Uterine Tears


Chapter 160

Uterine Tears



David E. Freeman


Uterine tears, ruptures, and lacerations are among the most common causes of postpartum peritonitis in mares. Among causes of postpartum deaths in 98 mares in one study, uterine tear (6% mortality rate) was the third most common cause of death, after ruptured uterine artery (40%) and cecal perforation (19%), and in 163 mares referred with postpartum emergencies, uterine tear was diagnosed in 5.5% of the cases. Uterine tears are as likely to develop spontaneously during stage II of parturition as during correction of dystocia. Tears also develop before parturition, in association with hydramnios and uterine torsion or as a complication of rolling the mare to correct late-gestation uterine torsion. Uterine tear has also been reported as a consequence of uterine lavage.


Uterine tears have been reported in the uterine horns and in the body, and in ventral and dorsal sites in both (Table 160-1). Right horn involvement is more frequent, a difficult finding to explain because pregnancy should be equally distributed between both horns.



TABLE 160-1


Location of Tears and Success Rates for Successful Diagnosis on Palpation*
































Tear Location as Determined at Surgery Sutter et al, 2003 (33 Mares) Javsicas et al, 2010 (49 Mares)
Uterine body 8/30 (27%) 7/27 (26%)
Uterine horn 22/30 (73%) 20/27 (74%)
Right horn 22/30 (73%) 13/18 (72%)
Left horn 8/30 (27%) 5/18 (28%)
Successful identification of tear in uterine body by palpation 8/8 (100%) 5/5 (100%)
Successful identification of tear in uterine horn by palpation 3/22 (14%) 4/17 (24%)


* The differences between the total numbers in the study and the denominators in any category result from variations in the final number for which the information was recorded or in which the procedure was attempted. For example, for palpation of a uterine horn tear, data are presented for the number of correct identifications out of the total number attempted when the tear was actually confirmed in that location.



 Palpation was transvaginal in the Javsicas study and either transvaginal or per rectum in the Sutter study.



Diagnosis


Few mares presenting with signs and physical findings supporting a presumptive diagnosis of uterine tear have another lesion that could present in a similar manner. Affected mares typically are presented for evaluation up to 6 days after parturition, but the sooner a diagnosis of a uterine tear is made, the better the prognosis. The classic presentation is a mare that has depression, inappetence, colic, congested membranes, reduced frequency of borborygmus, and fever within the first few days after parturition. One fourth to one half of affected mares have gastric reflux.


Diagnosis by transrectal or transvaginal uterine palpation is complicated by the large size of the postpartum uterus in mares, which puts most uterine horn tears beyond reach (see Table 160-1). Also, pronounced postpartum endometrial folds can conceal small or partial-thickness tears. In large tears that develop secondary to uterine torsion, the foal can be palpated in the abdominal cavity directly through the rectal wall and more cranially in the abdomen than is usual. In such cases, the uterus can feel smaller than expected and highly toned.


Leukopenia is strongly associated with a diagnosis of uterine tear, although leukopenia can also be detected to a lesser extent in mares with metritis and postpartum disease of the cecum and small colon. Although mares with uterine tear associated with dystocia can have leukocytosis and neutrophilia with a left shift on the day of delivery, this is followed by marked leukopenia and neutropenia developing by day 3 after parturition and persisting to day 5. Circulating neutrophils frequently have toxic changes on cytology.


Abdominal ultrasonographic examination immediately after foaling may reveal no abnormal changes, but increased quantities of abdominal fluid with increased echogenicity and possibly fibrin tags are suggestive of peritonitis, and this can be confirmed by abdominocentesis. It is important to realize that normal parturition and even prolonged obstetrical manipulations do not change the peritoneal fluid profile from normal. A high value for a single peritoneal fluid analysis parameter can be considered as incidental, but two or more of the following could indicate severe postpartum disease: total protein concentration higher than 3.0 g/dL, total nucleated cell count higher than 15,000 cells/µL, and percentage of neutrophils higher than 80%. In mares with a uterine tear, peritonitis is exacerbated when uterine infusion is performed to remove a retained placenta and by fecal peritoneal contamination from foals that had fetal diarrhea during birth. Microbial culture of peritoneal fluid may yield no growth or polymicrobial growth, but monomicrobial growth is the most common culture result. Microorganisms isolated from peritoneal fluid can have a similar profile to the species of bacteria cultured from the uterus of postpartum mares. On cytologic examination, phagocytized bacteria, hemosiderin-laden macrophages, degenerated neutrophils, and extracellular bacteria can be seen.


In a small proportion of mares, uterine tears can be complicated by concurrent gastrointestinal lesions, such as large colon volvulus or evisceration (through the tear) of the large colon, small colon, or small intestine; hemorrhage from the vagina and uterine artery rupture are additional possible complications. Eviscerated intestine should be lavaged with warm sterile 0.9% saline and examined for mesenteric and vascular damage before it is returned to the abdomen, and abdominal surgery for resection and anastomosis may be necessary. Rare presentations that have been reported are a long-standing tear that caused a 16-month history of infertility as the sole clinical sign in one mare, and a partial-thickness tear that formed a small fluid-filled diverticulum covered by intact serosa in another mare.

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Jul 8, 2016 | Posted by in EQUINE MEDICINE | Comments Off on Uterine Tears

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