Pyometra

Question 1

Pyometra Definition

Answer 1

• Pyo (pus) + metria (uterus)
• Hormonally mediated dioestral disorder in bitch
• Bacterial infection
• Mild – life-threatening bacteraemia & toxaemia

Question 2

Pyometra - Predisposing Factors

Answer 2

• Age – bitches >6yrs (repetitive exposure to progesterone)
• Breed – bullmastiffs, golden retrievers, Dogue de Bordeaux
• Uterine disease – cystic endometrial hyperplasia (CEH)
• Exogenous P4/ oestrogen admin

Question 3

Ovulation Overview

Answer 3

1. FSH = follicles dev
2. E2 increases
3. Granulosa cells start to form & release P4
4. E2 decreases
5. Stims LH surge
6. Ovulation
7. CL forms
8. CL produces P4
9. P4 increases
10. CL persists
11. P4 levels plateau, gradually decline as CL degens
12. P4 falls, prolactin released from anterior pituitary
13. Prolactin = luteotrophic
    - Stims & maintains CL

Question 4

Cystic Endometrial Hyperplasia

Answer 4

• P4 induced endometrial hyperplasia precedes pyo >6yrs
• Abnormal uterus response to chronic & repeated P4 exposure
•  in size & number of endometrial glands – secretory
• Pathologic hyperplasia -> cystic (CEH)
• Fluid -> hydrometra/ mucometra
• -> Infertility/ chronic endometritis -> **pyo

Question 5

Exogenous Admin
E2
P4

Answer 5

• Oestrogens -> big stim effect of P4 on uterus
• Progestogens -> postpone heat, skin conditions in cats

Question 6

Bacteria

Answer 6

E. coli** = G -ve rod
- decreased Muc1 gene expression =
increased E. coli adherence

Question 7

Signalment

Answer 7

• Intact F
• Middle age-older
• Breed
• Hx of abnormal seasons
• Hx of admin of progestins/ oestrogens
• 4-8wks after season

Question 8

History:

Answer 8

• Lethargy/ depression
• Inappetence
• PU/PD
• V+/D+
• Abdo enlargement
• Sanguinous – creamy/ yellow purulent vulval discharge

Question 9

Open Pyo:

Answer 9

• Open cervix
• Systemically well early
• PU/PD, V+, discharge

Question 10

Closed Pyo

Answer 10

• Closed cervix
• Systemically ill
• No discharge
• Depression, abdominal enlarged/ pain

Question 11

Clinical Exam:

Answer 11

~palpable uterine enlargement
~ vulvar discharge
~ pyrexia
Septicaemia/ endotoxaemic:
o Tachycardia
o Increased CRT
o Weak femoral/ peripheral pulse
o decreased rectal temperature

Question 12

Stump Pyo:

Answer 12

After OVH
Inflam and bacterial infection of stump tissue
Occur if
o Ovarian tissue in abdomen = ovarian remnant syndrome (ORS)
o Exogenous progestin/ oestrogen admin

Range of clinical signs

Question 13

Ovarian Remnant Syndrome (ORS):

Answer 13

Hx & clinical signs of oestrus after OVH/OVE

Diagnosis:
- vaginal cytology,
- hormone assays (serum PG increase,
oestradiol higher than neutered bitch),
- dynamic testing HCG/ GnRH,
- abdo US/ CT

Question 14

Haematology:

Answer 14

Raised WBC
o Neutrophilia w left shift

PCV -> 30-35%

Mild normocytic, normochromic non regen anaemia

Question 15

Biochem:

Answer 15

Increased TP – dehydration, hyperglobulinaemia

Increased creatinine/ urea
o Pre-renal azotaemia = dehydration
o Renal -> endotoxic damage

Increased ALT/ALKP if septic/ hypoxic

Question 16

Urinalysis:

Answer 16

1st = hypersthenuria (USG >1.030) -> dehydration

As progresses:
o Toxins damage tubules
o less Na/Cl exchange in medulla
o less hypertonicity in medulla
o less reabsorbed water in collecting ducts
o PU/PD

Isosthesnuria/ Hyposthenuria:
o Immune complex deposition in glomeruli
o Glomerulonephropathy
o Leak plasma proteins -> proteinuria

Question 17

Xrays:

Answer 17

Large uterus
o Compare to intestine size
o SI displaced cranially

Pregnancy -> uterus visible 3rd – 4th week, mineralisation 6th week

Peritonitis – lose normal contrast between abdominal viscera

Wont always see uterus if small/ open pyo

Question 18

Ultrasound:

Answer 18

• Size of uterus
• Wall thickness
• Presence/ fluid type
• ID foetus, foetal remnants, placental tissue
• Uterine pathology – cysts, polyps, neoplasia

Question 19

Tx - Surgical

Answer 19

Ovariohysterectomy*
Support w
o IV fluids – lactated ringers/ Hartmann’s
o Antibiotics? – potentiated amoxycillins,
cephalosporins
o Antiprogestogens – aglepristone (alizin) =
dilate cervix

Surgical drainage = not v successful
o Place uterine catheters under GA, flush
daily
o Multiple procedures

Question 20

Surgery Considerations:

Answer 20

Friable tissue – gentle tissue handling
Risk rupture -> peritonitis
Lavage abdomen, stump

Question 21

Anaesthesia Considerations

Answer 21

Older patients
Large abdomen
Dehydrated
Hypovolaemic
Septic, vasodilation

Question 22

Medical Management:
Adv vs Disadv:

Answer 22

Adv:
Retain breeding potential
Not performing major surgical procedure

Disadv:
Not always successful
Recurs next season
Delay response
Increase expense

Question 23

Medical management Aims

Answer 23

o Minimise P4 effects
o Promote cervix relaxation
o Expel pus
o Facilitate uterine healing

Question 24

Medical Management - Drugs:

Answer 24

Broad spectrum antibiotics & antiprogestagens

Prostaglandins

Prolactin inhibitors

Question 25

Medical Management - Antibiotics:

Answer 25

- Ineffective on own - Broad spec - Vaginal swab = inaccurate

Question 26

Medical Management: Antiprogestogens -> Aglepristone:

Answer 26

Blocks P4 action: o Cervix relaxed o Increase myometrial activity o Inhibit P4 suppression of leucocytes

Question 27

Medical Management - Prostaglandins -> PGF2 Dinoprost (Lutalyse):

Answer 27

- Luteolysis -> decrease P4 - Uterine contractions - Don’t use if cardiac/ resp dx - Caution in closed cervix - Ensure not pregnant

Question 28

Medical Management: Prolactin Inhibitors -> Cabergoline (Galastop):

Answer 28

- Inhibit CL support by prolactin

Question 29

Cat Pyometra:

Answer 29

- Similar pathogenesis - Luteal phase - Tx same – off license

Question 30

Rabbit Pyometra

Answer 30

- Pus in uterus - Progress from endometritis - Pasteurella multocida, staph aureus