesicular sounds with coughing, tachypnea, cyanosis, lethargy, or a combination of these clinical signs. Radiographic examination revealed pneumothorax in both dogs and consolidation of a lung lobe in dog 2. Pneumothorax was alleviated following thoracocentesis in both dogs but recurred.

TREATMENT AND OUTCOME

Dog 1 was initially treated by placement of a thoracostomy tube but underwent thoracotomy when pneumothorax recurred after tube removal; left caudal lung lobectomy was performed because a ruptured bulla was suspected, and a pulmonary bulla was histologically confirmed. Dog 2 underwent thoracotomy with left caudal lung lobectomy and partial removal of the left cranial lung lobe; diffuse pulmonary emphysema was diagnosed. This dog underwent a second surgery for right caudal lung lobectomy because of torsion. When pneumothorax recurred and additional surgery was not considered feasible, pleural access ports were placed in both dogs for repeated removal of air from the thoracic cavity. Ports were used clinically for 17 days in dog 1 and 14 days in dog 2. Dog 1 successfully underwent another surgery when pneumothorax recurred 18 days after port placement but was euthanized 17 months later when dyspnea and tachypnea recurred. Pneumothorax had not recurred further in dog 2 twenty-three months after port placement.

CLINICAL RELEVANCE

Findings suggested that pleural access ports may have a role in the management of spontaneous pneumothorax in dogs.

Spontaneous pneumothorax in 35 cats (2001-2010)

Thirty-five cases of spontaneous pneumothorax were reviewed. In contrast to dogs, cats with an established etiology all had spontaneous pneumothorax associated with lung disease. Underlying diseases identified in affected cats included inflammatory airway disease, neoplasia, heartworm infection, pulmonary abscess and lungworm infection. Many cats were managed successfully with observation alone or needle thoracocentesis and specific therapy for their primary lung disease. Cats who present with spontaneous pneumothorax may be treated successfully with non-surgical therapies and appear to have a better prognosis than previously extrapolated from canine studies.

Video-Assisted Thoracoscopic Surgery for Pneumothorax Induced by Migration of a K-Wire to the Chest

A 2 yr old female English setter dog was admitted for acute dyspnea. The dog underwent treatment of a T9T10 thoracic vertebral fracture subluxation at the authors' institution 15 mo earlier. Upon admission, a chest X-ray revealed a pneumothorax and a metallic foreign body in the left hemithorax. An emergency video-assisted thoracoscopic surgery was successfully performed to remove a 4.6-mm long Kirschner wire that migrated from the thoracic vertebral column to the thoracic cavity. The operating time was 27 min. The dog made an uneventful recovery and was discharged on the third day after surgery. Pneumothorax should be considered in patients that develop acute dyspnea and have a history of wire fixation in the thoracic vertebral column. Video-assisted thoracoscopic surgery is a safe and effective treatment of this condition.

Pneumothorax: A Review

Pneumothorax is a pathological condition in which air accumulates within the thoracic cavity. Pneumothorax affects animals without sex or age predilections; however, it has been suggested that the Siberian husky breed of dog has a predisposition for spontaneous pneumothorax. Pneumothorax occurs as the result of trauma or underlying disease and can present a clinical challenge with regard to diagnostic and therapeutic techniques. Topics reviewed include normal lung physiology; the pathogenesis, diagnosis, treatment, complications, and prognosis of pneumothorax; and current techniques in animals and humans.

Spontaneous Pneumothorax in a Dog Secondary to Dirofilaria Immitis Infection

A 5-year-old female spayed Labrador Retriever dog was referred to the Louisiana State University Veterinary Teaching Hospital for treatment of pneumothorax. Thoracic radiographs and computed tomography showed spontaneous pneumothorax, thoracic lymphadenopathy, pulmonary hypertension, and multifocal pulmonary bulla lesions. At surgery, numerous adult nematodes protruded from the parenchyma of the left caudal and accessory lung lobes and pulmonary arteries. On histopathology, multiple adult filarid nematodes were observed within the pulmonary blood vessels. Broad foci of necrosis of the pulmonary parenchyma were present. The tunica intima of the pulmonary arteries was markedly thickened by intimal fibrosis and medial hypertrophy. The final diagnosis was severe Dirofilaria immitis infection that resulted in pulmonary vascular lesions and focally extensive infarcts of the pulmonary parenchyma with bulla formation and rupture causing spontaneous pneumothorax. The dog received antibiotic and steroid therapy, as well as adulticide treatment, and recovered.

Spontaneous Feline Pneumothorax Caused by Ruptured Pulmonary Bullae Associated With Possible Bronchopulmonary Dysplasia

Spontaneous pneumothorax is rarely reported in the cat. This case report describes the use of computed tomography (CT) to diagnose pulmonary bullae in an adult cat with recurrent spontaneous pneumothorax. A large bulla in the right middle lung lobe and several blebs in other lobes were identified by CT. Partial lobectomy of the right middle and right and left cranial lung lobes was successfully performed to remove the affected portions of lung. Histopathological examination suggested bronchopulmonary dysplasia (BPD) as the underlying cause for development of the pulmonary bulla. This is the first case report in the veterinary literature describing the use of CT to identify pulmonary bullae in the cat with BPD as a possible underlying cause.

Pneumothorax secondary to pulmonary thromboembolism in a dog

OBJECTIVE

To describe a case of spontaneous pneumothorax secondary to pulmonary thromboembolism possibly associated with pituitary dependent hyperadrenocorticism.

CASE SUMMARY

A 7-year-old spayed female Collie weighing 26 kg was referred for evaluation of spontaneous pneumothorax. An exploratory thoracotomy was performed and revealed 2 lung lobes to be diffusely hemorrhagic and they were resected. Histologic examination of multiple sections documented diffuse thromboembolism. A 2-3 cm thrombus was visualized distal to the bifurcation of the pulmonary artery during an echocardiographic examination postoperatively. The dog was discharged to the owner after recovery from surgery. The thrombus had resolved at the 4-week recheck examination. Diagnosis of pituitary dependent hyperadrenocorticism was confirmed based on follow-up endocrine testing.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first report of pulmonary thromboembolism causing spontaneous pneumothorax in the dog.