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Pyometra and endometrial disorders


Synonym(s): Pyometra, Cystic endometrial hyperplasia, Endometritis, Hydrometra, Mucometra

Introduction

  • Cause:
    • Pyometra: bacterial infection of endometrial tissue which leads to the intraluminal accumulation of purulent exudate.
    • Bacrerial endometritis: bacterial infection of endometrial tissue along with an inflammatory response.
    • Cystic endometrial hyperplasia: fairly common.
  • Signs: may be asymptomatic in early stages. Failure to become pregnant, blood from vulva, vaginal discharge, signs of pseudopregnancy, closed cervix pyometra will progress to septicemia and shock.
  • Diagnosis: physical examination, ultrasonography, radiography, bloodwork, biochemistries, urinalysis, cytology of vaginal discharge, culture and sensitivity of uterine endometrial tissue, histopathology of uterine tissue following ovariohysterectomy for definitive diagnosis.
  • Treatment: immediate therapy for pyometra and sepsis: antimicrobial therapy, fluid therapy, ovariohysterectomy (treatment of choice), supportive care throughout the treatment period. Endocrine treatment: medical management can be tried, although ovariohysterectomy is preferred.
  • Prognosis: good to guarded, depending on cause.
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Presenting signs

  • May be asymptomatic in early stages.
  • Failure to become pregnant.
  • Blood from vulva: usually noticed with urination. Frank blood is seen at the end of micturition, may be intermittent or cyclic.
  • Vaginal discharge: intermittent or continuous; may be foul-smelling.
  • Signs of pseudopregnancy that could include lactation for 1-2 weeks.
  • Closed cervix pyometra will progress to septicemia and shock.
  • Poor breeding history: may have history of small litter size, increased numbers of stillborn or resorbed fetuses, dystocia Dystocia. May have history of abandoning pups.
  • Polyuria and polydipsia Polyuria/polydipsia may be seen with chronic pyometra.

Acute presentation

  • Abdominal swelling.
  • Palpable enlarged uterus.
  • Vaginal discharge: serosanguineous to purulent, blood-tinged.
  • Perineal and/or vulvar blood-tinged staining.
  • Lethargy.
  • Anorexia Anorexia.
  • Dehydration frequently seen.
  • Mammary gland enlargement.
    • Fluid-filled or firm.
    • Neoplasia may be present.
    • Mastitis may be present.
  • Febrile.
  • If significant blood loss, may be tachycardic, have pale mucous membranes.
  • If septicemic/shock: may be recumbent, pale mucous membranes, hypothermic, etc.

Geographic incidence

  • Worldwide.

Age predisposition

  • Higher incidence in sows older than 2-3 years.

Breed/Species predisposition

  • None.

Public health considerations

  • None.

Cost considerations

  • Diagnostics: lab work, imaging.
  • Surgery.
  • Medications.
  • Hospitalization.

Special risks

  • Risks of these diseases increases with age, starting at over 18 months.
  • Surgery: anesthetic risk. Also if there is excessive handling of gastrointestinal tissues may contribute to postoperative ileus or fibrinous adhesions Gastrointestinal stasis. Surgery is more challenging when uterus is abnormal (too large, filled with fluid, with adhesions, etc).
  • Peritonitis and sepsis possible with endometritis or pyometra.
  • Diseased uterine tissue may be friable.

Pathogenesis

Etiology

  • Pyometra: bacterial infection of endometrial tissue which leads to the intraluminal accumulation of purulent exudate.
  • Bacterial endometritis: infection of endometrial tissue along with an inflammatory response.
  • Bacteria commonly found in guinea pig pyometras and endometritis:
  • Cystic ovaries are common and often concurrent with endometritis, cystic endometrial hyperplasia, and mucometra Cystic ovarian disease.
  • Cystic endometrial hyerplasia is believed to be caused by estrogen stimulation and may be linked to uterine disorders in guinea pigs.
  • Neoplasia Neoplasia overview can be an underlying cause of pyometra or mucometra.

Predisposing factors

General

  • Sows with poor breeding history: may have history of small litter size, increased numbers of stillborn or resorbed fetuses, dystocia Dystocia. May have history of abandoning pups.

Specific

  • Cystic ovaries Cystic ovarian disease is a prevalent disease in guinea pigs and have been suggested as a cause of cystic endometrial hyperplasia and other uterine problems (such as uterine neoplasia). However, only approximately 1/4 of all ovarian cysts are hormonally-active. While the association of such prevalent cystic ovaries with uterine pathology may be just coincidence, the fact that most animals (if not all) with uterine pathology have cystic ovaries may indicate that those hormonally-active ovarian cysts may be a cause for uterine pathology.

Pathophysiology

  • Endometrial disorders can produce mild vaginal discharge to significant uterine hemorrhage.
  • Endometrial secretions provide excellent media for bacterial growth.
  • Bacteria ascend from the vagina or may be transmitted from the male during copulation.
  • Vaginitis can be a factor leading to uterine infections, endometritis and pyometra.
  • Estrogen production from hormonally-active cystic ovaries may cause uterine changes, including cystic endometrial hyperplasia, mucometra, or endometritis.
  • Note: hematogenous spread of bacteria to the uterus has not been reported in guinea pigs.

Timecourse

  • Factors leading up to changes in the uterus may be considered chronic.
  • Once septic, disease course is acute and may even be considered an emergency.

Epidemiology

  • Usually individual sow problem.
  • Endometrial hyperplasia is commonly reported when uterine biopsy is performed, or a necropsy. Other uterine conditions are considered uncommon in guinea pigs.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Veiga-Parga T, La Perle K M D & Newman S J (2016) Spontaneous reproductive pathology in female guinea pigs. J Vet Diag Invest 28 (6), 656-661 PubMed.
  • Minarikova A, Hauptmann K, Jeklova E et al (2015) Diseases in pet guinea pigs: a retrospective study in 1000 animals. Veterinary Record 177 (8), 200 PubMed.
  • von Engelhardt A B (2006) Treatment of the metritis/pyometra complex with aglepristone in a guinea pig. Praktische Tierarzt 87 (1), 14-17 VetMedResource.

Other sources of information

  • Hawkins M G & Bishop C R (2012) Disease Problems of Guinea Pigs. In: Ferrets, Rabbits, and Rodents Clinical Medicine and Surgery. 3rd edn. Eds: Quesenberry K E & Carpenter J W. Elsevier. pp 295-310.
  • Paul-Murphy J (2011) Pyometra and Non-neoplastic Endometrial Disorders. In: Blackwell's Five-Minute Veterinary Consult: Small Mammal. Ed: Oglesbee B L. Wiley-Blackwell. pp 321-322.
  • Hoefer H & Latney L (2009) Rodents: Urogenital and Reproductive D
  • disorders. In: BSAVA Manual of Rodents and Ferrets. Eds: Keeble E & Meredith A. British Small Animal Veterinary Association. pp 150-160.
  • Percy D H & Barthold S W (2007) Guinea Pigs. In: Pathology of Laboratory Rodents and Rabbits. 3rd edn. Eds: Percy D H & Barthold S W. Blackwell Publishing. pp 217-251.