Tuesday, June 24, 2014

1387. Yangon seminar July 5, 2014. Guidelines on treatment of pyometra in small animals.

Dr Sing Kong Yuen, BVMS (Glasgow), MRCVS. Founder of Toa Payoh Vets, Singapore
toapayohvets.com, 99pups@gmail.com

I graduated from Glasgow University in 1974 and founded Toa Payoh Vets in 1982. It is a private small animal practice in Singapore. For this July 5, 2014 Seminar, I share my approximately 40 years of experiences in the treatment of pyometra cases in dogs and cats in my practice. The focus is on the treatment of the following 3 types of pyometra. 

A stump pyometra is a progesterone-mediated infection of a remnant of the uterus.
Progesterone is a female hormone causing the uterus to be enlarged and cystic, making it susceptible to secondary bacterial invasion from the vagina.

Progesterone is released by the residual ovarian tissue or from synthetic progesterone hormone treatments like Depo-M and Contracep injections in Myanmar or Ovarid tablets in Singapore. 


CLINICAL SIGNS may include any of the following: foul smelling vaginal discharge, loss of appetite, fever, lethargy, weight loss, vomiting and diarrhea, or excessive thirst and urination. Caterwauling in "spayed" cats.

1. Ultrasonography is preferred. Thickened uterine wall and intraluminal fluid. A normal uterine wall is not visible.
2. Abdominal x-ray. A large uterine stump may be seen.
3. Blood test - CBC/Biochemistry
4. Vaginal cytology - determine if there is oestrogen circulating in the blood indicating the presence of functional ovarian tissue.

Antibiotics and surgery. Surgery to remove the infected uterine tissue and any remaining
ovarian tissues.
Surgical approach
Make a long skin incision. To locate the remaining ovarian tissues, take out the intestines. Look for the areas caudal to the kidneys. Usually, the ovarian tissues are enlarged, encasing the sutures as shown in the following image of a case of stump pyometra in the cat. The stump uterus is filled with pus.

TP 43053

Today, Jun 24, 2014. The owner came to Toa Payoh Vets to purchase 3 tablets of Ovarid 20 mg as he said that the cat was spayed by a vet on Jan 19, 2012. She still caterwauls and shows signs of heat every 2-3 months and so he asked for Ovarid tablets to suppress the heat cycle.

The first caterwauling was on Apr 22, 2012 and he was prescribed Ovarid 20 mg at 1/4 tablet SID for 7 days and 1/4 tablet alternate days for 3 weeks.  On August 28, 2013, he came to get 2 tablets of Ovarid. I advised surgery to remove the remaining ovarian tissue but he would wait and see. If stump pyometra develops, he may have no choice, but surgery.


1. Too short a spay incision into the linea alba. In such a short incision of less than 1 cm, the first swollen uterine horn and ovary of a cat or dog in estrus can be hooked out. However, there is no space for the second uterine horn and ovary to come out. The vet tugs the ovary out of this tight hole. The ovarian ligament breaks. The ovary drops into the abdomen. The vet takes out the second uterine horn, completes the surgery. 

2. The incision is too far away from the umbilical scar, usually more than 4 cm away. Therefore the ovaries are not easily hooked. Too vigorous tugging of the ovary breaks the suspensory ligament. The ovary drops into the abdomen. The vet completes the surgery.

I usually incise around 1.5  cm from the umbilical scar. I make a 1-cm incision and there is no problem exposing the whole ovary and tying its suspensory ligament. If necessary especially when the cat is in estrus, I will extend my incision caudally by a cm to take out the swollen uterine horns and ligate the uterine body. I use absorbable sutures. With this approach, I never had a stump pyometra or a "spayed" cat or dog still showing signs of heat.


OPEN PYOMETRA & CLOSED PYOMETRA are life-threatening infections of the uterus by bacteria and are medical emergencies. In open pyometra, the cervix is not closed unlike in closed pyometra and so sanguinous to mucopurulent vaginal discharge is seen.

1. Ultrasonography is preferred. Thickened uterine wall and intraluminal fluid. A normal uterine wall is not visible.
2. Abdominal x-ray. Large uterine horns may be seen.
3. Blood test - CBC/Biochemistry. Neutrophilia, normocytic, normochromic anaemia, hyperglobulinaemia, hyperproteinaemia, azotemia, ALT and ALP high with septicaemia or severe dehydration
4. Vaginal discharge cytology - regenerative polymorphonuclear cells and bacteria.

Review the blood test results to check especially for leucoytosis, anaemia, platelet count, serum BUN and creatinine, ALT and ALP, PCV to assess the prognosis of the case for the owner. The higher the abnormal values, the poorer the prognosis. Anaesthetic and surgery informed consent form to be signed by the owner.

The following is what I do in most cases of female dogs not valued for breeding
1. Inpatient for 3-7 days
2. Immediate IV fluid (glucose, dextrose saline, Hartmann's, amino acids and multivitamins) and Baytril antibiotics for one day.
2. Spay on the 2nd day. I do not operate immediately.
3. IV tolfedine as this is anti-fever and analgesic
4. IV fluid post-op and antibiotics for 14 days.

Prognosis and outcome are good after spay if the dog has no permanent kidney damage (vomiting, high serum BUN and creatinine, anaemia, low platelet count).

For female dogs valued for breeding. Medical treatment using prostaglandin 2alpha to contract uterine muscles to expel the pus.
1. Client education that the dog must have open pyometra and not azotemic. Dog with closed pyometra may lead to uterine rupture causing peritonitis. 
2. Details of the costly treatment and monitoring are in Pyometra and Cystic Endometrial Hyperplasia, Pg. 1101, The 5-minute Veterinary Consult, 3rd Edition.

3. In one case done by my associate, the valuable Pekinese with open pyometra was






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