Obstetrical Management of Partial Uterine Prolapse in a Mare

1. Case History
Prolapse of the uterus is a condition, in which the uterus becomes everted and protrudes through the vulva. It can be visually diagnosed by the red, corrugated soft mass hanging from the vagina (Farjanikish et al., 2016). The everted mass of the uterus is endowed with rich vascularity. The uterus of the mare is T-shaped and attached to the dorsal body wall by the broad ligament, keeping it comparatively well-positioned than other farm animals (such as cattle and buffaloes); hence, uterine prolapse is rarer in horses. However, either one horn or a major portion of the uterine body may prolapse immediately postpartum or several days later. Abortion, dystocia, retained placenta, any conditions that lead to straining (tenesmus), such as vaginal trauma, oxytocin overdose, the lack of uterine involution due to atony, and hypocalcemia are the predisposing factors of uterine prolapse in mares (Perkins et al., 1994). Sometimes, twin pregnancies can also be the cause of prolapse (Alamaary et al., 2020). Uterine prolapse can be complicated by rupture of uterine vessels (Finan & McKinnon, 2015), lacerations, septicemia, ischemia of viscera and endotoxemia (Hewes et al., 2011), endometritis, laminitis, peritonitis, or development of tetanus. The present paper described the rare incidence of partial uterine prolapse in a pony and its obstetrical management. 

2. Clinical Presentation
A six-year-old pluriparous pony on July 10, 2022, at 04:30 PM was brought to the Obstetrical Unit of the Veterinary Clinical Complex, Veterinary College and Research Institute, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu, with a mass hanging from the vagina. The mare had aborted the fetus during the eighth month of its gestation, the uterus had prolapsed a few hours later, a day before arrival at the hospital. The animal was administered with an anti-tetanus injection by a local veterinarian before arrival. On clinical examination, the animal was standing upright ambulatory with a slightly dull mentation. The tachycardia was noticed (heart rate: 80 bpm) and the mucous membranes were bilaterally severely congested (Figure 1) with a rectal temperature of 100.6°F. Upon examination of the prolapsed mass, the tissues were vital; however, there was severe congestion, edema, and multifocal grey and yellow areas, with a small amount of bleeding (Figure 2). No evidence of fetal membrane attachments was observed. The side closer to the right horn had completely prolapsed while the other side was incomplete. Upon vaginal examination, constriction of the cervical region was noticed. Whole blood and serum samples were collected and subjected to hematological and biochemical estimation (Ono et al., 2019).

3. Diagnostic Testing
Wet film examination was negative for blood protozoans. Hematological examination revealed a normal physiological range (hemoglobin: 14 g/dL, erythrocytes: 11.6×106 mm3, leucocytes: 4.6×103 mm3, PCV: 45%, neutrophils: 56%, lymphocytes: 32%, band cells: 11%, and monocytes: 1%). Among the serological values, a mild increase in the blood urea nitrogen (69 mg/dL), a slight decrease in serum calcium levels (calcium: 9.2 mg/dL), and an increase in the serum phosphorous levels (6.92 mg/dL) were observed but the rest of the values were in the normal physiological range (creatinine: 1.52 mg/dL, alanine transaminase (serum glutamic-pyruvic transaminase (SGPT)): 1 U/L, ALP: 1.61 U/L, ADT (SGOT): 1 U/L, total protein: 6 g/dL, and albumin: 3.41 g/dL) (Ono et al., 2019). 

4. Assessments
Caudal epidural anesthesia was performed with 2% lignocaine HCL (4 mL) at the inter-coccygeal space using a 20 G needle (Figure 3). Tail bandaging was performed to prevent hair contamination during the interventional procedure. The animal was stabilized with Ringer’s lactate (1 L) and 0.9% isotonic normal saline (1 L). The prolapsed mass of the uterus was washed and debris was cleaned with 0.1% KMnO4 solution. The hypertonic salt solution was applied to the mass directly in order to reduce inflammation (Yaliwal et al., 2020) (Figure 4).

Within a few minutes, the mass was more pliable and manageable, which indicated a reduction in edema. The prolapsed uterus was lubricated with Cetrimide cream (Kayvee Aeropharm Pvt. Ltd India) and it was reduced. As it was a partial uterine prolapse, the mass was repositioned by inverting the right ovarian bursal region through the invagination followed by the entire mass. The uterus was then flooded with 2 L of diluted povidone iodine (Stedman Pharmaceuticals Pvt Ltd, India) at the rate of 2% to ensure no invaginations would recur after the repositioning. Further vaginal speculum examination was performed to ensure the cervix was back in position (Figures 5 and 6). The intrauterine fluids were siphoned after 30 minutes. Because no straining was evident, Buhner’s sutures were not applied as there were no signs of prolapse (Cetin & Gurgoze, 2009).

The animal was administered with flunixin meglumine (1.1 mg/kg intravenously), oxytocin (40 IU intramuscularly), and a combination of streptomycin (20 mg/kg) and procaine penicillin (22,000 units/kg). The animal exhibited urination and mild straining after oxytocin administration; however, the uterus did not prolapse again. On a subsequent day, all vitals were normal. The congestion of the mucous membranes was reduced. Fluids were administered again, along with non-steroidal anti-inflammatory drugs (NSAID) and antibiotics. Intrauterine antiseptic douching using a diluted 5% povidone-iodine solution was performed. Upon vaginal speculum examination, cervical involution was appreciable. The antibiotic and NSAID were continued for five days and the mare had an uneventful recovery (Figure 7). 

Uterine prolapse in mares has to be addressed more prudently than in cattle as it is more fragile and softer (Chisholm, 1981). Moreover, it can be replaced with no trouble than a bovine uterine prolapse due to the nature of the uterus with the absence of cotyledons (Parkinson et al., 2019). A deficiency of calcium has been reported to develop secondary uterine inertia in debilitating animals resulting in uterine prolapse. In the present case, mild hypocalcemia owing to the start of lactation might be the reason for the uterine atony and hence resulted in partial prolapse of the gravid horn. Using oxytocin helps in maintaining contractibility and tonicity, leading to increasing the involution of the uterus, which further helps in preventing the recurrence (Causey et al., 2007; Farjanikish et al., 2016). In contrast to bovine, Buhner’s sutures or stay sutures in equine are not required, as the vulval suture may result in distorting the vulval anatomical contour and predispose the mare for pneumovagina.
Although the prolapse of the uterus is uncommon in mares, it has to be addressed as an emergency due to the possibility of systemic inflammatory response syndrome (SIRS). It is an emergency condition, which is clinically similar to fever, tachycardia, tachypnea, leucopenia, and increased immature polymorph nuclear cells. It can be synergistic with infections and sepsis encounters (Bone et al., 1992). Tumor necrosis factor and interleukins are the major inflammatory mediators resulting in the activation of platelet-activating factor, leukotrienes, nitric oxide, and prostaglandin E2 and the activation of neutrophils consequently leading to inflammation, tissue obliteration, and loss of function. Hence, the high level of inflammation may lead to an increased risk of survivability (Hewes et al., 2011). Uterine lavage with an antiseptic solution may aid in cleansing the pathogens and promote tissue regeneration. Strong, undiluted solutions or alcohol-containing solutions should not be used. 
The successful outcome in the treatment of uterine prolapse depends on the repositioning of the uterus and straining management. Lubricants, like Cetrimide cream help in easy repositioning and also act as a smoothening agent. Flooding the uterus with warm saline may help to ensure complete replacement of the uterine horns. The straining can be effectively controlled with the use of epidural anesthesia, sedatives, or general anesthesia depending on the nature of the animal’s demand. Small doses of oxytocin can be administered to begin with the involution process and intrauterine antibiotics can be given as douches or boluses. Systemic broad-spectrum antibiotics along with tetanus prophylaxis are essential in preventing the infection and aid in uneventful recovery.

Ethical Considerations

Compliance with ethical guidelines
There were no ethical considerations to be considered in this research.

Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors.

Authors' contributions
Methodology: Sengodan Raja, Anand Kuniyil Athira, Edara Silendra Kumar, Pandiyan Bhuvaneshwari and  Ravikumar Deepika Sri; Writing–original draft, review and editing: Sengodan Raja, Anand Kuniyil Athira, Soundarapandian Satheshkumar, Subramaniyan Prakash and Narayanasamy Arunmozhi.

Conflict of interest
The authors declared that there is no conflict of interest.

Acknowledgments
The authors thank the Dean, Veterinary College and Research Institute Orathanadu, and Director of Clinics, Tamil Nadu Veterinary and Animal Sciences University for the facilities provided for the study.

References

Alamaary, M., & Ali, A. (2020). Abortion and uterine prolapse in a thoroughbred mare with twin pregnancy: Clinical laboratory findings and treatment approach. Journal of Equine Science, 31(4), 95 - 99 [DOI:10.1294/jes.31.95][PMID][PMCID]

Bone, R. C., Balk, R. A., Cerra, F. B., Dellinger, R. P., Fein, A. M., & Knaus, W. A., et al. (1992). Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine. Chest, 101(6), 1644–1655. [DOI:10.1378/chest.101.6.1644][PMID]

Causey, R., Ruksznis, D., & Miles, R. (2007). Field management of equine uterine prolapse in a through bred mare. Equine Veterinary Education, 19(5), 254-259 [DOI:10.2746/095777307X208348]

Cetin, H., & Gurgoze, S. Y. (2009) Uterine prolapse in a purebred Arabian mare: A case report. Veterinarnia Medicina, 49(12), 473-475. [DOI:10.17221/5742-VETMED]

Chisholm, F. R. (1981). Uterine prolapse in a mare. The Canadian Veterinary Journal, 22(8),  267. [PMCID]

Farjanikish, G., Sookhthezari, A., & Raisi, A. (2016). Surgical treatment of uterine prolapse in a mare: Clinical report. Iranian Journal of Veterinary Surgery, 11(2),  53-56. [Link]

Finan, S. A., & McKinnon, A. O. (2015). Postpartum complications in broodmares. Robinson’s Current Therapy in Equine Medicine, 670 - 672. [DOI:10.1016/B978-1-4557-4555-5.00159-X]

Hewes, C. A., Johnson, A. K., Kivrtt, L. E., Stewart, A. J., & Weisman, J. L., et al. (2011). Uterine prolapse in a mare, leading to systemic inflammatory response syndrome, septic shock and death. Equine Veterinary Education, 23 (6), 273-278. [Link]

Ono, T., Yamada, Y., Hata, A., Shimokawa Miyama, T., Shibano, K., Iwata, E., et al. (2019). Reference values of hematological and blood biochemical parameters for the Noma horse. Journal of Equine Science, 30(3), 69 - 73. [DOI:10.1294/jes.30.69][PMID][PMCID]

Parkinson, T., & Noakes, D. (2019). Injuries and diseases consequent upon parturition. In D.E.  Noakes, T. J. Parkinson, & G. C. W. England (Eds.),  Veterinary reproduction and obstetrics.  Pennsylvania: WB Saunders. [DOI:10.1016/B978-0-7020-7233-8.00020-3]

Perkins, N. R., & Frazer, G. S. (1994). Reproductive emergencies in the mare. The Veterinary clinics of North America. Equine Practice, 10(3), 643–670. [DOI:10.1016/S0749-0739(17)30352-8][PMID]

Yaliwal, R., Hanjagi, G., Shiragur, S., Pujeri, S., Patil, N., &  Bhoosanur, S., et al. (2020). Table sugar and salt for the reduction of incarcerated prolapse with vescical calculi - A case report. The Journal of Medical Research, 6(6), 268-270. [DOI:10.31254/jmr.2020.6601]