Dystocia (egg retention)
Sterilization is rarely performed in reptiles, and therefore reproductive disease remains a common presentation. In oviparous reptiles, eggs (demonstrating various degrees of shell mineralization) may be retained, whereas in (ovo)viviparous species unfertilized ova or fetuses may be seen. In some cases, abnormal and persistent preovulatory follicles may also be diagnosed as spherical masses that fail to ovulate or resorb. Dystocia is generally not an acute presentation as in mammals or birds, and reptiles may retain eggs/fetuses for weeks or even months after the normal timing of laying/birth. Coupled with imprecise details of copulation, this can often make the distinction between normal gravidity and dystocia difficult in otherwise clinically healthy reptiles. Certainly, severe metabolic disturbance and infection can exacerbate the issue. In general, a presumptive diagnosis can be achieved through palpation and diagnostic imaging, especially radiography and ultrasonography. Hematology and plasma biochemistry may also help identify inflammatory/infectious changes and metabolic disturbances, especially hypercalcemia.
Unless there is evidence of acute disease, medical management may be tried, although it frequently fails. Improvements in husbandry (especially provision of solitude and a suitable substrate), corrections of any metabolic disturbances, subcutaneous dilute oxytocin/vasotocin, and potentially prostaglandin (PGF2a and PGE) may be helpful. In most cases, surgical ovariosalpingectomy is required (unless a valuable breeding animal) after medical stabilization.
A variety of prolapses may be seen emanating from the vent of reptiles, including cloaca, colon, oviduct, hemipenes/phallus, and (if present) bladder. Common causes include dystocia, copulation trauma, cloacitis, bacterial/fungal/parasitic infection, metabolic disease (especially secondary hyperparathyroidism), cystic calculi, renal disease, neoplasia, or any space-occupying lesion within the coelom causing tenesmus. It is important to identify the prolapsed organ, because some (eg, phallus/hemipenes) can be amputated, whereas others (eg, cloaca, colon, bladder) cannot. The prolapse should be gently cleaned, and the application of hyperosmotics may help reduce swelling and facilitate replacement. However, it is also important to determine the cause to prevent recurrence.
Prolapses of the hemipenes and phallus can be amputated after induction of general anesthesia or intrathecal (caudal spinal) block; this will render the animal infertile. If the prolapsed tissue is viable and can be replaced, purse-string sutures of the vent should be avoided, because they tend to deform the vent and may interfere with the urogenital openings. In such cases, it is preferable to use a transcutaneous cloacopexy technique. If the tissue is not viable, then careful and detailed surgery is required when attempting debridement and resection-anastomosis of the cloaca, colon, or bladder and often necessitates both cloacal and coeliotomy approaches.
Last full review/revision October 2015 by Stephen J. Divers, BVetMed, DZooMed, DACZM, DECZM (herpetology), FRCVS