A clinical review of pathophysiology, diagnosis, and treatment of uroabdomen in the dog and cat

Surgical interventions and outcome in a population of canine trauma patients

OBJECTIVE

To determine signalment, injury type, trauma severity score, and outcome of canine trauma patients undergoing surgical (emergency room [ER] or operating room [OR]) and nonsurgical treatment in addition to time to surgery, specialty services involved, and cost in the OR surgery population.

DESIGN

Retrospective evaluation of medical record and hospital trauma registry data on canine trauma cases.

SETTING

University teaching hospital.

ANIMALS

One thousand six hundred and thirty dogs presenting for traumatic injury between May 2017 and July 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographics and outcome were compared for canine trauma patients undergoing OR surgery (12.8%, 208/1630), ER surgery (39.1%, 637/1630), or no surgical intervention (48.2%, 785/1630). Among the 2 surgical groups, 98.9% (836/845) survived to discharge compared with 92.2% (724/785) of the nonsurgical group (P < 0.0001). The OR surgical group had significantly higher median Animal Trauma Triage scores (2 vs 1, P < 0.0001) and median days in hospital (2 vs < 1, P < 0.0001) compared with the other groups. For the OR surgical cohort, electronic medical records were reviewed to determine the specialty surgery service involved, time to and duration of anesthesia and surgery, and visit cost. The most common surgery services involved were orthopedics (45.2%, 94/208) and general surgery (26.9%, 56/208). Neurology and general surgery cases required the longest median length of stay in hospital, and ophthalmology and dentistry cases required the shortest. The median cost of visit was highest in neurology ($10,032) and lowest in ophthalmology ($2305) and dentistry ($2404).

CONCLUSIONS

Surgical intervention in canine trauma patients appears to be associated with higher survival rates, and among the surgery groups, mortality was highest in the ER and general surgery groups. OR surgical intervention, in particular general surgery and neurology, was associated with increased length of hospitalization, increased cost, and higher Animal Trauma Triage scores.

Case report: Utility, complications, and short-term outcomes in three dogs managed with percutaneous pigtail cystostomy catheters for urethral obstruction

Objective

This study aimed to describe the utility, complications, and short-term outcomes of three dogs managed with percutaneous pigtail cystostomy catheters placed in the emergency room (ER).

Case summary

Three dogs were presented separately to the ER for unalleviated mechanical urethral obstruction secondary to urolithiasis and urethral neoplasia. Retrograde urinary catheterization and urohydropulsion were not successful after multiple attempts. Percutaneous pigtail cystostomy catheters were placed under sedation to achieve temporary urinary diversion, and were successful in two of the three dogs. Complications encountered include mild abdominal effusion, unsuccessful placement resulting in hemorrhagic abdominal effusion, steatitis, abdominal pain, and kinking of the catheter. The two dogs diagnosed with urolithiasis were discharged from the hospital, and the dog diagnosed with urethral neoplasia was humanely euthanized due to poor prognosis.

New or unique information provided

When successful, the placement of pigtail cystostomy catheters allowed for temporary urinary diversion until definitive treatment could be performed and were well tolerated. Short-term outcomes were good. Complications arising from this procedure were common and increased morbidity. The risk of unsuccessful catheter placement may be increased when the procedure is performed in an over conditioned patient or by an inexperienced operator. Careful case selection and risk-benefit analysis should be considered before attempting this procedure. Further studies are necessary to evaluate the ideal technique, incidence of complications, and outcomes of this procedure.

The use of agitated saline as contrast agent in a contrast-enhanced cystosonography for detection of urinary bladder rupture in animal cadavers

OBJECTIVE

To determine the value of microbubble contrast cystosonography in the diagnosis of bladder rupture in animals.

DESIGN

Prospective, method comparison study from November 2019 to October 2020.

SETTING

University teaching hospital.

ANIMALS

Thirty-four ethically sourced cadavers of dogs, rats, and rabbits.

INTERVENTIONS

In a prospective and blinded study, the cadavers were divided into 2 randomized groups: with bladder rupture (CR), and without bladder rupture (SR). Urinary catheterization was performed in all cadavers. Through the urethral catheter, bladders in CR group were ruptured using a rigid stainless steel guide wire. Microbubble contrast was infused into the bladder through the urethral catheter, while a single, blinded observer sonographically assessed the bladder. The time to diagnosis and the number of attempts needed for diagnosis were recorded.

MEASUREMENTS AND MAIN RESULTS

The study included cadavers of 16 female Wistar rats, 6 female dogs, 11 male dogs, and 1 male rabbit. Time to diagnosis in dogs (2.25 ± 0.91 min) was statistically higher when compared to rats (1.15 ± 0.75 min; P = 0.03). Of the 34 cases, incorrect diagnosis of bladder rupture was made in only 2 dogs (6%), indicating a diagnostic sensitivity of 88.88%, specificity of 100%, and an accuracy of 94%. The positive predictive value was 1 and the negative predictive value was 0.9.

CONCLUSIONS

Our study showed that the described method is accurate, sensitive, and specific for the detection of bladder rupture in animal cadavers of different species, size, and sex.

N-terminal brain natriuretic peptide, cardiac troponin-I, and point-of-care ultrasound in dogs with cardiac and noncardiac causes of nonhemorrhagic ascites

BACKGROUND

Nonhemorrhagic ascites (NHA) can be caused by cardiac diseases (cNHA) and noncardiac diseases (ncNHA). N-terminal brain natriuretic peptide (NT-proBNP), cardiac troponin-I (cTnI), and point-of-care ultrasound (POCUS) may differentiate between cNHA and ncNHA.

HYPOTHESIS/OBJECTIVES

We compared NT-proBNP and cTnI concentrations as well as POCUS findings in dogs presented with cNHA and ncNHA.

ANIMALS

Dogs (n = 60) were enrolled based on identification of NHA with an effusion packed cell volume < 10%.

METHODS

Blood samples were collected and POCUS was performed on all dogs. Dogs were diagnosed with cNHA (n = 28) or ncNHA (n = 32) based on echocardiography. The cNHA group was subdivided into cardiac non-pericardial disease (n = 17) and pericardial disease (n = 11).

RESULTS

The NT-proBNP concentration (median; range pmol/L) was significantly higher in the cNHA group (4510; 250-10 000) compared to the ncNHA group (739.5; 250-10 000; P = .01), with a sensitivity of 53.8% and specificity of 85.7% using a cut-off of 4092 pmol/L. The NT-proBNP concentrations were significantly higher in the cardiac non-pericardial disease group (8339; 282-10 000) compared with the pericardial disease group (692.5; 250-4928; P = .002). A significant difference in cTnI concentration (median; range ng/L) between the cNHA group (300; 23-112 612) and ncNHA group (181; 17-37 549) was not detected (P = .41). A significantly higher number of dogs had hepatic venous and caudal vena cava distension in the cNHA group compared to the ncNHA group, respectively (18/28 vs 3/29, P < .0001 and 13/27 vs 2/29, P < .001). Gall bladder wall edema was not significantly different between groups (4/28 vs 3/29, P = .74).

CONCLUSIONS AND CLINICAL IMPORTANCE

NT-proBNP concentration and POCUS help distinguish between cNHA and ncNHA.

Urinary Tract Trauma in Cats: Stabilisation, Diagnosis and Management

PRACTICAL RELEVANCE

Traumatic injury of the urinary tract may be caused by external accidental trauma or due to iatrogenic injury (typically as a result of catheterisation procedures). Thorough patient assessment and careful attention to patient stabilisation are essential, with diagnosis and surgical repair delayed until the patient is stable, if necessary. Treatment depends on the location and severity of the trauma. If diagnosed and treated promptly, the chance of survival of a patient without other concurrent injuries is good.

CLINICAL CHALLENGES

Following accidental trauma, at the initial presentation urinary tract injury can be overshadowed by other injuries, but if left undiagnosed or untreated it can lead to serious morbidity and potentially mortality. Many of the surgical techniques described for management of urinary tract trauma can be associated with complications, and so comprehensive communication with the owners is necessary.

PATIENT GROUP

The main population affected by urinary tract trauma is young, adult male cats, owing to their roaming behaviour, as well as their anatomy and the resulting increased risk of urethral obstruction and its associated management.

AIMS

This article aims to serve as a guide to all veterinarians who treat cats for the diagnosis and management of urinary tract trauma in cats.

EVIDENCE BASE

This review summarises the current knowledge available from a number of original articles and textbook chapters in the literature that cover all aspects of feline urinary tract trauma, and is supported by the authors' own clinical experience.

The predominance and diagnostic value of neutrophils in differentiating transudates and exudates in dogs

BACKGROUND

There is disagreement in the literature about the proportion of neutrophils expected in canine transudates. A cutoff of <30% neutrophils has been recommended for distinguishing transudates from exudates, but its validity has not been established.

OBJECTIVE

The aim of this study was to evaluate differential cell counts in canine effusions and analyze the percentage and number of neutrophils in transudates and exudates.

METHODS

Effusion data were obtained retrospectively from 263 dogs with pleural or peritoneal effusion. Low-protein transudates, high-protein transudates, and exudates were classified using the total protein (TP) concentration and total nucleated cell count (TNCC). Differential percentages and absolute neutrophil counts were compared by the effusion type and underlying etiology.

RESULTS

Low-protein transudates (n = 63), high-protein transudates (n = 84), and exudates (n = 77) had a median (range) of 35% (0%-100%), 59% (0%-100%), and 90% (50%-98%) neutrophils (P < .0001). All effusions with <50% neutrophils were transudates, but 53% of transudates had ≥50% neutrophils, and 69% had ≥30%. Median neutrophil counts were 62/µL (0-892/µL), 538/µL (0-4550/µL), and 45 590/µL (5400-496 800/µL) in low-protein transudates, high-protein transudates, and exudates, respectively (P < .0001). Neutrophil counts correlated with TNCC (r²  = 0.99), such that using neutrophil cutoffs did not affect effusion classifications in most cases. Neutrophil percentages and counts were higher in effusions from dogs with uroabdomen and sepsis (P < .01); neutrophil counts were lower in dogs with hepatic insufficiency (P < .0001). Uroabdomen usually caused low-protein, high-neutrophil exudates.

CONCLUSIONS

Although effusions with <50% neutrophils are transudates, most transudates and exudates have ≥50% neutrophils, limiting the diagnostic usefulness of % neutrophils for classifying effusions. Absolute neutrophil cutoffs did not notably improve effusion classification but could warrant future studies.

Successful resolution of urothorax secondary to non-traumatic uroabdomen in a cat managed with peritoneal dialysis as a bridge to surgery

Case summary

A 9-year-old neutered male domestic shorthair cat was presented for evaluation of severe hemodynamic collapse and suspected lower urinary tract disease. On admission, severe metabolic acidosis, hyperkalemia and azotemia, and electrocardiographic findings consistent with cardiotoxicity were identified. The diagnosis of uroabdomen was made based on abdominal fluid to plasma concentration ratios of creatinine and potassium. A central line catheter was placed percutaneously into the abdomen for peritoneal drainage and used for peritoneal dialysis as a bridge to surgery. Retrograde contrast cystography confirmed rupture of the urinary bladder. Point-of-care ultrasound of the chest postoperatively revealed the presence of mild pleural effusion. Echocardiography was then performed showing no evidence of cardiac disease. Pleural fluid analysis revealed a transudate with a creatinine ratio of 2.38 ([Creatinine]_{pleural fluid}/[Creatinine]_plasma), consistent with the diagnosis of urothorax. The cat recovered uneventfully from surgery and was monitored for signs of respiratory distress during the rest of its stay in hospital. The cat was discharged 4 days later and the pleural effusion resolved without further medical intervention.

Relevance and novel information

There is limited information on the causes of urothorax and uroabdomen management of feline patients. Pleural effusion is a complication observed in critically ill cats secondary to fluid overload, underlying cardiomyopathy, primary thoracic pathology or a combination of these. To our knowledge, this is the first report of urothorax in a cat secondary to non-traumatic uroabdomen. Careful monitoring of respiratory signs consistent with pleural space disease is recommended in cases of uroabdomen.

Factors affecting survival to discharge in 53 cats diagnosed with uroabdomen: a single-centre retrospective analysis

OBJECTIVES

The aim of this study was to assess outcomes in cats diagnosed with uroabdomen at a single referral centre.

METHODS

Fifty-three cats diagnosed with uroabdomen at a veterinary teaching hospital were identified between June 2003 and September 2016. Data collected included signalment, presenting signs, aetiology, location of rupture, presence of concurrent injury, outcome of urine culture, presence of uroliths and packed cell volume (PCV)/creatinine/potassium levels at presentation. Cats managed medically and surgically were included, and the use of urinary catheters, cystotomy tubes and abdominal drains were recorded. It was determined if patients survived to discharge or if they were euthanased or died.

RESULTS

Seventy-four percent (n = 39) of cats survived to discharge. Elevations in creatinine (P = 0.03) were shown to be significantly correlated with survival to discharge. Sex, age, location of rupture, presence of uroliths, outcome of urine culture, presence of concurrent injury, potassium at presentation and PCV at presentation were not associated with survival to discharge. There was no difference in survival between cats that were medically or surgically managed.

CONCLUSIONS AND RELEVANCE

Cats that develop uroabdomen have a good chance of survival. Electrolyte and biochemistry values should be assessed at the time of presentation, in addition to the presence of concurrent injury.

Cystine Urolithiasis in Ferrets

Urolithiasis in captive domestic ferrets has previously been predominantly struvite uroliths, although more recent laboratory submissions show a shift to predominantly cystine uroliths. Genetic mutations for cystinuria have been identified in dogs, and it is suspected that underlying genetic mutations are partly responsible for this disease in ferrets. Currently, surgery remains the only definitive treatment of cystine urolithiasis in ferrets, since dietary dissolution protocols have not been thoroughly explored. Despite this, medical management with dietary and urinary manipulation should be considered for use in ferrets postoperatively based on principles of cystine urolithiasis management in dogs adapted for ferrets.

Resuscitation Strategies for the Small Animal Trauma Patient

Traumatic injuries in small animals are a common cause for presentation to emergency departments. Severe traumatic injury results in a multitude of systemic responses, which can exacerbate initial tissue damage. Trauma resuscitation should focus on the global goals of controlling hemorrhage, improving tissue hypoperfusion, and minimizing ongoing inflammation and morbidity through the concept of "damage-control resuscitation." This approach focuses on the balanced use of blood products, hemorrhage control, and minimizing aggressive crystalloid use. Although these tenets may not be directly applicable to every veterinary patient with trauma, they provide guidance when managing the most severely injured subpopulation of these patients.

Complications and clinical utility of ultrasonographically guided pyelocentesis and antegrade pyelography in cats and dogs: 49 cases (2007-2015)

OBJECTIVE

To describe the diagnostic utility and clinical safety of ultrasonographically guided percutaneous pyelocentesis and antegrade pyelography in cats and dogs.

DESIGN

Retrospective case series.

ANIMALS

39 cats and 10 dogs with 55 affected kidneys.

PROCEDURES

Medical records were reviewed to identify cats and dogs that underwent ultrasonographically guided pyelocentesis and antegrade pyelography between June 1, 2007, and December 31, 2015. Data collected included procedure descriptions; results of diagnostic imaging, urine cytologic evaluation, and bacterial culture; and evidence of complications. Animals were assigned to the pyelocentesis group (underwent only pyelocentesis) or to the antegrade pyelography group (underwent pyelocentesis followed immediately by pyelography).

RESULTS

The diagnostic rate for pyelography was 94% (31/33; 95% confidence interval [CI], 80.4% to 98.9%). The total, minor, and major complication rates for both treatment groups combined were 25% (95% CI, 15.8% to 38.3%), 24% (95% CI, 14.4% to 36.3%), and 2% (95% CI, 0.09% to 9.6%), respectively. Performing bacterial culture of urine obtained by pyelocentesis did not provide an advantage over performing bacterial culture of urine obtained from the lower urinary tract.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings indicated that ultrasonographically guided pyelocentesis and antegrade pyelography were well-tolerated techniques for investigating upper urinary tract disease in cats and dogs and that pyelography had a higher diagnostic rate than previously reported; therefore, pyelography should be considered for identification of mechanical and functional ureteral patency abnormalities in cats and dogs.

Association of abdominal effusion with a single decompressive cystocentesis prior to catheterization in male cats with urethral obstruction

OBJECTIVE

To evaluate the occurrence of abdominal effusion and its association with decompressive cystocentesis in male cats with urethral obstruction.

DESIGN

Prospective observational clinical study.

ANIMALS

Forty-five male neutered, client-owned cats with naturally occurring urethral obstruction.

PROCEDURES

Laboratory testing and point-of-care ultrasonography were performed. Presence of abdominal effusion was evaluated using the Focused Assessment with Sonography for Trauma (FAST) technique at presentation. Decompressive cystocentesis was then performed prior to catheterization by a standardized technique. Repeat FAST examination was performed 15 minutes after cystocentesis and the following day to further assess for the presence of abdominal effusion.

RESULTS

A mean volume of 92.3 ± 35.2 mL of urine was removed from each cat via cystocentesis prior to catheterization. At presentation, 15 of 45 (33%) had abdominal effusion (13/15 with scant effusion, 2/15 with mild), with an additional 7 cats developing scant effusion 15 minutes post-cystocentesis. By the following day, 4 cats still had scant effusion present. No significant complications secondary to cystocentesis were reported. No association was found between severity of azotemia, or volume removed by cystocentesis, and the presence of effusion at presentation or after decompressive cystocentesis was performed.

CONCLUSIONS AND CLINICAL RELEVANCE

A single decompressive cystocentesis prior to catheterization did not lead to development of clinically significant abdominal effusion or other discernable complications and appears to be a safe procedure in this population of patients. Abdominal effusion may be found at presentation in cats with urethral obstruction. The significance of this effusion remains to be determined.

Biomarker Guided Diagnosis of Septic Peritonitis in Dogs

Septic peritonitis (SP) is common in dogs and is associated with high mortality. Early recognition is essential to maximizing survival and may be aided by biomarker measurement. The present study aimed to evaluate the ability of biomarkers to discriminate septic peritonitis from non-septic ascites (NSA). Eighteen dogs with SP and 19 age-matched controls with NSA were enrolled. Contemporaneous blood and peritoneal effusion samples were obtained. Concentrations of cell-free DNA (cfDNA), cytokines, glucose, lactate, N-terminal pro-C-type natriuretic peptide (NT-proCNP), nucleosomes, and procalcitonin (PCT) were measured using commercial reagents and assays. Paired biomarker concentrations were compared with the Wilcoxon matched-pairs signed rank test, and biomarker concentrations between groups were compared with the Mann-Whitney U-test. P-values were adjusted for multiple comparisons using the Bonferroni correction. Receiver operating characteristic curves were generated to assess the ability of the above biomarkers to discriminate SP from NSA. Dogs with SP had significantly greater blood CCL2 concentrations than dogs with NSA (P = 0.032). Dogs with SP had significantly greater effusion CCL2, IL-6, IL-10, and lactate concentrations than dogs with NSA (P ≤ 0.0121). Blood-effusion concentration gradients of CCL2, glucose, IL-6, IL-10, and lactate were significantly different in dogs with SP compared to dogs with NSA (P ≤ 0.0165). Effusion lactate concentration had the highest AUROC value (0.866, 95% CI 0.751–0.980, P = 0.0001), although other biomarkers performed similarly. An effusion lactate concentration of 4.2 mmol/L was 72.2% (95% CI 46.5–90.3%) sensitive and 84.2% (95% CI 60.4–96.6%) specific for the diagnosis of SP.

Traumatic urethral rupture, its surgical management with temporary cystostomy and concurrent wound reconstruction in a cat

A 3-month-old male DSH cat was presented with a history of lethargy, anorexia, dysuria, urinary incontinence, dermatitis and swelling in the perineal area following a road traffic trauma. Retrograde positive-contrast urethrography revealed an intra-pelvic urethral rupture which was managed by performing transurethral catheterisation. Due to accidental removal, the case was presented for re-examination following a progressive urine scald dermatitis several days later. So, surgical placement of cystostomy tube was performed. The cat regained his ability to urinate normally a week later and the catheter was withdrawn. The extensive perineal dermatitis due to urine scald necessitated delayed primary closure. Topical and systemic antibiotics were administered for 2 weeks and second intention wound healing was completed after 5 weeks.

Outcomes in dogs with uroabdomen: 43 cases (2006-2015)

OBJECTIVE To determine the rate of and factors associated with survival to hospital discharge in dogs with uroabdomen. DESIGN Retrospective case series. ANIMALS 43 dogs with uroabdomen confirmed at 2 veterinary teaching hospitals from 2006 through 2015. PROCEDURES Medical records were reviewed and data extracted regarding cause and location of urinary tract rupture, serum creatinine concentration and other variables at hospital admission, and outcomes. Variables were tested for associations with survival to hospital discharge. RESULTS Urinary tract rupture occurred in the urinary bladder (n = 24 [56%]), urethra (11 [26%]), kidney (2 [5%]), ureter (1 [2%]), both the urinary bladder and kidney (1 [2%]), and undetermined sites (4 [9%]). Rupture causes included traumatic (20 [47%]), obstructive (9 [21%]), and iatrogenic (7 [16%]) or were unknown (7 [16%]). Surgery was performed for 37 (86%) dogs; the defect was identified and surgically corrected in 34 (92%) of these dogs. Hypotension was the most common intraoperative complication. Nineteen dogs had information recorded on postoperative complications, of which 10 (53%) had complications that most often included death (n = 3) and regurgitation (3). Thirty-four (79%) dogs survived to hospital discharge. Dogs with intraoperative or postoperative complications were significantly less likely to survive than dogs without complications. Serum creatinine concentration at admission was not associated with survival to discharge. CONCLUSIONS AND CLINICAL RELEVANCE A high proportion of dogs with uroabdomen survived to hospital discharge. No preoperative risk factors for nonsurvival were identified. Treatment should be recommended to owners of dogs with uroabdomen.

DIAGNOSIS AND TREATMENT OF A UNILATERAL RENAL CYSTADENOMA IN AN AFRICAN LION (PANTHERA LEO)

A renal tubular cystadenoma was diagnosed in a 14-yr-old male African lion (Panthera leo). During a routine health evaluation, a left renal mass was identified via physical examination, radiographs, and abdominal ultrasonography. The mass was 30 × 15 cm in size and had a thin capsule with central hypoechoic fluid, suggestive of a perirenal cyst. An exploratory celiotomy with partial nephrectomy was performed without complications. Histologically, the tumor was characterized by a thick fibrous capsule surrounding multiple, variable-sized cysts that markedly compressed the adjacent fibrotic and atrophied renal cortex. Immunohistochemical labeling for Aquaporin-1 and Tamm-Horsfall protein was consistent with a renal tubular cystadenoma of proximal tubule origin. Renal cystadenomas are an uncommon benign epithelial neoplasm. There are only two documented case reports in domestic cats. This report represents the first documentation, to the authors' knowledge, of a renal cystadenoma in a lion.

The impact of surgical timing and intervention on outcome in traumatized dogs and cats

OBJECTIVE

To review the relevant human and veterinary literature regarding the timing of surgical intervention for trauma patients and the impact on outcome.

DATA SOURCES

Original research, clinical studies, and review articles with no date restrictions from both human and veterinary literature.

HUMAN DATA SYNTHESIS

Despite extensive research into the ideal timing of surgical intervention for human trauma victims, debate is ongoing and views are still evolving. Prior to the 1970s, the standard of care consisted of delayed surgical treatment, as these patients were considered too ill to undergo surgery. Beginning in the 1970s, and continuing for nearly 2 decades, early definitive surgical treatment was recommended. The most recent evolution of human trauma management incorporates the concept of damage control surgery, which acknowledges the importance of early skeletal stabilization or laparotomy for reducing morbidity while attempting to avoid complications such as acute respiratory distress syndrome or multiple organ dysfunction syndrome.

VETERINARY DATA SYNTHESIS

Despite a relatively large amount of literature available regarding veterinary trauma, no evidence exists to provide the clinician guidance as to the ideal timing of surgery for trauma patients. With the exception of diaphragmatic hernia, no studies were identified that attempted to evaluate this variable.

CONCLUSIONS

Veterinary-specific studies are needed to evaluate the impact of surgical timing on outcome following trauma. The information that can be obtained from studies in this area can improve veterinary trauma care and may be used as models for human trauma care through translational applications.