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

Detecting pneumothorax during cardiopulmonary resuscitation: The potential of defibrillator measured transthoracic impedance

Introduction

Pneumothorax is a potentially life-treating condition that can represents a complication of cardiopulmonary resuscitation (CPR). An increase in the total amount of air within the thorax may act as an insulator increasing transthoracic impedance (TTI). The aim of this study was to evaluate the effects of pneumothorax on TTI and on resuscitation success in a swine model of cardiac arrest (CA) and CPR.

Methods

Forty pigs undergoing CA and prolonged CPR, and with a chest CT scan performed after resuscitation were included in the study. Pneumothorax was classified as mild, moderate, or severe whether the space occupied by the gas was <15 %, 15-50 %, or >50 % of the hemithorax. TTI was measured and recorded by the defibrillator before each defibrillation, and the last one was used for the analyses. Rate of return of spontaneous circulation (ROSC) and survival up to 96 h were assessed.

Results

Seven (17%) animals had mild-moderate pneumothorax and 10 (25%) severe pneumothorax. Mean TTI was significantly higher in pigs with pneumothorax compared to those without. The rate of ROSC was significantly lower in pigs with pneumothorax compared to those without (53% vs 83%). TTI increased progressively with the size of pneumothorax (mean TTI: 55 O no pneumothorax, vs 62 O mild-moderate vs 66 O severe pneumothorax). Rib fractures were present in all animals with mild-moderate and severe pneumothorax, and in 91% of those without. The total number of rib fractures was significantly higher in animals with severe pneumothorax compared to those without pneumothorax.

Conclusion

Pneumothorax causes TTI increases which are proportional to the size of the pneumothorax and ultimately reduce resuscitation success. High prevalence of chest skeletal injuries was observed in this study regardless of the presence of pneumothorax with higher amount of rib fractures in animals with severe pneumothorax. TTI measured by defibrillator can be used to detect the presence of pneumothorax during CPR. Future studies should explore this concept of TTI as a diagnostic tool, in order to improve resuscitation outcome in patients with pneumothorax.

Feasibility of lung lobectomy through a transdiaphragmatic approach in dogs

BACKGROUND

Different pulmonary pathologies may require a partial or total lung lobectomy as treatment. This study compared two techniques for performing a caudal pulmonary lobectomy: a traditional lateral thoracotomy (LT) and a novel transdiaphragmatic (TD) approach.

METHODS

TD and LT approaches were performed on each of 18 canine cadavers. The operator and order of intervention were randomised at the beginning of the study. To compare both techniques, surgical time, percentage of area of lobe removed, incision length and iatrogenic damage were recorded.

RESULTS

The mean length of surgery for the TD approach (1155 ± 232.8 seconds) was non-inferior to the LT approach (1126.8 ± 180.6 seconds) (p = 0.6131). The mean percentage of the area of caudal lobe that was successfully removed during the TD approach was 25.83 ± 8.95% (range 10.55‒40.72%) of the lobe surface, while 100% of the caudal lobe was removed during the LT approach. There was no statistical difference in iatrogenic damage between the procedures.

LIMITATIONS

This is a non-inferiority ex vivo study carried out by three different surgeons, and no leak test was performed after lobectomies.

CONCLUSION

Partial caudal lung lobectomy can be performed in dogs by the TD approach without greater iatrogenic damage or longer surgical duration than the traditional LT approach.

Computed tomography features and prevalence of focal diaphragmatic mineralization in 300 dogs

A focal area of mineral attenuation is commonly observed in the diaphragmatic crura of canine patients undergoing a thoracic CT. There is no mention of this finding in either the human or veterinary medicine literature. This retrospective study evaluates 300 canine thoracic CT studies with the aim of describing the CT appearance of this finding and establishing a prevalence in a large cohort of dogs. The presence of the mineral focus and its CT characteristics, including length, attenuation, and appearance, were recorded and correlated with the patient's signalments and anamnesis. The focus was observed in 43 of 300 studies (14.3%). The most common appearance was a thin, millimetric, toothpick-like mineral attenuating structure in the confluence of the diaphragmatic crura, just ventral to the aorta. There was no association with adjacent potentially pathological changes. A significant correlation was found between the presence of the focus and the patient's body weight (P = .03), as well as with a brachycephalic conformation (P = .03). This focus of mineralization represents a relatively common incidental finding in the canine diaphragm and has no evident association with pathology.

Ultrasonographic findings may be useful for differentiating interdigital abscesses secondary to migrating grass awns and interdigital furunculosis in dogs

Grass awn migration and furunculosis are common diseases in dogs that can lead to interdigital subcutaneous lesions with a similar clinical presentation, and occasionally similar ultrasonographic images, but different treatments are required. This retrospective, multicentric, analytical study aimed to determine whether epidemiological, clinical, and ultrasonographic features could be used to differentiate interdigital furunculosis and abscesses secondary to migrating grass awns. Fifty-nine dogs that underwent interdigital ultrasonography were included (interdigital furunculosis [IDF], n = 27; interdigital abscess secondary to a migrating grass awn [IAGA], n = 32). Ultrasonographic images were reviewed by two observers blinded to the diagnosis, who graded nine qualitative and four quantitative parameters for each patient. In both groups, pruritus/licking (IDF 74%, IAGA 70%), a discharging interdigital wound (63% for each group), and thoracic limb involvement (IDF 88%, IAGA 75%) were common features. On ultrasound, a subcutaneous multilinear hyperechoic main element was identified in most dogs (IDF 85%, IAGA 100%). The ability to display this element in a single plane (P < 0.01), the absence of additional hyperechoic linear elements in different planes (P < 0.01), and a surrounding hypoechoic halo (P < 0.05) were significantly more common in dogs with interdigital abscesses secondary to migrating grass awns. A cut-off value of 0.83 cm for the length of the main multilinear element provided a sensitivity of 91% and a specificity of 87% in the diagnosis of a migrating grass awn. Findings supported prioritizing a differential diagnosis of interdigital abscesses secondary to grass awns in dogs with these ultrasonographic characteristics.

Application of Ultrasound in Detecting and Removing Migrating Grass Awns in Dogs and Cats: A Systematic Review

Migrating grass awns are an important cause of disease in dogs and cats. Plant awns can migrate into several body tissues and cavities because of their fusiform shape and backward-pointing barbs. Their migration causes inflammatory tissue reaction and clinical signs depend upon their localization. Ultrasound has been described as a useful, noninvasive, and readily available tool to identify and guide vegetal foreign bodies removal in animals. The aim of this systematic review was to summarize current knowledge on the application of ultrasonography in the identification and removal of grass awns from various anatomic locations in dogs and cats. We selected and analyzed 46 papers on the application of ultrasonography in dogs and cats affected by migrating grass awns. The ultrasonographic appearance of grass awns is characteristic, although their size and location can influence the visualization and the attempt of removal. In some cases, migrating grass awns are not directly visualized by ultrasonography, but the lesions caused by their migration can be easily seen. Ultrasonography can be considered a useful diagnostic tool to localize and remove migrating grass awns; however, when the migration occurs in less accessible locations or discrete foreign bodies are present, this diagnostic tool should be considered as a part of a multidisciplinary approach with advanced diagnostic imaging modalities.

Bronchoscopic findings in dogs with bronchial vegetal foreign bodies: 84 cases (2010-2020)

OBJECTIVES

To describe endoscopic findings, foreign body location, success rate of removal and complications in dogs with bronchial vegetal foreign bodies.

MATERIALS AND METHODS

The current study retrospectively evaluated the case records of dogs diagnosed with bronchial vegetal foreign bodies at a veterinary hospital centre between January 2010 and April 2020. Information retrieved included breed, sex, age, bodyweight, the season of presentation, presentation and duration of clinical signs, previous removal attempts performed by the referring veterinarian, foreign body location and endoscopic and imaging findings.

RESULTS

Eighty-four cases were included. Fifty-nine dogs (70%) presented during spring and summer. Cough (77 of 84; 92%) and fever (15 of 84; 18%) were the main clinical signs. One to 10 bronchial vegetal foreign bodies were removed from each dog. Purulent exudate was observed in the ventral larynx, trachea and bronchi in 49 (65%), 61 (81%) and 71 (95%) dogs, respectively. In most cases, only the barbules of the vegetal foreign bodies were initially observed during endoscopy. The presence of large bronchial nodules or an irregular mucosal surface was a frequent finding (62 of 75; 83%). Mild bleeding was the main complication (58 of 75; 77%) of endoscopic removal, which was successful in 67 of the 84 (80%) cases.

CLINICAL SIGNIFICANCE

Mucosal nodules associated with purulent material within the airways are frequent endoscopic findings in dogs with bronchial vegetal foreign bodies. Bronchoscopy is a relatively safe and useful technique for diagnosis and treatment of bronchial vegetal foreign bodies in dogs.

CT can identify characteristic features of hypaxial muscle abscesses in dogs due to presumed migrating vegetal foreign material as well as additional changes along the migratory tract in other anatomic regions

Hypaxial muscle abscess is an important differential in dogs presenting for abdominal or back pain, lameness, and nonspecific signs like fever, lethargy, and hyporexia. It can occur concurrently with intrathoracic disease such as pyothorax secondary to migrating vegetal foreign material. Twelve dogs that underwent CT of the lumbar spine or abdomen and had a diagnosed hypaxial abscess on surgical and/or microbiological examination were included in this retrospective, descriptive case series. Computed tomography findings and findings from other imaging modalities employed were described. Eleven dogs were hunting breeds. Clinical signs included lethargy, fever, increased respiratory effort, and abdominal or back pain. Radiography and/or ultrasonography were employed during preliminary work up at clinician discretion and respectively revealed changes consistent with osteomyelitis in the cranial lumbar vertebrae and heterogenous, hypoechoic areas in the hypaxial musculature consistent with abscesses. Computed tomography findings included enlargement of hypaxial muscles with well-defined fluid attenuating noncontrast enhancing areas with a contrast-enhancing rim consistent with abscesses, periosteal reaction and lysis of vertebrae, and retroperitoneal effusion. Four of the 12 cases in this series had material identified and removed at surgery. The other eight cases were presumed to be the same disease process based on compatible signalment, imaging findings, and microbiological results. Migrating vegetal foreign bodies are a common problem at the authors' institution. Computed tomography provided expedient, thorough visualization of the relevant hypaxial lesions for diagnostic and surgical planning purposes and also characterized intrathoracic components of this disease.

Clinical and clinicopathological characteristics, treatment, and outcome for dogs and cats with confirmed foxtail foreign body lesions: 791 cases (2009-2018)

OBJECTIVE

To describe the clinical and clinicopathological characteristics, treatment, and outcome for dogs and cats with a confirmed foxtail.

DESIGN

Retrospective study utilizing a medical records database over a 10-year period from January 1, 2009 to December 31, 2018.

SETTING

University teaching hospital.

ANIMALS

Seven hundred and fifty-four dogs and 37 cats with a diagnosis of foxtail foreign body. Cases with direct visualization by a clinician or on histopathology were included. Information extracted for each case included signalment; anatomical foxtail location; clinicopathological and imaging findings; treatments and interventions provided; and outcome.

MEASUREMENTS AND MAIN RESULTS

The prevalence of foxtail associated disease was 0.25% in dogs and 0.07% in cats over this time period. Most animals were young to middle-aged and presented in the summer months. The most common location in dogs was the aural canal, cutaneous/subcutaneous space, and nasal canal. In cats, ocular foxtails were most common (30/37). Blood work changes were nonspecific. Ultrasound supervised by a boarded radiologist was utilized in 114 cases, mainly for subcutaneous, sublumbar, and intracavitary foxtail locations, with successful location of a foxtail in 72.8% of cases scanned. Computed tomography was performed in 78 dogs with suspected intracavitary foxtail migration, and in all cases, structural changes related to the presence of the foxtail were found. Anerobic bacteria were most commonly isolated when a culture was submitted, with Actinomyces spp. rarely isolated. The most common of the 120 anaerobic isolates were Bacteroides/Prevotella spp. (n = 38), Fusobacterium spp. (n = 32), and Peptostreptococcus anaerobius (n = 30).

CONCLUSIONS

The short-term outcome for foxtail-associated lesions is good, and most cases can be managed on an outpatient basis. A minority of cases develop life-threatening disease and may require a multidisciplinary approach of multimodal imaging, endoscopy, or surgery.

Comparison of computed tomography and surgical findings and investigation of their associations with outcomes for dogs with sublumbar abscesses

OBJECTIVE

To describe and compare the results of preoperative CT and surgical findings in dogs with sublumbar abscesses and investigate potential associations between these variables and the outcome of abscess recurrence.

ANIMALS

51 client-owned dogs.

PROCEDURES

A retrospective, records-based study was performed of dogs undergoing surgery for treatment of sublumbar abscesses diagnosed by use of CT between January 2010 and December 2018. Signalment, clinical signs, clinicopathologic data, CT findings, surgical techniques and findings, duration of hospitalization, postoperative treatment, and complications were recorded. Long-term follow-up was performed through telephone interviews. Logistic regression analysis was used to investigate associations between the variables of interest and abscess recurrence.

RESULTS

51 dogs met the study inclusion criteria; 48 were included in outcome analysis. The CT findings agreed with surgical findings for identification of a migrating vegetal foreign body for 39 of 51 (77%) dogs. All dogs survived to hospital discharge; 1 dog died of hemoabdomen 3 days after surgery, and 6 had minor (surgical wound) complications reported. Abscess recurrence developed in 12 of 48 (25%) dogs with a median time to recurrence of 6 months. Identification of diskospondylitis on CT examination was the only investigated factor significantly associated with recurrence; odds of recurrence in dogs with this finding were 8.4 times those for dogs without this finding.

CONCLUSIONS AND CLINICAL RELEVANCE

Our results suggested dogs with sublumbar abscesses have a good prognosis after surgery, although recurrence can develop. Preoperative identification of diskospondylitis was significantly associated with abscess recurrence in this study sample.

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.

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.

Use of CT sinography in 27 dogs and one cat

OBJECTIVES

To describe the clinical findings, imaging findings and outcome in patients in which CT sinography was performed, and assess to what degree this technique adds information about the extent of a tract or increases the accuracy of diagnosis of foreign bodies on CT.

MATERIALS AND METHODS

Retrospective review of medical records of 27 dogs and one cat with draining tracts that had CT sinography. Pre- and post-intravenous (IV) contrast CT series were compared with CT sinography in each patient.

RESULTS

Median duration of clinical signs before referral was 85 days (range 2 to 1478 days). The most common reported clinical signs were swelling (14/28, 50%) and regional pain (5/28, 18%). CT sinography revealed a more extensive tract than post-IV contrast CT in 21% cases. On post-IV contrast CT, 31% of foreign bodies were detected compared to 23% on CT sinography. All four foreign bodies detected by CT were observed in the non-contrast images. Surgery was performed after CT in 22 (79%) cases. Thirteen (46%) draining tracts resolved after surgery, three (11%) resolved without surgery, six (21%) persisted or recurred after surgery, and six (21%) were lost to follow-up.

CLINICAL SIGNIFICANCE

CT sinography provides limited additional information about the extent of draining tracts compared to pre- and post-IV contrast CT images and did not increase the number of foreign bodies identified.