Pyometra

Question 1

Define pyometra

Answer 1

suppurative inflammation of the uterus; pus in the uterus

Question 2

What hormonal condition predisposes the patient to pyometra?

Answer 2

high levels of circulating progesterone (ie. during diestrus)

Question 3

What 3 effects does progesterone have on the uterus?

Answer 3

1. promotes endometrial growth
2. promotes uterine glandular secretions
3. decreases functional ability of local uterine immunity

Question 4

How does progesterone predispose the uterus to bacterial infection?

Answer 4

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)

Question 5

What are the common bacteria found in pyometra

Answer 5

E. coli (most common)
klebsiella
pseudomonas
proteus
pasteurella

Question 6

What is the source of the bacteria found in pyometra?

Answer 6

normal vaginal flora

Question 7

What patients are at risk for acquiring pyo?

Answer 7

• 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

Question 8

What are mismatch injections?

Answer 8

estrogen is given to stop a pregnancy when an unwanted breeding has occurred

Question 9

Why do mismatch injections increase the risk of pyometra?

Answer 9

estrogen increases the effects of progesterone upon the uterus

Question 10

List the 2 types of pyometra

Answer 10

Open cervix

Closed cervix

Question 11

Define open cervix pyo

Answer 11

a bacterial uterine infection with dilation of the cervix, providing a route of drainage of any infected material from the uterus

Question 12

Define closed cervix pyo

Answer 12

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

Question 13

Which type of pyo has more severe CS? Wyhy?

Answer 13

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

Question 14

Two effects pyo has on the body

Answer 14

systemic inflammation –> sepsis

Question 15

CS of open cervix pyo (with and without systemic circulation)

Answer 15

• serosanguinous to mucopurulent vulvar discharge 4-6 weeks after standing heat
• systemic response –> lethargy, depression, anorexia, V/D
• PU/PD

Question 16

Why is PU/PD a CS of pyometra?

Answer 16

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

Question 17

CS of closed cervix pyo (with and without sepsis)

Answer 17

• nonspecific, vague signs
• lethargy, depression
• anorexia, weight loss
• PU/PD
• if septic –> V, D, dehydration, shock, coma, death

Question 18

Alterations of PE if pyo

Answer 18

• lethargic/depressed mentation
• pyrexia secondary to uterine inflammation/sepsis
• vulvar discharge
• may be able to palpate enlarged uterus

Question 19

alterations to CBC with pyo

Answer 19

closed –> systemic inflammation, neutrophilia

open –> normal WBC, but possible neutrophilia

Question 20

Alterations to serum chem with pyo

Hint: One of the changes happens secondary to sepsis occurring

Answer 20

dehydration marked by hyperproteinemia and azotemia

elevated ALT/ALP if sepsis has damaged hepatocytes

Question 21

Alterations to UA if pyo

Answer 21

decreased SG if e. coli is involved

Question 22

Alterations to abd rads with pyo

Answer 22

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

Question 23

Alterations to abd. US in pyo

Answer 23

dilated uterus containing variable amounts of fluid and no evidence of viable fetuses

Question 24

Pyo Sx management

Answer 24

OVH after patient is stabilized, keeping Sx time to a minimum and handling patient and uterus very carefully

Question 25

Who is a candidate for pyo medical management?

Answer 25

<6yr old
open cervix pyo
insistent owner who wants to save breeding integrity

Question 26

Primary med used in medical management; its goals & effects

Answer 26

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

Question 27

What is a common complication seen with pyo?

Answer 27

sepsis

Question 28

2 methods in which bacterial sepsis may occur in the presence of pyo

Answer 28

1. secondary to bacterial transmigration from the uterine lumen into the circulatory system
2. secondary to uterine rupture causing peritonitis and sepsis

Question 29

What clinical signs are the same between open and closed cervix pyo? At what point do those clinical signs develop?

Answer 29

Lethargy, depression, anorexia, PU/PD

Seen when systemic response is occurring in open pyo, but seen as nonspecific signs of infection in closed pyo

Question 30

How is lab work the same for open and closed pyo?

Answer 30

• dehydration marked by hyperproteinemia and azotemia

- decreased SG if E. coli present

Question 31

Contrast lab work for open and closed pyo

Answer 31

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.