Pyometra Flashcards
Define pyometra
suppurative inflammation of the uterus; pus in the uterus
What hormonal condition predisposes the patient to pyometra?
high levels of circulating progesterone (ie. during diestrus)
What 3 effects does progesterone have on the uterus?
- promotes endometrial growth
- promotes uterine glandular secretions
- decreases functional ability of local uterine immunity
How does progesterone predispose the uterus to bacterial infection?
During proestrus and estrus, bacteria is normally present. Normally, the body clears this bacteria before infection becomes a problem. But, when elevated progesterone levels are present during diestrus, any bacteria still present can overgrow because of the decreased functional ability of local uterine immunity (an effect of progesterone on the uterus)
What are the common bacteria found in pyometra
E. coli (most common) klebsiella pseudomonas proteus pasteurella
What is the source of the bacteria found in pyometra?
normal vaginal flora
What patients are at risk for acquiring pyo?
- intact female dogs that have gone through estrus but have not been bred or become pregnant
- patients getting exogenous progesterone
- older intact female patients that have experienced numerous heat cycles
- patients getting mismatch injections
What are mismatch injections?
estrogen is given to stop a pregnancy when an unwanted breeding has occurred
Why do mismatch injections increase the risk of pyometra?
estrogen increases the effects of progesterone upon the uterus
List the 2 types of pyometra
Open cervix
Closed cervix
Define open cervix pyo
a bacterial uterine infection with dilation of the cervix, providing a route of drainage of any infected material from the uterus
Define closed cervix pyo
cervix is completely closed and the infection is contained within the uterus with no route of drainage, effectively creating an internal abscess within the abdominal cavity
Which type of pyo has more severe CS? Wyhy?
Closed
b/c body recognizes the presence of infection quickly and responds with a severe, systemic inflammatory response; if enough inflammation is present to disrupt the integrity of the mucosal lining of the uterus (endometrium) it is possible for bacteria to transmigrate from the uterine lumen into systemic circulation –> SEPSIS
Two effects pyo has on the body
systemic inflammation –> sepsis
CS of open cervix pyo (with and without systemic circulation)
- serosanguinous to mucopurulent vulvar discharge 4-6 weeks after standing heat
- systemic response –> lethargy, depression, anorexia, V/D
- PU/PD
Why is PU/PD a CS of pyometra?
if caused by e coli, the e coli produce a toxin that interferes with antidiuretic hormone (ADH) upon the kidney by inhibiting it; inhibition of ADH results in diuresis with compensatory PD
CS of closed cervix pyo (with and without sepsis)
- nonspecific, vague signs
- lethargy, depression
- anorexia, weight loss
- PU/PD
- if septic –> V, D, dehydration, shock, coma, death
Alterations of PE if pyo
- lethargic/depressed mentation
- pyrexia secondary to uterine inflammation/sepsis
- vulvar discharge
- may be able to palpate enlarged uterus
alterations to CBC with pyo
closed –> systemic inflammation, neutrophilia
open –> normal WBC, but possible neutrophilia
Alterations to serum chem with pyo
Hint: One of the changes happens secondary to sepsis occurring
dehydration marked by hyperproteinemia and azotemia
elevated ALT/ALP if sepsis has damaged hepatocytes
Alterations to UA if pyo
decreased SG if e. coli is involved
Alterations to abd rads with pyo
Open
-may be hard to see uterus
Closed
- fluid-filled tubular structure (uterus)
- caudal abdomen (location)
- displaced intestines
in general, look for uterine rupture and peritonitis or presence of free air within peritoneal cavity
Alterations to abd. US in pyo
dilated uterus containing variable amounts of fluid and no evidence of viable fetuses
Pyo Sx management
OVH after patient is stabilized, keeping Sx time to a minimum and handling patient and uterus very carefully
Who is a candidate for pyo medical management?
<6yr old
open cervix pyo
insistent owner who wants to save breeding integrity
Primary med used in medical management; its goals & effects
administration of prostaglandins
- Goal = to increase uterine contractions and decrease progesterone levels
- increased contractions help expel infected contents of uterus
- decreasing progesterone concentrations removes the stimulus for endometrial growth and secretions making the uterine environment less inviting to bacteria
What is a common complication seen with pyo?
sepsis
2 methods in which bacterial sepsis may occur in the presence of pyo
- secondary to bacterial transmigration from the uterine lumen into the circulatory system
- secondary to uterine rupture causing peritonitis and sepsis
What clinical signs are the same between open and closed cervix pyo? At what point do those clinical signs develop?
Lethargy, depression, anorexia, PU/PD
Seen when systemic response is occurring in open pyo, but seen as nonspecific signs of infection in closed pyo
How is lab work the same for open and closed pyo?
- dehydration marked by hyperproteinemia and azotemia
- decreased SG if E. coli present
Contrast lab work for open and closed pyo
In open pyo, labs will be mostly normal but might show neutrophilia. If closed pyo, there will be neutrophilia and systemic inflammation. In closed pyo, if sepsis occurs, may see increased ALT and ALP due to liver damage.
