Pathology Flashcards
What are the stages of the diagnostic process?
- Detect any abnormalities
- Objectively describe the morphological features of the lesions
- Interpret the nature of the change - consider pathological processes/differential diagnosis
- Generate a preliminary diagnosis/morphological diagnosis
When describing a lesion, what should you include?
- Location/site – organ, structure, anatomical region
- Distribution and number/extent
- Shape
- Size
- Colour
- Texture
- Other features – contour, demarcation content, odour, patency, weight of an organ
What is included in the location/site description of a lesion?
- The anatomical location or organ/tissue
- Location within an organ
When multifocal, how can including number in a description be more helpful?
May be more helpful to provide a number. If too many to count, estimate the number – tens of, hundreds of, innumerable
How does extent describe a lesion?
Indicate the proportion of the organ/anatomical site affected
How does shape describe a lesion?
- 3 dimensional or 2 dimensional structure
- Contour – raised, flat, depressed, smooth, irregular
- Demarcation – well or poorly demarcated
How can colour be described to aid lesion description?
Modifiers – light, pale, dark, mottled, streaked, stippled
What does redness indicate about a lesion?
Amount of blood present
What does a white lesion indicate?
- High cellular density
- Connective tissue (fibrosis, fat)
- Mineralisation
- Reduced blood flow/ischaemia/necrosis
What does a yellow lesion indicate?
Fat, bilirubin, fibrin, necrosis
What does a green lesion indicate?
Bile, necrosis, post-mortem changes
What does a black lesion indicate?
Melanin, iron pigment, necrosis
What are the possible textures a lesion could be described as?
Soft – skin, subcutis, fat, muscle, stomach, intestines, lungs
Firm – liver, kidney
Hard – bone, cartilage
Spongy/flabby – lung
Friable (crumbly)
Granular
Gritty
Viscous
Mucoid
Gelatinous
Homogenous
Crepitant (crackling sensation)
What does watery liquid indicate about a lesion?
Clear or coloured, such as serosanguineous
What does viscous liquid indicate about a lesion?
Thick, such as mucus or fibrin present
What does an opaque liquid indicate about a lesion?
Contains cells or lipid droplets
What does a turbid liquid indicate about a lesion?
Cloudy/opaque and contains clumped suspended matter or material, such as fibrin, cells
What are the 6 basic pathological processes?
- Congenital disorders – functional or structural
- Adaptive changes in cell growth (hyperplasia)
- Neoplasia
- Cellular degeneration/necrosis
- Inflammation and healing
- Vascular circulatory disorders
What is a morphological diagnosis?
- A short phrase that summarises the most important aspects of the lesion
- Used to communicate the findings to other veterinary professionals
- May be changed or overturned by new information e.g. results of further diagnostic investigations
How is duration indicated in morphological diagnosis?
Peracute
Acute
Subacute
Chronic
Chronic-active
How is tissue reaction described in morphological diagnosis?
Fibrinous
Suppurative
Liquefactive
Granulomatous
Necrotising
Caseous
Oedematous
Hyperplastic
Proliferative
Erosive
How is site name described in morphological diagnosis?
Hepat- = liver
Dermat- = skin
Nephr- = kidney
Encephal- = brain
Arthr- = joint
How is process/disease described in morphological diagnosis?
-itis = inflammation
-osis = condition of
-opathy = disease
Define aneuploidy.
Alteration in the number of chromosomes
What are 2 examples of sex chromosome aneuploidies?
- XXY Klinefelter’s syndrome in male calico-tortoiseshell cats
- XO Turner’s syndrome in horses
Describe the pathology of freemartinism.
- Male/female twin pregnancies
- Placental vascular connections form between the placentae
- Increased androgens and effects of SRY gene
- Decreased development of female genitalia and masculinisation of female twin
What may accompany small ovaries?
- Absence of or decreased germ cell number
- Partially converted into testicles
- Small vulva
- Prominent clitoris
- Short, blind ending vagina
- Other Mullerian duct derivatives
- Wolffian duct structures
What do extreme XX disorders of sexual development cause?
Complete sexual reversal where the sex chromosomes are XX and the phenotype is male. Reported in dogs, pigs and goats
What are XY disorders of sexual development?
The majority are XY, SRY+ testicular disorders with a female phenotype
What is an example of an XY disorder of sexual development?
Mutation that produces a deficiency of intracellular androgen receptors = normal XY karyotype but no intracellular androgen receptors = no androgenic effect = small testicles
What are 5 possible developmental disorders?
- Agenesis of 1 or both ovaries. Reproductive tract absent or present.
- Duplication – rare
- Ovarian remnant syndrome – in previously spayed cats/dogs
- Hypoplasia – common in cows, bilateral
- Cysts
What are follicular cysts?
- Mature follicle that fails to ovulate
- Defects in pre-ovulatory LH increase or LH receptors
- Can reach up to 2.5cm diameter
- Single or multiple
- Associated with infertility
What is a luteinised follicular cyst?
Ovulation fails to occur and the theca undergoes luteinisation. Wall is thickened die to partial luteinisation.
What is a cystic corpus luteum?
A CL that has formed after ovulation and in which a central cavity has persisted in a mass of developing luteal tissue. Can have ovulation papilla present.
When is haemorrhage during ovulation normal?
‘Autumn follicles’ in the mare may fill up with blood and cause haemorrhage is ruptured. Manual removal of the CL in cows
What causes oophoritis in bovine and small animals?
Bovine viral diarrhoea virus causes vertical transmission. Bovine infectious rhinotracheitis/BHV is experimental
SA = usually bacterial
What is a dysgerminoma?
Composed by primordial germ cells. Rare in dogs, cats, pigs, horses and cows. Usually unilateral
What is a teratoma?
Rare, tumour that have extensive differentiation into tissues of multiple germ layers
What are the properties of granulosa-theca cell tumours?
- Usually unilateral
- Can be large, solid or cystic
- Often produce hormones, which can cause changes to the animal – permanent anoestrous, masculinisation
- Can be haemorrhagic
What are the properties of theca cell tumours?
- Solid
- White to orange
- Cell cytoplasm contains lipid droplets
What are papillary cystadenomas and papillary cystadenocarcinomas?
Tumours of the surface of coelomic epithelium
What are the properties of papillary cystadenomas and papillary cystadenocarcinomas?
- Often bilateral up to 10cm in diameter
- Cauliflower like appearance
- If malignant, peritoneal spread is possible, leading to lymphatic blockage and ascites
What are 6 developmental pathologies of the female reproductive tract?
- Segmental aplasia of paramesonephric ducts – complete absence of an entire horn is called uterus unicornis
- Incomplete fusion of the paramesonephric ducts
- Imperforate hymen
- Hypoplasia of the cervix
- Dilations and diverticula of the cervix
- Vaginal stenosis
What is hydrosalpinx?
Distension of the uterine tube by colourless mucus, obstruction of the lumen. Congenital or inflammatory basis
What is salpingitis?
Inflammation of the uterine tubes without significant enlargement
What is pyosalpinx?
Acute septic inflammations, distension of the uterine tube by pus in the lumen, ascending bacterial infection from uterus
What is the predisposing factor of cystic endometrial hyperplasia?
Predisposing factor is excessive and prolonged oestrogenic stimulation. Joint action of oestrogens and progesterone
What is cystic endometrial hyperplasia?
Increased oestrogen causes increased number of receptors of the endometrium. Dogs have long dioestrous phase so with progestins and progesterone they have hyperplasia of endometrium.
What are the predisposing factors of inflammation of the uterus?
Post-partum
AI
Trauma
What is the appearance of endometritis in cattle?
The lumen contains chocolate coloured lochia. The mucosa appears oedematous and scattered haemorrhages can also be observed together with necrotic and suppurative phenomena.
What are the characteristics of a uterus with metritis?
- The uterus is usually paretic
- The wall appears thickened, oedematous and friable
Define pyometra.
An acute or chronic suppurative infection of the uterus with accumulation of purulent exudate (pus) within the uterine lumen.
What predisposes pyometra in dogs?
High progesterone levels of diestrum predispose to uterine infection
What are the 2 main clinical signs of pyometra in dogs?
Polyuria and polydipsia
What is caused by pyometra in cattle?
Uterine infection causes the corpus luteum to persist and maintain a high progesterone level due to a reduced production of PGF2α by the affected endometrium
What can cause cervicitis?
Usually extension of uterine or vaginal inflammation
What is a specific infectious diseases that may cause cervicitis?
Contagious equine metritis (taylorella equigenitalis)
What are some non-specific causes of cervicitis?
Post parturient inflammatory processes affecting the uterus and vagina
Trauma from AI
What is granular vulvitis?
The result of mild inflammation of the vulval mucosa. Granular appearance histologically and organised into lymphoid follicles. Ureaplasma diversum may be involved in cows
What is the pathology of viral vaginitis/vulvitis?
- Epitheliotropic virus (intranuclear inclusions) produces focal lesions/necrotic foci with secondary erosion/ulceration
- Highly contagious, spread through coitus
- Possible secondary infection with vaginal mucopurulent discharge
What is the aetiology of dourine?
Trypanosoma equiperdum (notifiable) affects equids by natural transmission by coitus
What are the clinical signs of dourine?
- Swelling of the external genitalia and ulcerations that leave depigmented scars
- Cutaneous lesions
What are the characteristics of squamous cell carcinomas in the vagina and vulva?
- Invasive and locally aggressive, metastasis late in the disease
- Greater exposure to UV light
- Predisposing factor is degree of local epithelial depigmentation
What are the characteristics of fibropapilloma of the bovine vulva?
Bovine papillomavirus 1. Usually affects young animals
What are the characteristics of canine transmissible venereal tumour?
Coitus causes tumour cells to shed and implant to external genitalia as a xenograft. Small to large isocytes up to 15cm, papillary or irregular. Sometimes ulcerated and friable mass. It has a histiocytic phenotype.
What are the predisposing factors of embryonic death?
Viruses, drugs and radiation
Why is the predominant spread of infectious agents causing embryonic death haematogenous and transcervical in cattle and horses respectvively?
Fetomaternal interface highly susceptible due to predisposing factors such as decreased oxygen concentration, elevated temperature
What are the non-infectious cases of embryonic death?
Plants, hormones, nutrition, metabolic, genetic
What do brucella species cause in reproductive tracts?
Necrotising placentitis and/or pneumonia in the foetus are often observed.
What does Schmallenberg virus cause?
- CNS, the axial skeleton and skeletal muscle congenital malformations
- Arthrogryposis
How does bovine viral diarrhoea virus cause bovine reproductive disease?
- Oophoritis
- Fertilization failure
- Embryonic death
- Absorption or abortion
- Mummification
- Stillbirth
- Birth of calves smaller than normal, weak or with congenital defects such as microencephaly, cerebellar hypoplasia, thymic aplasia, microphthalmia
- Persistently infected calves
What is the effect of toxoplasma gondii on sheep and goat placentas?
Foetal cotyledons of the placenta have characteristic lesions. They appeared bright to dark red with numerous white flecks or small soft white nodules = strawberry cotyledons
What are the characteristics of mycotic abortions?
- Characteristic cutaneous lesions/plaques, which are not always present
- Placenta leathery and necrotic
What is hydramnios?
Amniotic fluid normally swallowed by the foetus and absorbed but with abnormal foetus due to malformation, fluid accumulates
What is hydrallantois?
Associated to uterine and placental diseases
Describe the pathology of bovine uterine torsion .
- Develops abdominal pain, progressive anorexia and constipation
- The uterus becomes severely congested and oedematous, the placenta separates from the uterus and the foetus dies.
- Necrosis and rupture of the uterus are possible sequelae. If this occurs, maternal death results from toxaemia, peritonitis, haemorrhage and shock
What is the predisposing factor of prolapse in cattle and pigs?
Uterine hypotony
Associated with prolonged dystocia and postparturient hypocalcaemia
What are the consequences of prolapse?
Congestion and oedema leading to trauma and haemorrhage and so necrosis and shock
Distinguish contagious and environmental mastitis.
Contagious mastitis – obligate mammary pathogens are transmitted from cow to cow. Staph aureus and strep agalactiae
Environmental mastitis – environmental microbial contaminants contaminate the teat. E.coli and Klebsiella
What are the properties of staphylococcal mastitis?
- Contagious mastitis
- Coagulase-negative is more common in heifers
- Coagulase-positive is more common in older ager groups
- Produce gangrenous mastitis
What are the characteristics of coliform mastitis?
- Environmental mastitis
- Usually E.coli
- Extensive oedema and haemorrhage are characteristic
What are the characteristics of streptococcal mastitis?
- Predominantly contagious
- Usually permanent
- Fibrosis and involution of the affected quarter are possible sequalae
What are the clinical signs of viral mastitis?
Hard udders with no milk production, interstitial inflammation
What are the characteristics of canine mammary neoplasia?
- Origin in glandular epithelium or a combination of glandular and myoepithelial components
- Mammary hyperplasia can progress to dysplasia and neoplasia
- Benign mixed mammary tumours may contain cartilage and bone
What are the characteristics of fibroadenomatous hyperplasia?
- Luteal phase of oestrous, early pregnancy, or after progestogen therapy
- Mammary glands affected are hot and painful
- Proliferation of mammary ducts and fibrous stroma
What are the causes of scrotal inflammation?
Causes of dermatitis:
- Besnoitia besnoiti (protozoan) in bovine
- Chorioptes ovis (mite) in sheep
- Dermatophilus congolensis (bacterium) in bovine
How does scrotal inflammation cause testicular degeneration?
Inflammation increases temperature
What is hydrocele?
Fluid within the cavity around the scrotal contents. It occurs with any cause of fluid building up in the peritoneal cavity.
What is haematocele?
Accumulation of blood in the vaginal cavity. It is the result of trauma, and it is usually seen in stallions with mating injury and in boars housed together.
What are the species differences in cryptorchidism?
- Right testicle more frequent in dogs, sheep and goat
- Left testicle more frequent in bulls
- Cat, horse and boar are indifferent
What is the outcome of cryptorchidism?
- Degenerates or undergoes torsion
- Seminomas in inguinal canal
- Sertoli cell tumours in the abdomen
What is common sequalae to testicular atrophy and degeneration?
Fibrosis and mineralisation are common sequalae
What are the possible causes of testicular atrophy and degeneration?
Trauma
Stress
Hormones
Heat
Aging
Viral infections
Plants
Nutritional disorders
Chemicals
Radiation
What causes a spermatic granuloma of the epididymal head?
Blind-ending efferent ductules fill with spermatozoa and with spermiostasis may rupture and form a spermatic granuloma
What is epididymitis usually caused by?
Brucella species
What does epididymitis cause?
- Inflammation causes constriction and stasis, leading to rupture and spermatic granulomas
- Chronic epididymitis due to mineralisation and fibrosis
What is orchitis?
Intratubular/granulomatous orchitis in seminiferous tubules. Rare and usually secondary to epididymitis.
What are the characteristics of seminomas?
- Benign
- Does not alter the production of hormones
- Grey-white, soft, coarsely lobulated, bulging mass
- Intratubular or diffuse
- Focal lymphocytic infiltration
What are the characteristics of teratomas?
- In foals in cryptorchid testes
- A cystic and/or multilocular structure
- Hair/mucoid/sebaceous secretions are seen
- Yellow white solid masses with fibrous, adipose, cartilaginous and bony tissue are also frequent
What are the characteristics of interstitial Leydig cell tumours?
- Nodular hyperplasia may be a preneoplastic change
- Multiple, spheroidal and well-demarcated
- Haemorrhagic areas
- Soft
- Surrounding compression atrophy
What are the characteristics of Sertoli cell tumours?
- Large, solid/cystic, multiodular, form masses of white tissue
- Can produce oestrogens or inhibin
What are the effects of the oestrogen or inhibin produced by Sertoli cell tumours?
Hyperoestrogenism
Behaviour changes (attract males)
Gynecomastia
Symmetrical alopecia
Prostatic squamous metaplasia
Bone marrow suppression
What is varicocele?
Dilatation and tortuosity of the veins of the pampiniform plexus
What are the 2 forms of inflammation of vesicular glands/vesicular adenitis?
Inflammation in ampullae - degenerative or necrotic form and chronic interstitial form
What are the predisposing factors of vesicular adenitis?
Young bulls
Stress
Reflux of urine or semen
Congenital defects
Distinguish intraprosatic and paraprostatic cysts.
Intraprostatic cysts-lined by epithelium
Paraprostatic cysts - no epithelium. Can become huge, infected and abscessed but usually sterile.
What are the clinical signs of acute prostatitis?
Oedema, haemorrhages, necrosis, abscesses
What are the clinical signs of chronic prostatitis?
Replacement by fibrous tissue. Blood/pus in urine, straining or pain when urinating
What is canine prostatic hyperplasia?
- Testosterone dependent/higher oestrogen: testosterone ratio
- Hyperplasia epithelium causes uniform enlargement of the prostate
- Obstipation frequent
What is prostatic squamous metaplasia?
Affected epithelium become stratified squamous with keratin squames in the lumen.
What are the possible causes of prostatic squamous metaplasia?
- Administration of oestrogens
- Sertoli cell tumours
- Mycotoxins in pigs
What are the characteristics of prostate carcinomas?
- Asymmetric and irregular
- Cyst formation
- Metastasis
- Heterogeneity and poor differentiation
- Mixed phenotype
What are the possible causes of penile hypoplasia?
Early castration and DSD (disorders of sexual development). Lack of testosterone at critical periods.
What are the possible causes of penile haematomas?
- Deviation during mating
- Rupture and haemorrhage
- In dogs, fracture of the os penis
- In bulls a prolonged eversion, due to inadequate muscles in the prepuce, can predispose to trauma, desiccation, oedema and inflammation.
- Tearing of the preputial mucosa
Define balanitis.
Inflammation of the head of the penis
Define posthitis.
Inflammation of the prepuce
Define balanoposthitis.
Inflammation of the mucosa of the penis and preputial mucosa
What are the predisposing factors of balanoposthitis?
- Urea hydrolysing bacteria
- High protein diet
- Preliminary lesion
- Necrosis and ulceration of the prepuce
What is the appearance of bovine balanopostitis?
Grey/white necrotic foci leading to ulcers
What is the appearance of equine coital exanthema?
Vesicles causing yellow pustules with raised borders and depressed centres in the body of the penis causing ulcers
