Reproductive Pathology

Question 0

Describe how failure of the caudal parts of the paramesonephric ducts to fuse causes aberrant fusion of the distal tract

Answer 0

Complete failure of fusion - duplication of vagina and cervix and non fusion of the body of the uterus. Failure of fusion of cervix and uterine body - duplication of cervix and uterine body (normal in some rodents/lagomorphs). Double cervix - with a dorsoventral septum dividing the anterior vagina. Result in varying degrees of sterility.

Question 1

What is Segmental aplasia of uterine horns/and uterine body?

Answer 1

Degree and site of aplasia may vary. Complete absence of one horn. Portions of tract proximal to the aplastic segment may become cystic/filled with necrotic debris. Clinical history of infertility and objection to coitus.

Question 2

Describe the effect of failure of fusion of the paramesonephric ducts (uterus) with the urogenital sinus (vagina).

Answer 2

Imperforate hymen with remnant of tissue cranial to urethral opening.. It may be complete or just a small piece of tissue. If complete, the uterine secretions may accumulate and distend the uterus.

Question 3

Describe Follicular Cysts of the Ovary

Answer 3

Failure of the follicle to ovulate due to failure of luteinising hormone release. Secrete oestrogen - can alternate cyclic activity. e.g Anoestrus and changes in rest of reproductive trarct.

Question 4

Describe Luteinised follicles (cysts) of the ovary

Answer 4

Failure to ovulate due to inadequate or delayed luteinising hormone release. Cyst partially Luteinised. No oestrogen production.

Question 5

Describe haemorrhage of the ovary

Answer 5

Intrafollicular - occurs at ovulation, no signifcance, corpus haemorrhagicum. Pathological - after manual enucleation of corpus luteum, can be severe and fatal.

Question 6

Describe inflammation of the Ovaries

Answer 6

Rare. Seen in cattle secondary to ascending infection from the uterus, peritonitis, reproductive tract surgery. Ovary has fibrin tags, granulation tissue and fibrous adhesions to bursa which may result in tubovarian cyst formation.

Question 7

Name the three different origins of Neoplasia in the Ovaries

Answer 7

From gonadal stroma - tumours of the granulosa/thecal cells and their Luteinised forms. Granulosa-theca cell tumour most common. Usually unilateral and benign. Encapsulated, nodular white grey surface. May be cystic and haemorrhage. Of germ cell origiin - teratoma, dysgerminoma. Tumours of surface epithelium and subsurface epithelial structures - I.e cystadenoma - may be bilateral and may also have cystic endometrial hyperplasia. Pale nodular, cauliflower like. May present with ascites

Question 8

Describe potential acquired pathologies of the uterine tubes/oviduct.

Answer 8

Obstruction- hydrosalpinx, i.e uterine tubes distended with mucus secretions. May be congenital or acquired.
Inflammation - salpingitis/pyosalpinx. May affect fertility and is often only detectable microscopically.May be secondary to ascending infection from uterus.

Question 9

Describe the pathology of abnormal positioning in the non pregnant uterus.

Answer 9

Torsion - uterus enlarged, due to pregancy or pyometra, seqelae: congestion, oedema, foetal death, uterine rupture. Prolapse - postpartum, secondary to hypocalcaemia, prolonged dystocia. Sequelae congestion, oedema, necrosis, shock. Rupture - secondary to torsion/prolapse, iatrogenic due to untreated dystocia.

Question 10

Describe Endometrial Growth Changes seen

Answer 10

Atrophy - due to loss of ovarian function.
Hyperplasia - cystic endometrial hyperplasia, related to hormone influence, non cystic hyperplasia also occurs.
Endometrial polyps - with focal enlargement of uterine horn. Pedunculated mass of stroma and dilated glands. May prolapse.

Question 11

Describe Inflammation of the Uterus

Answer 11

Endometritis: inflammation of the endometrium
Metritis: inflammation of the whole uterine wall
Placentitis: inflammation of the foetal attachment point of the uterine wall
Endometrosis: chronic endometritis
Pyometra: accumulation of pus in the uterine lumen

Question 12

Describe the main routes of infection and the defence mechanisms of the uterus

Answer 12

Via cervix - at oestrus/mating or parturition
Haematogenous - mainly pregnant uterus
Defence mechanisms - closed cervix except at oestrus and post partum, mucus secretions, leucocytosis of oestrus, oestrogen levels at oestrus render the uterus unsuitable for growth of certain organisms.

Question 13

Describe how the uterus can become infected at mating

Answer 13

First mating causes a mild non specific endometritis. Infection is usually rapidly cleared by neutrophils. Also infection carried via infected semen - artificial insemination or natural infection e.g contagious equine metritis in horses which leads to a purulent endometritis and cervicitis.

Question 14

Describe how infection of the uterus can occur post partum

Answer 14

Infection of the non pregnant uterus post partum via the vagina after parturition or abortion. Increased risk if retained placenta, dystocia or failure of involution. Possible agents: cow - trueperella pyogenes, fusobacterium necrophorum. Sheep: clostridium, Bitch/queen: E. coli, staph, strep. Mare: strep zooepideicus, pseudomonas, Klebsiella spp.

Question 15

What are the sequelae to infection in the uterus?

Answer 15

Septicaemia: fever, depression
Embolic spread - endocarditis, renal infarcts
Ascending infection - salpingitis
Descending infection - cystitis, pyelonephritis
Chronic endometritis - fibrosis and lymphoplasmacytic inflammation
Pyometra - suppurative infection of the uterus with pus accumulating in the lumen. Uterus is susceptible to infection but the cervix is closed. Pyometra may also occur as a result of mechanical obstruction of the cervix.

Question 16

What is Cystic Endometrial Hyperplasia in the dog?

Answer 16

Accumulation of pus in the uterus as a sequel to hormonal disturbance with sometimes bacterial complication. In bitches it is seen in older animals, not bred,, post oestrus phase. Aetiology: elevated progesterone with oestrogen priming leads to cystic endometrial hyperplasia. Mucoid secretion > secondary bacterial infection = pyometra. The cervix may be closed or open and increased severity of signs of cervix closed. Distended uterine horns with congested serosal surfaces. Variable uterine content - red brown/purulent. Endometrial hyperplasia with inflammatory cells, congested blood vessels etc.

Question 17

What are common Neoplasia’s of the genital tract?

Answer 17

Usually primary tumours - metastasis is rare. Uterine carcinoma - cow, incidental finding at slaughter. Metastases in lungs. Common in rabbits. Leiomyoma - tumour of smooth muscle, most common in the bitch, leiomyosarcomas also seen.

Question 18

Describe possible Neoplasia’s of the Vagina/vulva

Answer 18

Squamous cell carcinoma - due to solar radiation
Transmissible venereal tumour - transmitted at coitus by transfer of intact cells.
Leiomyomas/fibromas/lipomas.
Melanotic tumours
Sarcoids

Question 19

What is the normal anatomy of the pregnant uterus?

Answer 19

Mare and pig - diffuse placenta
Dog and cat - zonary placenta
Ruminants - cotyledonary placenta. Cotyledons are area of attachment of foetal placenta. Caruncles are the maternal endometrial attachment site. Cow have a convex placentome and ewes have a concave placentome.

Question 20

Discuss the general responses to disease (+/infection) during pregnancy?

Answer 20

Death of the foetus and resorption - return to oestrus.
Mummification - no bacterial infection, fluids resorbed, foetus retained as black leathery mass.
Maceration and emphysema - uterine infection early in pregnancy results in maceration and expulsion. Emphysema occurs when dead foetal tissue is invaded by putrefactive bacteria.
Abortion - before foetus viable, secondary to feotal death due to damage to uterus. Stillbirth - after foetus potentially viable. Liver birth - normal or abnormal neonate. Congenital malformation - genetic factors, inherited or acquired, environmental factors - physical, chemical, nutritional, hormonal. Retained foetal membranes - metritis/endometritis.

Question 21

Discuss non-infectious conditions of the pregnant uterus

Answer 21

Rupture - usually during parturition as a result of mishandled dystocia. Ventral herniation - result of muscle weakness, old age, trauma. Adventitial placentation - fomation of additional sites of placentation between existing placentomes. Hyydroamnios/hydroallantois - accumulation of excess fluid in amniotic and allantoic sacs. Either of which may result in anasarca of foetus. Prolonged gestatioin - due to foetal malformation e.g absence of pituitary gland, anencephaly. Disturbance of foetal pituitary adrenal axis leads to failure of release of corticosteroids by foetus and failure of induction of parturition.

Question 22

Describe the route of milk flow out of the mammary gland

Answer 22

Alveoli> Ducts > Gland cistern/sinus > teat cistern/sinus > Streak canal. The myoepithelial cells surround the alveoli and ducts and under the influence of oxytocin, control milk flow. Ducts are lined by a double layer of epithelial cells while the teat canal is lined by stratified squamous epithelium with an innermost layer of smegma.

Question 23

Describe the changes to the mammary gland during puberty lactation and involution.

Answer 23

Before puberty thereis mainly a primitive duct system surrounded by loose connective tissue. After puberty the glandular tissue increases as ducts ranch. During pregnancy there is rapid proliferation of glandular epithelium. During lactation the glandular secretory epithelium accumulates lipid droplets and consists of tall columnar cells. After lactation the gland undergoes involution. Glandular tissue regresses due to reduction in the area of secretory epithelium and increased glandular stroma.

Question 24

Name some congenital conditions of the mammary glands.

Answer 24

Neonatal animals may secrete fluid/milk from thei rmammary glands (galactorrhoea) due to the effects of maternal hormones on feotal pituitary. Galactorrhoea may also be seen in bitches which undergo ovariohysterectomy during dioestrus - due to prolactin surge. Mammary gland/nipple aplasia, hypoplasia, inversion, non patency. supernumerary teats also relatively common in cattle.

Question 25

Describe Mammillitis

Answer 25

Inflammation of the skin of the teat and udder. Caused by bovine herpesvirus 2 - a localised infection results in ulcerative mammilitis in lactating dairy cows. Usually occurs sporadically and is secondary to teat trauma. Due to teat pain, the cow may be reluctant to be milked which can contribute to secondary mastitis. Gross pathology: teat swelling + pain, 1-2cm diameter plaques with central necrosis, ulceration,

Question 26

What is mastitis?

Answer 26

Inflammation of the Mammary gland - can be peracute, acute, subacute or chronic. It can be subclinical, severe or even fatal. It us usually due to bacterial infection via one of the following routes: haematogenous, percutaneous, invasion of the teat canal. Most common in bovine mastitis include streptococcus, staphylococcus and E. coli. Inflammation and epithelial cell death which lead to exudation and desquamation, respectively causing clots in the milk. Neutrophils migrate into milk.

Question 27

Describe the different patterns of mastitis

Answer 27

Acute catarrhal - with hyperaemia, interstitial oedema and migration of neutrophils into interlobular tissue. Acute suppurative - organism survives in the ducts and penetrates the connective tissue with production of purulent material. Necrotising - the organism or toxin penetrates and causes acute necrosis. Granulomatous - may all invade deeply into the tissue and result in persistent foci of infection with subsequent granulomatous inflammation. Endotoxic shock syndrome - often associated with necrotising vascular damage due to endotoxic injury. Often per acute with serous inflammation and oedema or possibly haemorrhagic inflammation.

Question 28

Describe other types of bovine mastitis?

Answer 28

Summer mastitis - T pyogenes causes sporadic cases of mastitis usually following penetrating injuries and results in necrotising and suppurative inflammation targeting the ducts. May be seen in dry animals. Mycoplasma mastitis - often causes sudden agalactia with a firm, swollen and painless gland. There is abundant migration of neutrophils initially, with alveolar and ductal hyperplasia in more chronic cases. Tuberculosis mastitis - due to mycobacterium bovis and usually due to haematogenous infection with spread along the ducts.

Question 29

What are the clinical signs of mastitis?

Answer 29

May have no gross abnormalities in the udder or milk or there may be marked abnormalities of the udder and milk (clinical mastitis) with swelling, heat , redness and pain of the mammary tissues and thin, to watery to bloody milk secretion with flakes, clots or purulent material and decreased milk production.

Question 30

Describe the main causes of mastitis in sheep and goats

Answer 30

Two main in sheep are staphylococcus aureus and mannheima haemolytica: result in acute necrotising or gangrenous mastitis - often sudden unexpected death, only one gland affected with acute necrotsing disease, which may be discoloured blue with watery milk expressed, animals may die within 12-48 hours due to toxaemia. a)affected mammary tissue sloughs over 3-4 week period due to vascular thrombosis and necrosis b)the vascular supply is maintained or reestablished and the surviving tissue heals with fibrosis. Contagious agalactia due to mycoplasma agalactiae is primary seen in goat and sheep. Initially animal is septicaemic and if it survives this there is keratoconjunctivitis arthritis and mastitis. Maedi-visna is a lentivirus which typically affects the lungs and may also cause bilateral, lymphoplasmacytic mastitis. Goats develop a similar mastitis due to caprine arthritis-encephalitis virus.

Question 31

Describe Mastitis in Sows

Answer 31

Generally seen sporadically in intensive breeding units and thought to have contributory factors such as hygiene/husbandry levels and teat injuries. Coliforms cause acute infection in the early post partum period. Mastitis-metritis-agalactia syndrome occurs 12-48 hours post partum and manifests as lethargy, pyrexia, swollen firm mammary glands with agalactia.

Question 32

Describe two non neoplastic mammary mases

Answer 32

a)Mammary ductal and lobular hyperplasia: hyperplasia of intraductal and epithelial cells and secretory acini, respectively.
B) Mammary fibroepithelial hyperplasia - cycling or pregnant queens. May regress spontaneously or require speying. MArked swelling of mammary tissue with erythema +/- ulceration and necrosis.

Question 33

Describe Mammary gland neoplasia.

Answer 33

Mammary gland neoplasia in the dog generally affects the fourth and fifth glands and as these tumours are hormonally depending, ovariohysterectomy prior to first oestrus decreases the risk of their development. Approx 50% of tumours are malignant and metastasize to the lungs and regional lymph nodes. Benign tumours include simple/complex Adenomas, fibroadenomas, benign mixed tumours etc. Complex tumours include the acinar epithelial component and spindle shaped myoepithelial component. Malignant tumours include ductular carcinoma, simple complex carcinoma etc.

Question 34

What is the scrotum?

Answer 34

A pouch of perineal skin, lined by evagination of peritoneum (the tunica vaginalis which has parietal and visceral layers). Developmental anomalies include apparent Agenesis (in cryptorchid animals) or failure of fusion resulting in scrotal clefts or bifurcation.

Question 35

Describe Scrotal Hernias and fluid accumulation.

Answer 35

Generally rare except in the horse. Congenital and acquired form in horses. Note: may occur following open castration especially in species with large inguinal canal. e.g guinea pigs. Fluid may accumulate between the layers of the tunica vaginalis (which communicates with the peritoneal cavity) e.g hydrocoele in animals with ascites or anasarca. Haematocoele is an accumulation of blood usually due to trauma.

Question 36

Describe the spermatic cord and possible pathologies of it.

Answer 36

The spermatic cord comprises the testicular artery, vein nerves and deferent duct. Torsion - especially in cryptorchid testes due to increased mobility. May lead to venous/arterial infarction. Variocoele - dilation of spermatic vein within pampiniform plexus. Incidental but can interfere with thermoregulation. Funiculitis - inflammation of the cord especially following castration. Castration wound chronically infected with staph aureus.

Question 37

What is Anorchia?

Answer 37

Complete failure of testicular development or testicular agenesis (failure of development of one testis).

Question 38

What is cryptorchidism?

Answer 38

Incomplete descent of teh testes which may be found at any site from the posterior pole of the kidney to the external inguinal ring. One of the most common abnormalities especially in the horse and cat. Usually unilateral but may be bilateral. the cryptorchid testis is sterile because of high environmental temperature and is at increased risk of developing neoplasia (especially sertoli cell tumours in the dog) and also has an increased risk of developing testicular torsion.

Question 39

What is testicular Hypoplasia?

Answer 39

Can be spontaneous or associated with intersex or cryptorchidism. May be bilateral or unilateral. Usually detected at or after puberty because of lowered/lack of fertility. Development of accessory genitalia is usually normal. Hormone secretion unimpaired. Aetiology includes genetic factors, environmental factors, hormonal factors, chromosomal abnormalities (XXY). Macroscopically: small, freely movable in scrotum. Seminferous tubules small and often lined by Sertoli cells only. No inflammatory reaction.

Question 40

What is testicular Degeneration?

Answer 40

The most common cause of reduced fertility (low sperm count or increased number of abnormal sperm). One or both testes depdending on whether the cause is local or systemic. Regeneration can occur if the aetiological agent is removed before the spermatogonia are completely destroyed. Aetiology - infection, nutritional disorders, chemical/hormones - endogenous (oestrogen) and exogenous (dexamethasome). Physical (hyperthermia) e.g excess periscrotal fat, increased pressure within the tunica albuginea. e.g back pressure from blockage of the epididymis, tumour, granuloa. Ionising radiation. Hypoxia - slowly developing arterial and venous occlusion.

Question 41

Describe circulatory disturbances of the testes

Answer 41

Testicular blood supply vulnerable to trauma - arterial supply and venous return are restricted within the spermatic cord and at the inguinal rings and the tunica albuginea is relatively inelastic and cannot adjust to sudden increases in intra testicular pressure. General septicaemia and toxaemia, occlusion of testicular artery/compression of spermatic cord causes coagulative necrosis e.g burdizzo castration, torsion of spermatic cord. Thromboss of artery or venous thrombosis with/without haematoma following trauma. Inflammation/infection e.g migrating strongyle larvae,

Question 42

What is Orchitis?

Answer 42

Inflammation of the testes. Orchitis is generally rare/sporadic other than in areas with endemic TB or brucella abortus. Aetiology: release of sperm into interstitial tissue - granulomatous response.
Infections - haemotogenous bacterial / viral infection. Secondary infection following localised trauma, ascending infection caused by intratubular orchiitis. Necrosis of seminiferous epithelium and desquamation. Granulomata are often a feature of severe orchitis due to brucella spp of infection.

Question 43

Describe testicular neoplasia

Answer 43

Most common in the dog. There may be multiple tumours of the same type. Bilateral neoplasia and / or more than one tumour type within a testis. There is an increased incidence of tumours in cryptorchid testes and these may be very large when identified. Although most primary tumours are generally benign, malignancy is reported and it is important to section spermatic coord to check for metastatic spread. Teratoma, seminoma, Sertoli cell tumours, leydig cell tumours.

Question 44

What is feminisation syndrome?

Answer 44

Associated with Sertolli cell tumours due to oestrogen production. Attractive to male dogs, decreased libido, symmetrical alopecia, mammary hyperplasia, preputial oedema, squamous metaplasia of the prostate, contralateral testicular atrophy. May have also bone marrow suppression due to presence of high levels of circulating oestrogen which is myelotoxic.

Question 45

What is a sperm granuloma of the epididymis

Answer 45

Sperm escape into adjacent tissues and stimulate an imunne response. Can be caused by blind-ending efferent tubules, usually in the head of the epididymis, leads to pressure degeneration of the testis.

Question 46

What is a spermatocoele of the epididymis?

Answer 46

Cystic dilation of the epididymis - causes accumulation of semen, inspissation, rupture sperm granuloma, due to congenital or acquired occlusions of the ducts.

Question 47

What is epididymitis?

Answer 47

Inflammation of the epididymis and may occur along with inflammation of the accessory sex glands. Epididymitis may be confused with orchitis and is often due to ascending bacterial infection but systemic spread, direct penetrating injury and viral infection also occur.

Question 48

What is seminal vesiculitis?

Answer 48

Most common in young bulls kept in groups - poss due to trauma. Pus in semen. Rectal palpation reveals disparity between the two glands and pain in the affected gland. The diseased gland is initially larger, then smaller.

Question 49

Describe possible congenital anomalies of the penis

Answer 49

Agenesis – usually seen only as part of a major whole body malformation. Persistent penile frenulum - associated with cork screw or deviation of the penis.

Question 50

Describe congenital anomalies of the prepuce

Answer 50

Absence of agenesis - may be associated with pseudo hermaphroditiism. Absence of preputial orifice - seen in pups. Phimosis - small preputial orifice , penis cannot be extruded from prepuce. Paraphimosis - prepuce can be drawn behind the glans but cannot return after erection. Hypospadias/epispadius - failure of anatomical closure of prepuce and/or urethra.

Question 51

What is posthitis?

Answer 51

Inflammation of the prepuce

Question 52

What is balanitis

Answer 52

Inflammation of the glans penis

Question 53

Describe possible Neoplasia of the prepuce

Answer 53

Transmissible fibropapilloma - multiple luxuriant growths, painful, easily traumatised. b) squamous cell carcinoma - especially horses, low grade malignancy may ulcerate and haemorrhage. C) melnoma - occur on prepuce and scrotum of grey horses. Often benign. d) transmissible venereal tumour - Proliferative nodular or papilloform mass often with friable/ulcerated surface. e) Sarcoids - equine skin tumour secondary to infection with bovine papillomavirus. May occur anywhere on body including the equine prepuce. Variable macroscopic appearance. Thickened epidermis and fibroblast proliferation.