Surgical Diagnosis and Management of a Full-Term Ectopic Pregnancy in a Gerenuk (Littocranius walleri walleri)
A 4-year-old 30 kg female gerenuk (Littocranius walleri walleri) in late-term gestation was examined for weight loss and acute onset of ventral mandibular edema. Based upon last known breeding date, the gerenuk was approximately 208 days into gestation at the time of initial presentation (normal gestation length in gerenuk ∼210 days). The gerenuk had given birth to a healthy male calf the previous year with mild cranioventral abdominal edema noted approximately 1-week post-partum that resolved spontaneously within several days. Significant findings at physical examination included thin body condition, moderate pitting edema in the intermandibular space, and a large late-term fetus palpable within the abdominal cavity. Abdominal ultrasound detected a fetal heart beat with increased fluid within the placental membranes. Large fetal size prohibited more detailed ultrasonography. Hydrops amnion or allantois was suspected. Two days following initial presentation the mandibular edema had resolved spontaneously, and fetal movement was noted on visual examination and confirmed through abdominal palpation.
Pregnancy was monitored through visual observation of transabdominal fetal movements and repeat abdominal ultrasonography to detect fetal heartbeat. Fetal movement was not visualized beyond 213 days gestation and abdominal ultrasound attempted at 217 days gestation was unsuccessful due to struggling of the dam. At 229 days gestation the gerenuk was immobilized for caesarian removal of the calf. Medetomidine (70 µg/kg, Domitor, Pfizer Inc., New York, NY, USA) and ketamine (2.2 mg/kg, Ketaset, Fort Dodge Laboratories, Inc., Fort Dodge, IA, USA) were administered IM for induction. The gerenuk was intubated (9.0 mm ETT), and surgical anesthesia was maintained on 3% isoflurane (Isoflurane, U.S.P., Halocarbon Laboratories, River Edge, NJ, USA) in oxygen for the duration of diagnostic and surgical procedures.
Based upon in-house reference values, hematologic and serum chemistry analysis revealed decreased hematocrit (30.6%; normal range = 36.9–51.1), anemia (red blood cell count = 7.62 × 106/µl; normal range = 8.69–12.13), leukocytosis (6.46 × 103/µl; normal range = 2.03–5.58), neutrophilia (5.62 × 103/µl; normal range = 0.97–3.44), lymphopenia (0.323 × 103/µl; normal range = 0.586–2.032), monocytosis (0.517 × 103/µl; normal range = 0.005–0.315), decreased platelet count (211 × 103/µl; normal range = 306–573), hypoproteinemia (4.7 g/dl; normal range = 5.8–7.1), hypoalbuminemia (6 g/dl; normal range = 2.6–3.4), elevated alanine transferase (140 IU/L; normal range = 25–53), elevated aspartate transferase (444 IU/L; normal range = 66–151), and elevated amylase (626 SU; normal range = 124–280) values.
Pre-operative radiographs identified a fully mineralized calf in dorsal recumbency misaligned with the pelvic canal. A fetal heartbeat could not be verified by abdominal ultrasound. The abdomen was entered through a 12 cm incision made in the right flank approximately midpoint between the caudal rib and coxofemoral joint. Approximately 2 L of serosanguinous fluid were removed from the abdominal cavity. A nonviable full-term male fetus was identified and lifted to the surgical incision, which was lengthened approximately 4 cm to accommodate the fetus. A thin white friable membrane containing cotyledons was tightly adhered to the fetus and attached it to the omentum. Large vessels within the omentum supplying this sac were identified and ligated to facilitate removal of the fetus and all abnormal tissue. Exploration of the abdomen revealed a thickened peritoneum with diffuse hemorrhagic changes observed along the serosal surface of the abdominal organs. The uterus and ovaries were identified and found to be normal with no evidence of pregnancy. The omental defect was repaired and the surgical site was closed routinely in three layers. Atipamezole (0.25 mg/kg, Antisedan, Pfizer Inc., New York, NY, USA) was administered (50% IV and 50% SC) for reversal of the medetomidine following discontinuation of isoflurane anesthesia. The gerenuk recovered uneventfully. Intraoperative enrofloxacin (10 mg/kg IV, Baytril, Bayer Corp., Shawnee Mission, KS, USA) and ampicillin (20 mg/kg IV, Apothecon, Bristol-Myers Squibb Co., Princeton, NJ, USA) were administered. Enrofloxacin (5 mg/kg SC BID for 14 days) and amoxicillin (15 mg/kg SC BID for 14 days) were continued in the postoperative period. Cytologic examination of the abdominal fluid obtained during surgery revealed moderate numbers of degenerative red and white blood cells. No organisms were detected after aerobic and anaerobic bacterial culture. Monitoring of hematologic and serum chemistry parameters demonstrated gradual return to normal levels over the next 4 weeks.
Postmortem examination of the 3.18 kg stillborn fetus revealed a full-term completely developed male calf undergoing autolysis. Placental lesions observed during histologic examination were compatible with premature separation of cotyledons occurring several weeks prior to surgical removal of the fetus. Meconium found embedded within the placenta suggested fetal stress at the time of separation with no histologic evidence of an infectious process.
Two months following surgery, the gerenuk was examined for nasal discharge. Focal pneumonia was identified on thoracic radiographs. The gerenuk improved with florfenicol therapy (20 mg/kg SID for 7 days, Nuflor, Schering-Plough, Union, NJ, USA) but remained a “poor-doer” and never regained normal weight. A subsequent pregnancy was confirmed on ultrasound examination but the fetus was resorbed during early gestation. Approximately 9 months following caesarian removal of the ectopic fetus, the gerenuk died following a 1-week history of abdominal distension and tympany. Postmortem examination revealed generalized cachexia, mild peritonitis with omental adhesions present at the previous surgical site, periodontal disease, ruminal bloat, and small, multifocal ruminal ulcerations. Aspirated material was present within the tracheal lumen and pneumonia was identified in both cranioventral lung lobes. Fusobacterium necrophorum, Prevotella loescheii, and Serratia marcescens were recovered on aerobic and anaerobic bacterial culture of the lung.
This report documents a full-term ectopic pregnancy occurring in an exotic hoofstock specimen. Visual observation of fetal movement and detection of fetal heartbeat by abdominal ultrasound technique confirmed fetal viability through day 213 gestation. Development of a placental attachment to the omentum allowed full-term fetal development. Clinical history and histopathologic findings suggest that fetal death followed normal placental separation at time of parturition with an inability for normal uterine delivery. Hematologic and serum chemistry abnormalities detected within the dam most likely reflect the presence of a dead fetus within the abdominal cavity. A review of the current literature suggests that this is the first documentation of a full-term ectopic pregnancy occurring in a species of exotic hoofstock.