MEDICAL MANAGEMENT OF PYOMETRA IN THREE RED WOLVES (CANIS RUFUS)

Transcription

1 MEDICAL MANAGEMENT OF PYOMETRA IN THREE RED WOLVES (CANIS RUFUS) Author(s): Kadie Anderson, D.V.M. and Karen N. Wolf, D.V.M., M.S., Dipl. A.C.Z.M. Source: Journal of Zoo and Wildlife Medicine, 44(4): Published By: American Association of Zoo Veterinarians DOI: URL: BioOne ( is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne s Terms of Use, available at terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.

2 Journal of Zoo and Wildlife Medicine 44(4): , 2013 Copyright 2013 by American Association of Zoo Veterinarians MEDICAL MANAGEMENT OF PYOMETRA IN THREE RED WOLVES (CANIS RUFUS) Kadie Anderson, D.V.M., and Karen N. Wolf, D.V.M., M.S., Dipl. A.C.Z.M. Abstract: Pyometra is a serious, life-threatening disease of both domestic and non-domestic species often requiring ovariohysterectomy to preserve the life of the animal. Medical management of pyometra has been successful in domestic and non-domestic species, and the consideration of such treatment is of marked importance in a critically endangered species. Of the canids, the red wolf (Canis rufus) is second only to African hunting dogs (Lycaon pictus) in terms of the prevalence of both cystic endometrial hyperplasia and pyometra. In this report, three red wolves were medically managed for pyometra. Aside from vaginal discharge, none of the wolves exhibited clinical signs, nor were there reflective inflammatory changes in the laboratory findings. All wolves received standard treatment for pyometra, including prostaglandin F 2a and antibiotic therapy, while one wolf was more aggressively managed with uterine lavage. Pyometra recurred in two of the treated wolves, while the most aggressively managed wolf continues to show ultrasonographic resolution 2 yr posttreatment. Aggressive medical management of pyometra should be considered a treatment option in certain red wolf females, as it may preserve the animal s reproductive potential. Key words: Canis rufus, cystic endometrial hyperplasia, ovarian cyst, pyometra, red wolf. INTRODUCTION Endogenous hormone levels, parity, and age of the dam are all believed to play a role in the development of pyometra in the domestic dog (Canis familiaris). 12 Prolonged exposure to certain hormones, particularly progesterone, can lead to cystic endometrial hyperplasia (CEH) and can predispose the uterine environment to infection, particularly during the diestrus or postpartum phase. 6,7 Pyometra is not an uncommon entity for intact female canids. In a life study of the domestic dog, pyometra affected 23 24% of intact bitches by 10 yr of age. 5 CEH and pyometra have been reported 1,11,14,15 in several nondomestic canids and felids. As a result of the hormonal profile of the canid reproductive cycle, canids are considered to be at higher risk for the development of this syndrome. 3 Further, a recent publication 3 suggests that of the seven examined canid species, red wolves (Canis rufus) had the second highest incidence of both CEH (75%) and pyometra (11.1%), suggesting possible species-specific sensitivity to this syndrome. Clinical signs of pyometra in domestic dogs include lethargy, vaginal discharge, pyrexia, and anorexia. 12 Left untreated, pyometra can progress to sepsis and death. Affected bitches usually have an inflammatory leukogram, azotemia, hyperproteinemia, and hyperglobulinemia, with occasional From the Point Defiance Zoo & Aquarium, 5400 North Pearl Street, Tacoma, Washington 98407, USA (Anderson, Wolf). Correspondence should be directed to Dr. Anderson (Kadie.anderson@pdza.org). increases of alkaline phosphatase and alanine phosphatase activities. 12,22 The treatment of choice has historically been ovariohysterectomy. In a critically endangered species such as the red wolf, surgical intervention is often undesirable, as it permanently removes the animal from contributing genetically and demographically to the population. This article describes the clinical presentation, medical management, and reproductive outcome of three red wolves diagnosed with CEH and pyometra. Case 1 CASE STUDIES In March 2008, a 7-yr-old, 21.5-kg, female red wolf (wolf A) presented with a 3-mo history of intermittent hemorrhagic vaginal discharge. This wolf had produced litters of pups in 2005 and 2007 and had received a deslorelin (4.7 mg s.c., Suprelorin, AZA Wildlife Contraception Center, Saint Louis Zoo, St. Louis, Missouri 63110, USA) implant in late November Wolf A was anesthetized with medetomidine (0.04 mg/kg i.m., Pfizer, New York, New York 10017, USA) and butorphanol (0.4 mg/kg i.m, Fort Dodge Laboratories, Fort Dodge, Iowa 50501, USA) for examination. Transabdominal ultrasonography confirmed small amounts of intraluminal uterine fluid with no uterine distention. The ovaries were not examined. Vaginal cytology was performed and was consistent with an animal in estrus. Vaginal culture 1010

3 ANDERSON AND WOLF MEDICAL MANAGEMENT OF PYOMETRA IN RED WOLVES 1011 Table 1. Vaginal culture and sensitivity results. Wolf A Wolf B Wolf C Antibiotic Escherichia coli Staphylococcus Escherichia coli Staphylococcus Escherichia coli Amikacin Sensitive Sensitive Sensitive Sensitive Sensitive Amoxicillin/clavulanate Sensitive Sensitive Sensitive Resistant Sensitive Ampicillin Sensitive Sensitive Resistant Resistant Sensitive Cefazolin Sensitive Sensitive Sensitive Resistant Sensitive Ceftoxitin Sensitive Sensitive Sensitive Resistant Sensitive Cefpodoxime Sensitive Resistant Sensitive Cefovecin Sensitive Resistant Sensitive Ceftiofur Sensitive Sensitive Sensitive Resistant Sensitive Cephalothin/cephalexin Sensitive Sensitive Chloramphenicol Sensitive Sensitive Sensitive Resistant Sensitive Doxycycline Sensitive Erythromycin Sensitive Sensitive Enrofloxacin Sensitive Sensitive Resistant Resistant Gentamicin Sensitive Sensitive Sensitive Sensitive Sensitive Imipenem Sensitive Sensitive Sensitive Sensitive Marbofloxacin Sensitive Resistant Resistant Penicillin Resistant Rifampin Resistant Sensitive Tetracycline Sensitive Sensitive Ticarcillin/clavulanate Sensitive Sensitive Sensitive Intermediate Sensitive Ticarcillin Sensitive Sensitive Intermediate Sensitive Trimethoprim sulfa Sensitive Sensitive Sensitive Sensitive Sensitive revealed moderate numbers of Escherichia coli, presumed to be overgrowth of normal vaginal flora secondary to inflammation. During the exam, wolf A received combination penicillin G benzathine and penicillin G procaine (35,000 IU/ kg s.c., Combi-Pen-48, Bimeda Inc., Oakbrook Terrace, Illinois 60181, USA) and meloxicam (0.25 mg/kg s.c., Boehringer Ingelheim, Ridgefield, Connecticut 06877, USA). Following the procedure, anesthesia was reversed with naltrexone (4 mg/kg i.m., ZooPharm, Fort Collins, Colorado 80522, USA) and atipamezole (0.2 mg/kg i.m., Antisedan, Pfizer). The vaginal hemorrhage resolved and no further problems were reported. In May 2009, wolf A was re-examined for a 1- mo history of hemorrhagic vaginal discharge using the anesthetic protocol described above. Vaginal cytology revealed a mixture of intermediate and superficial squamous cells with mixed cell inflammation. Vaginal aerobic culture grew E. coli and coagulase-negative Staphylococcus spp. with little to no antibiotic resistance (Table 1). A complete blood count (CBC) and serum chemistry revealed a mild leukocytosis (16,100 white blood cells [WBCs]/ll) with predominant neutrophilia (13,370/ll), with no associated serum biochemical changes. 10 Wolf A was immobilized 1 wk later for ultrasonographic examination, which revealed a thickened and corrugated uterine wall measuring cm in thickness with extensive cystic endometrial change. The uterine lumen contained a small amount of thick, echogenic fluid. A large, anechoic follicle was present on the right ovary. A wellmarginated nodule measuring cm was located on the spleen and was aspirated for cytologic analysis, revealing lymphoid hyperplasia. The wolf received combination penicillin G benzathine and penicillin G (50,200 IU/kg s.c.) and ranitidine (0.5 mg/kg s.c., Bedford Labs, Bedford, Ohio 44146, USA) during the examination. Physical examination and ultrasonographic findings were consistent with cystic endometrial hyperplasia and pyometra. Combination luteolytic and antibiotic therapy was instituted (Table 2). Nineteen days later, wolf A presented for a recheck ultrasound examination to monitor for response to treatment, which showed resolution of intraluminal fluid with persistent moderate thickening of the uterine wall ( cm) and extensive cystic endometrial change. Follicular activity was visible in the right ovary, and the left ovary was unremarkable. Findings were interpreted as resolved pyometra with persistent cystic endometrial hyperplasia and probable low-grade

4 1012 JOURNAL OF ZOO AND WILDLIFE MEDICINE Table 2. Case overview. Wolf A Wolf B Wolf C Age (yr) Stage of estrus Diestrus Anestrus Anestrus Anestrus Diestrus Contracepted Yes, deslorelin No No Treatment antibiotics a Ovariohysterectomy antibiotics), PGF 2a, (PGF 2a, b uterine lavage PGF 2a, antibiotics c Ovariohysterectomy Sterilized Pyometra recurrence 4 mo later Sterilized Ultrasonographic resolution of disease Outcome Pyometra recurrence 4 yr later a Dinoprost trimethamine (0.25 mg/kg s.c. s.i.d. for 5 days, Lutalyse, Pfizer, New York, New York 10017, USA) and enrofloxacin (10 mg/kg p.o. s.i.d. for 49 days, Baytril, Bayer Animal Health, Shawnee Mission, Kansas 66201, USA). b Dinoprost trimethamine (0.2 mg/kg s.c. for 3 days) and orbifloxacin (3 mg/kg p.o. s.i.d. for 54 days). c Dinoprost trimethamine (0.25 mg/kg s.c. for 5 days), orbifloxacin (3 mg/kg p.o. s.i.d. for 5 days), and amoxicillin trihydrate (15 mg/kg p.o. b.i.d. for 30 days, Clavamox, Pfizer, New York, New York, 10017, USA). metritis. No further treatment was initiated when the wolf completed its prescribed course of antibiotic therapy. The wolf failed to conceive or carry pups to term during the following two breeding seasons. Additional followup on this animal was not pursued until December A reproductive ultrasound revealed normal left and right ovaries, and the uterus had a uniform endometrial surface with no cystic changes or intraluminal fluid. The uterine wall was mildly thickened ( cm). An ultrasound-guided fine-needle aspirate was obtained from the right uterine horn for cytologic analysis and findings were consistent with chronic active inflammation. Serum was submitted for progesterone analysis and the resultant value was 0.5 ng/ml, consistent with levels expected for an anestrus animal. 12,18,21 Four months later, this wolf had recurrent vaginal hemorrhage post-estrus. The wolf was otherwise normal and, despite being paired for breeding, was not suspected to be pregnant. The wolf was briefly restrained for an ultrasound examination, which revealed moderate dilation and thickening of the uterine endometrium (wall thickness 2.1 cm) with highly echogenic fluid within the uterine lumen, interpreted as recurrent pyometra. CBC and serum biochemical analyses were unremarkable. 10 As a result of the age of this female (11 yr), ovariohysterectomy was elected. The procedure was routine, and the animal recovered with no complications. On gross evaluation of the reproductive tract, a small amount of hemorrhagic material was present in the uterine lumen, and a submitted culture grew Enterococcus spp. The uterine walls were severely thickened and tortuous, with marked cystic endometrial hyperplasia. Histopathology of the uterus and ovaries revealed moderate cystic endometrial hyperplasia, moderate pyometra with lymphoplasmacytic metritis, moderate multifocal adenomyosis, large mature corpora lutea, and both primary and secondary follicles. Case 2 In June 2011, a 6-yr-old, 25-kg female red wolf (wolf B) presented 6 wk postpartum with vulvar swelling and purulent vaginal discharge. The pups were believed to have been stillborn and consumed by the female, evidenced by fetal remains found in the feces of the dam. In the previous year, this female produced a stillborn litter of pups that had also been consumed. At the time of presentation, red wolf B was immobilized with a combination of dexmedeto-

5 ANDERSON AND WOLF MEDICAL MANAGEMENT OF PYOMETRA IN RED WOLVES 1013 midine (0.02 mg/kg), butorphanol (0.4 mg/kg), and midazolam (0.1 mg/kg, Hospira Inc., Lake Forest, Illinois 60045, USA). Abdominal radiographs were taken with no significant findings. A brief ultrasound examination revealed a hypoechoic region in the uterine lumen. Results of CBC and serum biochemical analysis were largely unremarkable. 10 Urinalysis revealed trace proteinuria and moderate struvite crystalluria. The urine protein:creatinine ratio was within normal limits for domestic dogs (0.4). Vaginal cytology collected 3 days prior to examination was consistent with septic, suppurative inflammation. Serum progesterone level was 1.4 ng/ml, which was considered elevated for an anestrus individual (anticipated,1 ng/ml). 12,18,21 As results were strongly suggestive of metritis or pyometra, treatment was initiated using meloxicam (0.15 mg/kg p.o. s.i.d. initially, then 0.1 mg/kg p.o. s.i.d. for 4 days), combination penicillin G benzathine and penicillin G procaine (24,000 IU/kg s.c. q. 48 hr for 4 doses), and orbifloxacin (3 mg/kg p.o. s.i.d. u.f.n., Orbax, Intervet, Summit, New Jersey 07901, USA). Ten days later the wolf presented for additional diagnostics and was anesthetized using the same protocol described previously. Mucopurulent vulvar discharge was present and the uterus was enlarged on abdominal palpation. Ultrasound examination revealed mild dilation of both uterine horns (wall thickness cm), with swirling, cellular echogenic fluid in the uterine lumen consistent with pyometra. The uterine walls were thickened, irregular, and cystic. A cm cyst was identified on the left ovary and was drained for therapeutic purposes and cytologic analysis. A repeat vaginal swab was collected for bacterial culture and sensitivity. The wolf was started on a luteolytic agent and antibiotic therapy was continued (Table 2). Cytology of the cystic ovarian mass was consistent with necrosis. The following organisms were cultured from the vaginal discharge: mixed commensal (nonpathogenic) genital flora, Staphylococcus spp. (coagulase positive), and E. coli. Sensitivity results for the agents revealed multidrug resistance for E. coli and mild antibiotic resistance for Staphylococcus spp. (Table 1). Two weeks later the wolf was immobilized for a second ultrasound examination and therapeutic uterine lavage. Ultrasound examination findings showed a reduction in the size of the uterine horns (wall thickness 1.4 cm), with persistent echogenic fluid in the lumen of both uterine horns and uterine body. The ovarian cyst visualized previously was no longer present. Interpretation was consistent with chronic, low-grade metritis and pyometra, with suspected inspissation of the luminal fluid. A shortened, 8-mm endotracheal tube was utilized as a vaginal speculum to prevent vaginal abrasion and collapse of the vaginal walls. A 3.5-mm rigid endoscope was passed through the endotracheal tube to visualize the cervix before passing a sterile 5-french polypropylene catheter into the uterine lumen via the cervical os. One gram of ceftiofur sodium (Naxcel, Pfizer) was added to 500 ml of 0.9% saline solution and instilled into the uterus. Fluid evacuated was serosanguineous and contained white, flocculent material. An additional 240 ml of 0.9% saline was instilled into the uterus until returning fluid was clear. Following the uterine flush, 200 mg of gentamicin (Gentamax 100, Phoenix Pharmaceuticals, Burlingame, California 94010, USA) diluted in 58 ml of 0.9% saline was instilled into the uterus. Brief ultrasound examination performed after the procedure showed small amounts of hypoechoic fluid within the uterine lumen. Normosol-R (40 ml/kg s.c., Hospira Pharmaceuticals), maropitant (1 mg/kg s.c., Cerenia, Pfizer), and meloxicam (0.12 mg/kg s.c.) were administered during the procedure. Fluid collected from the uterine flush was submitted for cytology, and blood was collected for CBC and serum biochemistry. The wolf was continued on the current dose of orbifloxacin (3 mg/kg p.o. s.i.d.) and scheduled for a recheck examination in 2 3 wk. Blood work results from the exam revealed a mild lymphopenia (960 cells/ll) and hyperglycemia (143 mg/dl), 10 interpreted as secondary to the stress of capture and anesthesia. Serum progesterone level was 1.4 ng/ml, which was considered elevated for an anestrus animal. 12,18,21 Cytology of the uterine fluid obtained revealed vacuolated, rounded cells consistent with endometrial hyperplasia, with no definitive pathogens identified. One week after the uterine flush, this wolf was manually restrained and blood was collected for hormone analysis. Serum progesterone level was 0.6 ng/ml and consistent with an anestrus animal. 12,18,21 Three weeks later, wolf B presented for a followup ultrasound examination. The examination revealed that the uterine horns (,9 mm in thickness) and body (1.4-cm wall thickness) were less dilated, with persistent cystic endometrial change. Central echogenic material was present in the lumen and was interpreted to represent either caseated luminal material or residual endometrial hypertrophy. Ultrasound-guided fine needle aspirates were taken of the uterine horns and revealed

6 1014 JOURNAL OF ZOO AND WILDLIFE MEDICINE no cytologic evidence of suppuration. Serum progesterone level was 0.3 ng/ml, reflecting probable lysis of the corpus luteum and a decline in the secretion of progesterone. Cervical catheterization was performed using the technique described previously and 120 ml of 0.2 mg/ml ceftiofur sodium (Naxcel, Pfizer) was instilled into the uterus. No fluid was returned. The wolf was recovered and continued on orbifloxacin (3 mg/kg p.o. s.i.d.) for two more weeks. Two weeks after discontinuing antibiotic therapy, the wolf was manually restrained for blood collection to reevaluate the serum progesterone level, which was 0.5 ng/ml, interpreted as serologic evidence of continued resolution of pyometra. In December 2011, this wolf was anesthetized using the previously described protocol for followup evaluation of the reproductive tract prior to breeding. Ultrasonographic findings were consistent with resolution of CEH and pyometra. The serum progesterone level was 0.7 ng/ml and consistent with levels anticipated during anestrus. 12,17,21 Despite being paired for breeding in 2012, this wolf did not become pregnant. Followup ultrasound exams in June and December 2012 as well as June 2013 showed continued resolution of CEH and uterine measurements that were within normal limits. Case 3 In December 2011, a 9.5-yr-old, 25-kg female red wolf (wolf C) was immobilized utilizing a combination of dexmedetomidine (0.02 mg/kg i.m.) and butorphanol (0.4 mg/kg i.m.) for inclusion in a red wolf reproductive study. This wolf had been paired for breeding during the 5 yr prior ( ) and had produced a single litter in The wolf was reportedly clinically normal. On examination, hemorrhagic mucopurulent vaginal discharge was present. A complete ultrasonographic exam was performed, identifying a markedly thickened, irregular endometrium, with scattered areas of cystic endometrial hyperplasia. Large pockets of swirling, echogenic fluid were present in the lumen of both uterine horns but did not extend into the uterine body or cervix. The uterine wall thickness was 2.2 cm (uterine body) to 2.8 cm in diameter (uterine horns). The left ovary was normal in appearance, and the right ovary had a large anechoic cyst measuring cm, with multiple smaller cysts measuring cm. Two milliliters of purulent fluid was aspirated from the uterine lumen by ultrasound guidance and submitted for culture and sensitivity, yielding a pure culture of E. coli that was resistant to fluoroquinolones (Table 1). The right ovarian cyst was drained completely, yielding clear, colorless fluid. Serum biochemical analysis and CBC were performed, with no significant abnormalities identified. 10 Serum hormone analysis reflected a progesterone value of 1.3 ng/ml and an estradiol value of pg/ml, both of which were considered elevated when compared to expected anestrus hormone concentrations in both the domestic dog and gray wolf. 12,18,21 The wolf was started on a luteolytic agent and an oral antibiotic (Table 2). Five days into therapy, the originally prescribed antibiotic was discontinued and wolf C was started on an alternative antibiotic (Table 2) based on antibiotic sensitivity results (Table 1). Thirty days after diagnosis, the wolf was anesthetized for re-evaluation using an identical protocol to the one described above. On physical exam, a small amount of hemorrhagic vaginal fluid was present. A complete reproductive ultrasound examination was performed and revealed resolution of intraluminal fluid and CEH. A cyst measuring mm was still present on the right ovary but was reduced in size. Ultrasoundguided fine-needle aspirates were taken from the right uterine horn for cytologic analysis, revealing moderate to marked mixed cell inflammation. Blood was collected for repeat serum progesterone analysis, which was 0.4 ng/ml, a level that would be expected for this stage of the cycle in other canids. 12,18,21 Three months later, this wolf was re-evaluated postestrus to evaluate for recurrence of pyometra. The wolf had been paired for breeding but the mate had died during the breeding season. No clinical signs of illness were reported by keeper staff; however, serosanguineous vaginal discharge was reported. The wolf was anesthetized using an identical protocol to the one described above, and an ultrasound examination identified multiple mass-effect lesions within the uterine lumen, with adjacent peritoneal fat reaction. Uterine wall thickness varied from 2.2 to 4.8 cm in thickness. Large bilateral ovarian cysts (right: cm, left: up to 1.1 cm in diameter) were also identified. CBC and serum biochemical analysis revealed a mild leukocytosis (15,400 WBCs/ll) with predominant neutrophilia (11,858/ll) and moderate anemia (hematocrit 26.8%), most consistent with chronic inflammation. 10 Serum progesterone was 3.8 ng/ml, most consistent with a periovulatory animal or an animal in diestrus. 12,18,21 As a result of the refractory nature of this animal s pyometra

7 ANDERSON AND WOLF MEDICAL MANAGEMENT OF PYOMETRA IN RED WOLVES 1015 and suspected uterine perforation and peritonitis, ovariohysterectomy was elected. At surgery, the left uterine horn was dilated, with purulent material with no gross evidence of perforation. The right uterine horn was subjectively normal. The animal recovered from surgery with no complications. Culture of the uterine lumen revealed E. coli with sensitivity to all antibiotics except fluoroquinolones, as noted in Histopathology of the reproductive tract revealed the following abnormalities: severe CEH with squamous metaplasia, severe pyometra and transmural necrotizing suppurative metritis with serosal mesothelial hyperplasia, primary and secondary ovarian follicles, and cystic corpora lutea. DISCUSSION Point Defiance Zoo & Aquarium (PDZA) has the largest captive red wolf population in the United States, currently comprising 23 adult females and 12 adult males. In the past 4 yr, pyometra has been reported in five of PDZA s female wolves (including these cases), causing mortality in 2/5 (40%) of these animals. The two mortalities attributed to pyometra involved females that had closed cervix pyometras. One of the wolves exhibited no clinical signs prior to death; the other wolf was euthanatized as a result of renal failure secondary to pyometra. Institutions reporting to the Red Wolf Species Survival Plan Veterinary Advisor in the same time period reported an additional three cases of pyometra; two of these wolves were euthanatized as a result of age and complications secondary to pyometra (renal failure). The remaining wolf was treated with ovariohysterectomy. In a previous study 1 on mortalities in red wolves, only two of 62 animals died or were euthanatized as a result of pyometra. In domestic canids, pyometra often occurs concurrently with CEH. 6,22 These endometrial changes predispose the uterine environment to bacterial colonization and are more common in middle-aged to older animals. All red wolves discussed in this case report had both pyometra and moderate CEH. In a study on uterine pathology in nondomestic canids, 41% of red wolves examined had CEH. 15 More recently published data 3 are supportive of the idea that red wolves may be predisposed to the development of CEH and pyometra when compared to other non-domestic canids, with a prevalence of 11.1% for pyometra and a 75% prevalence for CEH. This prevalence for both conditions is second only to that of the African hunting dog (Lycaon pictus) for the canid species examined. 3 Wolves in this report were diagnosed with pyometra at several stages of the estrous cycle. Pyometra is classically considered a disease of diestrus; however, it can occur at any stage of the cycle. 19 Approximately one-third of domestic dogs present with pyometra during anestrus. 22 In wolf B, it is suspected that changes consistent with CEH were present prior to the last two breeding cycles and predisposed this animal to the development of postpartum metritis and eventual pyometra. As with wolf B, wolf C developed pyometra during the anestrus phase. Wolf A developed pyometra during the diestrus phase following the breeding season. Both wolf A and wolf C developed recurrent pyometra following an estrus cycle, although wolf A s pyometra did not recur until 4 yr after initial successful medical management. Previous reports 15,17 have linked the use of synthetic progestins to the development of pyometra or CEH in domestic and non-domestic canids. While limited information is available on whether GnRH agonists induce uterine pathology, it is possible that this contributed to the development of CEH and pyometra in wolf A. While these three wolves are not necessarily reflective of the entire population, it is noteworthy that two-thirds of the animals were diagnosed during anestrus, which is not typical of domestic canids (Table 2). All wolves in this case report had large unilateral ovarian cysts present at the time of diagnosis with pyometra. It is not possible to determine whether the cyst or the CEH-pyometra developed first in the onset of this disease. In the domestic dog, ovarian cysts can be paraovarian, epithelial, or stromal, and most do not secrete hormones. 13 Cysts larger than 8 mm in domestic dogs are often classified as stromal cysts, which secrete either progesterone or estrogens and can lead to uterine pathology. 13 All progesterone analysis for these wolves was performed at the Phoenix Central Laboratory in Mukilteo, Washington (USA), using a solid-phase, competitive chemiluminescent enzyme immunoassay (Immulite 2000). Serum progesterone levels were never remarkably high (compared to those of domestic dogs) in any of the animals; however, concentrations declined with therapy to levels suggestive of anestrus (,1 ng/ml) in domestic dogs and gray wolves (Canis lupus), 7,12,18,21 particularly reflected in wolf B. In wolf C, estradiol levels were elevated at the time of diagnosis with pyometra in conjunction with increased progesterone (expected estradiol levels for domestic dogs in anestrus,15 pg/ml). 12 After therapy with dinoprost trimethamine, progester-

8 1016 JOURNAL OF ZOO AND WILDLIFE MEDICINE one levels fell to within normal range but estradiol remained elevated, suggesting that the persistent ovarian cyst was secreting estradiol. This persistent cyst may have been a new cyst or may have developed from the smaller cysts visualized at the first exam. Following recurrence of pyometra, histopathologic examination confirmed that the ovarian cysts in wolves A and C were cystic corpora lutea as well as primary and secondary follicles. As red wolves are seasonally monoestrus, follicular activity at this time of year is unusual and likely contributory to the severity of the uterine and ovarian lesions. In wolf B, multidrug-resistant E. coli was cultured at the beginning of therapy and contributed to difficulties in resolving this case. Though sensitivity to orbifloxacin was not pursued, this strain of E. coli was resistant to other fluoroquinolones, including marbofloxacin and enrofloxacin. Uterine lavage with gentamicin, an agent to which this bacteria was sensitive, led to significant ultrasonographic improvement and eventual resolution in this animal. Both cases A and C cultured minimally resistant bacteria that are common inhabitants of the vaginal tract of domestic canids. 2,9 Interestingly, two of the three wolves cultured bacteria that were resistant to both fluoroquinolones tested. As a result of difficulties in medicating these non-tractable animals, antibiotics that can be administered by once daily dosing are often preferred. As such, fluoroquinolones have historically been used to treat a variety of clinical conditions in the wolves housed at this facility. Resistance findings suggest that the frequent use of these drugs has likely contributed to the development of antibiotic resistance in this population and emphasize the importance of performing bacterial culture and sensitivity to ensure proper treatment of pyometra. In domestic and exotic canids, pyometra is a life-threatening emergency that necessitates immediate medical or surgical intervention. The majority of animals with pyometra present with clinical illness, including polyuria, polydipsia, pyrexia, vomiting, lethargy, and anorexia with or without vaginal discharge. 12 Clinically ill bitches have inflammatory leukograms and may present with secondary renal failure. In the domestic dog, up to 25% of bitches can have a normal leukogram. 22 None of the red wolves represented in this case report presented with overt clinical signs of disease, nor was the severity of the uterine infection reflected in the blood work. This is in contrast to a recent report 11 of pyometra in three African hunting dogs, in which all wild dogs presented with clinical signs and inflammatory leukograms. Of the wolves in this case report, wolf C, which had partial uterine perforation and peritonitis, had a mild inflammatory leukogram, reflecting the highest leukocyte count of the three wolves included in this report. Traditional treatment for pyometra includes supportive care and ovariohysterectomy. Medical management can be pursued for clinically normal animals with draining pyometras in which preservation of fertility is desired. Treatment in domestic dogs involves the use of prostaglandins and antiprogestins. 4,8,16,20 Treatment for the wolves in this case report involved prostaglandin therapy to evacuate the uterus combined with oral antibiotics. Two out of three of the wolves presented in this article developed recurrent pyometra necessitating ovariohysterectomy, while wolf B continues to show ultrasonographic evidence of resolved CEH and pyometra. This female was managed the most aggressively of the wolves via uterine lavage. Such aggressive measures may be necessary to achieve complete resolution of pyometra. Medical management of pyometra in an endangered, genetically valuable animal should be considered because it may preserve reproductive potential. The recurrence rate for domestic dogs successfully treated for pyometra has been shown 22 to be no different than the probability of a naïve bitch of the same age developing pyometra. Domestic dogs successfully treated for pyometra have had conception rates ranging from 50 to 75%. 22 Aggressive treatment and thorough, regular follow-up examinations are necessary to improve the chances of reproductive success in treated animals. This case study represents the first published case-based report of medical management of pyometra in three red wolves. Although two wolves developed refractory pyometra, one wolf was successfully treated following aggressive uterine lavage and antibiotic therapy. This individual has continued to show clinical and ultrasonographic evidence of resolution of pyometra; however, long term success and reproductive potential have yet to be determined. Medical management of pyometra should be considered in appropriate circumstances and shows promise in returning affected animals to reproductive health. Acknowledgments: The authors would like to thank the following individuals for their assis-

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