Submitted by: Patricia Shea, DVM
Vet Clin North Am Small Anim Pract 2018;48(4):639-661
Pyometra in small animals
Hagman R.
This is Part II of a two part summary. You can view Part I in the April 2019 edition of the Scratching Post, here.
In queens with pyometra, sepsis is a complication present in approximately 86% of cases, while sepsis is identified in only 60% of affected bitches. Pyometra may be accompanied by either continuous or intermittent mucopurulent to hemorrhagic vaginal discharge (open cervix) or no discharge at all (closed cervix). A patient with a closed cervix pyometra can be much sicker systemically because there is no drainage from the septic uterus. In queens, vaginal discharge, even if present, may not be noted due to the cat’s fastidious grooming habits. The most common clinical signs of pyometra in queens are lethargy, vaginal discharge, and gastrointestinal problems such as anorexia, vomiting and diarrhea. Other signs displayed by cats suffering from pyometra include weight loss, dehydration, abdominal pain, abnormal mucous membrane coloration, polydipsia/polyuria, tachycardia, tachypnea, and poor grooming. Fever may or may not be present in either species.
Signalment, history, clinical signs, physical examination, hematologic and biochemical screening, abdominal radiography, and ultrasonography can all contribute to the diagnosis of pyometra. Although affected animals may present with signs of illness post-estrus, pyometra can occur at any time during the estrus cycle. Abdominal ultrasonography is the most valuable diagnostic modality, as the distended abdomen that may occur with pyometra may be mistaken for pregnancy; moreover, it is possible for a cat to have a pregnancy in one uterine horn and pyometra or another pathologic condition such as hydrometra or mucometra in the other. Ultrasound imaging will identify intrauterine fluid as well as any pathologic changes in the uterine wall and/or ovaries. However, echogenicity of uterine fluid, while helpful in some cases, is not diagnostic of pyometra; ultrasonographic data must be coupled with other clinical findings. Patients with pyometra will be generally sicker, more lethargic, have more gastrointestinal disturbances, and have a more pronounced inflammatory response than those with mucometra or hydrometra.
Surgical treatment in the form of ovariohysterectomy, following emergency stabilization, is the safest and most effective form of therapy for animals with pyometra, especially in cases of closed cervix pyometra or pyometra with complications such as peritonitis. Surgery should not be unnecessarily delayed, as the risk of sepsis and other complications persists as long as the infected uterus remains in the animal. Ovariohysterectomy eliminates the source of infection, removes bacteria and their toxic products, and prevents recurrence.
Initial antimicrobial therapy should involve a broad-spectrum antibiotic known to be effective against E. coli, the most common pathogen in pyometra. Bacterial culture and antimicrobial sensitivity results obtained from uterine fluid obtained after ovariohysterectomy are then used to adjust further antibiotic therapy, ideally to an agent with a narrower spectrum. Intensive postoperative care is required, but most uncomplicated cases can be discharged one to two days after surgery, with a good prognosis; mortality rates vary from 3% to 20%. Clinicopathologic parameters positively correlated with morbidity as reflected by duration of hospitalization in cats include total leukocyte counts, neutrophils, band neutrophils, monocytes, and percentage of band neutrophils, while serum albumin concentrations were negatively correlated with length of hospital stay. Queens experiencing uterine rupture associated with pyometra can have a mortality rate of 57%. Approximately 20% of pyometra patients will experience complications, most commonly peritonitis (12%).
Only carefully selected patients, generally those with open cervix pyometra, should be treated with medical therapy only, taking into consideration the animal’s age, acute and chronic health status, and reproductive value. Animals receiving medical therapy only should also be hospitalized and monitored closely as some medications may take up to 48 hours to take effect, the medications themselves may have adverse effects, and complications or deterioration in the patient’s health status can occur, in which case ovariohysterectomy is indicated.
Many medical treatments for open cervix pyometra have been evaluated extensively in dogs, but fewer have been studied in cats. Pharmaceuticals used include agents that will prevent production or block the action of progesterone, as well as systemic antimicrobials to eliminate the infection. Other supportive care such as intravenous fluids may be needed in some cases. Medical therapy of open-cervix pyometra in cats is reported to resolve clinical illness in 95% of patients, and allow return to fertility in 60%. The reported mean recurrence rate of pyometra in medically treated queens is 0-14%.
Drugs used for medical therapy of open cervix pyometra in queens are either natural or synthetic (cloprostenol) prostaglandin F (PGF)2a, which are luteolytic, uterotonic, and stimulators of smooth muscle contraction, and the progesterone receptor blocker aglepristone. Dosing and protocol information for queens with these agents is provided by the author; all of them have been successful in resolving signs of pyometra in queens. However, no side effects are observed with the use of aglepristone, while PGF2a is associated with transient side effects such as vocalization, vomiting, and diarrhea. Both natural and synthetic PGF2a have a narrow therapeutic index and accurate dosing calculations are crucial. Aglepristone is not licensed for use in the USA, and its use in cats is extralabel anywhere. In bitches, cabergoline or bromocriptine, both dopamine agonists which have antiprolactin effects that promote luteolysis, may be used in conjunction with PGF2a, but no studies have been performed using these agents in a similar manner in the cat.
Stump pyometra can occur in both incompletely spayed dogs and cats, usually due to the presence of hormone-producing ovarian remnants and their effect on residual uterine tissue. Abdominal ultrasonography is a useful modality for diagnosing this condition. Exploratory surgery to remove ovarian and uterine tissue still present within the animal is required along with supportive care and antibiotic therapy.
J Vet Intern Med 2018;32:1692-1702.
Relationship of the mucosal microbiota to gastrointestinal inflammation and small cell intestinal lymphoma in cats
Garraway K, Johannes CM, et al.
The importance of the gastrointestinal microbiota in health and disease has come to prominence in human medicine in recent years, and veterinary researchers are now recognizing its significance in animal species as well. Small cell gastrointestinal lymphoma and inflammatory bowel diseases (IBD) are commonly encountered in middle-aged and elderly feline patients. In the 40-year time span from 1964 to 2004, diagnosis of small cell gastrointestinal lymphoma (SCGIL) in cats increased six-fold; this disease is characterized by chronic weight loss, vomiting, and diarrhea. Appetite may vary from excessive to poor. IBD has a clinical presentation similar to SCGIL; the etiologies of both diseases are not well understood, but are probably multifactorial, involving such factors as genetics, diet, and chronic inflammation.
The intestinal microbiome found in healthy cats is known to altered in IBD. In this retrospective case control study of 14 cats with IBD and 14 cats with SCGIL evaluated and diagnosed with endoscopic or laparoscopic biopsies at 3 different veterinary teaching hospitals, these researchers were interested in characterizing the microbiome of cats with SCGIL and determine whether specific bacterial groups are associated with this disease. Previous studies in cats have demonstrated that dysbiosis (alteration of the microbiome) is associated with benign mixed mucosal inflammation in the form of lymphoplasmacytic enteritis with IBD and gastrointestinal lymphoid malignancy. In addition to the biopsies, all patients were assessed with routine hematologic and biochemical analyses, including serum total T4. All cats in both study cohorts had negative fecal parasite ova tests, and were dewormed regardless of fecal test results before the biopsies were collected. Most cats were retrovirus tested as well.
The authors made efforts to include only cats who had no history of antibiotic administration for at least two weeks prior to collection of biopsies, but this information was not always present in the medical records. A diagnosis of IBD or SCGIL on each biopsy was reached by the use of routine hematoxylin-eosin staining, immunophenotyping, and in some cases, a PARR (polymerase chain reaction for antigen receptor rearrangement) assay.
Bacterial groups were identified in the biopsies by fluorescence in situ hybridization (FISH) and were correlated to CD11b+ and NF-KB expression. Differentiated myeloid cells carrying the CD11b+ marker are known to be significantly involved in tumor progression in rodents and humans with colorectal cancer, while NF-KB, a protein complex of transcription factors, has many roles, including involvement in immune regulation, DNA transcription, and pro-inflammatory cytokine and chemokine production. In humans, dysregulation of NF-KB activation is known to be associated with carcinogenesis because of resulting overproduction of pro-inflammatory cytokines and cell transformation.
The study also sought to determine if there was a relationship between gastrointestinal mucosal bacteria and the mucosal expression of NF-KB and infiltrating CD11b+ immune cells in the gastrointestinal biopsies of those cats with SCGIL in comparison with the gastrointestinal biopsies of the cats with IBD. In the intestinal biopsies of all 28 cats, the number of mucosal CD11b+ myeloid cells and NF-KB expression were quantified.
Bacteria quantified in the biopsies were divided among four well-defined mucosal compartments: (1) bacteria within free mucus; (2) bacteria within adherent mucus; (3) bacteria attached to surface epithelium; and (4) bacteria invasive within the mucosa. Only a few bacteria were identified as invasive within the mucosa. Those biopsies diagnosed as SCGIL had significantly increased numbers of Fusobacterium spp. in the three non-invasive mucosal compartments of the colon compared to the biopsies of the cats with IBD. Also in those cats with SCGIL, there were significantly increased counts of Fusobacterium spp. in the adherent mucus compartment of the ileum and colon as compared with biopsies of the cats with IBD.
Bacteroides spp. numbers were also significantly increased in the three combined non-invasive mucosal compartments of the ileum and the ileal adherent mucus in biopsies of patients with SCGIL compared to ileal biopsies of cats with IBD. However, the total counts of all bacteria, as well as numbers of Clostridium spp., Enterobacteriaceae, Helicobacter spp., and Faecalibacterium spp. were not significantly different in the colonic and ileal biopsies of the SCGIL cats relative to similar biopsies in the IBD cats. All of the above listed bacterial phyla as well as Fusobacterium spp. and Bacteroides spp. are found in the feces of healthy cats.
Those cats with SCGIL had significantly increased numbers of CD11b+ cells within the lamina propria of both ileal and colonic biopsies relative to those with IBD. Likewise, the cats with SCGIL had markedly increased expression of NF-KB in the lamina propria of both ileal and colonic biopsies compared to the IBD cats. A positive correlation was also found between the total numbers of Fusobacterium spp. and the total numbers of CD11b+ cells and cells expressing increased NF-KB.
The investigation of the relationship between the gastrointestinal microbiome and enteric health and disease is still in its infancy, especially in veterinary species. In humans, an increased risk for colorectal and pancreatic cancers as well as some oral squamous cell carcinomas is associated with some of the Fusobacterium spp. In one study of humans with late stage colorectal cancer, Fusobacterium nucleatum counts were found to be positively correlated with tumor size and shortened survival times. Based on these studies as well as others in rodent models, it appears that chronic IBD-type conditions are a potential risk factor for inflammatory and dysplastic processes that can lead to carcinogenesis.
Changes in the gastrointestinal microbiome such as increased numbers of mucosal Fusobacterium spp., which are pro-inflammatory, have virulence factors that promote invasive and adhesive properties, and have pro-oncogenic features, could reflect a progression from high grade chronic lymphoplasmacytic IBD to lymphoid intestinal cancer, or could simply be an effect of the gastrointestinal malignancy itself. The presence of increased numbers of CD11b+ myeloid cells and increased expression of NF-KB in the biopsies of cats with SCGIL was positively correlated with the numbers of Fusobacterium spp. in the same biopsies. A valuable and logical focus for future research would be to determine whether the observed increase in Fusobacterium spp. in biopsies demonstrating feline SCGIL is an etiologic factor in the development of this disease or an associated effect.
J Am Vet Med Assoc 2019;254:1172-1179.
Evaluation of the nutritional adequacy of recipes for home-prepared maintenance diets for cats
Wilson SA, Villaverde C, et al.
The popularity of homemade diets for pets has burgeoned in the last decade, as an increasingly health-conscious and foodist culture in the first world extends its expanding interest in dietary therapy and its potential role in optimizing human health and treating disease, to companion animals. An information explosion largely centered on the Internet and online social media, as well as in print media, has allowed pet owners to seek dietary information and recipes for home-prepared foods from a wide array of channels other than the family veterinarian, and has also led to a search for alternatives to commercial pet foods by a substantial number of pet owners.
Cats in particular, as obligate carnivores who cannot, like many other species, synthesize de novo a number of essential nutrients and must instead acquire them from their diet, have specialized dietary needs. This paper outlines the findings of the first systematic study of home-prepared diets for adult cats published in books and online sources, involving 114 recipes which were each analyzed qualitatively and quantitatively. The nutritional profiles of these recipes were compared with the recommended allowances (RAs) of essential nutrients for adult cats as published by the National Research Council (NRC). Some of the recipes evaluated were authored by veterinarians and some by non-veterinarians. Only those recipes not labeled for medical conditions, gestation, lactation, or growth, use as a treat, or for supplemental or intermittent feeding, were analyzed in the study. Computer software was used to compare the nutrient profiles of the recipes with the NRC RAs.
The source of 48 recipes was the Internet, and books provided the other 66. Ten of the recipes did not provide enough information for computerized nutritional analysis. All but one of the 94 recipes that could be analyzed using computer software had issues with clarity of directions in one or more areas: specification of amounts and types of ingredients or supplements, preparation instructions, and/or feeding directions.
None of the 94 recipes analyzed by computer met all NRC RAs for adult cats, and those designed by non-veterinarians (including anonymous sources) contained more nutrient levels that were lower than the NRC RAs than those created by veterinarians. Potentially toxic ingredients, including garlic, onions, and leeks, were found in 8/114 recipes. Over half of the recipes (50/94) contained inadequate taurine levels. Based on the NRC RAs for adult cats, most recipes (72/94) were choline-deficient; other notable deficiencies found included iron (72/94), thiamine (59/94), zinc (58/94), manganese (54/94), vitamin E (54/94), and copper (43/94). Some of the recipes also contained nutrient concentrations that exceeded the safe upper limit for specific ingredients established by the NRC.
Almost all of the recipes met the NRC RAs for all essential amino acids except for taurine, which is crucial in the prevention of diet-associated dilated cardiomyopathy in cats. No warnings regarding food safety concerns associated with the use of raw animal products were provided with most of the recipes involving the use of these foodstuffs.
The authors state that none of the home-prepared diets they evaluated were nutritionally adequate for long-term feeding of adult cats. Another concern associated with the use of such diets is “ingredient drift,” wherein owners may modify recipes on their own, or substitute or omit ingredients included in the original recipe, which can further increase the risk of nutritional inadequacy and/or imbalance associated with the feeding of a home-prepared diet. The advice of a board-certified veterinary nutritionist in evaluating and producing a recipe for home-prepared food, and providing guidelines for ingredient selection, preparation, and feeding, will substantially reduce the risk of development of health problems associated with long-term feeding of an unbalanced diet, and is strongly recommended. Several veterinary teaching hospitals and private concerns offer online consulting services provided by board-certified veterinary nutritionists, who can create customized recipes for individual patients in any healthy lifestage as well as for animals with disease conditions.