Chapter 126 - pyometra

Question 1

pyometra typically occurs during which stage of the oestrus cycle under the influence of which hormone?

Answer 1

dioestrus, progesterone

Question 2

risk factors for pyometra?

Answer 2

increasing age
nulliparity
breed
exogenous oestrogen
progesterone administration

Question 3

clinical signs of cystic endometrial hyperplasia?

Answer 3

infertility

Question 4

name some effects of progesterone on the uterus

Answer 4

stimulates endometrial growth
stimulates glandular secretary activity
reduces myometrial contractility
maintains cervical closure
decreases neutrophil chemotaxis & phagocytosis
increases endometrial bacterial adherence

Question 5

role of oestrogen in the pathogenesis of CEH?

Answer 5

up-regulation of endometrial progesterone and oestrogen receptors

Question 6

T/F bacterial colonisation in pyometra is via ascension during cervical dilation that occurs in oestrus

Answer 6

T

Question 7

most common bacterial isolate in pyometra (60-70%)?

Answer 7

E coli

Question 8

which breeds have been found to have an increased incidence of pyometra?

Answer 8

rough coated collies
rottweilers
CKCS
golden retrievers

Question 9

average interval from the onset of proestrus to diagnosis

Answer 9

35 days (range 20-70d)

Question 10

differentials for uteromegaly on abdominal radiographs

Answer 10

pyometra
pregnancy <42d
mucometra
hydrometra
CEH
uterine neoplasia
coagulopathy

Question 11

T/F anaemia of chronic disease is a common finding in pyometra

Answer 11

true - 70%

Question 12

how does E coli endotoxin cause PU/PD?

Answer 12

causes polyuria - inhibits response to ADH in the distal convoluted tubules and collecting ducts, impairing concentrating ability

Question 13

what is associated with a poorer prognosis?

Answer 13

> 60mg/dL

Question 14

mechanisms of increased ALT, AST & ALP in pyometra?

Answer 14

hypoxia from dehydration
hepatocellular damage (reversible) due to cytotoxic necrotising factor-positive E coli

Question 15

biochemical markers that differentiate between pyometra from CEH w/ mucometra

Answer 15

% band neutrophils (>19.9% is very sensitive and moderately specific)
C reactive protein*
ALP
circulating prostaglandin-F metabolites (PGFM)*
*not readily available

Question 16

T/F bitches with pyometra commonly have concurrent UTI

Answer 16

T

Question 17

preferred antibiotic spectrum of activity & examples

Answer 17

broad spectrum a/bs, effective against gram negatives:
amoxicillin
amoxicillin/clavulanic acid
enrofloxacin
gentamicin
streptomycin
sulfamethoxazole
tetracycline
trimethoprim

Question 18

length of antibiotic treatment in surgical and medically treated cases?

Answer 18

10d v 30d

Question 19

rationale for treatment with polyvalent equine antiendotoxin hyperimmune plasma (anti-LPS)?

Answer 19

antibiotics can increased LPS concentration 2000-fold and worsen endotoxemia

Question 20

argument against treatment with anti-LPS?

Answer 20

likely that antibodies will be formed against the foreign proteins (especially with repetitive treatments)
efficacy unknown

Question 21

MOA and rationale for use of aglepristone during stabilisation?

Answer 21

used to convert closed- to open-cervix pyometra
competes for uterine receptors at a fixating rate 3x that of progesterone
promotes evacuation of exudate & clinical improvement

Question 22

survival rate with pyometra after OHE?

Answer 22

92%

Question 23

rationale behind use of PGF2a in medical therapy of pyometra

Answer 23

myometrial contractility (expels uterine contents)
causes luteolysis, decreasing progesterone concentration

Question 24

timeline of and examples of side effects of PGF2a

Answer 24

within 15 minutes, can last 2 hours
panting
salivation
anxiety
vomiting
diarrhea
urination
abdominal contrations
ataxia
queens: also show vocalisation, grooming, kneading, mydriasis, lordosis)

Question 25

strategies to decrease chance of recurrence following medical management?

Answer 25

breed on next cycle

consider aglepristone + antibiotics