Case Report Peritonitis Secondary to Necrosis of the Apex of the Urinary Bladder in a Post Parturient Mare K

26 EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2006

Case Report Peritonitis secondary to necrosis of the apex of the urinary bladder in a post parturient mare K. L. SNALUNE† AND T. S.MAIR* Bell Equine Veterinary Clinic, Mereworth, Maidstone, Kent ME18 5GS, UK. Keywords: horse; peritonitis; bladder

Introduction assisted vaginal delivery. The cause of the dystocia was fetal oversize, and the foal was dead when delivered. A small tear in The urinary bladder has a well-protected position in the the caudal vagina was detected after foaling, and a course of abdomen, and traumatic damage to the organ is, therefore, oral potentiated sulphonamides was dispensed. The pregnancy unusual. Trauma to the equine urinary bladder is most followed a successful artificial insemination, and the mare had commonly recognised in neonatal foals, where bladder experienced no complications until parturition. rupture (cystorrhexis) occurs sporadically, especially in male foals (Rooney 1971; Richardson and Kohn 1983; Adams and Clinical findings and diagnosis Koterba 1988; Livesey 1998). It is believed that rupture occurs when high intrauterine pressure is applied to the distended At presentation, the mare had urine scalding of the perineum bladder during parturition. In mature horses, rupture of the and was incontinent with persistent dribbling of urine, normal urinary bladder is uncommon, but has been reported as a rectal temperature (38.3°C), mild tachycardia (44 beats/min) consequence of external trauma (Beck et al. 1996), urethral and normal respiratory rate (12 breaths/min). The oral mucous obstruction due to urolithiasis (McCue et al. 1989; Gibson et membranes were normal in colour and capillary refill time was al. 1992) and parturition (White 1977; Nyrop et al. 1984; normal (2 secs). Intestinal borborygmi were reduced at all Jones et al. 1996; Rodgerson et al. 1999; Higuchi et al. 2002). sites. Palpation per rectum elicited a marked pain response Bladder rupture during parturition is a rare condition in mares, over the pelvis/bladder area, and a soft tissue mass was and has been estimated to occur at a frequency of only 1 in palpable extending from the right side of the cervix into the 10,000 births (Higuchi et al. 2002). It is assumed that the pelvis and over the pelvic brim. Manual and visual vaginal bladder of the foaling mare may become traumatised or examination revealed a generalised vaginitis and vaginal devitalised if it becomes trapped between the pelvic brim and oedema, and a small, granulating vaginal tear was present in the fetus during the tremendous pressures exerted by the caudodorsal roof. A soft fluctuant swelling was palpable in abdominal contractions (Nyrop et al. 1984; Livesey 1998). This the right lateral vaginal wall. Catheterisation of the bladder report describes the medical treatment of a post using a 24 gauge French catheter (Portex horse catheter)1 parturient mare that developed septic peritonitis yielded 5 l of blood-stained urine with a heavy sediment at the secondary to necrosis of the urinary bladder wall end of the flow. following dystocia. Haematology and serum biochemistry were unremarkable except for hyperfibrinogenaemia (5.0 g/l; normal <4.0 g/l). Case details Ultrasonography of the right vaginal wall using a 5 mHz linear array transducer revealed an anechoic haematoma containing History internal septa and echogenic clots. The haematoma extended cranially beyond the cervix. Ultrasonography per rectum A 10-year-old Connemara mare was referred to the hospital revealed a haematoma adjacent to the right side of the body of with a 6 h history of depression, straining, passing small spurts the uterus and within the retroperitoneal tissues of the of urine frequently and mild abdominal pain. Twelve days dorsolateral caudal abdomen and right pelvic canal. Cystoscopy earlier the mare had required veterinary intervention for an was performed using a 180 cm flexible videoendoscope passed via the urethra. A large, roughly circular area of necrotic/haemorrhagic mucosa was observed at the apex of the *Author to whom correspondence should be addressed. †Present address: Newnham Court Veterinary Hospital, Bearsted Road, bladder and extending to the right-hand side. With the bladder Maidstone, Kent ME14 5EL, UK. fully distended by air, this area was estimated to be EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2006 27

Fig 1: Cystoscopic appearance of the apex of the bladder 7 days after admission. The necrotic mucosa is pale and leathery in appearance.

Fig 2: Diagram showing the arterial supply to the approximately 5 cm diameter. No tears of the bladder wall were genitourinary tract of the mare (courtesy of Dr G. Frazer, The identified. Endoscopy of the uterus was unremarkable. Ohio State University). Peritoneal fluid obtained by paracentesis was orange and cloudy. Total protein concentration was 40.1 g/l (normal 2–4 g/l) bladder. Rectal examination revealed that the mass on the right and total nucleated cell count was 23.3 x 109 cells/l side of the vaginal wall had reduced considerably in size. (normal <5.0 x 109 cells/l). Cytology revealed 90% mature/ The ability to urinate was monitored. The mare dribbled degenerate neutrophils and 10% reactive mesothelial cells. The urine intermittently and voided small amounts of urine creatinine concentration of the peritoneal fluid (98 µmol/l) was frequently. The bladder was catheterised daily for one week. similar to the serum concentration (103 µmol/l). No calcium Urine obtained 24 h after admission for analysis was thick and carbonate crystals were identified in the fluid. The peritoneal cloudy in appearance, with 3+ proteinuria, 1+ blood fluid changes were considered consistent with septic peritonitis; however, bacterial culture of the fluid produced no growth and and 3+ leucocytes, pH 8.5 and crystals characteristic of no bacteria were identified by cytology. calcium carbonate. Escherichia coli, sensitive to gentamicin, was cultured from the urine. Ammonium chloride (20 g Initial therapy q. 24 h per os) was added to the diet in an attempt to acidify the urine and prevent sabulous urolithiasis. The mare was hospitalised, initial therapy included sodium At 2 weeks following admission, cystoscopy showed a benzylpenicillin (10 mg/kg bwt i.v. q. 12 h), gentamicin significant reduction in size of the necrotic lesion (to 2 cm sulphate (6.6 mg/kg bwt i.v. q. 24 h) and flunixin meglumine diameter) with the area of granulation tissue increasing in size. (0.25 mg/kg bwt i.v. q. 6 h). The bladder was catheterised daily. Peritoneal fluid analysis was normal, with a total protein concentration of 14.7 g/l and total nucleated cell count Follow-up and outcome 3.74 x 109 cells/l. The cell population included 60% mature, hypersegmented polymorphonuclear cells, 30% mesothelial Over the next 24 h the mare remained bright but was anorexic. cells and 10% small mononuclear cells. Repeated rectal and vaginal examinations showed no changes. At this stage, treatment with i.v. antibiotics was Hysteroscopy revealed no uterine tears, but a small amount of discontinued and oral potentiated sulphonamides (30 mg/kg purulent material was present, especially in the right horn. Fine bwt per os q. 12 h) commenced. The mare was discharged with needle aspiration of the vaginal mass yielded serous fluid. a 2 week course of oral potentiated sulphonamides. Normal Bacterial culture of this fluid produced no growth. full-stream urinations were observed before discharge from the Over the next few days, the mare’s appetite returned to hospital. The mare was re-examined 2 months after discharge, normal and the horse remained bright and alert, with normal at which time she was fit and well. Endoscopic examination of rectal temperature and pulse and respiratory rates. Progression the bladder was considered normal. Four years after discharge, of the condition was monitored by cystoscopy and abdominal the mare was clinically normal and urinating normally. paracentesis every 48 h. Over the first week, cystoscopy showed the well-demarcated necrotic mucosa at the apex to adopt a Discussion pale leathery appearance (Fig 1), and slowly reduce in size. At 10 days after admission the affected area had reduced to Foaling injuries involving the urinary tract can result in rupture, approximately 3.5 cm diameter; a small island of granulation prolapse or eversion of the urinary bladder (White 1977; Behr tissue was observed protruding through this area centrally. et al. 1981; Nyrop et al. 1984). The pathogenesis of bladder Three smaller patches (<1 cm diameter) of necrotic mucosa rupture in parturient mares may involve compression and were identified on the ventral floor of the body and neck of the contusion of the bladder between the foal and the pelvic brim 28 EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2006

of the mare, leading directly to rupture of the bladder, or to In man, the diagnosis of bladder contusion can be aided by crushing and subsequent necrosis of the bladder wall (White contrast cystography which reveals an intact bladder deformed 1977; Nyrop et al. 1984; Jones et al. 1996). Rodgerson et al. by a pelvic haematoma, giving a teardrop appearance and (1999) suggested that the ventral and lateral regions of the deviation/elevation to one side of the pelvis (Brosman and Fay urinary bladder are more susceptible to trauma because the 1973). Unfortunately, such techniques are not possible in fetus may possibly dampen dorsally directed pressures. In the mature horses, but the diagnosis in this mare was aided by present case, although the main area of trauma was at the cystoscopy and ultrasonography. Endoscopic examination of apex (cranial aspect), subsequent cystoscopy revealed smaller the urinary tract was a particularly useful diagnostic tool, as in areas of devitalised mucosa on the ventral floor of the body previously reported cases (Gibson et al. 1992; Nyrop et al. and laterally at the neck of the bladder. Necrosis rather than a 1984). In the present case there appeared to be no discrete tear discrete tear of the bladder wall was observed in this mare. of the bladder wall and this permitted adequate insufflation to This has been recorded previously in a gelding with urethral allow a thorough endoscopic examination. The identification obstruction (Gibson et al. 1992), and is recognised in male and visualisation of full-thickness tears in the bladder wall may cattle with urolithiasis (O’Connor 1974; Kerkenezov 1975; not always be possible, because of the inability to distend the Bowman and Walker 1979). Although we did not definitively ruptured bladder with air (Higuchi et al. 2002). Gibson et al. prove that the necrosis extended through all layers of the (1992) used cystoscopy to identify an area of necrosis of the bladder wall, the presence of septic peritonitis suggested that bladder in a mature gelding following urethral obstruction by a this was the case. Examination of the serosal surface of the urinary calculus, and endoscopic examination was also bladder by laparoscopy was considered, but was not extremely useful in the present case as a means of monitoring performed because of financial constraints. the healing of the lesion. Parturition in this mare was complicated by dystocia, and Abdominocentesis was also found to be valuable in some previously recorded cases of post partum bladder monitoring the response to treatment. Peritonitis has not been trauma have also been associated with dystocia (Jones reported frequently after urinary bladder rupture in foals et al. 1996; Rodgerson et al. 1999). However, other authors (Hackett 1984), but appears to be a common sequela in mature have stated that bladder rupture is usually seen following a horses (Firth 1976; Trotter et al. 1981; Higuchi et al. 2002). normal delivery (Higuchi et al. 2002). Gibson et al. (1992) proposed that most cases of septic Another potential cause for the bladder wall necrosis in peritonitis following bladder rupture in mature individuals are this mare was ischaemia associated with damage to the cranial related to the presence of bacterial cystitis, often associated vesicle artery secondary to rupture of the internal pudendal with urolithiasis. However, urine itself can cause a chemical artery. Rupture of the uterine arteries is a well-recognised peritonitis and uroperitoneum may predispose the abdominal cause of periparturient colic and death, especially in old, cavity to secondary bacterial infection (Sockett and Knight multiparous mares (Rooney 1964; Dwyer 1993; Rossdale 1984). In the present case, urine analysis revealed evidence of 1994). Less commonly, the internal pudendal artery and its bacterial cystitis and the septic peritonitis was assumed to have branches may become damaged and a haematoma from been caused by leakage of bacteria through the necrotic these vessels may dissect along the fascial planes within the bladder wall into the peritoneal cavity. Although no bacteria pelvic canal, presenting as a unilateral vaginal and/or vulvar were cultured from the peritoneal fluid, the mare was on swelling (Rossdale 1994). A right unilateral vaginal antibiotic treatment at the time that the sample was taken and haematoma was present in this mare, suggesting that rupture this could have affected the culture results. Similar concerns of the internal pudendal artery may have occurred. The relate to the culture results of the urine and the sample of fluid possibility of infection of this retroperitoneal haematoma as a aspirated from the haematoma. There was no evidence of cause of the depression in this mare was considered on initial uroperitoneum in this mare and the peritoneal creatinine examination, but the absence of pyrexia and the results of concentration was similar to the serum concentration. If subsequent fluid analysis ruled this out. uroperitoneum had been identified, surgical repair of the The internal pudendal artery is the first branch off the bladder wall defect would probably have been attempted. A internal iliac artery, and subsequently branches to give rise to similar recommendation has been made in man, where the umbilical artery. The umbilical artery gives off a branch to peritoneal fluid creatinine levels have been used to aid the the ureter before narrowing and losing its patency as the decision to perform an exploratory laparotomy in intraperitoneal vestigial round ligament of the bladder. Just before it loses its bladder injuries following trauma (Deck and Porter 2000). patency, the umbilical artery gives off the cranial vesicle artery, The preferred method of treatment of ruptured bladder which supplies the apex of the bladder (Fig 2). It is reasonable is primary surgical closure (Livesey 1998). In neonatal foals, to speculate, therefore, that rupture and haematoma rupture of the bladder most commonly occurs on the cranial formation involving the right internal pudendal artery might dorsal surface, and surgical repair via a ventral midline have affected blood flow within the umbilical and cranial laparotomy is usually possible (Livesey 1998). Occasionally, vesicle arteries, which subsequently resulted in ischaemia of ventral ruptures that extend into the neck of the bladder are the apex of the bladder. The fact that the necrotic area of encountered, making exposure and repair of their caudal bladder wall was placed slightly towards the right side would margin difficult (Robertson and Embertson 1988). In mature support this proposed mechanism. horses, the location and dimension of the tear determine EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2006 29

the most appropriate surgical approach for attempted bladder, a urethral catheter attached to continuous suction repair. In post partum mares, tears are most commonly provided effective drainage (Gibson et al. 1992). Beck et al. reported on the ventral, cranial or lateral aspects of the (1996) used a passive drain with a one-way valve to provide bladder (White 1977; Nyrop et al. 1984; Jones et al. 1996; drainage of the bladder in an 18-month-old filly. Rodgerson et al. 1999; Higuchi et al. 2002). Exposure of Although necrosis of the urinary bladder wall is a rare tears on the ventral and caudal aspects of the bladder can complication of parturition, such damage should be be impossible using a standard ventral midline approach considered in mares presenting with signs of dysuria or (Nyrop et al. 1984; Rodgerson et al. 1999). Prolapse of the uroabdomen in the post partum period. The possibility of bladder via a vaginal and/or urethral incision in a standing ischaemic damage to the apex of the bladder should also be position has proved to be a successful technique in a considered in mares that present with signs of rupture of the number of mares (Rodgerson et al. 1999; Higuchi et al. internal pudendal artery. Abdominocentesis, ultrasonography 2002). Surgical treatment by subtotal cystectomy was (rectal and abdominal), rectal palpation and cystoscopy can be considered in the present case but, in the absence of used to make a definitive diagnosis. uroperitoneum or a visible tear in the bladder wall, it was decided to treat the mare conservatively. Manufacturer’s address The successful medical management of a 9-year-old gelding with uroperitoneum associated with bladder wall 1Arnolds Veterinary Products Ltd, Shrewsbury, Shropshire, UK. necrosis has been described previously (Gibson et al. 1992). Treatment of the mare in the present report included Acknowledgements administration of broad-spectrum bactericidal antibiotics, ‘anti-endotoxin doses’ of flunixin meglumine and repeated The authors are grateful to colleagues at the Bell Equine urinary catheterisation. Repeated catheterisation was chosen Veterinary Clinic for assistance with this case. The advice of Dr in preference to use of an indwelling urinary catheter. The Grant Frazer, The Ohio State University, is gratefully efficacy of indwelling urethral catheters in horses remains to acknowledged. T.S.M. is in receipt of a Specialist Clinical be determined. In man, indwelling urethral catheters are an Award from the Home of Rest for Horses. important component of conservative therapy for bladder rupture and prevent pooling of urine and aid healing of the References defect by second intention within 2–3 weeks. Potential Adams, R. and Koterba, A.M. (1988) Exploratory celiotomy for complications related to the use of urethral catheters include suspected urinary tract disruption in neonatal foals: a review of 18 urinary tract infections, calculi formation, urethritis and cases. Equine vet. J. 20, 13-17. stricture formation (Lavoie and Harnagel 1988). For these Beck, C., Dart, A.J., McClintock, S.A. and Hodgson, D.R. (1996) reasons, in particular the difficulties in maintaining catheter Traumatic rupture of the urinary bladder in a horse. Aust. vet. J. cleanliness in a mature mare, we chose not to use an 73, 154-155. indwelling urinary catheter. However, daily catheterisation was Behr, M.J., Hackett, R.P., Bentinck-Smith, J., Hillman, R.B., King, J.M. performed and this might also have predisposed to infection. and Tennant, B.C. (1981) Metabolic abnormalities associated with In man, multiple catheter changes have been associated with rupture of the urinary bladder in neonatal foals. J. Am. vet. med. Ass. 178, 263-266. an increased risk of bacterial colonisation and infection (Kotkin Bowman, K.F. and Walker, D.F. (1979) Surgical repair of a ruptured and Koch 1995), although indwelling catheter hygiene is more urinary bladder diverticulum in a bull. J. Am. vet. med. Ass. 175, easily achieved than in horses. 454-456. Initially the mare in the present report was capable of Brosman, F.A. and Fay, R.F. (1973) Diagnosis and management of passing only small amounts of urine, but showed no signs of bladder trauma. J. Trauma 13, 687-694. straining or abdominal pain following the initial treatment. Deck, A.J. and Porter, J.R. (2000) Diagnostic peritoneal lavage as sole Daily catheterisation was found to be well tolerated and was indicator of intraperitoneal bladder rupture: case report. J. Trauma considered necessary to evacuate the bladder completely and 49, 946-947. remove debris, calcium carbonate crystals, bacteria. After the Dwyer, R. (1993) Postpartum deaths of mares. Equine Dis. Quart. 2, 5. first week, the mare was capable of passing increased volumes Firth, E.C. (1976) Urethral spincterotomy for delivery of vesical calculus of urine spontaneously, and catheterisation was no longer in the mare: a case report. Equine vet. J. 8, 99-100. considered necessary. The catheterisation and endoscopic Gibson, K.T., Trotter, G.W. and Gustafson, S.B. (1992) Conservative examinations were performed with strict aseptic technique, management of uroperitoneum in a gelding. J. Am. vet. med. Ass. since they are recognised as potential factors leading to 200, 1692-1694. iatrogenic infection of the urinary bladder (Lavoie and Harnagel Hackett, R.P. (1984) rupture of the urinary bladder in neonatal foals. Comp. cont. Educ. pract. Vet. 6, S488-S494. 1988). Although an indwelling urinary catheter was not used in this mare, this technique has been used successfully in Higuchi, T., Nanao, Y. and Senba, H. (2002) Repair of urinary bladder rupture through a urethrotomy and urethral sphincterotomy in previously reported cases. An indwelling catheter attached to a four postpartum mares. Vet. Surg. 31, 344-348. continuous suction drainage led to sealing of a bladder defect Jones, P.A., Sertich, P.S. and Johnston, J.K. (1996) Uroperitoneum in 5 days in one foal (Lavoie and Harnagel 1988). In another associated with ruptured urinary bladder in a postpartum mare. report of a mature gelding with an intact but devitalised Aust. vet. J. 74, 354-358 30 EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2006

Kerkenezov, P. (1975) Subtotal cystectomy in a Santa Gertrudis bull. Robertson, J.T. and Embertson, R.M. (1988) Surgical management of Aust. vet. J. 51, 322-323. congenital and perinatal abnormalities of the urogenital tract. Vet. Kotkin, L. and Koch, M.O. (1995) Morbidity associated with Clin. N. Am.: Equine Pract. 4, 359-379. nonoperative management of extraperitoneal bladder injuries. J. Rodgerson, D.H., Spirito, M.A., Thorpe, P.E. and Hanson, R.R. (1999) Trauma 38, 895-898. Standing surgical repair of cystorrhexis in two mares. Vet. Surg. 28, Lavoie, J.-P. and Harnagel, S.H. (1988) Nonsurgical management of 113-116. ruptured urinary bladder in a critically ill foal. J. Am. vet. med. Ass. Rooney, J.R. (1964) Internal hemorrhage related to gestation in the 192, 1577-1580. mare. Cornell Vet. 54, 11. Livesey, M.A. (1998) The ruptured bladder. In: Current Techniques in Rooney, J.R. (1971) Rupture of the urinary bladder in the foal. Vet. Equine Surgery and Lameness, Eds: N.A. White and J.N. Moore, Pathol. 8, 445-451. 2nd edn., W.B. Saunders Co., Philadelphia. pp 206-208. Rossdale, P.D. (1994) Differential diagnosis of post parturient McCue, P.M., Brooks, P.A. and Wilson, W.D. (1989) Urinary bladder haemorrhage in the mare. Equine vet. Educ. 6, 135-136. rupture as a sequela to obstructive urethral calculi. Vet. Med. 84, 912-914. Sockett, D. and Knight, A.P. (1984) Metabolic changes associated with Nyrop, K.A., DeBowes, R.M., Cox, J.H. and Coffman, J.R. (1984) obstructive urolithiasis in cattle. Comp. cont. Educ. pract. Vet. 6, Rupture of the urinary bladder in two postparturient mares. Comp. S311-S315. cont. Educ. pract. Vet. 6, S510-S513. Trotter, G.W., Bennett, D.G. and Behm, R.J. (1981) Urethral calculi in O’Connor, J.P. (1974) Urethral obstruction and rupture of the urinary five horses. Vet. Surg. 10, 159-162. bladder in cattle. Irish vet. J. 28, 233-236. White, K.K. (1977) Urethral sphincterotomy as an approach to repair Richardson, D.W. and Kohn, C.W. (1983) Uroperitoneum in the foal. of rupture of the urinary bladder in the mare: a case report. J. J. Am. vet. med. Ass. 182, 267-271. equine Med. Surg. 1, 250-253.

Clinical Commentary Assessment of peritonitis in the complicated post partum mare C. A. RAGLE Washington State University, Pullman, Washington, USA.

The list of complications that can result from the act of foaling Mair (2006) was, in my opinion (not being there), most is long and diverse (Frazer 2003a,b). Despite this variety of probably due to the distended, traumatised bladder. In my complications, the presenting signs are often vague and experience, few conditions will elicit as much reaction on nondistinct. The above report by Snalune and Mair (2006) transrectal examination as digital pressure on an overly full demonstrates this, with the recorded history of depression, bladder (innervated). It is interesting to speculate on the mild colic and pollakiuria. Clinical signs that might be explained mechanism and sequence of bladder damage and by a wide range of disease processes dictate a complete history, dysfunction. Did bladder trauma during the dystocia lead to close observation and a thorough clinical examination. Only dysfunction with overflow incontinence, or was the mare with a systematic diagnostic plan can a complete and accurate unable or unwilling, due to pain, to posture and urinate problem list be derived. As the old adage goes, for every one normally, thereby adding more insult (e.g. over-distension) to thing you miss for not knowing, you will miss 10 for not an already damaged bladder? Perhaps a large blood clot had looking. A positive sign in the report was that the horse arrived obstructed the urethra for a period of time, building up back- 12 days after a dystocia having normal temperature, pulse, pressure and causing further bladder damage and respiration and mucous membrane colour and refill time. In dysfunction? These are the types of questions that we can addition, the single alteration of the blood evaluation, a mild never answer retrospectively. Having questions that we elevation of fibrinogen, was indicative of a minimal systemic cannot answer also highlights the need to focus on the response. That said, the literature is replete with seriously ill questions we can answer. The urogenital examination horses that looked much better on paper! This also reminds us revealed minor damage to the vaginal vault and a of the importance of monitoring the progression of a disease haematoma on the right side of the vagina and uterus, as process vs. the status at a single point in time. well as serosanguinuous fluid in the bladder, with mucosal Careful examination of the caudal abdomen is required in damage. Through the use of endoscopy, it was determined all complicated post partum mares. The painful response to that there were no direct rents between the urogenital tract transrectal palpation in the mare described by Snalune and and abdomen. EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2006 31

Fig 1: Laparoscopic view from right paralumbar fossa in a post Fig 2: Laparoscopic view from right paralumbar fossa in a post partum mare. A = Dorsal edge of mesocolic rent; B = ventral partum mare. A = Haematoma within mesocolon; a = devitalised portion of ruptured mesocolon; C = left ovary, seen through the portion of haematoma wall; B = duodenum; C = caecum. mesocolic rent.

Since other pathology (e.g. disruption of the decending particular, in this mare, the endoscopy provided the important mesocolon) can occur in the abdomen, abdominocentesis is information that the uterus was intact but areas of obvious warranted in all complicated post partum cases (Fig 1). There compromise existed in the bladder. Although an uncommon has been speculation in the past as to whether peritoneal route of infection of the peritoneum, it is important to values are generally altered in the mare after foaling. A study remember that the abdominal cavity of the mare addressing this (Frazer et al. 1997) concluded that a single, communicates with the uterus, and therefore the external mildly elevated peritoneal value (total protein, total nucleated environment, via the Fallopian tubes. In this mare, purulent cell count, percentage of neutrophils) is likely to be an material seen during endoscopy in the right uterine horn could incidental finding, whereas 2 or more elevated values inevitably have contributed to the peritonitis. signal the onset of clinical abnormalities. Normal peritoneal The downside of endoscopy of the uterus and bladder is values for the horse are: total protein <20 g/l; total nucleated that it allows viewing only of the endometrial and mucosal cell count 1–10 x 109 (most agree with <5 x 109); differential surfaces respectively; it is therefore of little help with cell count 45–75% polymorphonuclear neutrophils and transmural lesions. Whenever a hollow viscus has been 30–50% mononuclear cells (monocytes, macrophages and traumatised, the ideal standard would be to view both the mesothelial cells); and glucose 5.0–6.4 mmol/l (Browning interior and exterior surfaces to assess viability and integrity. I 2005). Classifications of body cavity effusions include suggest that the complicated post partum mare is an ideal transudate (normal protein and cell count), modified candidate for exploratory laparoscopy (Hassel and Ragle 1994; transudate (elevated protein with normal cell count) and Ragle et al. 1997). Financial constraints are faced by every exudates (elevated protein and elevated cell count). Exudates equine clinician and horse-owner; how much money is spent can be further classified as having a septic (presence of bacteria and on what reflects the art of veterinary medicine as much as and degenerative neutrophils or positive culture) or nonseptic any other aspect of practice. Most clients will risk the money if (no bacteria and nondegenerative neutrophils) cause. Other they have evidence that the horse’s condition has a reasonable values helpful in determining septic peritonitis are peritoneal chance of responding to the proposed treatment. It costs fluid pH <7.3, glucose <300 mg/l and fibrinogen concentration money to determine that prognosis and course of action, and >2 g/l. A serum to peritoneal glucose concentration difference money invested up-front can save a lot being expended over >500 mg/l is a strong indicator of septic peritonitis (Hoogmoed several weeks. It is never the patients that get better or die et al. 1999). Grey zones exist in any classification scheme, but quickly that cause the majority of headaches to us or our a major indicator of an abnormal peritoneal fluid sample is clients; it is those that will do neither, and the sooner they are identification of a compartment for further evaluation. The identified the better! Any risk of the laparoscopy procedure is mare in the report by Snalune and Mair (2006) had peritoneal very low and the potential for valuable clinical information is protein elevated to a greater degree relative to the nucleated high. When combined with endoscopy and ultrasound, cell count. Mares with a haematoma of the broad ligament can laparoscopy will provide the most clinically useful set of images have peritoneal protein values up to 50 g/l and a normal total possible. This is extremely important in achieving a complete nucleated cell count (Frazer et al. 1997). picture of the various sites of trauma (as in this mare, more The challenge for any veterinarian is determination of the than one site of contusion or disruption is common), as well as site or sites of damage eliciting the inflammatory reaction and establishing the primary foci of inflammation, if there is one. proper management of that injury. The use of diagnostic The primary indicator in the complicated post partum mare of imaging, including endoscopy and ultrasound, is an excellent a problem involving the abdominal cavity is abnormal way to define lesions that are hidden from direct viewing. In peritoneal fluid indicating peritonitis. It is reported that the 32 EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2006

nucleated cell count in the abdominal fluid of horses with In summary, any structure in the abdominal cavity can be peritonitis does not always correlate with the severity of the injured during foaling and such injury often leads to peritonitis disease or the prognosis (Dickinson 2003). This observation with vague clinical signs. It is imperative that the primary parallels my experience and I have found laparoscopy very sources of inflammation be identified as soon as possible to helpful in bridging the gap between abdominal fluid analysis allow rapid surgical or medical treatment. Timely and and clinical signs. I think that, as veterinarians, there is only so complete visual evaluation of the urogenital and abdominal much we can expect to determine from peritoneal fluid cavity and early intervention is the most successful and cost analysis; when in doubt, it is much better to view the parietal effective method of management of the complicated post and visceral surfaces of the abdominal cavity for direct partum mare. appearances of inflammation. This is especially true when the area of interest is the caudal abdomen and pelvic inlet, as this References is one of the most viewable areas of the horse’s abdomen. It has been noted that laparoscopy itself will affect abdominal Browning, A. (2005) Diagnosis and management of peritonitis in fluid parameters, but in this author’s opinion the value of the horses. In Pract. 27, 70-75. information gained far outweighs any temporary loss of Dickinson, C. (2003) Peritonitis. In: Equine Internal Medicine, 2nd sensitivity of abdominal fluid analysis (Fig 2). edn., Eds: S.M. Reed, W.M. Bayly and D.C. Sellon, W.B. Saunders Co., Philadelphia. pp 941-949. The clinicians involved in the preceding report (Snalune Frazer, G.S. (2003a) Post partum complications in the mare. Part 1: and Mair 2006) are to be commended for their successful Conditions affecting the uterus. Equine vet. Educ. 15, 36-44. management of this mare. Although the bladder survived the Frazer, G.S. (2003b) Post partum complications in the mare. Part 2: insult, repair of ruptured bladder in the mature horse, Fetal membrane retention and conditions of the gastrointestinal especially if it involves partial resection, can be difficult due to tract, bladder and vagina. Equine vet. Educ. 15, 91-100. the poor exposure afforded via a ventral abdominal approach. Frazer, G., Burba, D., Paccamonti, D., Blouin, D., LeBlanc, M., I have minimal experience with prolapse or eversion of the Embertson, R. and Hance, S. (1997) The effects of parturition and bladder into the vaginal vault for surgical closure, but it would peripartum complications on the peritoneal fluid composition of be my technique of choice in mares where no vaginal mares. Theriogenol. 48, 919-931. haematoma obstructs access. If vaginal access were an issue, Hassel, D.M. and Ragle, C.A. (1994) Laparoscopic diagnosis and a laparoscopic approach could be used, as in the stallion conservative treatment of uterine tear in a mare. J. Am. vet. med. Ass. 205, 1531-1533. (Walesby et al. 2002). The bladder is a robust structure in the Hoogmoed, L.V., Rodger, L.D., Spier, S.J., Gardner, I.A., Yarbrough, adult, with resilient healing properties to trauma (especially T.B. and Snyder, J.R. (1999) Evaluation of peritoneal fluid pH, surgical trauma). Maintaining continence, function as a glucose concentration, and lactate dehydrogenase activity for reservoir for urine and the ability to fill and empty normally is detection of septic peritonitis in horses. J. Am. vet. med. Ass. 214, the goal of any intervention. The mechanism proposed by 1032-1036. Snalune and Mair (2006) of apical bladder necrosis due to Ragle, C.A., Southwood, L.L., Galuppo, L.D. and Howlett, M.R. (1997) vascular occlusion of right cranial vesical artery is interesting. I Laparoscopic diagnosis of ischemic necrosis of the descending have previously expressed a similar proposed mechanism for colon after rectal prolapse and rupture of the mesocolon in two postpartum mares. J. Am. vet. med. Ass. 210, 1646-1648. signs of abdominal pain post ovariectomy, i.e. uterine horn tip Snalune, K.L. and Mair, T.S. (2006) Peritonitis secondary to necrosis of ischaemia by occlusion of the uterine branch of the ovarian the apex of the urinary bladder in a post parturient mare. Equine artery; evidence now suggests that I was wrong. Collateral vet. Educ. 18, 20-24. circulation is well developed in the urogenital tract, and at this Walesby, H.A., Ragle, C.A. and Booth, L.C. (2002) Laparoscopic repair point we must allow time and other inspired and inquiring of ruptured urinary bladder in a stallion. J. Am. vet. med. Ass. 221, minds to separate fact from theory. 1737-1741.

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Authors: H.M. Clayton, P.F. Flood and D.S. Rosenstein Publisher: Mosby, 2005 Binding: Hardback | 240 pages

This new volume is the first photographic atlas of equine anatomy to integrate illustrations of prepared specimens with correlative images of the same structures as visualised by each of the commonly used imaging modalities; radiography, ultrasound and endoscopy. Additional artwork illustrates the position and orientation of these structures in the living animal, as they would most commonly be encountered, either in the course of a physical examination or as they present in the prone animal, during a surgical procedure. Thus the atlas has a true utility for the practitioner as well as the student.

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