The clinical examination of pyometra infected dogs revealed lethargy/depression (100%, 12/12), inappetence (100%, 12/12), vaginal discharge (83.33%, 10/12), polydipsia (83.33%, 10/12), abnormal mucous membranes (75%, 9/12), uterine distension (75%, 9/12), polyuria (66.66%, 8/12), vomition (41.66%, 5/12), fever (41.66, 5/12) and dehydration (33.33%, 4/12) (Fig 1). Vaginal examination revealed brown chocolate malodorous vaginal discharge.
The progesterone stimulation during diestrus period, make a suitable environment for bacterial proliferation which lead to accumulating the uterine secretions, prominent endometrial gland crypts and immune suppression and as a result pyometra developed
(Dow 1957). Presence of mature corpora lutea in pyometra infected bitches can supporting a synergistic hormonal effect
(Strom et al., 2001). Progesterone-mediated pathologic proliferation leads to the growth of endometrial glands. When there is no bacterial infection of the uterus, the infection may be subclinical or mild
(Hagman et al., 2006). In open pyometra cases, a continuous or intermittent mucopurulent to hemorrhagic vaginal discharge is often observed but absent in closed pyometra
(Borresen et al., 1979). In closed pyometra, the systemic illness is more severe than those with open-cervix pyometra and the uterus becomes severely distended
(Pretzer 2008; Jitpean et al., 2017). In closed pyometra, closed cervix prevents the elimination of the infectious uterine material and as a result it is complicated with septicemia, endotoxemia (most commonly associated with
E.
coli infection) and septic peritonitis
(Nelson et al., 1982).
Major clinical signs observed in the present study were Fever, dehydration, vomiting, abdominal pain on palpation, anorexia, depression/lethargy, polydipsia, polyuria, tachycardia, tachypnea, increased pulse rate, abnormal visible mucous membranes and gait abnormalities which was also supported by
Borresen et al., (1979). The increased level of rectal temperature, heart rate, pulse rate and respiration rate of pyometra affected bitches might be due to uterine inflammation and septicemia, bacteremia and toxaemia
(Nath et al., 2009; Jena et al., 2013). However, shallow respiration rate was also reported in pyometra infected bitches
(Feldman and Nelson 2004).
Diagnosis of pyometra by imaging techniques
The radiographic projections in most cases revealed a craniodorsal displacement of the small intestine and a twisted uniform tubular opacity in the caudoventral abdomen at lateral recumbency (Fig 2: A1). There was a cranial and medial displacement of the small intestine when the animal was in the ventro dorsal position (Fig 2: A2). Here in Fig 2 (A1 and A2), the largely distended uterus was visualized. Cranial and dorsal displacement of the small bowel is apparent. The abdominal ultrasonographic examination revealed an anechoic to hyperechoic fluid filled uterus with distention (Fig 2: B1 and B2).
Diagnostic imaging is efficacious for crucial the female internal reproductive organ size and to rule out alternative causes of female internal reproductive organ enlargement. X-ray and ultrasonography have the advantage of detecting intrauterine fluid, even when the uterine diameter is within the normal range and of revealing additional pathologic changes of the uterine tissue and ovaries, such as ovarian cysts or CEH, which may affect the outcome of medical treatment negatively. Additional sophisticated diagnostic imaging techniques are hardly ever necessary. Differential diagnoses include mucometra, hydrometra and hematometra that may have similar clinical presentation and ultrasonography findings
(Bigliardi et al., 2004; Haji et al., 2017). The radiographic projections in most cases at lateral recumbency revealed that there was the craniodorsal displacement of the small bowel and a twisted uniform tubular opacity in the caudoventral abdomen
(Root 2002). Radiography wills insensible for sleuthing pyometra as female internal reproductive organ distention generally can’t be detected till the diameter of the womb is larger than that of the adjacent tiny bowels
(Root 2002). Additionally, radiography cannot distinguish pyometra from alternative causes of female internal reproductive organ distension, like mucometra or early maternity (before craniates skeletal mineralization). The irregular and thickening of the uterine wall revealed during USG examination might be due to prolonged or repeated stimulation of progesterone hormone on the endometrium. An increased level of progesterone concentration (>40 ng/ml) during pyometra promotes endometrial hyperplasia
(Haji et al., 2017). In a case of uterine rupture, there may be free fluid within the abdominal cavity and the omentum may be hyperechoic secondary to bacterial peritonitis
(Dennis and Brian 2012). Abdominal prenatal diagnosis also can be wont to exclude alternative conditions that may cause female internal reproductive organ enlargement or discharge, like early maternity.
Influence of pyometra on vaginal cytology
The vaginal cytology revealed that there was a large number of neutrophils, intermediate and parabasal cells (Fig 3) in the open cervix pyometra of bitch.
The cytological examination is not a proper diagnostic tool for pyometra without additional confirmatory testing as same findings are also observed in vaginitis. The absence of excessive neutrophils and bacteria in the vaginal discharge would warrant reconsideration of the cause
(Dennis and Brian 2012). Meanwhile, vaginal cytology findings in bitch with completely closed-cervix pyometra may only reflect the stage of the estrous cycle. Intermediate and parabasal cells are the predominance cells during diestrus stage and an influx of non-degenerate neutrophils in early diestrus
(Dennis and Brian 2012). The presence of neutrophils in vaginal cytology might be due to increased progesterone concentration during pyometra which promotes endometrial hyperplasia and provides excellent media for bacterial growth
(Corrada et al., 2006).
Microbial species isolated from the uterus of bitches with pyometra
The coli form bacteria
i.
e.
Escherichia coli was the leading pathogen isolated from pyometra uteri of bitches (75.00%), other than that other species of
Staphylococcus,
Streptococcus,
Pseudomonas,
Proteus,
Pasteurella and
Clostridium perfringens were also responsible for the cause, the percentage is depicted in Fig 4.
Several bacterial species can be involved in pyometra, but the cultures are sometimes negative
(Grindlay et al., 1973). In a normal physiological state, the uterus eliminates bacteria those able to enter through the cervical opening, but the capacity may compromise in the sick uterus.
E coli infection leads to CEH/pyometra during the luteal phase compared to other oestrous cycle stages
(Nomura et al., 1988). The infection is most likely ascending because the same strains are present in the gastrointestinal tract, but haematogenic spread could also occur
(Agostinho et al., 2014). The natural inhabitants of
E.
coli in vaginal flora
(Watts et al., 1996), may have an increased ability to adhere with specific receptors in a progesterone-stimulated endometrium
(Sandholm et al., 1975). These bacteria and bacterial products play a major role as a potent inducer of local and systemic inflammation which induces fever, lethargy, tachycardia and Tachypnea
(Van Miert and Frens 1968).
Uterine pathological alterations of the bitches affected with pyometra
Macroscopic findings
The uterine horns were swelled, hyperemic and having full of whitish pus in the lumen and thickening of the uterine mucosa in most of the cases (Fig 5). The uterine mucosa of pyometra infected bitches showed longitudinal folds with ulcerated areas. There was congestion and ecchymotic haemorrhage of the body of the uterus of bitch.
The macroscopic examination revealed swollen and hyperemic uterine horns with full of whitish pus in the lumen. Longitudinal folds and certain ulcerated areas were also observed in the uterine mucosa. There was congestion and ecchymotic haemorrhage of the body of the uterus of bitch which was also observed by
Coggan et al., (2008). They also reported that the epithelial cells and glandular uteri were degenerated which was also observed in this study.
Histopathological changes
The surface of the endometrium was a pseudostratified
ciliated columnar epithelium; with hyperplasia of subepithelial tissue and thick muscularis with primary and secondary folds (Fig 6). The degenerated surface epithelial cells and cystic degeneration on the glandular uteri were markedly observed. The stratum vasculature showed the evidence of leukocytosis. In other cases, the glandular uterus having degenerative hyperplasia and atrophy and the stromal connective tissue was characterized by congestion and haemorrhage.
Effect of pyometra on physiological parameters of bitches
In the present study, there was an increase in mean rectal temperature, heart rate (bpm), pulse rate (bpm) and respiration rate of pyometra affected bitches (102.32±0.23
oF, 125.83±3.14 beats/min, 135.46±3.07 beats/min and 32.4±1.44 per min, respectively) in comparison to healthy bitches (99.76±0.23
oF, 102.91±2.91 beats/min, 110.0±2.33 beats/min and 22.33±0.53 per min, respectively).
Effect of pyometra on haematological parameters
In the present study, it was observed that the haematological parameters
viz. Hb, PCV, RBC, were significantly decreased (P<0.01) in pyometric bitch in comparison to healthy which indicated anaemia (Table 1).
The DLC analysis revealed neutrophilia, lymphocytosis with eosinophilia in pyometra affected bitches (Table 1) as compared to healthy.
A microcytic hypochromic type of anaemia observed in pyometric bitch might be due to the loss of red blood cells by diapedesis into the uterine lumen apart from depressed feed intake and impaired erythropoiesis under the toxaemic condition in severely affected cases. The findings of the present study are in concordance with the previous reports
(Nath et al., 2009; Jena et al., 2013). Different degree of leucocytosis observed in pyometra infected dogs might be due to varying degree of the inflammation
(Dabhi et al., 2009) which is in agreement with the previous reports
(Dabhi et al., 2009; Babu et al., 2018).
The observed neutrophilia, lymphocytosis with eosinophilia in pyometra affected bitches might be due to uterine infection, which exerts a chemotactic effect on neutrophils resulting in accelerated granulopoiesis and lymphocytosis
(Leib and Monnie 1997).
Effect of pyometra on blood metabolites
Total protein
The mean total protein level (9.17±0.35 g/dl) of pyometra affected bitches was significantly (p<0.01) higher, than healthy ones (7.75±0.35 g/dl) (Table 1).
BUN and Creatinine
The kidney function test
viz. blood urea nitrogen (BUN) and creatinine level (66.12±6.51 mg/dl and 1.95±0.24 mg/dl, respectively) was significantly (P<0.01) elevated in pyometra affected bitch as compared to healthy (35.41±3.53 mg/dl and 1.30±0.18 mg/dl, respectively) (Table 1).
Liver enzymes activity in pyometric bitches
The respective mean activities of liver enzymes
viz. serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in pyometric bitches (39.62±4.30 IU/L, 55.80 ± 4.22 IU/L and 155.71±11.20IU/L, respectively) were significantly (P<0.01) increased (Table 1) as compared to healthy bitches (30.33±3.69 IU/L, 42.50 ± 4.02 IU/L and 86.25±9.34IU/L, respectively).
The elevated total protein, BUN and creatinine concentrations in pyometra affected bitch might be due to chronic inflammation and dehydration
(Dennis and Brian 2012). Bacterial endotoxemia and reduced liver perfusion are thought to contribute to elevated liver enzyme activities. The alterations of liver enzymes ALT, AST and ALP in pyometric bitches reflect the function of the liver, including hepato-cellular damage due to toxaemia or the impaired hepatic circulation due to dehydration
(Borresen et al., 1979).
