Canine Pyometra: Current Perspectives on Causes and Management – A Review

Abstract

Canine pyometra is a pathological condition of endometrium
which results in accumulation of purulent semisolid substance in
uterus. Canine pyometra is a sequlae of cystic endometrial
hyperplacia (CEH) which results from hormonal imbalance.
Despite of enormous veterinary medical research and
development, still its main aspect of etio-pathology is not fully
known. Canine pyometra is mostly associated with other similar
uterine pathological conditions, i.e., hydrometra, mucometra and
chronic endomertitis.

Full text

Indian J. Vet Sci. Biotech (2018) Vol. 14 No. 1 52
The Indian Journal of Veterinary Sciences & Biotechnology (2018) Volume 14, Issue 1, 52-56
ISSN (Print) : 2394-0247 : ISSN (Print and online) : 2395-1176, abbreviated as IJVSBT
10.21887/ijvsbt.v14i1.12998
Canine Pyometra: Current Perspectives on Causes and Management – A Review
Alok Kumar* and Atul Saxena
Institute of Paraveterinary Sciences, (DUVASU), Mathura, UP, India
Department of Veterinary Gynaecology and Obstetrics,
College of Veterinary Science, DUVASU Mathura, U.P., India.
Publication Info
Article history:
Received : 02-06-2018
Accepted : 11-06-2018
Published : 20-07-2018
Key Words:
Canine pyometra, Uterus, Cystic
endometrial hyperplacia (CEH),
Hormones.
*Corresponding author:
dr.alokshukla.vet@gmail.com
This work is licensed under the
Creative Commons Attribution
International License (http://
creativecommons.org/licenses /
by/4.0/P), which permits
unrestricted use, distribution and
reproduction in any medium,
provided the original work is
properly cited.
Copyright @: 2018 by authors
and SVSBT.
Abstract
Canine pyometra is a pathological condition of endometrium
which results in accumulation of purulent semisolid substance in
uterus. Canine pyometra is a sequlae of cystic endometrial
hyperplacia (CEH) which results from hormonal imbalance.
Despite of enormous veterinary medical research and
development, still its main aspect of etio-pathology is not fully
known. Canine pyometra is mostly associated with other similar
uterine pathological conditions, i.e., hydrometra, mucometra and
chronic endomertitis.
Introduction
Canine pyometra is a common reproductive
syndrome of intact, sexually mature bitches
during met/diestrous stage with various clinical
as well as pathological signs specific to
reproductive system along with systemic signs
(Fransson, 2003). Other terms to describe canine
pyometra in relation to pathogenesis like chronic
endometritis, chronic purulent metritis, cystic
endometrial hyperplasia (CEH) or cystic
endometrial hyperplasia - pyometra complex etc.
also coined (Sandholm
et al
., 1975). Canine
Pyometra can be categorized based on status of
cervix as open-cervix or closed-cervix; however
closed type is more serious condition, which
needs surgical intervention so as to prevent
concomitant sepsis and fatality (Smith, 2006).
Pyometra can be defined as pathological
condition of uterus in which there is accumulation
of purulent semisolid-liquid substance inside the
uterus of intact bitches, generally during post-
progesterone dominant phase of estrous cycle.
Several authors suggested that pyometra should
be classified as CEH- pyometra complex because
of the fact that subacute endometritis later

Indian J. Vet Sci. Biotech (2018) Vol. 14 No. 1 53
develops as CEH is most important predisposing
factor of pyometra (Sandholm
et al
., 1975).
However, others classified both condition
separately based on histopathology and clinical
reports which profess pyometra without CEH (De
Bosschere
et al
., 2002).
Etiology
Several researches indicated predominant
role of reproductive hormones, i.e., progesterone
and estrogen as predisposing factors for pyometra
in which former being most dominant one. It is
well established that progesterone stimulates
endometrial glands secretions as well as
suppresses myometrial contraction which is
favorable for bacterial growth and colonization
(Cox, 1970). Estrogen has indirect role as it
enhances endometrial response to progesterone.
Etiology of bacterial origin can be traced by most
common presence of
E. coli
along with endotoxins
(Hageman, 2004; Bondade
et al
., 2010) Virulence
factor of
E. coli,
i.e., K antigen and cytotoxin
necrotizing factor are associated with pathological
conditions; however several other pathogenic
bacteria are also identified as causative agent,
i.e.,
Klebsiella Spp.
,
Streptococci, Staphylococci
,
anaerobic bacteria,
Pseudomonads
(Dhaliwal
et
al
., 1998). Several workers narrated that
susceptibility of host and pathogenic bacteria
along with progesterone appears to be an
important components leading to disease
condition (Krekeler
et al
., 2012a; 2012b).
Prevalence, History and Clinical Findings
Canine pyometra is commonly reported from
mature bithches ranging from 4 to 16 years, but
most common at the age of 7.5 years with
regular and repeated estrous cycle (Johnston
et
al
., 2001). Recently disease occurrence was
reported as 19% in bitches below 10 years of
age and 20% in older female dogs (Jitpean
et al
.,
2014). Breed susceptibility is also observed in
this condition with high risk include Rottweiler,
Saint Bernard, Chow chow, Golden Retriever,
Miniature Schnauzer, Irish Terrier, Airedale Terrier,
Cavalier King Charles Spaniel, Rough Collie, and
Bernese Mountain dog (Smith, 2006). Moreover,
a few breeds possess low risk like German
Shepherd, Daschunds, and Swedish hounds.
Breed susceptability strongly indicates the
contribution of genotype towards increase or
decrease risk of disease (Jitpean
et al.,
2012).
Pathogenesis
During luteal phase of estrous cycle blood
progesterone level increases which in turn leads
to increased secretions from endometrial glands,
increase proliferation of endometrium, reduced
myometrial contraction and closure of cervix
(Hardie, 1995) that favours occurrence of disease.
Factors associated with bacteria as well as their
receptor expression may lead to enhance bacterial
attachment to endometrium (Gabriel
et al.,
2016).
Wijewardana
et al.
(2015) described negative
correlation between progesterone on maturation
of antigen presenting dendritic cells which may
lead to reduction of cell mediated immunity
(CMI). Gultiken
et al.
(2016) reported increased
expression of 3β-hydroxysteroid dehydrogenase
on endometrial tissue in bitches suffering from
pyometra which further indicates influence of
local production of progesterone on disease
occurrence even at its normal range. Therefore
reduced CMI due to progesterone dominance in
luteal phase (Sugiura
et al
., 2004), along with
suppressed local immunity is favorable uterine
environment for pathogens leading to their
enhanced growth and colonization.
Clinical Signs and Diagnosis
Clinical signs of pyometra include
endotoxaemia, septic shock, peritonitis and multi-
organ failure. Jitpean
et al.
(2014) described
peritonitis as most common finding in pyometra
which ranges 10% of total cases. Cytological
examination of vaginal discharge generally shows
neutrophilia with more number of degenerative
neutrophils. Bacteria may be seen in vaginal
discharge.
Biochemical analysis shows considerable
increase in serum urea nitrogen, creatinine, ALT,
AST, ALP, globulin; however albumin level
decreases highly significantly thus causing
enhanced ratio of globulin:albumin in pyometra
cases (Jitpean
et al
., 2014). Destruction of tissue
due to effect of endotoxin can be attributed to
elevated levels of serum urea nitrogen and
creatinine. Hypoalbuminaemia and
hyperglobulinaemia can be a result of acute
phase reaction and dehydration respectively
(Patil
et al
., 2013; Shah
et al.,
2017).

Indian J. Vet Sci. Biotech (2018) Vol. 14 No. 1 54
Haematological evaluation shows
erythrocytopenia, reduced level of haemoglobin
(Hb), decreased packed cell volume (PCV),
azotemia and leucocytosis with neutrophilia as
consistent findings associated with disease (Patil
et al.,
2013). Gupta and Dhami. (2013) explained
that reduced level of Hb, PCV, total erythrocyte
count (TEC) and platelets along with elevated
level of erythrocyte sedimentation rate (ESR),
total leucocytes count (TLC) and
polymorphonuclear (PMN) cells indicates
toxaemia whereas raised level of leucocytes,
PMN cells and declining lymphocytes point out
recovery from toxemia. Therefore these altered
hematological values can be used as aid to
diagnosis as well as prognosis of canine pyometra
(Mohan
et al
., 2015). Most common finding in
bitches affected with closed cervix pyometra
shows leucocytosis with shift to left. (Nath
et al.
,
2009). Anaemia in bitches can be sequelae of
erythrocyte diapedesis into uterine lumen along
with depression of erythropoiesis in the bone
marrow associated with toxaemia (Nath
et al.
,
2009). The azotaemia follows glomerulonephritis
which occurs due to deposition of antigen-
antibody complex on basement membrane of
glomerulus; moreover this condition is further
aggravated by pre-renal azotaemia (Pretzer,
2008).
Advanced diagnostic techniques like
ultrasonographic imaging is one of the best
diagnostic tool in which uterus is observed as
enlarged and hypoechoic tubular organ containing
echogenic fluid (Gupta
et al
., 2013), however
sometimes pus shows slow, whirlpool like pattern
(Bigliardi
et al
., 2004).
X ray can be another mode of diagnosis, but
with some limitation as observation is sometime
misdiagnosed with pregnancy especially of pre-
mineralization stage (less than 45 days) (Pretzer,
2008).
Treatment
Surgical Approach
Spaying remains the choice of treatment for
majority of obstetrician, however recently
Laparoscopic Assisted Ovariohysterectomy
(LAOVH) is advocated for treatment of select
cases of canine pyometra, which is proved to be
efficacious over conventional open method with
careful case selection in order to improve success
rate (Adamovich Rippe
et al
., 2013; Wallace
et
al.,
2015; Becher-Deichsel
et al.,
2016).
Medical Approach
Medical approach mainly aims at systemic
and intrauterine application of medicines.
Subcutaneous administration of prostaglandin
(PGF2α) at the dose rate of 150-200 µg/kg/day
for more than 10 days showed 100% results
(Myhre, 2016), which may be due the fact that
PGF2α causes luteolysis which leads to
progesterone block (Renton
et al
., 1993). Another
protocol with combination of cabergoline (@ 5
Pg/kg PO once daily) and cloprostenol (@ 1 Pg/
kg once daily) for seven days was found
enthusiastic. However, in recent times use of
progesterone blockers such as mifepristone
(Hoffman and Schuler, 2000) or aglepristone
(Wehrend and Traschbostedt, 2003; Arnold
et al
.,
2006) has proved better protocol of choice.
Further Contri
et al
. (2015) successfully used a
protocol in which aglepristone combined with a
short duration (6 days) antibiotic cover proved
efficacious. Another recent protocol used for the
treatment of pyometra is administration of third
generation GnRH antagonist acyline @ 330 μg/
kg orally (single dose) with amoxicillin- clavulanate
@ 12.5 mg/kg twice a day, orally for seven days
provided promising results (Batista
et al.,
2016),
Conclusion
In spite of greater pace of veterinary
pharmacological and pathological advancement
in research and innovation, satisfactory treatment
for canine pyometra is still not formulized. One
of the several reasons for this condition can be
narrated as lack of complete and detailed
information regarding etio-pathology of canine
pyometra due to very complex nature of disease.
It is need of the hour to find well established
medical treatment with maximum recovery rate
which can be used as alternative to stressful,
costly and laborious surgical approach.
Acknowledgment
Authors are thankful to the Professor & Head
and staff of Department of Veterinary
Gynaecology and Obstetrics, College of Veterinary
Science, Mathura.

Indian J. Vet Sci. Biotech (2018) Vol. 14 No. 1 55
Conflict of interest:
All authors declare no conflict of interest.
References:
Adamovic-Rippe, K.N., Philipp, D.M., Jeffrey, J.R.,
William, T.N.C.
et al.
(2013). Evaluation of
laparoscopic assisted ovariohysterectomy for
treatment of canine pyometra.
Vet. Surgery,
42:
572-578.
Arnold, S., Reichler, I. and Hubler, M. (2006). Canine
pyometra: new approaches to an old disease. In
WSAVA., pp. 691-692.
Batista, P.R., Blanco, P.G. and Gobello, C. (2016).
Treatment of canine pyometra with the GnRH
antagonist acyline: A case series.
Topics in
Companion Animal Medicine
, 30(1): 25-27
Becher-Deichsel, A., Aurich, J.E., Schrammel, N.
and Dupré, G. (2016). A surgical glove port
technique for laparoscopic-assisted
ovariohysterectomy for pyometra in the bitch.
Theriogenology
, 86: 619-625.
Bigliardi, E., Prmigiani, E., Cavirani, S., Luppi, A.,
Bonati, L. and Corradi, A. (2004). Ultrasonography
and cystic hyperplasia-pyometra complex in the
bitch.
Reprod. Dom. Anim
., 39: 136-140.
Bondade,S., Nema, s.p. and Shukla, S.P. (2010).
Isolation of
E.coli
organisms from canine
pyometra.
Indian J. Field Vet.,
6(2): 63-65.
Contri, A., Gloria, A., Carluccio, A., Pantaleo, S., and
Robbe, D. (2015). Effectiveness of a modified
administration protocol for the medical treatment
of canine pyometra.
Vet. Res. Commun.
, 39: 1-
5.
Cox, J.E. (1970). Progestagens in bitches: A review.
J. Small. Anim. Pract.,
11(12): 759-778.
De Bosschere, H., Ducatelle, R., Vermeirsch, H. et
al. (2002). Estrogen-á and progesterone receptor
expression in cystic endometrial hyperplasia and
pyometra in the bitch.
Anim. Reprod. Sci.
70(3-
4): 251-259.
Dhaliwal, G.K., Wray, C. and Noakes, D.E. (1998).
Uterine bacterial flora and uterine lesions in
bitches with cystic endometrial hyperplasia
(pyometra).
Vet. Rec.,
143(24): 659-661.
Fransson, B. (2003).
Systemic Inflammatory Response
in Canine Pyometra: The Response to Bacterial
Uterine Infection
. Doctoral Thesis (Veterinaria),
Swedish University of Agricultural Sciences,
Uppsala.
Gabriel, C., Becher-Deichsel, A., Hlavaty, J., Mair, G.
and Walter, I. (2016). The physiological expression
of scavenger receptor SR-B1 in canine
endometrial and placental epithelial cells and its
potential involvement in pathogenesis of pyometra.
Theriogenology
, 85: 1599-1609.
Gupta, A. K.and Dhami, A. J. (2013). Haematological
alterations in bitches affected with pyometra.
Indian J. Field Vet.,
9(1): 1-5.
Gupta, A. K., Dhami, A. J., Patil, D.B., Kumar, D. and
Darr, M. (2013) Clinical and ultrasonographic
evaluation of Bitches affected with pyometra.
Indian J. Field Vet.,
8(3): 1-4.
Gultiken, N., Yarim, M., Yarim, G. F., Gacar, A. and
Mason, J.I. (2016). Expression of 3â-
hydroxysteroid dehydrogenase in ovarian and
uterine tissue during diestrus and open cervix
cystic endometrial hyperplasia-pyometra in the
bitch.
Theriogenology
, 86: 572-578.
Hageman, R., (2004).
New Aspects of Canine
Pyometra: Studies on Epidemiology and
Pathogenesis.
Doctoral thesis, Swedish University
of Agricultural Sciences Uppsala.
Hardie, E.M. (1995). Life-threatening bacterial infection.
Compend. Contin. Educ. Pract. Vet.,
17(6): 763-
778.
Hoffmann, B. and Schuler, G. (2000). Receptor
blockers - general aspects with respect to their
use in domestic animal reproduction.
Anim.
Reprod. Sci.,
60(61): 295-312.
Jitpean, S., Hagman, R., Ström Holst, B., Höglund,
O.V., Pettersson, A., and Egenvall, A. (2012).
Breed variations in the incidence of pyometra and
mammary tumours in Swedish dogs.
Reprod.
Domes. Anim.,
47 (Suppl. 6): 347-350.
Jitpean, S., Ström-Holst, B., Emanuelson, U., Höglund,
O.V., Pettersson, A., Alneryd-Bull, C. and Hagman,
R. (2014). Outcome of pyometra in female dogs
and predictors of peritonitis and prolonged
postoperative hospitalization in surgically treated
cases.
BMC Vet. Res.,
10: 6.
Johnston, S.D., Kustritz, M.V.R. and Olson, P.N.S.
(2001). Disorders of the canine uterus and uterine
tubes (oviducts) In: Kersey R, editor.
Canine and
Feline Theriogenology
. W.B. Saunders Co., pp.
206-224.
Krekeler, N., Lodge, K. M., Anderson, G. A., Browning,
G. F., Charles, J. A., and Wright, P. J. (2012a).
Effect of simulated stages of the canine estrous
cycle on
Escherichia coli
binding to canine
endometrium.
Reprod. Dom. Anim.
, 47 (Suppl 6):
331-334.
Krekeler, N., Marenda, M.S., Browning, G.F., Holden,
K.F., Charles, J.A., and Wright, P.J. (2012b).

Indian J. Vet Sci. Biotech (2018) Vol. 14 No. 1 56
Uropathogenic virulence factor FimH facilitates
binding of uteropathogenic
Escherichia coli
to
canine endometrium.
Comp. Immunol. Microbiol.
Inf. Dis.
, 35: 461-467.
Mohan, P., Subramanian, A. and Nambi, A.P. (2015).
Haematological changes in open cervix pyometra
following PGF2á therapy in canines.
Indian J. Vet.
Sci. Biotech
., 11(1).
Myhre, A.S. (2016).
Canine Pyometra: the Efficiency
of Medical Treatment of Pyometra
-
Integrated
Studies of Veterinary Medicine
. Master theses.
Faculty of Veterinary Medicine Lithuanian
University of Health Sciences Veterinary Academy.
Nath, K., Tiwari, S.K. and Kalim, O. (2009).
Physiological and haematological changes in
bitches with Pyometra.
Indian Vet. J
., 86: 734-
736.
Patil, A.R., Swamy, M., Chandra, A. and Jawre, S.
(2013). Clinico-haematological and serum
biochemical alterations in pyometra affected
bitches. Afri. J. Biotechnol., 12(13): 1564- 1570
Pretzer, S.D. (2008). Clinical presentation of canine
pyometra and mucometra: A review.
Theriogenology,
70: 359-363.
Renton, J.P., Boyd, J.S. and Harvey, M.J.A. (1993).
Observations on the treatment and diagnosis of
open pyometra in the bitch (
Canis familiaris
).
J.
Reprod. Fertil. Suppl.
47: 465-469.
Sandholm, M., Vasenius, H. and Kivisto, A.K. (1975).
Pathogenesis of canine pyometra.
J. Am. Vet.
Med. Assoc.,
167(11): 1006-1010.
Shah, S.A., Sood, N.K., Wani, B.M., Rather, M.A.,
Beigh, A.B. and Amin, U. (2017). Haemato-
biochemical studies in canine pyometra.
J.
Pharmacogn. Phytochem
., 6(4): 14-17.
Smith, F.O. (2006). Canine pyometra.
Theriogenology
,
66: 610-612.
Sugiura, K., Nishikawa, M., Ishiguro, K., Tajima, T.,
Inaba, M., Torii, R.
et al
. (2004). Effect of ovarian
hormones on periodical changes in immune
resistance associated with estrous cycle in the
beagle bitch.
Immunobiology,
209: 619-627.
Wallace, M. L., Case, J. B., Singh, A., Ellison, G. W.,
and Monnet, E. (2015). Single incision,
laparoscopic-assisted ovariohysterectomy for
mucometra and pyometra in dogs.
Vet. Surgery
,
44 (Suppl 1): 66-70.
Wehrend, K. and Traschbostedt, H. (2003). Treatment
of the closed type of pyometra by the antigestagen,
aglepristone in bitch.
Kleintierpraxis,
48: 679-683.
Wijewardana, V., Sugiura, K., Wijesekera, D. P.,
Hatoya, S., Nishimura, T., Kanegi, R. and Inaba,
T. (2015). Effect of ovarian hormones on maturation
of dendritic cells from peripheral blood monocytes
in dogs.
J. Vet. Med. Sci.
, 77: 771-775.
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