FR
ENWhat is pyometra in dogs?
Over repeated heat cycles, progesterone prepares the uterus for a pregnancy that never occurs. This repeated hormonal stimulation thickens the uterine lining (cystic endometrial hyperplasia) and promotes fluid retention; an ideal environment for bacterial growth. When bacteria (often Escherichia coli) colonize the uterus, pus accumulates and the infection can rapidly become systemic.
Two forms to distinguish
The open-cervix form is easier to detect because it produces visible discharge. The closed-cervix form is often more dangerous since the infection stays trapped with no external signs.
Pus drains through the vulva
- Purulent or mucoid vulvar discharge, often foul-smelling
- May stain bedding or floor; dog licks frequently
- Faster diagnosis because the discharge is visible
- Still an emergency: the uterus remains severely infected and distended
Pus is trapped inside the uterus
- No visible vulvar discharge; infection appears silent from outside
- Abdomen progressively distends and becomes painful
- High risk of uterine rupture and septic peritonitis
- Often diagnosed later; more guarded prognosis
Why does this happen?
Each hormonal cycle exposes the uterus to weeks of progesterone stimulation. Without a pregnancy, this repeats cycle after cycle. Over time, the uterine lining degrades: it retains secretions, local immune defenses weaken, and even minor bacterial contamination can escalate into severe infection. Risk increases with age and the number of unfertilized cycles.
Signs and symptoms
Symptoms vary depending on whether the cervix is open or closed, and how quickly the infection progresses. Recognizing early signals allows faster intervention and a better prognosis.
Early stage
- Lethargy; less active or enthusiastic than usual
- Reduced appetite or complete refusal to eat
- Increased thirst (polydipsia) and more frequent urination
- Mild fever; sometimes absent
- More withdrawn behavior, less social
Intermediate stage
- Purulent or foul-smelling vulvar discharge (open cervix)
- Distended, tender abdomen (closed cervix)
- Intermittent vomiting
- Abdominal pain on handling
- Visible weight loss despite drinking normally
Advanced stage
- Severe depression; unable to rise
- Marked dehydration
- Dark urine: possible sign of kidney failure
- Pale or blue-tinged gums (septic shock)
- Respiratory distress, extreme panting
- Collapse
These signs: go to an emergency vet right now
Pyometra can escalate to septic shock within hours. If you observe any of the following signs, do not wait: every minute matters.
- Visibly distended and painful abdomen; the dog refuses to be touched
- Pale, white, or bluish gums or tongue: sign of shock or hypoxia
- Difficulty breathing, intense and continuous panting unrelated to heat or exercise
- Uncontrollable, repeated vomiting or diarrhea
- Sudden collapse; total inability to stand
- Persistent whimpering, acute pain expressed when touched
How is the diagnosis made?
The diagnosis of pyometra combines clinical examination, patient history, and targeted tests. Several results can be obtained rapidly in-clinic to guide the treatment decision without delay.
History and clinical signs
Unspayed female, age, last heat cycle, any vulvar discharge: this information immediately directs the diagnosis. Polydipsia in an unspayed dog over 5 years old within 4 to 8 weeks of her last heat must always raise suspicion of pyometra.
Complete physical examination
Abdominal palpation to detect a distended or painful uterus. Assessment of mucous membranes (gums), heart rate, body temperature, and hydration status. The exam also guides the urgency and extent of pre-surgical stabilization.
Blood work
Complete blood count: leukocytosis (elevated white blood cell count), typical of active bacterial infection. Biochemistry panel to assess kidney and liver function, often compromised by circulating bacterial toxins.
Abdominal radiographs
Useful when the uterus is very distended: shows a tubular mass in the abdomen. Less precise than ultrasound for evaluating uterine walls and fluid content.
Abdominal ultrasound
The reference exam: confirms fluid accumulation inside the uterus, visualizes wall thickness and integrity, and guides the surgical decision. Essential before any intervention.
Treatment options
Surgery is the treatment of choice in the vast majority of cases. Medical treatment is only considered under very specific circumstances and carries important limitations.
Supportive care in all cases
- IV fluid therapy to correct dehydration and support blood pressure
- Broad-spectrum antibiotics, adjusted based on bacterial culture when available
- Analgesics if pain is confirmed
- Close monitoring of kidney function, blood parameters, and body temperature
What to expect?
The prognosis depends largely on how quickly treatment begins and the dog's general condition at the time of presentation.
Post-surgical recovery is generally well tolerated. Most dogs return to normal activity in 10 to 14 days. Completing the full antibiotic course and monitoring the surgical wound are essential to prevent complications.
Management, recovery, and prevention
After surgery: the recovery period
- Give all prescribed medications through to the end of the course
- Inspect the surgical site daily: excessive redness, swelling, discharge, or wound opening must be reported right away
- Restrict jumping, running, and stair use for at least 10 to 14 days
- Keep fresh water available at all times to encourage hydration
- Offer small, frequent meals if nausea persists in the first few days
- Provide a calm, warm resting space; minimize stress
- Attend all scheduled follow-up appointments (day 7 minimum)
Signs to watch for after surgery
- Persistent fever or shivering
- Wound that opens, bleeds, or weeps
- Vomiting or diarrhea lasting more than 24 hours after surgery
- No urine output or very dark urine
- Complete refusal to eat more than 48 hours post-operation
What to avoid
- Self-medicating with antibiotics: this can mask symptoms, delay diagnosis, and complicate surgery
- Waiting for symptoms to worsen: every hour counts in a closed-cervix pyometra
- Stopping prescribed medications early because the dog seems to feel better
The best protection: spaying
Early spaying (ovariohysterectomy or ovariectomy), ideally before the first heat or within the first years of life, is the only fully reliable prevention against pyometra. It also significantly reduces the risk of mammary tumors and eliminates other hormone-dependent conditions. If your dog is not intended for breeding, spaying is the single most protective decision you can make for her long-term health.
Frequently asked questions
My dog has discharge after her heat: is it always pyometra?
At what age does pyometra most commonly occur?
Can pyometra be treated without surgery?
My vet recommends immediate surgery. Is it really that urgent?
Can my dog still have puppies after medical treatment for pyometra?
Do hormonal contraceptives in dogs increase the risk of pyometra?
This guide is provided for informational and educational purposes only. It does not constitute veterinary medical advice and is not a substitute for a consultation with a qualified veterinarian. Every animal is unique and their health must be evaluated individually. If you have concerns about your pet's health, contact our clinic or consult a veterinarian promptly.