Pyometra in female dogs: symptoms, emergency signs and surgery

What is pyometra?

Pyometra is a severe bacterial infection of the uterus in which pus accumulates in the uterine cavity. It affects unspayed female dogs, most commonly from 5–6 years of age onwards, although it can occur at any age. It is the most common gynaecological emergency in dogs and can be fatal within days without treatment.

It typically develops 4–8 weeks after a heat cycle, when progesterone levels are high and the cervix is either open (open pyometra) or closed (closed pyometra — more dangerous).

Types

• Open pyometra: the cervix is open and pus drains to the outside (purulent vaginal discharge). Owners usually notice the discharge, prompting earlier diagnosis.
• Closed pyometra: the cervix is closed and pus is retained. The abdomen may become visibly distended. Deterioration is faster and the risk of uterine rupture with peritonitis is high.

Symptoms

• Purulent, bloody or foul-smelling vaginal discharge (open pyometra).
• Marked lethargy and weakness.
• Polydipsia (drinking excessively) and polyuria (urinating frequently) — a classic sign of pyometra.
• Loss of appetite and vomiting.
• Distended, tense abdomen (especially in closed pyometra).
• Fever (not always present — advanced cases may show hypothermia).

Treatment

Pyometra is a veterinary emergency. The standard treatment is surgical ovariohysterectomy (removal of the uterus and ovaries). This resolves the condition permanently and prevents recurrence.

• Pre-operative stabilisation: IV fluids, antibiotics (amoxicillin-clavulanate as first line), correction of dehydration.
• Medical treatment (alternative): prostaglandins + antibiotics — only for young dogs with open pyometra and a breeding intention. Recurrence rate >70 %. Contraindicated for closed pyometra and severe cases.

Prognosis

Good when surgery is performed within the first 24–48 hours. Cases complicated by peritonitis or sepsis carry a significantly worse prognosis. Mortality without treatment is very high.

Prevention

• Spaying (ovariohysterectomy or ovariectomy) before the first heat eliminates the lifetime risk of pyometra.
• If your dog is not spayed, monitor for pyometra signs 4–8 weeks after every heat cycle.
• Avoid exogenous progestogens (hormonal contraceptives) unless strictly necessary.