Introduction

• Disease of the luteal phase.
• Hormonally mediated cystic hyperplastic endometritis associated with a bacterial infection.

Pathogenesis

Etiology

• Secondary bacterial infection of the material in the endometrial glands (embryotroph) may include Escherichia coli  Escherichia coli, Proteus spp, B-hemolytic streptococci  Streptococcus spp and occasionally anaerobes.

Predisposing factors

General

• Middle to old age.
• Successive luteal phases without pregnancy.

Specific

• Prolonged use of progestagens for the prevention or suppression of estrus.

Pathophysiology

• Successive luteal phases without pregnancy, ie following non-fertile mating-induced ovulation or occasionally spontaneous ovulation (pseudopregnancy Pseudopregnancy), or progestagen use   →   repeated and prolonged progesterone concentrations   →   cystic endometrial hyperplasia   →   pyometra.

• Renal disease: several aspects of the renal changes associated with pyometra are incompletely understood but some suggestions include:

Prerenal uremia

• Dehydration, shock and toxemia   →   poor renal perfusion   →   Antibody / Antigen (Ab-Ag) complexes deposited on the basement membrane of the glomerular apparatus   →   glomerular disease   →   persistent proteinuria.
• Bacterial toxins or immune complexes interfere with Na+ resorption from the distal convoluted tubule and collection ducts   →   tubular disease   →   impaired ability to concentrate urine   →   polyuria   →   dehydration and electrolyte loss.
• Concurrent renal disease may be found in older cats.

Acid base balance

• Metabolic acidosis is more common but metabolic alkalosis may develop through prolonged vomiting.

Electrolytes

• Vomiting, uterine loss and renal dysfunction   →   Na+/K loss.

White cells

• Neutrophilia Hematology: neutrophil with a left shift.

Diagnosis

Treatment