Pyometra in bitches

The world pyometra is derived from latin “Pyo” meaning pus and “Metra” meaning uterus. pyometra is uterine inflammation with accumulation of purulent material or pus in the uterus and one of the most common problem in bitches.

Pyometra can be classified as open cervix or closed cervix pyometra. Open cervix pyometra is prevalent and postulated in bitches. Closed cervix pyometra are predominant and it particularly dangerous, because rapidly of septicemia and toxaemia and if left untreated can result in death of bitches.

Fig: 1. normal uterus and uterus with pyometra

Incidence:

Its incidence range from three to seven years of age, and it affect bitches towards

or mid diestrous stage of estrous cycle.

Breed susceptibility:

High risk: Golden Retriever, Chow Chow, Terrier, Collie etc..

Low risk: German shepherd, Daschunds, hounds etc..

Etiology:

The exact etiology of pyometra is still unclear. Several researches indicate predominant role of reproductive hormone, i,e progesterone and estrogen as predisposing factor for pyometra. Several other pathogenic bacteria are also identified as causative agent such as E-coli, Klebsiella spp, Streptococci, Staphylococci, Pseudomonas spp..

E-coli is the most prevalent organism that cause pyometra in the dog and cat. and is normally present in the urine and faeces of affected bitches. Estradiol cause cervical dilation during estrous cycle and therefore allow bacteria that are part of normal flora of the vagina (especially E-coli and streptococcus spp.) to ascend into the uterus.

Pathogenesis:

The pathogenesis of pyometra is not yet completely understood but involved both hormonal and bacterial factor. The uterine environment during the luteal phase is suitable for pregnancy but also for microbial growth. During luteal phage of estrous cycle blood progesterone level increase which turn lead to increasen secretion from endometrial gland, suppression of myometrium contraction, that

favors occurrence of disease.

Hormonal and bacterial factor are involved in the pathogenesis and progesterone play a key role.

Clinical sign:

In open cervix pyometra: polyuria, polydipsia, malodors, sanguineous and mucopurulent vaginal discharge. 

In close cervix pyometra: present with inappetience, frequent vomition, depression, polydipsia, lethargy and abdominal distension. Fever and elevated white blood cellcount, peritonitis, congested mucus membrane and sternal recumbency. 

In cat, pyometra is not common which is believed to depend on less progesterone dominance due to seasonality and induced ovulation.

Fig: 2. Canine pyometra uterus 

  

Fig: 3. Purulent vaginal discharge in a bitch with open cervix pyometra

Fig: 5. Uterine horn containing abundant sanguinopurulent fluid.

Clinical pathology:

Uterine change: infection of the uterus followed by accumulation of pus caused distension of uterine horn. Inflammatory change of uterus can cause loss of wall elasticity and gradually distended from their normal size.

Blood component: pyometra affected bitches suffer from non- regenerative anemia, which was either normocytic normochromic or microcytic hypochromic anemia. Due to accumulation of metabolic waste products or diapedesis of erythrocyte into uterine lumen and toxic depression of bone marrow.

Diagnosis:

Ultrasonography and Radiography. The disease is easy to recognize in classic cases but can be more challenging when there is no vaginal discharge (i,e closed cervix). In open pyometra mucopurulent or serosanguineous malodorous discharge through vagina. Pyometra should be differential diagnosis in bitches admitted with sign of illness after estrous, but the disease can occur at any time during the estrous cycle.

Bacteriologic culturing of the vaginal discharge is not helpful for the diagnosis because the same microbes are present in the vagina in healthy animal.

Biochemical test:

ALT, AST, Creatinine, Globulin, Haematological evaluation show erythrocytopenia, reduced level of Hemoglobin (Hb), decreased packed cell volume (Pcv), azotemia and leukocytosis.

During recent year it has been mentioned that due to severe uterine infection and toxemia blood parameter evaluating liver and kidney function test can be used as prognostic indicator for the future outcome of pyometra affected bitches.

Treatment:

Medical approach: mainly aims at systemic and intrauterine application of medicines. Subcutaneous administration of prostaglandin (PGF2 alpha) at the dose rate of 150-200µ/kg/day for more then 10 days show 100% result. (Myhre,2016). Which may be due the fact that PGF2alpha cause luteolysis which lead to progesterone block (Renton et al., 1993). another recent protocol used for the treatment of pyometra is administration of 3^rd generation GnRH antagonist acyline @330µ/kg orally with amoxicillin @125 mg/kg twice a day orally for 7 days providing promising result. (Batista et al., 2016).

Surgical approach: surgical ovariohysterectomy (OHE) is the safest and most efficient treatment.

Dr. Manoj karki (BVSC&AH) AND GJULAM RAZA SHAH