Key Points

The word pyometra can be divided into two root words

• Pyo means pus
• Metra refers to the uterus

Pyometra starts after a dog goes through a heat cycle, usually within about 3 to 5 weeks

Spaying is the treatment of choice

Prognosis is usually favorable, providing that the patient is not profoundly ill

Anatomy

• The uterus is a Y-shaped organ that has two horns
• An ovary is located at the end of each horn of the uterus

Pathophysiology

• The word pyometra can be divided into two root words
  • Pyo means pus
  • Metra refers to the uterus
• Pyometra starts after a dog goes through a heat cycle, usually within about 3 to 5 weeks
• Stimulation of the uterus with abnormal levels of hormones (estrogen and progesterone) cause the lining of the uterus to become thickened and fluid accumulates inside the uterus
• Infection develops in the uterus
• As the infection progresses, the uterus fills with pus
• If the pet has closed pyometra the cervix is not open and pus cannot drain to the outside
• If open pyometra is present, the pus can drain through the cervix
• The infection is life-threatening; closed pyometra may cause a pet to become more ill than open pyometra

Clinical signs

• Pus may or may not drain from the vagina/vulva (see photo below)
• Increased thirst/increased urination
• Enlargement of the abdomen as the uterus fills with pus
• Lethargy
• Poor appetite
• Weight loss
• Enlargement of the abdomen
• Fever
• Dehydration
• Clinical signs are variable from pet to pet

Diagnostic tests

• Complete blood cell count usually shows an elevated white count
• Chemistry profile to evaluate function of internal organs
• Radiographs of the abdomen
• Ultrasound of the uterus (photo below shows a uterus filled with pus – black structure)
• Culture of the pus from the uterus
• Biopsy of the uterus if cancer is suspected

Treatment

• Fluid therapy via an IV to correct dehydration
• Antibiotics
• Transfusions of plasma, Hetastarch, whole blood
• Surgical removal of the uterus; photo below shows a very enlarged uterus that is filled with pus

Nonsurgical Treatment

• Fluid therapy
• Antibiotics
• Prostaglandins help the uterus to expel pus and alters the hormone levels of the ovaries
• This treatment should not be used if the pet is quite ill
• This treatment should not be used if your pet has closed pyometra
• This treatment may not work and surgery will need to be done
• If this treatment is successful, the next time the dog goes through heat, pyometra will usually recur unless the dog is bred and becomes pregnant

Aftercare

• Antibiotic therapy
• Restrict activity for 3 weeks
• Encourage eating and drinking
• Check incision for signs of infection

Potential complications

• Anesthetic death
• Bladder infection
• Peritonitis, which is infection of the abdomen
• Abdominal abscess formation
• Disseminated intravascular coagulation, which is a clotting disorder from the infection and causes death in many patients.
• Sepsis – poisoning of the body by toxins from bacteria

Prevention of pyometra

• Simply having your pet spayed at a young age will prevent pyometra and will decrease the risk of mammary cancer