StAndARdS of CARe UROABDOMEN. march 2009 DIAGNOSTIC CRITERIA. Peer Reviewed

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1 Peer Reviewed CE march 2009 StAndARdS of CARe EMERGENCY AND CRITICAL CARE MEDICINE VOL CE CONTACT HOURS FROM THE PUBLISHER OF COMPENDIUM UROABDOMEN Katrina Abell, DVM Emergency Veterinarian Jennifer Waldrop, DVM, DACVECC Senior Veterinary Associate Emergency Department Massachusetts Veterinary Referral Hospital Woburn, Massachusetts Uroabdomen is the accumulation of urine in the peritoneal and/or retroperitoneal spaces. Leakage of urine can originate from the bladder, urethra, ureters, and kidneys. Regardless of the underlying cause, uroabdomen can have severe, life-threatening consequences. Rapid diagnosis and prompt treatment are crucial to reducing patient morbidity and mortality. In small animals, uroabdomen is most frequently caused by abdominal or pelvic trauma. the bladder and urethra are the areas of the urinary tract most commonly injured by traumatic events such as blunt abdominal trauma, penetrating abdominal wounds, urethral catheterization, aggressive bladder palpation, cystocentesis, and cystoscopy. Other potential etiologies include bladder wall neoplasia; urinary tract obstruction due to calculi, neoplasia, or stricture; surgical site dehiscence; and chronic/severe urinary tract infections. DIAGNOSTIC CRITERIA Historical Information Gender Predisposition male dogs and cats may be more prone to bladder rupture secondary to blunt abdominal trauma than females due to the inability of the long, narrow male urethra to dilate in response to increased abdominal/bladder pressure. male cats and dogs have an increased tendency to roam and may be more prone to traumatic causes of uroabdomen than females. more common in male cats than females, possibly due to iatrogenic complications related to feline lower urinary tract disorder (FLUtd). Age Predisposition Older animals may be more prone to neoplastic causes of uroabdomen. Species/Breed Predisposition none. Owner Observations hematuria, anuria, dysuria, or stranguria. Vomiting and diarrhea. Anorexia. Lethargy. Collapse. Abdominal discomfort or distention. Perineal swelling or discoloration. Other Historical Considerations/Predispositions Abdominal or pelvic trauma or urinary tract manipulation. history of urolithiasis. Physical Examination Findings depend on the cause of uroabdomen and concurrent injuries. Also in this issue: 6 Septic Peritonitis In partnership with the Veterinary Emergency and Critical Care Society Visit SOCNewsletter. com VECCS. org

2 hematuria, stranguria, dysuria, and anuria are common but are insensitive indicators of urinary tract rupture. Some animals pass urine normally despite urinary tract rupture. Abdominal discomfort or pain secondary to chemical or septic peritonitis and concurrent injuries. mental depression. Reluctance to walk or lameness. dehydration (tacky mucous membranes and decreased skin turgor). Abdominal distention or an abdominal fluid wave. Sublumbar pain secondary to ureteral rupture. Subcutaneous cellulitis, inflammation, bruising, and pain of the perineal and ventral abdominal region and of the caudal aspect of the hindlimbs consistent with urine extravasation from distal urethral rupture. early (bounding pulses, tachycardia, tachypnea, shortened capillary refill time [CRt]) or late (weak pulses, tachycardia or bradycardia, prolonged CRt, hypothermia) stages of shock. Bradycardia may be seen secondary to hyperkalemia (K + >7.0 meq/l; reference range: meq/l). A palpable bladder or the ability to pass a urinary catheter and obtain grossly normal urine does not rule out bladder rupture. Laboratory Findings Chemistry panel $ Progressive increase in BUn, creatinine, potassium, and phosphorus. Progressive decrease in sodium and chloride. mild metabolic acidosis. Complete blood count $ neutrophilic leukocytosis due to peritoneal inflammation or infection. Septic peritonitis can develop secondary to bacteriuria or penetrating abdominal wounds. Urinalysis: may reveal evidence of hematuria, bacteriuria, crystalluria, or neoplastic cells. $ Urine culture: Indicated in all cases. $$ A B O U T V E C C S the Veterinary emergency and Critical Care Society was formed in 1978 in an effort to raise the level of patient care for seriously ill or injured animals through quality education and communication programs. Over 3,500 members strong, VeCCS has spawned three distinct national organizations ACVeCC (for veterinarians), AVeCCt (for veterinary technicians), and SVeCCS (for veterinary students) whose focus is on training and core knowledge in veterinary emergency and critical care medicine. For more information, visit veccs.org. Key to COStS $ indicates relative costs of any diagnostic and treatment regimens listed. $ costs less than $250 $$ costs between $250 and $500 $$$ costs between $500 and $1,000 $$$$ costs more than $1,000 march 2009 VOL 11.2 StAndARdS of CARe EMERGENCY AND CRITICAL CARE MEDICINE Editorial Mission: To provide busy practitioners with concise, peer-reviewed recommendations on current treatment standards drawn from published veterinary medical literature. This publication acknowledges that standards may vary according to individual experience and practices or regional differences. The publisher is not responsible for author errors. Standards of Care: Emergency and Critical Care Medicine is published 11 times yearly (January/February is a combined issue) by Veterinary Learning Systems, 780 Township Line Road, Yardley, PA The annual subscription rate is $90. For subscription information, call , fax , soc.vls@medimedia.com, or visit Copyright 2009, Veterinary Learning Systems. Editor in Chief douglass K. macintire, dvm, ms, dacvim, dacvecc Executive Director, VECCS Gary L. Stamp, dvm, ms, dacvecc Veterinary Advisor dorothy normile, Vmd, Chief Medical Officer Editorial tracey L. Giannouris, ma, Executive Editor , ext tgiannouris@vetlearn.com Kirk mckay, Managing Editor Robin A. henry, Senior Editor Chris Reilly, Associate Editor Benjamin hollis, Editorial Assistant Design and Production michelle taylor, Senior Art Director Bethany L. Wakeley, Studio Manager Stephaney Weber, Production Artist Client Services dawn Unterreiner, Associate Production Manager Standards of Care is a refereed publication. Articles published herein have been reviewed and approved by at least two diplomates of the American College of Veterinary emergency and Critical Care. 2 M A R C H V O L U m e

3 Other Diagnostic Findings Abdominal Radiography $ may aid in determining the presence of abdominal or retroperitoneal effusion. decreased serosal detail as fluid begins to accumulate and eventual loss of any discernible structures within the abdomen as the amount of effusion increases. Retroperitoneal fluid (indistinct renal margins, increased opacity, streaking, widening of the space, and ventral displacement of abdominal viscera) may signify a rupture of the kidney or proximal ureter. Presence of opaque calculi may suggest a cause of uroabdomen. the bladder may appear displaced, collapsed, or emphysematous. A clear bladder outline does not rule out bladder rupture. the kidneys may appear displaced or asymmetric. Ileus may be present secondary to chemical peritonitis. Other injuries consistent with pelvic/abdominal trauma such as diaphragmatic hernia or pelvic fractures. Abdominal Ultrasonography $$ If the above diagnostic findings are suggestive of uroabdomen and ultrasound is available, abdominal effusion should be confirmed using ultrasonography before abdominocentesis is attempted. the FASt (Focused Assessment with Sonography for Trauma) technique may be useful for abdominal fluid detection in dogs. the FASt examination involves obtaining transverse and longitudinal views of the subxiphoid region, the midline position over the bladder, and the right and left flank views to evaluate for the presence of abdominal fluid. Ultrasonography is also useful to detect radiolucent calculi, assess bladder wall abnormalities, and detect lesions in other areas of the urinary tract. Abdominocentesis $ If available, ultrasound-guided abdominocentesis should be attempted to avoid iatrogenic damage to abdominal structures. Blind abdominocentesis should be attempted when ultrasound is not available. the first attempt should be 2 3 cm caudal to the umbilicus at the ventral midline. A four-quadrant abdominocentesis should be attempted if the above techniques are unsuccessful, using the umbilicus as the center point. Collect fluid into both edta (purple top) and serum (red top) tubes for further analysis. Abdominal Fluid Analysis $$ the amount and appearance of abdominal fluid vary. the fluid is most often a serosanguineous transudate but can be a modified transudate or an exudate, depending on its dwell time in the abdomen and the presence of nucleated cells. Chemical analysis using point-of-care analyzers (such as a nova or Vetstat machine) allows rapid evaluation of blood and abdominal fluid. Abdominal fluid creatinine and potassium values greater than blood values are suggestive of uroabdomen. however, in some nonurinary cases of ascites, the creatinine and potassium levels are slightly greater than those of concurrent blood levels. Abdominal Fluid Culture $ Aids in antibiotic selection. Positive-Contrast Studies $$ $$$ Required to confirm and localize the site of leakage. Positive-contrast cystourethrography is used to evaluate for bladder and urethral ruptures. Fluoroscopy provides better temporal resolution of contrast leakage than radiography and may help to better localize the site of rupture. excretory urethrography is recommended for suspected upper urinary tract lesions of the kidney or ureter or when positive-contrast cystourethrography is not conclusive. Advanced Diagnostics $$ $$$$ Laparoscopic sonography, ultrasonographic contrast cystography, cystoscopy, and computed tomography with contrast may be available at a limited number of referral institutions. Summary of Diagnostic Criteria Abdominal fluid creatinine and potassium values greater than serum values. Verification of site of urine leakage with radiologic contrast studies. Progressive azotemia. Diagnostic Differentials Other causes of ascites and azotemia include hemoabdomen, septic or bile peritonitis, neoplastic or chylous effusion, right heart or liver failure, portal hypertension, hypoalbuminemia, pancreatitis, steatitis, and feline infectious peritonitis. most of these differentials can be ruled out by evaluating the abdominal fluid to peripheral blood ratios of creatinine and potassium. If the ratios are equivocal or normal despite a high concern for uroabdomen, the values should be STANDARDS of CARE: e m e R G e n C y A n d C R I t I C A L C A R e m e d I C I n e 3

4 rechecked in 1/2 to 1 hour to determine if they are improving or worsening. If they are worsening, imaging studies should be performed to confirm the site of leakage. If they are improving, uroabdomen is unlikely. TREATMENT RECOMMENDATIONS Initial Treatment Treatment for Shock $ Intravenous isotonic crystalloid fluids such as normosol-r, lactated Ringer s, or 0.9% sodium chloride should be given in small boluses ( of the shock dose; the shock dose is 90 ml/kg in dogs and 60 ml/kg in cats) until resuscitation end points have been reached. Treatment for Hyperkalemia $ Should be instituted if potassium >8 meq/l or ecg conduction disturbances are evident. Characteristic ecg findings consistent with hyperkalemia include a peaked, narrow t wave (K + >5.5 meq/l); a prolonged QRS complex and PR interval and a depressed R-wave amplitude and St segment (K + >6.5 meq/l); a depressed P-wave amplitude (K + >7 meq/l), atrial standstill, and the development of sinoventricular rhythms (K + >8.5 meq/l); and the development of a biphasic QRS complex, ventricular flutter, fibrillation, and asystole (K + >10 meq/l). treatment of severe hyperkalemia involves administration of 10% calcium gluconate ( ml/kg IV over 5 10 minutes during ecg monitoring), 25% dextrose (1 2 g/kg IV over 3 5 min), regular insulin ( U/kg IV) in combination with 25% dextrose (1 2 g/u IV), and sodium bicarbonate (1 2 meq/kg IV over 20 min). 10% calcium gluconate can be given faster during a cardiopulmonary arrest or an impending arrest. ecg abnormalities that necessitate slowing or stopping its administration include a prolonged PR interval, widened QRS complex, shortened Qt interval, shortened or absent St segment, and widened t wave. Following insulin administration, blood glucose needs to be monitored closely for 12 to 24 hours. Patients often require a constant rate infusion of dextrose to prevent hypoglycemia. Pain Control $ For treatment of peritoneal inflammation and concomitant injuries, opioids such as buprenorphine ( mg/kg IV or Im q6 12h), morphine ( mg/kg Im or SC q4 6h in dogs and mg/kg Im or SC in cats), and hydromorphone ( mg/kg IV or Im q4 6h) are commonly used. $ Medical Management Temporary urinary diversion Goals: Promote effective diuresis and correction of electrolyte, metabolic, and acid base derangements. Improve patient comfort by minimizing accumulation of urine in the peritoneal cavity. monitor urine output. methods: Urinary catheter placement in all cases to aid in the quantification of urine output. $ temporary cystostomy tube placement when placement of a urinary catheter is not possible due to urethral obstruction. $$ $$$ Balloon-tipped Foley catheters, mushroomtip catheters, and low-profile gastrostomy tubes can be surgically placed in the bladder. Percutaneous cystostomy catheters, such as Stamey malecot and pigtail catheters, may be difficult to place and maintain due to the bladder s mobility. Percutaneous peritoneal catheter placement for short-term peritoneal drainage. $$ $$$ A multifenestrated peritoneal dialysis catheter is preferred. Other options include trocar chest tubes, red rubber catheters, and Foley catheters. temporary nephrostomy tube placement in cases of ureteral rupture. $$ $$$ Foley catheters, red rubber catheters, and pigtail catheters can be placed into the renal pelvis either surgically or percutaneously with ultrasound guidance. total fluid output from all indwelling catheters should be tabulated regularly (every 1 to 4 hours). Intravenous fluid therapy to replace free water, sodium, and chloride depletion. Fluid deficits should be replaced over 6 to 24 hours while taking into account total losses and maintenance fluid requirements. $ $$ Broad-spectrum antibiotics such as cefazolin (22 mg/kg IV tid) or ampicillin (22 mg/kg IV tid) are recommended if bacteruria or concurrent septic peritonitis is confirmed pending urine or abdominal culture. $ Surgical Management $$$$ to minimize anesthetic risks, surgery should not be pursued until medical treatment has resolved the patient s metabolic, electrolyte, and acid base derangements, often within hours. 4 M A R C H V O L U m e

5 Urethral injuries: Options include debridement and repair of the defect or urethral anastomosis. minor lacerations or punctures can be left to heal by second intention while a urethral catheter and/or a temporary cystostomy tube are in place (5 7 days). A urethrotomy or a permanent cystostomy tube are indicated in cases in which the urethra cannot be repaired. Bladder injuries: debridement and closure are indicated. Partial excision of the bladder may be indicated depending on the type and extent of the injury. Ureteral injuries: Options include debridement and repair, anastomosis, or reimplantation into the renal pelvis or bladder depending on the type and location of the injury. In some cases, nephrectomy may be indicated. Renal injuries: Suturing of the capsule or parenchyma may be necessary to control hemorrhage. Partial or complete nephrectomy may be indicated in cases of severe injury. Anaerobic and aerobic bacteriologic cultures of the abdomen should be obtained after abdominal lavage. $$ tissue samples should be collected as indicated at the time of surgery for histopathologic evaluation. $ $$ Alternative/Optional Treatments/Therapy When surgery is not an option or urethral injury is mild, medical management alone can be attempted for bladder and/or urethral injuries. the use of an indwelling urinary catheter for 1 to 4 weeks has been successful in treating feline bladder rupture and urethral tears. A cystourethrogram should be obtained after catheter removal to verify healing. $$$$ Spontaneous sealing of iatrogenic bladder tears has been reported in dogs. Patient Monitoring hematuria and pollakiuria are common postoperatively but should resolve in 2 to 4 days. Surgical repair of urethral and ureteral injuries can result in stricture formation. Signs of urethral stricture formation include urinary incontinence, stranguria, and dysuria. Uremia may develop due to bilateral ureteral strictures or if the contralateral kidney cannot compensate for a unilateral ureteral stricture. Uroabdomen may recur secondary to surgical site dehiscence. Home Management exercise restriction while surgical incisions heal. Antibiotic therapy for 3 to 6 weeks depending on the results of the abdominal culture obtained at the time of surgery. $ $$ Treatment Contraindications nsaids should be avoided in azotemic animals due to their potentially nephrotoxic effects. Steroids should be avoided due to their potentially immunosuppressive effects. excretory urethrography is contraindicated in dehydrated animals due to its reported nephrotoxic effects from iodinated contrast media in humans secondary to prolonged excretion. PROGNOSIS STANDARDS of CARE: e m e R G e n C y A n d C R I t I C A L C A R e m e d I C I n e Generally favorable; depends on the underlying cause, concurrent injuries, and prompt treatment. mortality rate in dogs reported as 42.3% to 56.2%. mortality rate in cats reported as 38.4%. Favorable Criteria early diagnosis and treatment. metabolic, electrolyte, and acid base derangements responsive to medical therapy within 24 to 48 hours. Surgically correctable cause of uroabdomen. Unfavorable Criteria Cause of uroabdomen cannot be surgically repaired. Severe chemical or septic peritonitis. Severe concurrent injuries. RECOMMENDED READING Beck AL, Grierson Jm, Ogden dm, et al. Outcome of and complications associated with tube cystostomy in dogs and cats: 76 cases ( ). JAVMA 2007;230(8): Boysen SR, Rozanski ea, tidwell AS, et al. evaluation of a focused assessment with sonography for trauma to detect free abdominal fluid in dogs involved in motor vehicle accidents. JAVMA 2004;225(8): Gannon Km, moses L. Uroabdomen in dogs and cats. Compend Contin Educ Pract Vet 2002;24(8): hayashi K, hardie RJ. Use of cystostomy tubes in small animals. Compend Contin Educ Pract Vet 2003;25(12): mcloughlin ma. Surgical emergencies of the urinary tract. Vet Clin North Am Small Anim Pract 2000;30(3): Schmeidt C, tobias Km, Otto Cm. evaluation of abdominal fluid: peripheral blood creatinine and potassium ratios for diagnosis of uroperitoneum in dogs. J Vet Emerg Crit Care 2001;11(4): (continues on page 11) 5

6 UROABDOMEN (continued from page 5) See box below for instructions. ARTICLE #1 CE TEST CE 1. For what reason(s) are male cats more likely to develop uroabdomen than female cats? a. the anatomy of the male urethra b. increased tendency of males to roam and sustain traumatic injury c. increased risk of developing FLUTD d. all of the above 2. In cases of uroabdomen, which of the following is false regarding the abdominal fluid? a. The abdominal fluid is most often serosanguineous. b. The abdominal fluid may contain bacteria. c. An abdominal fluid creatinine value greater than the concurrent blood value is always due to uroabdomen. d. The abdominal fluid is most often a transudate. 3. Injury to which two areas of the urinary tract most commonly results in uroabdomen? a. ureter and bladder b. bladder and kidney c. urethra and ureter d. urethra and bladder 4. Which statement regarding surgery for cases of uroabdomen is false? a. In some cases, minor urethral injuries can heal with medical management alone. b. Surgery should always be pursued immediately following the diagnosis of uroabdomen. c. Hematuria is common postoperatively. d. Surgical ureteral repair may result in ureteral stricture formation. 5. What apparatus can be used to establish peritoneal drainage in cases of uroabdomen? a. a red rubber catheter b. a Foley urinary catheter c. a trocar chest tube d. all of the above The Auburn University College of Veterinary Medicine approves these articles for 1 contact hour each of continuing education credit. Those who wish to apply this credit to fulfill state relicensure requirements should consult their respective state authorities regarding applicability. Subscribers may take individual CE tests online and get real-time scores free of charge at SOCNewsletter.com. STANDARDS of CARE: E M E R G E N C Y A N D C R I T I C A L C A R E M E D I C I N E 11