Non-cardiac thoracic ultrasound in 75 feline and canine patients

Prognostic factors and outcome in cats with thymic epithelial tumours: 64 cases (1999-2021)

OBJECTIVES

To describe the clinical presentation, treatment and outcomes of cats diagnosed with thymic epithelial tumours and to determine prognostic factors for survival and recurrence.

MATERIALS AND METHODS

Clinical records of cats diagnosed with a thymic epithelial tumour between 1999 and 2021 at three referral institutions were retrospectively reviewed.

RESULTS

Sixty-four cats were included. Paraneoplastic syndromes were present in nine cats and metastatic disease was seen in two cats, one at diagnosis and one at the time of recurrence. Median tumour diameter was 6 cm (range, 2 to 15) and a cystic appearance was described on imaging in 25 cats. Surgical excision was attempted in 54 cats with a perioperative mortality rate of 11%. Median survival time for cats surviving to hospital discharge was 897 days (range, 21 to 3322). The 1-, 2- and 5-year survival rates for surgically treated thymic epithelial tumour were 86%, 70% and 66%, respectively. Survival was longer for cats with Masaoka-Koga stage I and II tumours compared to stages III and IV (1366 days versus 454 days; P=0.002). Masaoka-Koga stage was the only significant prognostic factor detected on multi-variable analysis, with stage III and IV tumours associated with increased risk of death (hazard ratio: 5.67, 95% confidence interval: 1.29 to 24.91, P=.021). Tumour recurrence occurred in 11 cats at a median of 564 days (range, 93 to 1095); no significant prognostic factors for recurrence were identified.

CLINICAL SIGNIFICANCE

Cats with thymic epithelial tumours had a good long-term prognosis following surgery. Tumour recurrence can occur late in the disease course and ongoing monitoring should therefore be considered. Masaoka-Koga stage may influence survival time and could be used to predict outcome.

Computed Tomographic Features of Thymus in Dogs: Correlation with Age, Gender, Breed and Body Fat Content

BACKGROUND

The thymus is the first lymphoid organ formed to regulate a newborn's immunity. It reaches its maximum size during puberty, after which it undergoes an atrophic procedure called involution, but its ability to grow again in response to some stresses, such as infections, neoplasia, surgeries, chemotherapy, and radiotherapy is maintained. There is no comprehensive study on computed tomographic features of thymus in dogs. So, the goal of the present study is to gain better insight into the thymus using computed tomography as a non-invasive method.

METHODS

One hundred and fifty dogs classified in five age groups and five breed groups were recruited to this study and the thymus was evaluated using a 2-slice computed tomography machine. The inclusion criteria for the present study were having a normal complete blood count, plain and post-contrast CT scan examination of the thoracic region and no history of neoplasia, chemotherapy or radiotherapy. The visibility, density, enhancement, grade, size, volume, shape, borders and lateralization of the thymus were evaluated and statistical analysis was performed. The effect of obesity on thymic grade and volume was also investigated.

RESULTS

The visibility, density, dorsal length, volume and grade decreased with increasing age. The thymic shape and lateralization were mostly wedge shaped and left sided, respectively. The borders became concave with aging and increasing body fat content caused an increase in the fatty degeneration of the thymus.

CONCLUSIONS

Declining thymic density, grade, size and volume with aging are related to thymic involution and fatty degeneration was accelerated by increasing body fat content. Females and males were different only in thymic shape and small and large breeds were different only in thymic volume. The thymus was visible in some geriatric dogs with no underlying disease. We expect that the present work can be used by radiologists in reading thoracic computed tomography but investigation of thymic characteristics in dogs with neoplasia and history of chemotherapy, radiotherapy and thoracic surgeries can complete this study.

Imaging and endoscopic diagnosis of lung diseases in small animals. A review

Diagnostic imaging plays a fundamental role in the diagnosis of pulmonary diseases. Radiography, ultrasound, computed tomography, and endoscopy are important tools for achieving a diagnosis. The choice of diagnostic procedure varies according to the patient, the suspected diagnosis and the risk/benefit ratio. Culture, cytology and histology are nearly always necessary to obtain a definitive diagnosis. Several biopsy sampling techniques are described. Surgical biopsies are the gold standard for the diagnosis of bronchiolitis or interstitial lung diseases but often not performed due to the high risk. In humans, the introduction of transbronchial cryobiopsies has led to excellent results in the study of interstitial lung diseases.

Surgical management of intrathoracic wooden skewers migrating from the stomach and duodenum in dogs: 11 cases (2014-2020)

Objectives

To describe the clinical presentation, management and outcome of cases presenting with intrathoracic wooden skewers originating from the abdominal gastrointestinal tract.

Materials and Methods

Clinical records of dogs presented and treated for an intrathoracic wooden skewer were reviewed from June to August 2020. Data included signalment, clinical presentation, duration of clinical signs, haematological and biochemical abnormalities, diagnostic imaging findings, surgical procedure, postoperative complications and outcome.

Results

Eleven dogs were included in the study. In all cases, the foreign body was identified as a wooden skewer. The most common clinical signs were anorexia/hyporexia (n=7), vomiting/regurgitation (n=7), lethargy (n=6), pyrexia (n=4) and gait abnormalities/lameness (n=3). CT correctly identified a wooden skewer in all cases when performed (n=7). A coeliotomy combined with transdiaphragmatic thoracotomy was performed in six of 11 cases (55%), a coeliotomy combined with median sternotomy in four of 11 cases (36%) and a median sternotomy alone was performed in one case. Foreign bodies penetrated from the stomach (n=10) or the duodenum (n=1). Intrathoracic trauma was most commonly identified to the lungs (n=3) and pericardium (n=3). Complications occurred in three of 11 cases (27%), two minor and one resulting in death. Ten of the 11 cases (91%) survived to discharge. Long‐term outcome was available for seven of 11 cases (66%), all of them excellent.

Clinical Significance

Despite the challenges of managing wooden skewers penetrating the thoracic cavity from the abdominal gastrointestinal tract, the majority of the patients are stable to undergo diagnostic procedures, surgical exploration and management with low morbidity and excellent short‐ and long‐term prognosis.

Canine Epithelial Thymic Tumors: Outcome in 28 Dogs Treated by Surgery

Simple Summary

Thymoma is a tumor of the cranial mediastinum rarely reported in dogs and should be differentiated from mediastinal lymphoma. CT and fine-needle aspirates or core biopsies are helpful in differential diagnosis, but flow cytometry may improve the pre-operative diagnostic ability. In thymomas, paraneoplastic syndromes such as myasthenia gravis and hypercalcemia may develop concurrently with the tumor. Their role as prognostic factors is not well determined. Surgical excision is the treatment of choice, but adjuvant radiotherapy and/or chemotherapy may prolong survival in cases of incomplete excision or if a thymic carcinoma is diagnosed. Local recurrence and metastasis are infrequently reported; therefore, a long survival is expected if the tumor is completely excised or if adjuvant therapy is undertaken. This article reports the authors’ experience with 28 dogs affected by 18 thymomas and 10 thymic carcinomas surgically treated from January 2000 to August 2021. The median overall survival time of the entire population was 1137 days; the median disease-free time was 903 days. Dogs with thymic carcinomas had significantly shorter disease-free intervals and shorter, although not statistically significant, survival times. Dogs with Masaoka Stage III tumors had worse outcomes.

Abstract

Thymoma is a tumor rarely reported in dogs and should be differentiated from mediastinal lymphoma. Clinical signs may have a late onset, and thymoma is often diagnosed when symptoms related to the space-occupying effect or paraneoplastic syndromes occur. CT and fine-needle aspirates or core biopsies are helpful in differential diagnosis, but flow cytometry may improve the pre-operative diagnostic ability. Concurrent paraneoplastic syndromes such as myasthenia gravis and hypercalcemia have been reported; however, their role as prognostic factors is not well determined. Surgical excision is the treatment of choice; adjuvant radiotherapy and/or chemotherapy may prolong survival in cases of incomplete excision or when a thymic carcinoma is diagnosed. Local recurrence and metastasis are infrequently reported; therefore, a long survival time is expected if the tumor is completely excised or if adjuvant therapy is undertaken. This article reports the authors’ experience with 28 dogs affected by 18 thymomas and 10 thymic carcinomas. The median overall survival in this series was 1173 days, and the median disease-free interval was 903 days. Dogs with thymic carcinoma had significantly shorter disease-free intervals and shorter, although not statistically significant, survival times. Dogs with Masaoka Stage III tumors had worse outcomes.

Usefulness of Chest Ultrasonography in Predicting Diagnosis in Non-emergency Small Animal Patients With Lung Parenchymal and Pleural Disease

Chest ultrasonography has become an indispensable tool for pulmonary specialists in human medicine, but its current use in dogs and cats is primarily for emergency. The diagnostic performances of various ultrasonographic features other than comet-tail artifacts are of limited information in veterinary literatures. Therefore, the aims of this retrospective study were to investigate ultrasonographic findings in feline and canine respiratory patients with lung parenchymal and pleural space diseases, and to assess how ultrasonographic features correspond to specific diagnoses. Sixty-five non-emergency cases with radiographically identified lung parenchymal and pleural space abnormalities were included. Medical records and ultrasound video clips were reviewed, and additional follow-up information was subsequently collected. Common findings such as comet-tail artifacts (87.7% of cases), consolidation (84.6%), and thickened/irregular pleura (69.2%) were not distinguishable for a specific diagnosis. The presence of nodular/mass-like lesion (OR = 212, p < 0.001) and consolidated lesion with heteroechogenicity (OR = 240, p < 0.001) was significantly associated with and strongly predictive of neoplasia after age, body weight and other sonographic findings were adjusted. The finding of nodular/mass-like lesion has the best diagnostic performance (AUC = 0.93) for neoplasia, with sensitivity of 91.7% and specificity of 93.6%. For predicting a diagnosis of pneumonia, although several sonographic features were found to be statistically associated with pneumonia, only a negative finding of nodular/mass-like lesion showed good diagnostic performance (AUC = 0.83, sensitivity 95.7%, specificity 71%). These findings demonstrate the value of chest ultrasonography in predicting diagnosis in non-emergency cases. The application of thoracic ultrasound in small animal respiratory patients as part of non-invasive assessment warrants further investigation.

Coughing in Small Animal Patients

Cough is one of the most common complaints in human medicine. In veterinary medicine cough is equally frequent and plays a significant role in an owner's perception of their pet's quality of life. In human and veterinary medicine, therapy for chronic cough is often ineffective. The complexity of the cough pathway and species differences have made it difficult to develop an effective antitussive agent for veterinary patients. The few effective antitussive agents currently available are associated with significant adverse effects. Fortunately, several promising drugs currently being studied in human clinical trials may offer options for use of novel antitussive therapies in small animal patients. This article reviews current understanding about cough pathophysiology, diagnostic strategies used to uncover underlying etiology of cough, and examines available options for controlling cough, including novel antitussive therapies used in human medicine.

Long-term survival in six cats with mediastinal cysts

CASE SERIES SUMMARY

Mediastinal cysts were diagnosed as incidental findings in six cats evaluated for non-thoracic disease, including staging for historical bladder leiomyosarcoma, flea dermatitis and hairballs, and hyperthyroidism. Radiographically, the cysts appeared as soft tissue opacities cranial to the heart. Ultrasound revealed the masses to be thin-walled, single lumen, anechoic, fluid-filled structures. One cat also had thoracic and abdominal CT performed for cancer staging; the CT revealed a well-defined, fluid-attenuating mass without peripheral contrast enhancement in the cranial mediastinum. Fine-needle aspiration confirmed acellular fluid consistent with a cyst in five cases; in one case the cyst ruptured during aspiration and no fluid was obtained. Post-aspiration, all masses were no longer visible with ultrasound or radiographs. No treatment was recommended for the cysts. Long-term follow-up (2-9 years post-diagnosis) was available in all six cats. The cysts recurred in five cats but were never associated with clinical signs.

RELEVANCE AND NOVEL INFORMATION

Mediastinal cysts are an important benign differential for cranial mediastinal masses in cats. Treatment for the cysts does not appear to be indicated. This series also includes the first CT description of this clinical entity.

Radiographic Differentiation of Cranial Mediastinal Lymphomas from Thymic Epithelial Tumors in Dogs and Cats

In both dogs and cats, the most common cranial mediastinal masses (CMMs) are lymphoma and thymic epithelial tumors (TETs). Pretreatment differentiation of these tumors using fine needle aspiration or biopsy is essential because lymphomas are treated medically, whereas TETs are treated surgically. The purpose of this retrospective study was to determine whether thoracic radiographic findings can be used to aid clinicians in preliminarily differentiating the two tumor types before cytology or histopathology results become available. Medical records, available cytologic or histologic samples, and thoracic radiographs were evaluated for 62 dogs and 28 cats. Seventeen radiographic criteria were assessed by two examiners, and regression modeling was performed to test for significant predictors of tumor type. In dogs, CMMs with at least two well-defined radiographic margins on a lateral view and CMMs causing a rightward shift of the cardiac silhouette on a ventrodorsal or dorsoventral view were significantly more likely to be TETs than lymphomas (P < .001 and P < .01, respectively). No significant predictive variables were identified in cats. Radiographic findings do not eliminate the need for invasive sampling, but in dogs, they may guide the clinician in providing preliminary information to owners regarding the staging and therapeutic measures that may eventually be recommended.

HEART MEASUREMENTS OF NON-HUMAN PRIMATES BY RADIOGRAPHIC TECHNIQUES

Abstract Thoracic Radiology is a diagnostic technique used to study several aberrations, including cardiac abnormalities, which can be determined by VHS (vertebral heart size). The heart length and width are measured, and the CTR (cardiothoracic ratio) is calculated, by comparing the heart width to the thoracic diameter. This study aimed at measuring the cardiac silhouette of non-human primates (PNH) belonging to the genus Sapajus sp., and the Alouatta guariba species through VHS and CTR. From among the eight animals assessed, it was evident that in both the Sapajus sp. and the Alouatta guariba, the highest HSV change index was observed, depending upon the age of the animal. However, although the individuals of the Alouatta guariba species are bigger in size and heavier, the animals of the genus Sapajus sp. have a larger heart size in proportion to their body.

The feasibility of contrast enhanced ultrasonography (CEUS) in the diagnosis of non-cardiac thoracic disorders of dogs and cats

BACKGROUND

This study describes the feasibility of Contrast Enhanced Ultrasonography (CEUS) in the diagnostic work-up of non-cardiac thoracic disorders of small animals. The second aim is to assess the usefulness of CEUS as a direct guide for sample procedures.

RESULTS

Forty animals, 28 dogs and 12 cats, were included in the study. Thoracic disorders included 23 pulmonary lesions [primary carcinoma (14), lymphoma (1), sarcoma (1), histiocytic sarcoma (1), abscess (1) and pneumonia (5)] and 17 mediastinal lesions [lymphoma (8), thymoma (3), mesothelioma (1), melanoma (1), carcinomatous lymphadenopathy (1), mixsosarcoma (1), lipoma (1), and abscess (1)]. The majority of neoplastic pulmonary lesions showed an inhomogeneous distribution of contrast medium, whereas inflammatory lesions had a homogenous distribution with typical pulmonary vessels ramification. The majority of mediastinal malignant lesions showed an inhomogeneous distribution pattern. The lung and mediastinal abscesses had peripheral enhancement of the wall with an avascular center. All cytological and biopsy samples obtained after CEUS were diagnostic. Quantitative analysis, performed in 19/23 pulmonary lesions, showed a statistically significant difference (P < 0.0001) between the arrival time of the malignant (7.27 s - range 4.46-13.52 s) and benign (4.52 s - range 2.87-6.06 s) pulmonary lesions.

CONCLUSIONS

CEUS may be a useful tool for the evaluation of non-cardiac thoracic lesions. The contrast medium allows for the precise definition of lesion edges, the presence of necrotic areas, and the distribution of pulmonary vessels. Based on our preliminary results, the use of ultrasonographic contrast medium can be recommended for improving the diagnostic usefulness of cytology and biopsy sampling, because CEUS may help to define necrotic areas from viable tissue.

Cardiothoracic ratio and vertebral heart size (VHS) to standardize the heart size of the tufted capuchin (Cebus apella Linnaeus, 1758) in computerized radiographic images

Abstract: The VHS and CTR were assessed using computerized thoracic radiographs of ten clinically healthy tufted capuchin monkeys (five males and five females) from the Wild Animal Screening Center in São Luís (Centro de Triagem de Animais Silvestres de São Luís-MA-CETAS). Radiographs were taken in laterolateral and dorsoventral projections to calculate the cardiothoracic ratio (VHS) and vertebral heart size (CTR). The VHS showed mean values of 9.34±0.32v (males) and 9.16±0.34v (females) and there was no statistical difference between males and females (p>0.05). The CTR showed mean values of 0.55±0.04 (males) and 0.52±0.03 (females) and there was no statistical difference between the sexes (p>0.05). There was positive correlation between VHS and CTR (r=0.78). The thoracic and heart diameters showed mean values of 5.70±0.48cm and 2.16±0.40cm in the males, respectively. In the females they measured 5.32±0.39cm and 2.94±0.32cm. There was no statistical difference between the sexes. Our results show that the high correlation found between VHS and CTR permitted the verification with similar clinical precision between the two methods to estimate alterations in the heart silhouette by radiographic examination of tufted capuchin, making it an easy technique to apply that can be considered in the investigation of heart problems for this wild species.

Interval between injection of contrast material and positive contrast cheliography affects accurate diagnosis of diaphragmatic hernia

The aim of this study was to evaluate the clinical, surgical and diagnostic imaging findings in 11 cats and 3 dogs with suspected acute and chronic traumatic diaphragmatic hernia, and to compare the results of positive contrast cheliography (peritoneography) taken immediately and 5 min after the injection of contrast material. Thoracic and abdominal radiography, ultrasonography, and positive contrast cheliography of all animals were performed. Eight cases were considered as acute and six cases were considered chronic. The contrast images taken immediately after the injection of contrast material revealed the contrast material in the thoracic cavity in 8/8 acute trauma patients, but in none of the chronic cases. In 5/6 of these cases contrast material was seen in the thoracal cavity only in additional images taken after 5 min. One patient was diagnosed with FIP and excluded from the study. Twelve cases had complete resolution and one animal died during the early postoperative period. Our results suggest that positive contrast cheliography performed immediately after the injection of contrast material may not reveal chronic cases of diaphragmatic hernia and a second imaging (or imaging after 5 min) is indicated in order not to overlook chronic cases.

Feline respiratory disease: what is the role of Mycoplasma species?

PRACTICAL RELEVANCE

Non-hemotropic Mycoplasma species are frequently implicated in cases of respiratory disease, and also conjunctivitis, in cats.

CLINICAL CHALLENGES

Mycoplasma species are considered commensal bacteria of the conjunctiva and the upper respiratory tract of cats, and hence their role as a primary pathogen is difficult to determine. These organisms certainly appear to play a significant role as a secondary pathogen in the upper airways, and there is increasing evidence that in some animals they may represent a primary infection. However, mycoplasmas have not been found in the lower airways of clinically healthy cats - suggesting that, when present, they likely represent a pathologic process. Diagnostic challenges exist as well; Mycoplasma species are not typically identified via cytology due to their small size, and culture of these organisms requires special media and handling. Although PCR has improved identification and allowed for speciation, conflicting culture and PCR results can create a dilemma regarding the clinical relevance of infection.

EVIDENCE BASE

This article draws on original research and case reports to provide information about the role of Mycoplasma species in the feline upper and lower respiratory tract, diagnostic methods and associated challenges, and treatment options.

AUDIENCE

The goal is to provide small animal practitioners with a current and organized review of the often-conflicting literature regarding the role of Mycoplasma species in feline respiratory infections.

Computed tomography and cross-sectional anatomy of the thorax of the live bottlenose dolphin (Tursiops truncatus)

Pulmonary disease is one of the leading causes of cetacean morbidity and mortality in the wild and in managed collections. The purpose of this study was to present the computed tomographic (CT) appearance of the thorax of the live bottlenose dolphin (Tursiops truncatus) out-of-water and to describe the technical and logistical parameters involved in CT image acquisition in this species. Six thoracic CT evaluations of four conscious adult bottlenose dolphins were performed between April 2007 and May 2012. Animals were trained to slide out of the water onto foam pads and were transported in covered trucks to a human CT facility. Under light sedation, animals were secured in sternal recumbency for acquisition of CT data. Non-contrast helical images were obtained during an end-inspiratory breath hold. Diagnostic, high quality images were obtained in all cases. Respiratory motion was largely insignificant due to the species' apneustic respiratory pattern. CT findings characteristic of this species include the presence of a bronchus trachealis, absence of lung lobation, cranial cervical extension of the lung, lack of conspicuity of intrathoracic lymph nodes, and presence of retia mirabilia. Dorsoventral narrowing of the heart relative to the thorax was seen in all animals and is suspected to be an artifact of gravity loading. Diagnostic thoracic computed tomography of live cetaceans is feasible and likely to prove clinically valuable. A detailed series of cross-sectional reference images is provided.

Pulmonary ultrasound findings in a bottlenose dolphin Tursiops truncatus population

Lung disease is common among wild and managed populations of bottlenose dolphins Tursiops truncatus. The purpose of the study was to apply standardized techniques to the ultrasound evaluation of dolphin lungs, and to identify normal and abnormal sonographic findings associated with pleuropulmonary diseases. During a 5 yr period (2005 to 2010), 498 non-cardiac thoracic ultrasound exams were performed on bottlenose dolphins at the Navy Marine Mammal Program in San Diego, California, USA. Exams were conducted as part of routine physical exams, diagnostic workups, and disease monitoring. In the majority of routine exams, no abnormal pleural or pulmonary findings were detected with ultrasound. Abnormal findings were typically detected during non-routine exams to identify and track disease progression or resolution; therefore, abnormal results are overrepresented in the study. In order of decreasing prevalence, abnormal sonographic findings included evidence of alveolar-interstitial syndrome, pleural effusion, pulmonary masses, and pulmonary consolidation. Of these findings, alveolar-interstitial syndrome was generally nonspecific as it represented several possible disease states. Pairing ultrasound findings with clinical signs was critical to determine relevance. Pleural effusion, pulmonary masses, and pulmonary consolidation were relatively straightforward to diagnose and interpret. Further diagnostics were performed to obtain definitive diagnoses when appropriate, specifically ultrasound-guided thoracocentesis, fine needle aspirates, and lung biopsies, as well as radiographs and computed tomography (CT) exams. Occasionally, post mortem gross necropsy and histopathology data were available to provide confirmation of diagnoses. Thoracic ultrasound was determined to be a valuable diagnostic tool for detecting pleural and pulmonary diseases in dolphins.

Getting to the point: indications for fine-needle aspiration of internal organs and bone

The technique of fine-needle biopsy (fine-needle aspiration or fine-needle fenestration) for cytologic evaluation can be extended to many sites beyond the traditional lymph node and skin. Intra-abdominal, intrathoracic, and bone lesions can be easily and rapidly evaluated cytologically. Percutaneous fine-needle aspiration and fine-needle fenestration are useful, accurate, and inexpensive techniques with a rapid turnaround time, and outpatient applicability. For most pets, these minimally invasive techniques do not require anesthesia or analgesia. Although risks are inherent with any invasive procedure, complications are uncommon even with visceral and intrathoracic fine-needle biopsy. Attention to appropriate technique and close patient monitoring minimize the morbidity and improve the diagnostic utility. The low cost, low risk, minimal invasiveness, and high diagnostic yield make fine-needle biopsy particularly attractive to clients. In combination with ultrasound guidance and newer staining techniques, these diagnostic procedures are invaluable to the veterinary clinician.

Lower respiratory tract infections in cats: reaching beyond empirical therapy

PRACTICAL RELEVANCE

Lower respiratory tract infections (LRTIs) in cats can be due to bacteria, parasites, fungi and viruses. This review details the practical investigation of these infections and highlights specific therapy where possible. The aim is to avoid the all-too-frequent temptation in practice to treat cats with lower respiratory tract signs empirically for feline bronchial disease (FBD)/asthma. This is potentially hazardous as immunosuppressive therapy for FBD/asthma could exacerbate disease due to a LRTI. Empirical treatment of suspected LRTI is also difficult to recommend given the wide range of potential pathogens.

CLINICAL CHALLENGES

Making a clinical ante-mortem diagnosis of LRTI in a cat can be challenging. Consistent historical, clinical, haematological and radiographic abnormalities are often lacking and findings may be non-specific. Astute clinical acumen, thorough investigation and high quality laboratory analysis are usually required for a diagnosis. Bronchoalveolar lavage, if feasible, and tests for lungworm should be routine in cats with lower respiratory tract signs. Lung fine needle aspiration may be useful in cases of diffuse or nodular pulmonary disease. Histopathology is rarely employed in ante-mortem investigations.

EVIDENCE BASE

The authors have reviewed a substantial body of literature to provide information on many of the reported bacterial, parasitic, fungal and viral pathogens, including some that occur in Asia. Attention has been given to specific therapy for each pathogen, with evidence-based comments when there is a deviation from routine recommendations.

Congenital peritoneopericardial diaphragmatic hernia in an alpaca

An adult alpaca was presented because of abdominal pain and was diagnosed with an intestinal obstruction. The putative diagnosis at surgery was an intestinal obstruction caused by peritonitis and intra-abdominal adhesions. The cause of the inflammation was not determined at that time. The alpaca died soon after surgery from post-surgical complications and a peritoneopericardial diaphragmatic hernia that was not diagnosed until necropsy.

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.

Thoracoscopic-assisted lung lobectomy in the dog: report of two cases

The benefits and application of thoracoscopy with selective ventilation, as an adjunct to thoracotomy, in facilitating pleural exploration and lung lobectomy in two dogs are presented. Similar thoracoscopic-assisted procedures are commonly used in human patients because there is better exposure and they are technically less demanding than thoracoscopy alone, while causing less postoperative morbidity than conventional thoracotomy. There are no previous reports of thoracoscopic-assisted surgery in the veterinary literature. In the cases described, thoracoscopic-assisted mini-thoracotomy was an effective, minimally-invasive approach for ipsilateral hemithorax exploration and lung lobectomy.

Pleural Effusion in the Cat: A Practical Approach to Determining Aetiology

Practical relevance Diverse disease processes result in sufficient fluid accumulation within the pleural space to cause respiratory compromise. Determining the underlying aetiology is key to appropriate management. This review outlines a practical approach to cases of pleural effusion, focusing on early recognition and confirmation of pleural space disease, stabilisation of the patient and logical diagnostic investigation. It emphasises the importance of a holistic approach, incorporating fluid analysis with other clinical data to determine the underlying aetiology.

Clinical challenges Cats with pleural effusion often have severe respiratory compromise at presentation. Careful handling and prompt and adequate stabilisation, incorporating supplemental oxygen and therapeutic thoracocentesis, is essential to avoid respiratory failure. The typical, stepwise approach to the case must be adapted and the clinician may have to proceed, at least initially, without the luxury of information gained from a full history and physical examination. The challenge is to juggle stabilisation, localisation and confirmation of pleural effusion, owner communication and minimally invasive examination while remaining vigilant for clues that allow ranking of the differentials to formulate a diagnostic plan.

Evidence base Appropriately designed studies to determine the utility of diagnostic techniques in cases with confirmed aetiology are limited. The evidence supporting this review is grade II, III and IV, comprising a small number of prospective studies, several case series, reviews, extrapolation from other species, pathophysiological justification and combined clinical experience of those working in the field.

Positive contrast peritoneography in the diagnosis of a pleuroperitoneal diaphragmatic hernia in a cat

A young adult entire male domestic shorthair cat was presented with a known history of a road traffic accident. Survey radiographs suggested a congenital diaphragmatic hernia unrelated to the recent trauma. Positive contrast peritoneography was undertaken and findings were consistent with a pleuroperitoneal diaphragmatic hernia (or true hernia). This was repaired surgically and was thought to be an incidental finding. This case report demonstrates the use of positive contrast peritoneography as a simple and effective tool in the diagnosis of pleuroperitoneal diaphragmatic hernias.

Intra-thoracic pyogranulomatous disease in four working dogs

CASE HISTORY

Four working dogs were presented to veterinary clinics in New Zealand for weight loss or swelling of the thoracic wall. All dogs were large-breed males between the ages of 4 and 7 years, and actively involved in farm work. The two dogs with swelling of the thoracic wall had recent histories of work-related trauma.

CLINICAL FINDINGS AND DIAGNOSIS

All four dogs were diagnosed with intra-thoracic pyogranulomatous disease via diagnostic imaging and surgical exploration. Two dogs had confirmed infection with Actinomyces viscosus, while a third had suspected Actinomyces or Nocardia spp. infection. The fourth dog had a streptococcal infection, and a grass-seed foreign body was removed at surgery. Two dogs successfully returned to work, however euthanasia was requested by the owners of the other two, either during surgery, due to intra-thoracic haemorrhage, or shortly after, with post-operative meningitis.

CLINICAL RELEVANCE

Due to the high value of working dogs in New Zealand, and the higher-than-average risk profile for intra-thoracic pyogranulomatous disease, veterinarians should be aware of this syndrome, and should seek to appropriately diagnose and aggressively treat it surgically.

Ultrasound of the thorax (noncardiac)

Ultrasound examination of the thorax is an extremely valuable adjunct imaging modality in chest wall, pleural, mediastinal, and pulmonary disease. While air-filled lungs will obscure some deeper pulmonary lesions, ultrasound can evaluate peripheral pulmonary disease, mediastinal masses, and the extent and character of pleural effusions. Ultrasound guidance of needle biopsies and thoracocentesis provides safe and accurate lesion sampling.

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.

Approach to the respiratory patient

Several challenges arise when evaluating a dog or cat with respiratory disease. The history can span a long period, and some owners may have a difficult time in recognizing or describing respiratory abnormalities. A good history and thorough physical examination are essential when evaluating the respiratory patient. There are some noninvasive diagnostics that can aid in the diagnosis of respiratory disease; however, other more invasive tests often require anesthesia, which can be a potential hazard with a respiratory patient. This article focuses on reviewing the function of the respiratory system and how best to identify and diagnose cats and dogs with respiratory disease by implementing a thorough history and physical examination as well as appropriate diagnostic testing.

USE OF RADIOGRAPHY IN COMBINATION WITH COMPUTED TOMOGRAPHY FOR THE ASSESSMENT OF NONCARDIAC THORACIC DISEASE IN THE DOG AND CAT

Computed tomography (CT) of the thorax was performed in 28 dogs and five cats and findings were compared with previous thoracic radiographs. The sample population included all animals that had thoracic radiographs and a CT study within 5 days of each other, where the complete imaging studies were available for review. Thoracic radiographs were considered indeterminate in 31 patients and CT examinations were done to acquire additional information. The presence of additional information from CT relating to presence of pathology, location of pathology, extent of pathology, and involvement of mediastinal structures was recorded. Whether there was a change in diagnosis based on the CT findings was also recorded. In only 4/33 animals (all dogs) did CT fail to provide any new information for the parameters evaluated when compared with survey thoracic radiographs. Additional information about the pathology that was present was gained by CT in 5/5 cats and 21/ 28 dogs. New information on compartmental location of pathology was seen in 4/5 cats and 19/28 dogs. New information on pathology extent was noted in 5/5 cats and 20/28 dogs. Additional information regarding involvement of mediastinal structures was obtained in 2/5 cats and 10/28 dogs. A change in diagnosis was made in 3/5 cats and 13/28 dogs. In conclusion, CT is a valuable tool for evaluating intrathoracic disease. CT provides additional cross-sectional anatomic information that can aid in anatomic localization and evaluation of the extent of the pathology in question.

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.

Percutaneous fine-needle biopsy of deep thoracic and abdominal masses in dogs and cats

Percutaneous fine-needle biopsy was used to investigate thoracic and abdominal masses in the dog and cat. One hundred and thirty-two cases were included in the study; 20 cases were excluded from the comparative study due to poor cellularity or blood contamination (retrieval rate 86.8 per cent). One hundred samples (56 dogs and 44 cats) were classified by cytology as neoplastic. All the cytological diagnoses of neoplasia were confirmed by histological samples obtained either by non-surgical methods, at surgery or during postmortem examination. No false positive diagnoses of neoplasia were made. Thirty-two samples were cytologically classified as 'negative for neoplasia'. Subsequent histological examination revealed 18 true negative and 14 false negative results. The procedure had an overall 89.4 per cent (118 cases out of 132) agreement between the diagnosis of inflammatory disease versus neoplasia, with a sensitivity of 87.8 per cent, a specificity of 100 per cent, a predictive value of a positive test of 100 per cent and a predictive value of a negative test of 56.3 per cent.

Long-term outcome of cats treated conservatively or surgically for peritoneopericardial diaphragmatic hernia: 66 cases (1987–2002)

OBJECTIVE

To determine long-term outcome of cats treated conservatively or surgically for peritoneopericardial diaphragmatic hernia (PPDH).

DESIGN

Retrospective study.

ANIMALS

67 cats with PPDH.

PROCEDURE

Medical records of cats with a diagnosis of PPDH made from 1987 through 2002 were reviewed. Information regarding long-term outcome was obtained from owners.

RESULTS

Prevalences of PPDH in domestic longhair and Himalayan cats were significantly greater and prevalence of PPDH in domestic shorthair cats was significantly lower than prevalence of PPDH in the hospital cat population over the 15-year study period. Historical problems most commonly related to the respiratory and gastrointestinal tracts. Peritoneopericardial diaphragmatic hernia was the primary diagnosis in 40 cats and an incidental finding in 27 cats. One cat died prior to arrival at the Veterinary Medical Teaching Hospital. Thirty-seven of 66 cats were treated surgically, and 29 were treated conservatively. The postoperative mortality rate was 14%. Postoperative complications developed in 29 of 37 cats, the most common of which was hyperthermia. Two of 22 conservatively treated cats had progression of clinical signs necessitating surgical intervention or resulting in death. Owner satisfaction with treatment choice and long-term outcome was rated as very satisfied by 88% of owners of surgically treated cats and 68% of owners of conservatively treated cats.

CONCLUSIONS AND CLINICAL RELEVANCE

Cats with overt clinical signs attributable to PPDH are good candidates for surgical herniorrhaphy. Postoperative complications may develop but are generally minor and self-limiting. Long-term outcome of cats treated conservatively or surgically was rated as very good by most owners.

Use of ultrasound to diagnose diaphragmatic rupture in dogs and cats

Twenty-one cats and six dogs that presented to a first-opinion clinic with signs of dyspnea and muffled cardiac auscultation received ultrasonography to look for signs of diaphragmatic rupture. The presence or absence of diaphragmatic rupture was subsequently determined on the basis of unequivocal radiographic signs, surgical findings, or necropsy. Consistent findings in animals with diaphragmatic rupture were irregular or asymmetric cranial aspect of the liver and abdominal viscera in the thorax. Accuracy of ultrasonography was 25/27 (93%). One false-negative result occurred in a cat with a chronic diaphragmatic rupture in which adhesions between the liver and lung simulated the appearance of an intact diaphragm. One false-positive result occurred in a dog with an abscess involving the left lung and pleural cavity, which was misinterpreted as the stomach. The results of this study support use of ultrasonography in animals with suspected diaphragmatic rupture.

Cranial mediastinal cysts in nine cats

Nine cats, from 11 to 17 years of age (mean 13.6 years of age), were diagnosed with a cranial mediastinal cyst. Thoracic radiographs in all cats were characterized by an increased soft tissue opacity in the cranial mediastinum confirmed to be a cyst by ultrasonography or necropsy. Ultrasonographically cysts appeared as an anechoic mass. A low-cellularity clear fluid was obtained on aspiration. The majority of the cats (n = 8) presented for unrelated conditions with no signs of respiratory distress. No treatment for the cyst was pursued except for drainage during ultrasonographic-guided aspiration in several cats. On follow-up of eight cats, none were symptomatic for the cyst from 3-45 months after diagnosis. Mediastinal cyst should be considered when a cranial mediastinal mass is evident radiographically in an older cat. The majority of feline cranial mediastinal cysts are benign with no need for treatment.

Correlation between fine-needle aspiration cytopathology and histopathology of the lung in dogs and cats

Medical records from 28 patients having fine-needle aspiration (FNA) cytopathology and histopathology of pulmonary lesions were reviewed. Clinical signs, thoracic radiographs, cytopathology, histopathology, and complications associated with FNA were evaluated. Correlation between cytopathological and histopathological diagnoses was determined. Cytopathological specimens were classified as neoplastic, inflammatory, or nondiagnostic. Histopathological diagnoses were categorized as neoplastic or inflammatory. No complications were observed following FNA. Diagnoses obtained by FNA cytopathology accurately reflected the diagnosis obtained on histopathological examination in 82% of cases. Fine-needle aspiration cytopathology of the lung is a useful and safe diagnostic tool in dogs and cats with pulmonary parenchymal lesions.

Syncope associated with paroxysmal atrioventricular block an ventricular standstill in a cat

A four-and-a-half-year-old neutered male shorthair cat was presented with a three-week history of episodic fainting. Twenty-four hour electrocardiographic (Holter) recording revealed frequent prolonged episodes of complete atrioventricular (AV) block with ventricular standstill. The fainting episodes coincided with the longest periods of ventricular inactivity. A permanent transjugular pacemaker was placed to prevent further life-threatening episodes of syncope. Three months after discharge, the patient was re-presented with sudden onset dyspnoea associated with chylothorax and electrocardiography showed a third degree (complete) AV block. The pacemaker was reprogrammed in view of the third degree AV block and the chylous effusion was successfully treated by repeated thoracocentesis and long-term diuresis. However, the patient's general condition deteriorated progressively and the cat was euthanased five and a half months after implantation of the pacemaker.

Comparison of results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage fluid, and histologic evaluation of lung specimens in dogs with respiratory tract disease: 16 cases (1996-2000)

OBJECTIVE

To compare results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and histologic evaluation of biopsy and necropsy specimens in dogs with respiratory tract disease and to determine whether histologic evaluation provides important diagnostic information not attainable by the other methods.

DESIGN

Retrospective study.

ANIMALS

16 dogs.

PROCEDURE

BAL fluid was classified as normal, neutrophilic, eosinophilic, mononuclear, mixed, neoplastic, or nondiagnostic. Radiographic abnormalities were classified as interstitial, bronchial, bronchointerstitial, or alveolar. Histologic lesions were classified as inflammatory, fibrotic, or neoplastic, and the predominant site of histologic lesions was classified as the alveoli, interstitium, or airway.

RESULTS

The predominant radiographic location of lesions correlated with the histologic location in 8 dogs. Of 11 dogs with histologic evidence of inflammatory disease, 8 had inflammatory BAL fluid. Of the 2 dogs with histologic evidence of neoplasia, 1 had BAL fluid suggestive of neoplasia, and the other had BAL fluid consistent with septic purulent inflammation. Two dogs without any histologic abnormalities had mononuclear or nondiagnostic BAL fluid. Two dogs with histologic evidence of fibrosis had mononuclear or mixed inflammatory BAL fluid.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that although thoracic radiography, cytologic evaluation of BAL fluid, and histologic evaluation of lung specimens are complementary, each method has limitations in regard to how well results reflect the underlying disease process in dogs with respiratory tract disease. Lung biopsy should be considered in cases where results of radiography and cytology are nondiagnostic.