Postpartum Metritis in Dogs and Cats

Postpartum metritis in dogs and cats is a bacterial infection and inflammation of the uterus that occurs shortly after giving birth, typically within the first week postpartum.

Etiology

Acute and severe bacterial infection of the uterus occurring in the postpartum period caused by retained fetuses or placental membranes, obstetric contamination of the cranial vagina, cervix, or uterus and by dystocia.

Pathophysiology

Though clinically similar to pyometra that occurs in the nongravid uterus, postpartum metritis is not caused by underlying uterine pathology.

Uterine discharge is generally les purulent than that which occurs with the cystic endometrial hyperplasia / pyometria complex.

The relaxed postpartum cervix allows discharge of uterine contents.

Clinical Signs

• Normal lochia is generally reddish-brown and persists 2-6 weeks.
• Vaginal discharge with endometritis differs from normal lochia.
• Usually sanguinopurulent or frankly hemorrhagic. May be copious, often quite odorous.
• Systematic signs such as fever, inappetence, dehydration and malaise, inattention to pups/kittens decreased milk production are common.

Diagnosis

• Suspicious systematic and local signs are noted on physical examination. Vaginal cytology is indicated to characterize the nature of the discharge. Presence of degenerated neutrophils, epithelial cells and neutrophils with intracellular bacteria.
• Obtain a guarded cranial vaginal culture to determine pathogen(s) involved and their antibiotic sensitivity.
• Vaginoscopy can aid in localizing the source of vaginal discharge.
• A hemogram may reveal a moderate neutrophilia and left shift.
• Abdominal radiography and / or ultrasonography are performed. Note any retained fetuses. The finding of an enlarged uterus is expected in the postpartum period.
• Ulatrasonographic examination will determine if the uterine lumen is fluid filled.

Differential Diagnosis

• Lochia and mild fever; normal in the postpartum period
• Vaginitis
• Coagulopathy
• Othery systemic disease, including mastitis

Treatment

• Begin broad–spectrum antibiotic therapy (e.g., cephalosporins) while awaiting culture and sensitivity results.
• Begin supportive care such as parenteral fluid therapy.
• Ovariohysterectomy is curative if the female is not intended for future breeding.
• Prostaglandin F2 alpha (Lutalyse) 0.25 mg/kg SQ SID for 5 days can be used to promote uterine evacuation as an alternative to ovariohysterectomy. The female may be unable to care for pups/kittens during acute illness and temporary orphan care may be necessary.

Patient Monitoring

• Most bitches/queens respond well to aggressive medical management.
• Subsequent fertility is expected to be normal following prompt and successful resolution of the disease but studies to document future fertility are lacking.