Abnormal Cycles

Question 1

What is the normal length of the canine interestrus interval? (range)

Answer 1

4-12 months, its usually 6-8 months.

Question 2

What is the typical length of diestrus in dogs?

Answer 2

2 months

Question 3

what is the typical length of estrus in the dog?

Answer 3

9 days

Question 4

what is the typical length of proestrus in the dog?

Answer 4

9 days

Question 5

What are the 2 types of persistent anestrus?

Answer 5

1. primary anestrus – lack of estrous cycling by 24 months of age
2. secondary anestrus – prolonged interestrus interval (failure to cycle >12 months after a previous estrous cycle)

Question 6

What 3 drug types can cause persistent anestrus?

Answer 6

1. progestins
2. androgens
3. glucocorticoids

Question 7

T/F: increased activity/stress and plane of nutrition can cause persistent anestrus

Answer 7

true

Question 8

How can you prevent persistent anestrus that is caused by silent heat? (3 ways)

Answer 8

1. daily observation and wiping of vulva
2. weekly/biweekly vaginal cytologies
3. monthly+ serum progesterones

Question 9

what are 4 ovarian disorders that cause persistent anestrus?

Answer 9

1. congenital abnormalities (ovarian agenesis, ovarian hypoplasia, atypical gonads)
2. oophoritis
3. luteal cysts – sustained progesterone
4. granulosa cell tumors – secrete progesterone

Question 10

What length of heat would be classified as ‘persistent heat’?

Answer 10

> 6 weeks of combined proestrus and estrus OR significantly longer heat relative to the normal heat cycle for that particular bitch

remember normal heat = 2-3 weeks

Question 11

What 3 ovarian disorders can lead to persistent heat?

Answer 11

1. follicular cysts
2. granulosa cell tumors – secrete estrogen
3. oophoritis

Question 12

If a bitch presents to you because her owners report she has been in heat for 7 weeks, what is the first question you should ask them when obtaining history?

Answer 12

Ask them if the dog has been given any estrogenic medications or could the dog be in contact with someone taking estrogenic medications

Question 13

What are other diseases that cause prolonged vulvar discharge and are mistaken for persistent heat?

Answer 13

pyometra
vaginitis

Question 14

__________ can cause uterine diseases (CEH, endometritis, pyometra), bone marrow suppression** (aregenerative anemia, leukopenia, and thrombocytopenia), skin changes (alopecia, hyperkeratosis), and mammary gland development.

Answer 14

Persistent heat –> prolonged estrogen exposure

Question 15

__________ is a short proestrus period without ovulation followed 2-12 weeks later by normal fertile ovulatory heat

Answer 15

split heat

this most often occurs at pubertal heat and is considered normal in bitches under 4 yo, but you should probably still look into it further.

Question 16

What will result if serum progesterone never rises above 3.5 ng/mL?

Answer 16

ovulation failure

Question 17

If ovulation failure occurs, when would you expect the NEXT heat to occur?

Answer 17

2 months earlier.
Therefore, ovulation failure will shorten the interestrus interval

Question 18

T/F: medical abortions and pyometra treatments cause irregular interestrus intervals

Answer 18

true

Question 19

How can uterine disease cause irregular interestrus intervals?

Answer 19

uterine disease/inflammation –> prostaglanding (PGF2a) production –> premature luteolysis occurs

Question 20

what 5 ovarian pathologies can cause irregular interestrus intervals?

Answer 20

1. granulosa cell tumors – secretes progesterone
2. follicular cysts
3. congenital abnormalities
4. luteal cysts
5. oophoritis

Question 21

What drugs can cause irregular interestrus intervals?

Answer 21

1. mibolerone
2. MGA / progestins
3. GnRH superagonist implants

Question 22

Which systemic endocrine disease causes irregular interestrus intervals?

Answer 22

hyperadrenocorticism

Question 23

T/F: younger bitches are more likely to experience irregular interestrus intervals than older

Answer 23

false – older

Question 24

T/F: irregular interestrus intervals occurs after whelping

Answer 24

true

Question 25

which type of ovarian tumors are MOST common?

Answer 25

epithelial tumors such as adenocarcinoma and others.

2nd most common = sex cord/stromal tumors such as granulosa cell tumors, etc.

3rd most common = germ cell tumors such as teratomas, etc.

Question 26

What would you see on vaginal cytology if a bitch were in estrous?

Answer 26

cornified superficial epithelial cells

Question 27

what are 2 potential sources of estrogen?

Answer 27

ovaries
adrenal glands

Question 28

If a bitch presents to your clinic because the owners report she is 34 days in heat and has abdominal discomfort, what would be some appropriate diagnostics to run on this dog?

Answer 28

1. Physical exam
2. vaginal cytology (to look for estrogen influence and/or inflammation)
3. serum progesterone levels (determine ovulation status and to see if CL is present)
4. ultrasound (to look for intraluminal fluid, uterine and ovarian appearances, and adrenal glands)
5. CBC, Chem, UA, serum T4 (looking for bone marrow suppression, systemic inflammation, infection, etc.)

Question 29

T/F: if you do not know the cause of persistent heat, you should not prescribe progesterone or any other medications that would attempt to decrease estrogen levels.

Answer 29

TRUE
without knowing the underlying cause, this is not safe. It can cause pyometra.
You can safely perform an OHE.

Question 30

If a dog has a history of being spayed, but presents to you because the owners report she keeps having signs of heat (swollen vulva, male dogs interested, mucoid light brown vulvar discharge) what is your top differential?

Answer 30

ovarian remnant

Question 31

T/F: with ovarian remnants, you expect to see either serosanguinous discharge (ovariectomy) or no discharge at all (OHE)

Answer 31

true

Question 32

What vaginal tumors are hormone-dependent supporting the presence of ovarian tissue?

Answer 32

fibropapillomas or leiomyomas

Question 33

What AMH test result is consistent with a SPAYED female dog or CASTRATED male?

Answer 33

NEGATIVE

Question 34

Serum P4 < ___ equals a negative test.

Answer 34

0.2 ng/mL

Question 35

Serum P4 > ___ equals a positive test.

Answer 35

0.5 ng/mL

Question 36

What result on an LH test indicates presence of ovarian tissue?

Answer 36

NEGATIVE