Diagnosis and Treatment of Canine Pyometra Complicated with Abdominal Wall Hernia

Canine pyometra refers to the accumulation of a large amount of pus in the uterine cavity of dogs, accompanied by abnormal endometrial hyperplasia and bacterial infection. According to whether the cervix is open or not, it can be divided into open type and closed type. This disease mostly occurs in adult female dogs that have not been mated, pregnant, or ligated (ovariectomized), and is more common in middle-aged and older female dogs over 6 years of age. Affected dogs develop the disease within 3 to 8 weeks after estrus, and may have a history of long-term estrus disorders or endometritis. The causes of pyometra come from endocrine disorders, estrus, mating, bacterial infection caused by unhygienic behavior during parturition, history of hormone therapy, history of endometritis, etc.

Hernia is a common disease in which the abdominal viscera protrudes from a natural orifice or a pathological rupture opening into the subcutaneous tissue or other anatomical cavity. Abdominal wall hernia refers to a localized swelling on the abdominal wall; the swelling mostly contains protruding organs, and the hernia ring can be felt by hand. Clinically, abdominal wall hernia is mostly formed by blunt external force, and the hernia contents are mostly intestines and omentum; a protruding uterus is relatively rare. The clinical case of canine pyometra complicated with abdominal wall hernia is reported as follows.

1 Onset of the disease

The affected dog was 12 years old, a brown-black Pekingese. Body weight 13.5 kg. Three days before onset, bleeding from the vagina was found, and there was an oval swelling about 10 cm long and about 5 cm wide on the left lower abdominal wall. Pressing the protrusion by hand revealed tubular contents inside, but it could not be reduced and had a fluctuating sensation; auscultation of the swelling revealed no bowel sounds. It was initially diagnosed as an abdominal wall hernia. B-ultrasound examination showed that the contents were a pus-filled uterus. Surgery was decided upon.

2 Surgical method

2.1 Preoperative preparation

General anesthesia was performed with Canine Mianbao injection at a dose of 0.05 mg/kg by intramuscular injection. The affected dog was restrained in dorsal recumbency with all four limbs fully extended and fixed. The surgical site was shaved and disinfected.

2.2 Hysterectomy surgery

A surgical drape was applied, and an incision was made along the post-umbilical ventral midline with a length of 10 cm. The skin and subcutaneous adipose tissue were incised to expose the abdominal wall muscles and abdominal fascia. The abdominal midline was grasped and lifted with toothed forceps in the left hand; with the right hand, a scalpel was inserted through the abdominal midline into the abdominal cavity, puncturing the peritoneum, and then withdrawn. One blade of surgical scissors was inserted through the small incision deep into the abdominal cavity to cut open the abdominal midline and enlarge the incision. After the abdominal cavity was exposed, the uterine horn was explored, pulled out of the incision, covered with gauze soaked in physiological saline, and fixed by hand. The ovary was brought out forward, and the uterine body was brought out backward; along the uterine body, the contralateral uterine horn and ovary were brought out. The uterine arteries on both sides of the broad ligament of the uterus were doubly ligated; after the broad ligaments on both sides were ligated as a bundle, the broad ligament of the uterus was cut. The suspensory ligament of the ovary was ligated and then cut; finally, the uterine body was ligated with a transfixing suture, and the uterine body was cut 1.5 cm proximal to the ligature line. The ovaries and the pus-filled uterine horns were completely removed. The removed uterus was incised, and a large amount of yellow-white pus was seen flowing out.

2.3 Management of the abdominal wall hernia

The hernia opening was found to be a rupture of the peritoneum. Because it was close to the left inguinal side, an incision was made 4 cm to the left of the original incision, and the hernia opening was sutured. After the surgical site was flushed with penicillin physiological saline, the muscle tissue under the skin was sutured continuously, the skin on both sides of the incision was lifted and sutured with interrupted sutures, the skin wound edges were disinfected with iodine tincture, and a bandage was applied externally with a tied knot.

3 Postoperative care

3.1 For 6 d after surgery, ampicillin and physiological saline were administered intravenously. Sutures were removed at 6 to 8 d.

3.2 After surgery, the feeding amount was reduced, and easily digestible liquid food was appropriately given. The affected dog's movement was restricted, and it was kept as quiet as possible; the kennel was kept warm and clean.

4 Summary and discussion

4.1 Abdominal wall hernia is mostly caused by blunt external force; the external force tears the muscle, but the outer skin remains intact, so that abdominal organs fall into the rupture opening to form a protruding mass on the body surface with clear boundaries. The hernia contents are mostly omentum and intestines. The probability of the uterine horn falling into the hernia sac is very small; the uterus is located below the rectum in the pelvic cavity and rarely droops to the middle of the abdominal cavity. However, in this case, the hernia contents were the pus-filled uterine horn, which may have been caused by severe accumulation of pus in the uterine horn shifting the center of gravity forward so that it fell into the abdominal cavity.

4.2 The timing of surgery for hernia disease should be grasped. Congenital hernia disease may gradually shrink its hernia opening with age and achieve self-healing. However, some cases are the opposite. The characteristics of this case were that the dog was old and had increased complications; the disease history was long, and the contents could not be reduced for a long time, forming an incarcerated hernia. If surgery is not performed as early as possible, the organs incarcerated in the hernia sac are compressed, blood circulation is obstructed, and ischemia and even necrosis easily occur; the surgical success rate is very low, increasing the difficulty and risk of surgery. However, for reducible abdominal wall hernia, an appropriate surgical timing should be chosen. Within 10 d after the affected dog begins to show abdominal wall hernia, surgery cannot be performed, because at this time it is in the acute inflammation stage, and suturing easily tears, with a relatively low surgical success rate.

4.3 Canine pyometra is relatively common clinically. The common treatment methods include conservative therapy and surgical therapy. The former mainly uses hormone therapy combined with antibiotic treatment, but this treatment method has a low cure rate and is prone to recurrence, and hormones have certain side effects in most dogs. The latter is mainly surgical sterilization, removing the ovaries and uterus; it is not prone to recurrence after surgery and has a high cure rate, and is the preferred treatment method. When both uterine horns are severely filled with pus and one uterine horn in the hernia sac has already been compressed to a certain extent, surgical removal therapy must be adopted.

4.4 Pyometra can be diagnosed by B-mode ultrasound examination and vaginal smear examination. B-ultrasound examination provides rapid and relatively accurate diagnosis. Clinically, affected dogs mainly show sexual cycle disorders, emaciation, poor appetite, and sometimes elevated body temperature. If it is the open type, dripping to large amounts of uterine purulent secretion are discharged from the vulva, appearing cream-colored, gray, reddish-brown, etc., often accompanied by a fishy odor. The hair near the vulva, tail, and hock of the affected dog is contaminated. The vulva is red and swollen and even ulcerated, and the abdominal circumference is slightly increased. If it is the closed type, the vulva changes little and there is no discharge of secretion, and the abdominal circumference increases. The pus-filled uterus compresses the diaphragm, leading to an increased respiratory rate. The abdominal skin is tense, veins are distended, and the dog prefers to lie down.