Pyometra

Question 1

In what age and stage of estrus does pyometra usually occur in dogs?

Answer 1

unbred, middle-aged to older bitches during diestrus when estrogen-rimed endometrium comes under the influence of progesterone.

Question 2

what pathology may be occurring concurrently with pyometra?

Answer 2

cystic endometrial hyperplasia

Question 3

How does progesterone lead to the development of pyometra?

Answer 3

progesterone increases susceptibiltiy to bacterial infections by induced fluid accumulation in endometrial glands and uterine lumen, suppressing leukocyte activity, and decreasing myometrial activity.

Question 4

what are the clinical signs associated with pyometra?

Answer 4

Lethargy
Anorexia / Hyporexia
Fever
Dehydration
Vomiting / Diarrhea
Polyuria/Polydipsia
Pain on abdominal palpation or abdominal distension
+/- presence of purulent or hemorrhagic vaginal discharge
Lameness (hindlimb or sacral pain)
tachypnea, tachycardia

Question 5

what would u expect to see on CBC/Chem for pyometra case?

Answer 5

• leukocytosis (d/t neutrophilia) +/- left shift +/- toxic changes
• normocytic / normochromic anemia
• hyperglobulinemia
• hyperfibrinogenemia
• increased hepatic enzymes (AST, ALP)
• azotemia
• electrolyte inbalances

all consistent with inflammation +/- toxemia

Question 6

what bacteria is most commonly associated with pyometra?

Answer 6

E. coli

others may include: B-hemolytic strep, staph pseudintermedius, and other enterbacteriales (proteus)
secondary invaders are spore-forming anaerobes such as clostridium, as well as NSF anaerobes too.

Question 7

why can you not diagnose pyometra via swab of discharge from posterior vagina?

Answer 7

there is NF of the vagina so there results are not significant.

You can only collect from vaginal discharge if you suspect open pyometra, collected it with a guarded swab, or collect from the anterior vagina (near the cervix)

Question 8

what is the BEST sample to take to diagnose pyometra?

Answer 8

• FNA of surgical sample (once you’ve removed the uterus, use that sample)

Question 9

Do you need to do c/s for a suspected case of pyometra, why or why not?

Answer 9

yes – because E. coli (the most common culprit) is not predictably susceptible

Question 10

what causes PU/PD in pyometra cases?

Answer 10

E. coli endotoxin interferees with action of ADH on renal tubules. You get medullary washout and isosthenuria.
There is also often a mild interstitial and tubular nephritis.

urinalysis with culture is always a good idea bc a lot of these dogs also have cystitis.

Question 11

what are common differentials for suspect case of pyometra?

Answer 11

• endometritis
• metritis
• vaginitis
• sepsis

Question 12

what are risk factors for pyometra?

Answer 12

• irregular cycles
• exogenous hormones
• older, nulliparous bitches

Question 13

T/F: CEH causes irreversible changes to the endometrium

Answer 13

true

this can lead to infertility, pregnancy losses, reduced litter sizes, embryonic resorption, endometritis, hydrometra/mucometra, and pyometra

Question 14

if you take xrays of a pyometra case, what would you be likely to see?

Answer 14

• fluid filled uterus
  double bladder sign

Question 15

if you do ultrasound of a dog with suspect pyometra, what would you likely see?

Answer 15

fluid-filled uterus
moderate endometrial inflammation (thickened uterine wall)
+/- CEH signs

Question 16

when is a vaginal cytology indicated for suspect pyometra?

Answer 16

if its open pyometra.
you can see PMNs, vaginal epithelial cells, bacteria, and proteinaceous debris

note this does not confirm pyo alone, you must also see fluid in the uterus and clinical signs.

Question 17

T/F: closed pyometra is usually associated with more severe illness

Answer 17

true

Question 18

what are the 3 main antibiotics used in pyometra cases?

Answer 18

1. amoxicillin/clavulanic acid
2. enrofloxacin
3. trimethoprim/sulfa

caution with empirical use because there are issues with antimicrobial resistance. so use Abs based on culture.

Question 19

what type of supportive care treatments would you do for a pyometra case?

Answer 19

• fluids
• gastroprotectants (ondansetron, cerenia)
• NSAIDs
• analgesia
• antiemetics

Question 20

what does medical therapy entail for pyometra?

Answer 20

1. empty uterus – PGF2a (uterine contractions, luteolysis, cervical opening)
2. decrease progesterone (aglepristone – progesterone-receptor blocker)
3. luteolysis (cabergoline – prolactin inhibitor/dopamine agonsit)
4. antibiotics
5. gastroprotectants
6. analgesia & NSAIDs

continuous monitoring of: progesterone levels, ultrasound, CBC/Chem and blood gas.
Recommend she be bred on the next cycle, then OHE.

this takes 3-5d for improvement.

Question 21

___________ is a progesterone competetitive antagonist

Answer 21

alizin (aglepristone)

Question 22

_____________ is a synthetic prostaglandin that has few side effects.

Answer 22

Estrumate (cloprostenol)

Question 23

__________ is a natural prostaglandin that causes smooth muscle action, luteolysis, and myometrial contractions, but has a narrow therapeutic index.

Answer 23

Lutalyse (dinoprost)

Question 24

_______ stops prolactin feedback for better luteolysis.

Answer 24

cabergoline

Question 25

When should you STOP medical therapy in pyometra cases?

Answer 25

• confirm luteolysis is complete (progesterone <2 at least)
• uterus is empty and there is no vaginal discharge
• systemically improved

Question 26

what are 2 anesthetic concerns associated with surgical therapy for pyometra?

Answer 26

1. hypotension (d/t large loss of fluid)
2. electrolyte and renal derangements

Question 27

what are prognostic indicators for pyometra?

Answer 27

1. sepsis
2. endotoxemia
3. hypercoagulable state
4. MODS
5. DIC

Question 28

T/F: surgical tx of pyometra is best for refractory cases or non-breeding animals

Answer 28

true