Twin Reversed Arterial Perfusion Sequence and Fatal Amniotic Fluid Emboli in a Chimpanzee (Pan troglodytes)
A 36-year-old female chimpanzee (Pan troglodytes) from a zoological collection was presented for suspected dystocia of a near-term pregnancy. Each of this chimpanzee’s three previous pregnancies had resulted in an uncomplicated, vaginal delivery of a healthy baby. Her clinical history upon presentation included one week of intermittent mild vaginal bleeding and less than four hours of persistent regurgitation, severe lethargy, and pale mucous membranes. A diagnostic workup performed under general anesthesia included physical examination, complete blood count, plasma biochemistry panel, coagulation panel, and uterine ultrasound. These tests indicated that the chimpanzee was pregnant with congenitally malformed, deceased twins and was likely in anuric renal failure with sepsis and disseminated intravascular coagulation. Vaginal delivery of the feti was assisted with intravenous oxytocin, intravaginal misoprostol, and manual extraction. The chimpanzee went into cardiac asystole upon completion of the delivery and CPCR was unsuccessful. Necropsies revealed the cause of death of the feti as twin reversed arterial perfusion (TRAP) sequence. TRAP is a congenital malformation of monozygotic twins that results in an acardiac twin that is perfused by a pump twin through placental vascular anastomoses.1,2 The maternal cause of death was multifocal amniotic fluid emboli (AFE). Neither TRAP nor AFE has been reported in a chimpanzee.
The authors would like to thank the University of Tennessee Medical Center’s obstetrics service and the University of Tennessee Veterinary Medical Center’s anesthesia service for their professional assistance with this case.
1. Bornstein E, Monteagudo A, Dong R, Schwartz N, Timor-Tritsch IE. Detection of twin reversed arterial perfusion sequence at the time of first-trimester screening. J Ultrasound Med. 2008;27(7):1105–1109.
2. De Groot R, Van Den Wijngaard JPHM, Umur A, Beek JF, Nikkels PGJ, Van Gemert MJC. Modeling acardiac twin pregnancies. Ann N Y Acad Sci. 2007;1101:235–249.