Canine uterine pus is an acute or chronic disease that occurs in the late estrus period of dogs, mostly in adult dogs, and is the most clinically prevalent obstetric disease in female dogs, which can be categorized into atretic uterine pus and open uterine pus according to clinical signs. Clinical manifestations often involve multiple systems, and immunization levels of uterine cells are reduced mainly during the late estrous period in dogs, which is influenced by increased progesterone concentrations and decreased estrogen concentrations. Increased progesterone concentrations cause endometrial hyperplasia and increased glandular secretion, again favoring the growth and multiplication of foreign bacteria. The uterine mucosa is invaded by foreign bacteria and lesions occur, and uterine secretions increase. If the cervix is closed, no secretion will be discharged; but if the cervix is in an open state, a foul-smelling, bloody mucopurulent secretion will be discharged. In conclusion, canine uterine pus is a manifestation of uterine inflammatory lesions under the action of endometrial cystic hyperplasia, continuous stimulation of the endometrium by progesterone and bacterial infection. This article describes the etiology of canine uterine pus accumulation, in order to give help for the prevention and treatment of this disease.
Canine uterine pus
Oestrus cycle and causative organisms
The canine oestrus cycle refers to the development of the female canine to the first period of love after the reproductive organs and the whole organism undergoes a series of cyclic changes, week after week, until the age of cessation of sexual activity. The dog's estrous cycle is generally divided into pre-estrus, estrus, post-estrus (inter-estrus), recess (lack of estrus). Pre-oestrus is from the female dog vagina discharge blood secretion until the start of acceptance of mating, usually 5 d ~ 15 d, an average of 9 d. Oestrus is from the female dog began to accept mating to refusal of mating, usually maintain 7 d ~ 12 d, an average of 9 d. Inter-oestrus to the female dog began to refuse to mate as a sign, to the reproductive organs to return to normal, the period of 70 d ~ 90 d, an average of 75 d. Truce period of the female dog reproductive organs are in a state of stasis. The reproductive organs of the dog are in a state of stasis, usually 50 d~60 d, and this period is close to one year for dogs that come into heat only once a year.
Canine uterine pus accumulation occurs mainly in the first half of the late estrous period, which is obviously related to the elevated level of progesterone in the late estrous period. Progesterone reduces uterine resistance, which is the main reason why uterine pus accumulates more often in late estrus. The majority of studies have demonstrated that uropathogenic Escherichia coli is the main bacterium responsible for uterine pus and urinary tract infections, in addition to staphylococci, streptococci, Pseudomonas spp., Aspergillus spp., Pneumocystis spp., Nocardia spp. and other bacteria that are also responsible for uterine pus. Urethral pathogenic Escherichia coli can enter the uterus through the flaccid cervix during oestrus, and its special urethral infection causative factor can help the bacteria adsorb and colonize the mucous membranes of the urethra and the uterus, providing the necessary nutrients for the growth and reproduction of the bacteria. In the late oestrus, the resistance of the mucous membrane of the uterus decreases, and the pathogenic bacteria that enter through the loose cervical canal during oestrus are able to reproduce in large quantities, which makes the dogs in the late oestrus very susceptible to uterine pus accumulation.
On radiographs, there is a generalized increase in the density of the abdomen, but the margins are not well defined
Other factors
The age of onset of canine uterine pyometra can range from 4 months to 16 years of age, and all adult bitches of all ages are at risk of developing uterine pyometra. The incidence of uterine pus is higher in infertile bitches and bitches older than 6 years of age. This is due to the fact that older dogs are prone to ovarian dysfunction, which is characterized by ovarian atrophy, ovarian cysts, and a persistent corpus luteum. Progesterone is secreted by the corpus luteum over a long period of time and acts on the endometrium to cause cystic hyperplasia of the endometrium, which leads to uterine pus accumulation.
Canine uterine pus can occur in any breed of dog, but is more prevalent in the following breeds: Rottweiler, St. Bernard, Pine Schnauzer, Golden Retriever, Beardie, Irish Terrier, Aire Valley Terrier, Cavalier King Charles Spaniel, Rough Coated Sheepdog, and Bernese Mountain Dog.
Symptoms and treatment
The disease in the early stages of the disease, usually does not affect the appetite, the spirit and body temperature are normal, the affected dog systemic symptoms are not obvious. Generally 15~30 d after infection, the abdomen of the dog is enlarged, depressed, loss of appetite, drinking and urinating, sometimes vomiting. Open type uterine pus discharge from the pudenda, a large amount of purulent discharge, gray or reddish-brown, often accompanied by a fishy odor. In the case of atretic uterine pus, there is no discharge from the vulva, the abdominal circumference increases, and there is a fluctuating sensation on palpation; in the case of a long course of the disease, the enlarged uterus presses on the diaphragm, leading to an increase in the respiratory rate. ultrasound examination of atretic uterine pus shows that the uterus is relatively uniform in size on both sides, and more than two cystic masses are formed, with a thin, smooth wall and a clear boundary, and the contents of the echoes are not echoic. If the contents of the cellular components of the content of more, can be seen scattered clusters or scattered strong echogenic areas. Open uterine sepsis is not easy to observe the echo image of the fluid, if the inflammation time is long, the uterine wall can be seen to thicken 1 to 2 times, the formation of a strong reflective echoes. radiographs can be seen on the sick dog abdomen is obviously swollen, generally increased density, but the edge of the contour is not obvious.
Medication is mainly used for open uterine pus accumulation, which is facilitated by pharmacologic stimulation of uterine smooth muscle contraction to promote the emptying of uterine pus accumulation. Currently, the drugs that can induce uterine smooth muscle contraction include oxytocin, prostaglandin and ergonovine derivatives, among which prostaglandin is the most effective drug for clinical treatment. When there is no discharge from the vulva of the bitch after a few days of treatment, the medication can be stopped. At the same time, antibiotics are applied for systemic treatment, and cephalosporins can be used for intravenous injection of 25~35 mg/kg body weight, and hygromycin, tetracycline, or ciprofloxacin can be injected into the uterus transvaginally. Surgical removal of the uterus and ovaries is the most effective treatment for this disease. Since the recurrence rate of uterine pus accumulation in older bitches is up to 50% or more, ovariohysterectomy should be performed in bitches that do not need to be bred.
In view of the importance of the disease on the canine reproductive system, it is recommended that adult bitches, if they do not need to breed should be ligated as soon as possible, ovary - uterus removed completely, to avoid leaving residual tissues, causing the possibility of re-estrus, pregnancy and uterine pus accumulation, to reduce the occurrence of the disease.