CONDITION

Pyometra

Why this matters now

Pyometra typically develops in intact (unspayed) female dogs and cats, most commonly occurring 4-8 weeks after a heat cycle. The condition tends to affect middle-aged to older animals, though it can occur at any age in intact females. Risk increases with each successive heat cycle, and animals that have received hormone treatments may have elevated risk.

The condition can develop gradually with subtle early signs or progress rapidly to a serious state. In open pyometra, where the cervix remains open, discharge may be visible and provides an early warning. In closed pyometra, the cervix is sealed and infection accumulates without external signs, often leading to more rapid deterioration. Without intervention, toxins from the infection can enter the bloodstream, affecting multiple organ systems.

Signals & patterns

Early signals

Vaginal discharge

A cream, yellow, or bloody discharge from the vulva, often noticed on bedding or when the animal licks the area. Present only in open pyometra.

Excessive licking of vulvar area

The animal may pay more attention to cleaning this area than usual, sometimes indicating discharge or discomfort.

Reduced appetite

A gradual decline in interest in food is often one of the earliest signs of developing illness.

Increased thirst and urination

The toxins produced by the infection can affect kidney function, leading to increased water consumption and more frequent urination.

Later signals

Lethargy and weakness

As the infection progresses, the animal becomes increasingly tired and reluctant to engage in normal activities.

Vomiting

Systemic illness from the infection can cause nausea and vomiting as toxins circulate.

Abdominal distension

The uterus may enlarge significantly with accumulated pus, sometimes visible as a swollen belly.

Fever or subnormal temperature

Body temperature may be elevated initially but can become low as the animal deteriorates.

Click to read about the biological mechanisms

How this is usually investigated

Diagnosis of pyometra combines clinical history, physical examination findings, and imaging. Identifying the condition promptly allows for appropriate intervention while the animal is still stable.

History and physical examination

Purpose: Gathering information about recent heat cycles, current signs, and examining the vulva for discharge and the abdomen for enlargement.
Considerations: In closed pyometra, lack of discharge can make the condition less immediately obvious, making other examination findings particularly important.

Abdominal ultrasound

Purpose: Visualises the uterus to identify fluid accumulation and assess the extent of uterine enlargement.
Considerations: Generally considered the most useful imaging tool for confirming pyometra and assessing severity. Non-invasive and widely available.

Abdominal radiographs

Purpose: Can reveal an enlarged, fluid-filled tubular structure in the abdomen consistent with an enlarged uterus.
Considerations: May be less definitive than ultrasound but useful when ultrasound is not available or as an initial screening tool.

Blood tests

Purpose: Assess white blood cell count, kidney function, and other parameters that indicate systemic involvement and help guide treatment.
Considerations: Elevated white cells and markers of kidney dysfunction are common findings. Results help assess the animal's overall condition for treatment planning.

Vaginal cytology

Purpose: Examination of cells from vaginal discharge can help confirm the presence of infection and identify bacterial involvement.
Considerations: Useful when discharge is present but may not be diagnostic on its own.

Options & trade-offs

Treatment of pyometra focuses on removing the source of infection and providing supportive care. The approach depends on the animal's condition, the owner's breeding intentions, and the severity of illness.

Surgical removal (ovariohysterectomy)

Removal of the uterus and ovaries eliminates the infection and prevents recurrence. This is considered the standard treatment for most cases.

Trade-offs: Provides definitive treatment and prevents future episodes. Carries surgical and anaesthetic considerations, particularly in ill animals. Ends the animal's breeding potential permanently.

Medical management with prostaglandins

Medications that cause the uterus to contract and expel contents, combined with antibiotics, may resolve open pyometra in some cases.

Trade-offs: May preserve breeding potential. Carries risk of incomplete resolution and recurrence with future heat cycles. Not suitable for closed pyometra due to rupture risk. Requires close monitoring.

Stabilisation before surgery

Intravenous fluids and supportive care to improve the animal's condition before anaesthesia and surgery.

Trade-offs: May be necessary for severely ill animals but carries risk of deterioration during the stabilisation period.

Antibiotic therapy

Antibiotics are typically used alongside primary treatment to address bacterial infection.

Trade-offs: Supports other treatments but cannot resolve pyometra alone due to the nature of the accumulated infection.

Common misconceptions

Misconception:

"Pyometra only affects elderly dogs"

Reality:

While risk increases with age, pyometra can develop in any intact female after puberty. Middle-aged animals are commonly affected, but younger animals are not immune.

Misconception:

"If there is no vaginal discharge, the animal cannot have pyometra"

Reality:

Closed pyometra occurs when the cervix is sealed, trapping infection inside with no external discharge. This form can be more dangerous as it may go unrecognised until the animal is seriously ill.

Misconception:

"Antibiotics alone can cure pyometra"

Reality:

The infected material accumulating in the uterus cannot be effectively reached or cleared by antibiotics alone. Removal of the source of infection is typically necessary for resolution.

For owners of intact female dogs or cats, being aware of the normal timing and duration of heat cycles can help identify when something seems different. Noting any changes in behaviour, appetite, thirst, or discharge in the weeks following a heat cycle may provide valuable information. Understanding that spaying eliminates the risk of pyometra is relevant when considering the animal's reproductive future.

Last reviewed: Invalid Date · ConciergeVet Clinical Team