Mesometrial hemotoma causing peritonitis

Keywords: equine, hematoma, mesometrium, fatal, foaling, peritonitis

An unusual variation of a mesometrial hematoma caused by a ruptured uterine artery. 

In this case, the hematoma spread more caudally than is common. Eventually its contents seeped into the peritoneal cavity through the site marked by the forceps in this image. In addition, a small thread-like fistula existed between the caudal area of the cervix and the most caudal part of the hematoma. This fistula may have formed as a result of cervical laceration during foaling. A long blunt probe was passed through the fistula to reveal its location in this image.

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Several days after foaling, the mare developed severe acute peritonitis and died. It was concluded that infection had spread into the hematoma from the injury in the cervix (lowest red arrow), through the hematoma and into the peritoneal cavity (upper red arrow & forceps).

Because of the pressure required to dissect connective tissue and form this large hematoma, it was remarkable that blood had not burst into the peritoneal cavity at the time of foaling. Perhaps bleeding had been intermittent, allowing a degree of coagulation. This would have permitted the hematoma itself to act like a valve, preventing blood from entering the peritoneal cavity where the forceps are shown here. Also, there were no obvious signs of putrefaction in the blood clot although it was clearly the only source of infection for the peritonitis that ensued.  Cytology of the coagulum was not performed; an important omission in this case. In retrospect, it would probably have revealed many bacteria.

For consideration by clinicians: Routine examination of the mesometrium by ultrasonography immediately after foaling is seldom if ever done. The author is in favor of routine examination of the vagina after foaling to detect tears into the peritoneal cavity. However, some owners object to this practice on the basis that it could interfere with dam-offspring bonding. If an owner allows this, it may be good practice to examine the mesometrium and pelvis for hematomas at the same time. If a hematoma is detected via ultrasonography, one could consider prophylactic treatment with antibiotics and tetanus toxoid.

Ultrasonography of intra- and extrauterine hemorrhage.

Keywords: ultrasound, hemorrhage, uterus, mesometrium, equine

1. A hematoma seen in the mesometrium (Me) at the time of foal heat breeding.  Like the majority of mares with mesometrial hematomas, this mare showed no outward symptoms at the time of foaling. The structure was clearly palpable per rectum; hence the ultrasonograph.

2. A similar hematoma to that described above but older, more consolidated and more echogenic.

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3. Intra uterine (IU) hemorrhage in a mature mare presented because of a foul smelling vaginal discharge at 35 days post foaling. The mare was systemically normal but ultrasonography and a glove hand examination of the uterus revealed masses of clotted blood, seen here on ultrasound in the left uterine horn. This was hemorrhage was presumed to be due to a severe partial thickness endometrial tear, sustained during parturition. The hooves of foals can cause these tears.

Most of the clotted blood was removed by hand then the uterus was flushed with saline. Antibiotics and tetanus toxoid were administered. The uterus appeared to be normal on ultrasonography at the time of discharge but the mare was lost to follow up.

4. Two images of an unusual intra-endometrial (IE) multilocular cyst at the approximate time of foal heat. Its contents were not consistent with the non-echogenic fluid usually seen in endometrial lymphatic cysts. However, this mare was known to have endometrial lymphatic cysts before she conceived. Therefore it is possible that this was a group of cysts that was traumatized during foaling, causing hemorrhage within the cysts.

Reference

Dolente, B.A. et al. 2005. Mares admitted to a referral hospital for postpartum emergencies: 163 cases (1992-2002). J.Vet.Emergency and Critical Care 15: 193-200