PATHOLOGY - Small Mammal Reproductive Disease Flashcards
How do you sex guinea pigs?
Female guinea pigs have a Y shaped genitalia made up of the vaginal opening, urethral papilla and anus, whereas male guinea pigs have I shaped genitatia made up of the prepuce and the anus ± testes
How do you sex rats?
Female rats have nipples and a shorter distance between their urethral papilla and the anus. Whereas male rats do not have nipples and have a longer distance between their prepuce and anus, ± testicles
How do you sex chinchillas?
Both male and female chinchillas have conical urethral papillae, however female chinchillas have a shorter distance between their urethral papilla and the anus. Whereas male chinchillas have a longer distance between their prepuce and anus, ± testicles
How do you sex degus?
Female degus have a shorter distance between their urethral papilla and the anus. Whereas male degus have a longer distance between their prepuce and anus, ± testicles
What are cystic rete ovarii?
Cystic rete ovarii are serous fluid filled ovarian cysts which do not produce hormones but can grow to very large sizes
Which species is predisposed to cystic rete ovarii?
Guinea pigs
How do you identify cystic rete ovarii on clinical examination?
You can feel the enlarged ovaries on gentle abdominal palpation, these may be painful or non-painful on palpation
Make sure to do the rest of your clinical exam to ensure the patient doesn’t have concurrent disease
How you medically management cystic rete ovarii?
You cannot medically manage cystic rete ovarii as they are not hormonally active and thus won’t respond to management
How do you treat cystic rete ovarii?
Ovariohysterectomy
What makes ovariohysterectomy more challenging in guinea pigs?
Short ovarian ligament so exteriorisation is challenging
Much more sensitive to pain
What are follicular cysts?
Follicular cysts are hormonally active ovarian cysts
Often concurrent with cystic rete ovarii
What are the clinical signs of follicular cysts?
Abdominal distension
Abdominal pain
Vocalisation when handled
Bilateral, symmetrical alopecia
Nipple crusting
Reduced appetite
Weight loss
Lethargy
Vaginal bleeding
How can you medically management follicular cysts?
Human chorionic gonadotrophin
Gonadotrophin releasing hormone (GnRH)
How do you medically manage follicular cysts with human chorionic gonadotrophin?
Intramuscular (IM) Human chorionic gonadotrophin followed by a second dose 7 - 10 days later. Be aware due to being such a large dose, you will need to inject over multiple sites
What are the disadvantages of using human chorionic gonadotrophin to manage follicular cysts?
Painful on injection due to large dose
Risk of anaphylaxis
Immune response resulting in antibody production (reduces the effectiveness of the drug)
How do you medically manage follicular cysts with gonadotrophin releasing hormone (GnRH)?
Administer a dose of gonadotrophin releasing hormone (GnRH) followed by another dose 2 weeks later
What are the advantages of using gonadotrophin releasing hormone (GnRH) to medically manage follicular cysts?
Lower dose so better tolerated
No immune response or risk of anaphylaxis
What should you advise owners if they opt for medicial management of follicular cysts?
You should advise owners that medical management of follicular cysts may not work, and advise that ovarian neoplasia can also produce hormones and be confused with follicular cysts, so it may be preferable to do surgery
How can you differentiate between follicular cysts and ovarian neoplasia on ultrasound?
Follicular cysts will be filled with anechoic fluid however, ovarian neoplasia will being heterogenous with varying echogenicity and may even contain cysts
How can you surgically treat follicular cysts?
Ovariohysterectomy
Which species is prone to ovarian tumours?
Gerbils (especially gerbils over 2 years old)
What are the most common ovarian tumours in small mammals?
Granulosa cell tumours
Thecal cell tumours
Luteal cell tumours
Teratomas
How do you treat ovarian neoplasia?
Ovariohysterectomy
How can clinical signs of a pyometra vary in small animals?
Be aware that some small mammals (such as rabbits and rodents) cannot vomit, however ferrets can
What can often be confused with a pyometra in hamsters?
Hamsters produce copious post ovulatory discharge the day after ovulation which can be confused with pus. You should take a swab sample and do cytology to confirm, as well as assess any other clinical signs
Which species is prone to malignant uterine neoplasia?
Rabbits
What is the most common form of uterine neoplasia?
Uterine adenocarcinoma
Where does uterine adenocarcinoma metastasise to?
Uterine adenocarcinoma metastasises to the lungs
Which species is prone to benign uterine neoplasia?
Guinea pig
What is a key feature of a uterine leiomyoma?
Uterine leiomyomas is a benign tumour which often has a close affiliation with the bladder and thus can be challenging to resect
What are key indicators of dystocia in small mammals?
Dystocia is relatively rare
Continuous straining for over 20 minutes
Unproductive contractions for over 2 hours
Bloody or green vaginal discharge
How do you manage dystocia in small mammals?
- Radiography to assess for mechanical obstruction
- Ultrasound to assess for foetal viability
- If non-obstructive, manage with fluids, warmth, calcium gluconate and oxytocin
- If obstructive, do a caesarean section
When should you advise breeders to breed guinea pigs?
Guinea pigs’ pelvic symphysis fuses at 6 - 8 months of age so advise to breed before this as breeding after this can increase the risk of dystocia and a caesarean section
How can you tell when a guinea pig is close to parturition?
The pelvic symphysis will begin to widen and the gap will be externall palpable 10 days prior to parturition
How long does parturition last in guinea pigs?
15 - 40 minutes
What is a key indicator that a caesarean section is required in guinea pigs?
If the gap formed by the widening of the pelvic symphysis is less than 2.5cm, a caesarean section is indicated
Which species are prone to uterine prolapse after parturition?
Guinea pigs
Chinchillas
Which signalement is more prone to malignant mammary neoplasia?
Male guinea pigs
(T/F) Mammary neoplasia in rats is mostly benign
TRUE. However the tumours can grow to be very large resulting in pain and abnormal gain. Furthermore, they’re prone to ulceration
What can reduce the risk of mammary neoplasia in rats?
Ovariectomy/ovariohysterectomy before 4 months old
How do you manage mastitis in small mammals?
Surgical debridement of any necrotic tissue
Strip infected milk
Analgesia
Antibiotics (do culture and sensitivity)
What is an additional sign of pseudopregnany in rabbits?
Pulling fur from the ventral abdomen to line the nest
What can be used to manage pseudopregnancy in small mammals?
Cabergoline for 1 weeks
Which species is prone to orchitis?
Rats
(T/F) Testicular neoplasia is rare in small mammals
TRUE.
(T/F) Crypthorchidism is common in small mammals
FALSE. Crypthorchidism is rare in small mammals
(T/F) Testicular torsion is rare in small mammals
TRUE.
What should you be aware of in terms of accessory glands in male guinea pigs?
Male guinea pigs have very well developed seminal vesicles which can look a lot like a uterus. Furthermore, these seminal vesicles can accumulate uroliths
Which species is prone to prostatic hyperplasia?
Ferrets
What is prostatic hyperplasia commonly associated with in small mammals?
Prostatic hyperplasia is commonly associated with adrenal gland disease
What is the main risk of prostatic hyperplasia?
Urethral obstruction
How can you diagnose adrenal gland disease?
Ultrasound. If the adrenals measure more than 3.9mm there is disease
How can you medically manage adrenal gland disease (in ferrets)?
Deslorelin implant
Leuprolide acetate
What should you be aware of when using a deslorelin impant to manage adrenal gland disease?
There can be an initial hormonal surge with a deslorelin implant which can worsen prostatic hyperplasia and risk urinary obstruction
What is leuprolide acetate?
Leuprolide acetate is a synthetic GnRH agonist which can be used to manage adrenal gland disease and also shrinks the prostatic tissue for 12 to 48 hours (reducing the risk of urinary obstruction)
How can you surgically manage adrenal gland disease (in ferrets)?
Adrenalectomy or debulk if the right side as located very close to the caudal vena cava
Which species is prone to preputial tumours?
Ferrets
How do preputial tumours typically appear in ferrets?
Blue/gray mass at the entrance of the prepuce of varying size which can progress to large subcutaneous masses
(T/F) Preputial tumours in ferrets are often benign
FALSE. Prepucial tumours in ferrets are often malignant
How should you manage preputial tumours in ferrets?
Thoracic and abdominla radiography to investigate metastasis
Surgical resection
Adjunctive chemotherpay and/or radiotherapy
What are the risks associated with smegma build up?
Foreign bodies (such as shavings)
How do you manage smegma build up?
You should advise owners to be checking the penis regularly and wash the penis with warm water to remove the smegma
Which species are particularly prone to fur rings around their penis?
Chinchillas
How do you manage fur rings?
You should advise owners to be checking the penis regularly
Which species are prone to preputial abscesses?
Rats
How do you manage preputial abscesses?
General anaesthetic and milk out the pus
Antibiotics (culture and sensitivity)
How do you manage blocked oil glands?
General anaesthetic and milk out the sebum
What can happen to the anal sac in older guinea pigs?
Typically older, intact males
In older guinea pigs, they can lose the ability to fully expel faecal pellets, especially caecotrophs, resulting in an accumulation of the caecotrophs within the anal sac, resulting in stretching and flaccidity of the anal sac and local irritation and infection
How do you manage a flaccid anal sac in guinea pigs?
Emptying and gentle cleaning daily
Analgesia (as arthritis makes prehension of caecotrophs more challenging)
