Special path

Question 1

Myasthenia gravis

Answer 1

• disorder of neuromuscular impulse transmission
• inherited = animal born with too few acetylcholine receptors at neuromuscular junctions
• acquired = usually a primary lesion (thymoma), which produces acetylcholine receptor antibodies on post synaptic membrane
• no macro/micro lesions
• consequence = muscle weakness + atrophy, megaesophagus development

Question 2

hemangiosarcoma

Answer 2

• neoplasia of vascular endothelium
• primary = arises from heart, usually R auricle
• secondary = metastasis from spleen
• macro = red, bloody nodules
• common in GSD
• consequence = rupture leading to hemoperricardium and death from cardiac tamponade

Question 3

Edema disease

Answer 3

• disorder of rapidly growing, healthy feeder pigs being fed a high energy ration
• cause = E.coli, produces verotxoins
• pathogen: 1. dietary changes, 2. intestinal absorption of antitoxins, 3. fibrinoid necrosis of arteries and arterioles, 4. focal decrease in circulation through CNS -> infarct, 5. generalise edema
• extra neural lesions = swelling + transudation into body cavity
• organs affected = stomach, intestine
• micro = swine cerebral antipathy + neuronal necrosis
• consequence = 4- 8 weeks old piglet ie within 24 hrs

Question 4

black leg

Answer 4

• clostridium chauvoei
• pathogen: 1. spores ingested through intestinal tract, 2. disseminate through blood stream to skeletal muscles, 3. spores can remain latent/proliferative if bruising, 4. spores activate bacteria proliferate and produce toxins, 5. toxins cause capillary damage
• macro = gelatinous exudate, yellow, swollen, dark red
• micro = intramuscular blood + gas bubbles
• most common = acute death

Question 5

pyometra

Answer 5

• accumulation of pus within uterine walls
• cause = consequence of endometritis/metritis, E.coli (viscous brown exudate), strep (creamy yellow exudate)
• macro = necrotic areas with hemorrhagic areas
• micro = cystic endometrial hyperplasia
• consequence = widespread extramedullary hemaotpoiesis + immune complex glomerulopathy

Question 6

Hydrocephalus - pathogen

Answer 6

• accumulation of CSF within brain cavities (ventricular and subarachnoidal)
  1. non absorptive CSF, pressure in ventricles increase
  2. ventricles widen, ependyma is multi focally distrupted
  3. compression of periventricular white matter
  4. hydrostatic edema of white matter
  5. degeneration + atrophy of myelin + axons -> loss of tissue
  6. expansion of ventricles + compressive atrophy -> necrosis
• most common in brachiocephalic/miniature breeds
• manifestation in 1st 3 months of life

Question 7

tuberculosis

Answer 7

• mycobacterium bovis
• aerogenic infection or PO calves
• multiply in macrophages + spreads via LN + resp
• hypersensitivity 3 -> granulomatous infalm
• pneumonia, lymphadenitis + pleuritis (pearl disease)
• granuloma = caseous necrosis + multinucleate giant cells, epithelia cells, macrophages, lymphocytes and fibroblasts

Question 8

hydrocephalus causes

Answer 8

• blockage of intervenrticular foramen (unilateral)
• blockage of both interventriclar (bilateral)
• blockage of mesencephalic duct (bilateral)
• blockage of lateral apertures of 4th ventricle (bilateral)

Question 9

types of hydrocephalus

Answer 9

communicating - congenital
= less common, communication between ventricular and subarachnoidal space
non communicating - congenital
= obstruction in ventricular system + opening of 4th ventricle
compensating - congenital
= secondary due to loss of lack of brain tissue
acquired = appears in developed brain tissue
non communicating - acquired
= injuries/obstruction, neoplasms and abscess, blockage of fluid
compensating - acquired
= secondary after losing neural tissue due to brain infarction or brain ageing

Question 10

paratuberculosis

Answer 10

• Johne’s disease
• causes = mycobacterium avian sap paratuberculosis
• macro = chronic segmental thickening of ileum, cecum and proximal colon.
  = lepromatous form - prominent mucosal folds
  = tuberculoid form - caveating granulomas
  = arteriosclerosis

Question 11

canine distemper

Answer 11

• cause = morbillivirus
• pathogen: 1. transmitted to puppies in bodily fluids + invades upper resp tract and conjunctiva. 2. spreads to regional L.N + causes viremia, 3. infects almost all cells of body, particularly epi cells, 4. decrease immune response, decrease cytokine production nd predisposition for 2bact infection
• macro = diffuse interstitial pneumonia, necrotising, bronchiolitis + pneumocyte type 2 hyperplasia
• mico = eosinophilic inclusion in epi cells
• consequence = 2ary bacterial infection - bordetella bronchiseptica enamel hypoplasia, hyperkeratosis of nose and foot pads

Question 12

Sertoli cell tumour

Answer 12

• macro = well-circumscribed, firm white lobulated by fivbrous bands mass
• micro = abundant fivbrous tissue, intratubular/diffuse arrangement of Sertoli cells
• 1/3 of these tumours have a feminising effect - alopecia + hyperplasia or metaplasia of prostate

Question 13

GDV

Answer 13

• large- deep chested dog breeds = acute GDV
• simple gastric dilation = young pups + overeating
• predisposition = distending gas, fluid/feed obstruction of pylorus
• repeated dilation = stretching + relaxation of gastrohepatic ligament -> gastric rotation
• XS gas/obstruction -> dilation -> rotation of mesenteric axis -> compress of diaphragm , vena cava and portal vein s-> cardiac output and perfusion to abdomen viscera -> shock
• severe abdo distension, 180-360 degrees
• consequence = stomach rupture and death

Question 14

splenomegaly

Answer 14

• causes = blood accumulation, increase MMS cell number, lymphoid hyperplasia, inflammation and neoplasia
  uniform splenomegaly =
• bloody spleen (hyperemic) -> congestion; torsion, euthanasia by barbiturates,
• meaty (nonhyperemic) -> phagocytosis, deposti disease + cell proliferation
  nodular splenomegaly
• uneven contraction, hematoma, haemangiosarcoma
• splenic nodules with firm consistency = nodular hyperplasia, abscess, chronic granuloma

Question 15

infectious canine hepatitis

Answer 15

• causes = canine adenovirus 1
  1. exposure orally by urine/infected dogs
  2. causes viremia, multiplies in tonsils + spreads via L.N
  3. virus has a tropism for hepatocytes, vascular Endo + renal epi
• macro = haemorrhage in organs + seroa, enlarged friable liver + hyperaemic tonsils + LN, gall bladder wall edema and corneal edema
• micro = smaller, centrilobular necrosis, large, intranuclearl inclusions. Endothelial damage + haemorrhage

Question 16

vesicle

Answer 16

• fluid filled cavity within/beneath the epidermis less than 1cm in diameter
• cause = viral infections, pemphigus follia cells/vulvaris, thermal burns
• vesicle greater than 1cm = bulla

Question 17

exocytosis

Answer 17

mechanism of exiting a cell from basolateral surface

Question 18

hepatocellular steatosis

Answer 18

• excessive lipid within hepatocytes
• causes = incorrect nutrition ->increase feed starvation of fat animals, toxins, ketosis
  pathogen - increase dietary intake of fat + carbs, increased esterification + fat mobilisation, decrease oxidation + decrease secretion of lipoproteins
• macro = enlarged, yellow liver
• micro = swollen hepatocyte contain numerous vacuoles
• consequence = significance depends on cause, severity + duration. hepatocellular necrosis, fatty cysts, liver rupture which can lead to haemoabdo

Question 19

leydig cell tumour

Answer 19

• interstitial cell tumour of testes
• most common testifcular tumour in dogs
• almost always benign
• macro = spherical, well -demarcaated tan- organ coloured mass with areas of haemorrhage
• micro - finely encapsulated, cells in sheets or small groups, abundant vacuolated cytoplasm

Question 20

seminonoma

Answer 20

• germ cell neoplasm
• macro= homogenous, white- pink grey firm mass, fine fibrous trabeculae
• micro = intratubular/diffuse, large round neoplasic cells with little cytoplasm. high mitotic rate
• locally invasive but rarely metastatic

Question 21

mastitis

Answer 21

inflammation of mammary gland

cause -= strep, strap, ecology, mycoplasma Bovis

Question 22

urolithiasis

Answer 22

• presence of stones or calculi in urinary collecting system
• renal pelvis = nephroliths, ureter = urethroliths, urinary bladder = urocystolith/urethrea = urethrolith
• form when familial, congenital and pathophysiology factors occur together and cause precipitation of excretory metabolites which form grossly visible stones
• predisposing = decreased water, pH, cystitis
• consequence = obstruction of traumatic injury, infection
• mini schnauzers = struvite

Question 23

osteogenesis imperfecta

Answer 23

• inherited CT disorder
• cause = mutation in COLL1 gene
• consequence = bone fractures, joint laxity, blue sclera
• macro = decreased trabecular bone, delay in compaction of cortical bone + dental fractures
• micro = evidence of fractures and disorganised dentin
• calves, lambs, kittens and puppies

Question 24

pseudorabies

Answer 24

• Aujesky’s disease/ match itch
• cause = said herpes virus 1
  1. virus enters thru upper respiratory tract, tonsils
  2. replicates + enters sensory nerve ends
  3. transported to trigemeninal ganglia + bulbous olfactoria
  4. enters brain
• glycoproteins on surface of virus allows binding + entry into cells
• macro = leptomeningeal congestion
• micro = non purulent menegoencephalomyelitis
• consequence = fatal in piglets
• lesions outside CNS in pigs, in resp system, lymphoid, digestive and reproductive

Question 25

osteosarcoma

Answer 25

• malignant neoplasms of unknown origin
• cats + dogs, usually older + giant
• metaphysics of long bones
• characteristics = rapid growth, painful + aggressive
• class = simple, compound or pleomoprhic
• based on location = central, juxtacortical/ periosteal
• macro = grey-white mass containing variable amounts of mineralised bone. Random areas of hemorrhage

Question 26

bloat

Answer 26

• over-distension of rumen + reticulum with gas of fermentation
  primary = legume, dietary or frothy bloat
• legumes -> release chloroplasts particles -> rumen microbes colonise particles + degrade protein -> gas bubbles trapped + stable foam is fornmed. Organic acids + salivary bicarbonates -> CO2. Luminal fermentation + acid prod -> low pH
• legumes + fine particles -> decrease salivary secretion -> increase viscosity of rumen contents -> foam -> physical blockage of cardia
  secondary = physical obstruction/stenosis of oesophagus
• signs + lesion = abd distension, animal dead + rolled ono back, lots of frothy rumen content

Question 27

juvenile pancreatic atrophy of dogs

Answer 27

• GSDs 6-12m
• complex inheritance - multiple genes and environmental factors
• prob atrophy driven by autoimmune disease (lymphocytic pancreatitis)
• signs = maldigestion, rapid weight loss despite huge appetite
• macro = small pancreas, visible loss of parenchynma
• micro = islands of normal exocrine pancreatic tissue usually remains but otherwise tissue is markedly depleted

Question 28

infectious/ contagious ecthyma of sheep

Answer 28

• parapoxvirus
• lips, oral mucosa, eyelids and feet
• abrasions -> infections -> lesions characteristics for poxvirus
• high morbidity, low mortality but weight loss

Question 29

Cushing;s

Answer 29

• cortisol excess - adult dogs, infrequent in cats + rare in other domestic animals
• cause = functional neoplasm, ACTH secreting adenoma of pituitary gland, iatrogenic XS of corticosteroids
• function disorders = increased appetite, weakened + atrophies muscles of extremities and abdomen
• hepatomegaly, skin lesions

Question 30

acantholysis

Answer 30

• disruption of intercellular junctions between keratinocytes of epidermis
• cause: immune mediated, exfoliative toxins from staph
  1. damage of transmembrane glycoproteins, splitting of extracellular core of desmosomes
  2. desmosome plaque dissolve + intermediate filament retract
• micro= varies depending on location. Vesicles/ pustules, free-floating keratinocytes

Question 31

parvovirus enteritis

Answer 31

• feline and canine forms
  1. virus replicates in lymphoid tissue, cause lymphoid depletion, crypt cell destruction
  macro - hyperaemic intestine with serositis, SI maybe fluid-filled + hemorrhagic
• micro = basophilic intranuclear inclusions bodies in enterocytes, necrosis of crypt epi cells, permanent villous distortion + atrophy
• consequence = hemorrhagic diarrhoea + death from shock
• secondary bacterial infection with endotoxemia

Question 32

mast cell tumour

Answer 32

• dogs, cats, pigs + cattle
• malignant
• cell of origin: CT or mucosal mast cells
• most common in dogs - back of body + scrotum
• can look like inflammation due to degranulation + release of mediators
• micro = eosinophilic, flame figures, toluidine blue = mast cells are purplet

Question 33

tetralogy of fallot

Answer 33

• complicated cardiac anomaly with 4 lesions
  1. ventricular septa defect (1-3 = primary lesions)
  2. pulmonic stenosis
  3. destroposition of aorta
  4. hypertrophy of R. ventricular myocardial
• consequence = increase pressure on R side, shunting unoxygenated blood to underdeveloped left side systemic hypoxia + polycytemia
• humans = blue babies
• inherited in Keeshond dogs + frequent in bulldog

Question 34

cryptorchidism

Answer 34

• incomplete descent of tesits
• cause = failure of normal production of testosterone, failure of regulation by 1 or more genes for production of testosteronee or androgen receptor. = exposure to estrogen during pregnancy
• undescended testis can be anywhere from caudal to kidney but usually In abdominal by inguinal ring
• macro = testis is small + fibrotic
• micro = testis has interstitial collagen deposition, hyaline thickening and germinal epithelial degeneration
• consequence = more prone to neoplasia
• most often unilateral + DSD

Question 35

atelectasis

Answer 35

• incomplete distension of alveoli - congenital/acquire
  causes
  -congenital
  -> airway obstruction (aspiration) of amniotic fluid/meconium) + alteration in quantitquality of surfactant
• acquired
  -> compressive (neoplasia, bloat), obstructive (inflammation, parasites), contractive (due to pulmonary fibrosis)
• macro = lungs are dark, blue-red + w/o air
• micro = collapse of alveoli
• consequence
  = congenital = brain damage due to hypoxia “wanderer foals”

Question 36

pericardial effusion

Answer 36

• accumulation of fluid within pericardial sac
• causes = idiopathic, trauma or neoplasia
• types = hemorrhagic/ serosanguinous
• macro = pericardial sac filled with fluid/blood, pericardium thickened by diffuse fibrosis
• micro = lymphoplasmacytic infiltrate
• consequence = cardiac tamponade, death

Question 37

facciola hepatica

Answer 37

1. metacercariae ingested by rum, penetrate duodenum wall + enter liver
   - macro- hemorrhagic tracts of necrotic parenchyma, pale when repaired by fibrosis
   - micro = penductular fibrosis, ectasia + stenosis duct
   - consequence = acute peritonitis, hepatic abscess, death

Question 38

anthrax

Answer 38

• cause = bacillus anthracis
  1. spores ingested
  2. spores replicated locally
  3. spores spread to regional L.N
  4. disseminate systemically through bloodstream
  5. septicemia
• macro = splenomegaly, swollen, oedematous L.N, DIC
• micr = rod shaped bacteria in blood, congestion, hem
• necropsy + histopath not recommended
• alimentary, pulmonary
• consequence = death, hemorrhage

Question 39

retinal ablation

Answer 39

• retinal detachement - separation btw neuroretina + retinal pigment epi (RPE)
• causes = uveitis, neoplasia, trauma + retinitis
• types = exudative (accumulation of exudate or blood in sub-retinal space), tractional (vitresl membrane develop + pull neuroretina from RPE), rhegmatogenous (leakage of liquified vitreusin sub retinal space)
• micro = accumulation of material within sub retinal space, atrophy of outer retinal layer + hypertrophy of PRE
• consequence = blindness, glaucoma

Question 40

infectious bovine keratoconjuncitivities (pink eye)

Answer 40

• cause = gram neg coccobacillus mortadella bovis
• transmission = flies direct + indirect contact
• predisposition for develop UV light and infect with BHV-1
• bacterial virulence: cytotoxin + fimbriae
• initially shallow ulcers infiltration of neutrophils -> focal suppurative stroll keratitis -> release of collagen eases from neutrophils, corneal epi + keratocytes -> keratomalacia -> healing during few weeks

Question 41

pulmonary mannheimosis

Answer 41

• shipping fever
• cause = mannhemima haemolytic biotype A, serotypee 1
  1. bacteria release toxins
  2. toxins kill macrophages + neutrophils
  3. cells release TNF, IL-1, IL-8 + histamine
  4. necrosis of alveolar + bronchial epithelium
• macro = acute resp disease, severe fibrinous bronchopneumonia + fibrinous pleuritic + pulmonary sequestration
• micro = severe fibrinous bronchopneumonia, BALT hyperplasia
• conseq = death in acute phase, severe toxemia + scars
• maybe secondary bacterial infection to IBR

Question 42

hypothyroidism

Answer 42

• decreased secretion of thyroid hormones
• decreased Bmr = gain in body weight w/o changes in appetite
• increased cholesterol = atherosclerosis, hepatomegaly
• neoplasms/lymphocytic thyroiditis
• symmetric alopecia, hyperkeratosis, hyperpigment

Question 43

mega esophagus

Answer 43

• dilation due to insufficient/absent/uncoordinated peristalsis
• cause = innervation/denervation disorders, physical obstruction, stenosis
• congenital form = persistent R aortic arch, vascular ring prevents full dilation of oesophagus (cranial to heart)
• acquired = failure of relaxation of cardiac pshinceter of stomach dilation (cran to stomach)
  = idiopathic or secondary to polymyositis, myasthenia gravis or hypothyroidism, lead and thallium posioning
• increased risk = GSD, Irish setter + golden retreiver
• signs = regurgitation

Question 44

pancreatitis

Answer 44

• necrosis + variable inflammation of pancreas
• cause = obstruction of ducts - parasites, direct injury, toxins, trauma, ischemia and disturbances of enzyme trafficking within cytoplasm
• types acute and chronic

acute
= most common in dogs
- macro = oedematous pancreas, haemorrhage, necrosis and fat necrosis, peritoneal cavity contains blood-stained fluid, fibrinous adhesions - peritonitis
- micro = focally extensive haemorrhage, leukocytes influx + necrosis. 2 syndromes in cats: 1. acute pancreatic necrosis 2. suppurative pancreatitis
chornic
= all species due to obstruction of pancreatic ducts
- fibrosis + parenchymal atrophy
- in dogs there’s progressive destruction of pancreas by repeated mild episodes of acute pancreatic necrosis and pancreatitis
- macro = distorted shrunken nodular mass with fibrous adhesions to adjacent tissue

Question 45

strangles

Answer 45

• cause = strep equi
• pathogen: susceptible horse comes into contact with feed, exudate or air droplets containing bacteria. Bacteria penetrates nasal mucosa + drain to regional L.N
• macro = mucopurulent rhinitis, enlarged L.N, maybe purulent lymphadenitis
• consequence = bronchopneumonia, laryngeal hemiplegia + guttural pouch empyema
• bastard strangles = hematogenous spread of bacteria which causes metastatic abscesses elsewhere and is often fatal

Question 46

suppurative lymphadenitis

Answer 46

• suppurative inflammation of L.N
• cause = strep equi (strangles), porcinus + cornyebacteriu pseudotubulerculosis
• pathogen: L.N becomes infected after completing drainage of area affected by inflammation C. pseudotuerculosis
• macro = L,N enlargement due to accumulation, tissue protrudes on cut surface + is v. wet
• micro = neutrophil infiltration followed by macrophages, infection with C. pseudotuberculosis there’ll be eosinophils
• consequence = strangles= guttural pouch empire,a dysphagia

Question 47

pyelonephritis

Answer 47

• inflammation of renal parenchyma + renal pelvis
• usually from ascending tract infection
• more frequently in females
• cause- E.coli, klebsiella, stap, strep
• cow = corynebacterium renale, trueperella pyogenes
• pigs = actinobaculum suis
• urinary obstruction from any cause leads to urinary stasis
• macro = pelvic inflammation with extension to renal parenchyma unilateral but more often bilateral
• micro = transitional epi necrotic + sloughed, dilated tubules, intense neutrophils infiltrate, hemorrhage, edema

Question 48

osteoporosis

Answer 48

• skeletal disroders characterised by decreased bone mass + fractures
• imbalance between bone formation and resporption
• osteopenia = decreases bone mass but no clinical disease
• pathogen bone resorption exceeding bone formation
• cause = lack of physical exercise, malnutrition, prolonged, corticosteroid use + hyperadrenocorticism
• consequence = pain + fractures
• macro = decreased number + thinner trabecular cortex is thin + porous

Question 49

acute tubular necrosis

Answer 49

• most common cause of acute renal failure
• injury resulting in the death of tubular epithelial cells or ischemic damage
• cause = heavy metals, drgugs, plants or antifreeze
• macro = white - tan cortex (pale kidney)
• micro= pyknotic nuclei, swollen/granular cytoplasm, cellular casts + hyaline casts
• signs = oliguria

Question 50

excitoxicity

Answer 50

• mechanism often involved in develop of neuronal necrosis
• based on action of neuroexcitatory transmitter
• initial injury -> persistent activation of glutamine receptor of affected neurones -> influx of extracellular Ca ions -> impaired mitochondrial functioning + develop of COs -> damages lipid membranes of nerves

Question 51

feline leukemia virus

Answer 51

• retrovirus - causes feline lymphoma development
• FeLV + = younger cats, mediastinal + multi centric form of lymphomas + T lymphocytes origin
• FeLV - = older cats, alimentary form and B lymphocyte origin
• most are now FeLV- due to vaccination programmes
  1. cats become infected with virus through bodily fluids
  2. virus ingested/inhalded and deposited in mucous membranes
  3. virus replicates locally in mucosal epi cells
  4. virus spreads in macrophage + lymphocytes through lymphatic vessels to regional L.N
• macro = diffuse nodular enlargement of L.N, cut surface is short, white + bulging + loss of normal architecture
• micro = loss of architecture
• clinical signs depend on location of lymphoma
• consequences of FeLV infection = lymphoma formation

Question 52

rabies

Answer 52

• cause lyssavirus genus in rhabdovirdae family
  1. after bite, virus replicates in local myocyte
  2. enters nerve by nicotinic acetylcholine receptors
  3. transported to dorsal root ganglion
  4. enters spinal cord -> travels to Brian with ascent and descent tracts
  5 infects brain + spreads amoung neurones
  6. infects the eye + salivary glands through antegrade axonal transport
  7. secreted in saliva
• 1st centripetal spread (to brain), then centrifugal (away)
• macro not often
• micro. = lymphomonocytic meningeoencephalitisis, intracytopplasmic eosinophilic inclusions + spongiform lesions
• stages = prodromal + paralytic
• types: furios and dumb

Question 53

papillomavirus

Answer 53

• species and site specific pathogens
• infects epithelium through deficits and enter basal layer
  3 outcomes
  1. virus remains in DNA episome - in nucleus, out of chromosome, replication but no more change
  2. basal cell matures -> virus converts to productive infection with typical morphological changes
  3. virus becomes integrates into genome of host cell, causing malignant transformation and neoplasia, activate p53
• BPV1 + 2 infect fibroblasts -> fibropapilloma

Question 54

feline infectious perionitiis

Answer 54

• cause = FIPV, form of feline enteric coronavirus
  1. cats ingest virus either through contact with contaminated faeces or with carrerir cats
  2. feline enteric coronavirus, replicates in enterocyte + causes diarrhoea or is asymptomatic
  3. virus mutates, replicates in macrophages + causes systemic infection
  4. strong cell mediated response, replication is stopped + no disease
  5. if weak cell- mediated response = “dry” non effusive form
  6. if no cell-mediated response, just humour = “wet” effusive
  7. type IV hypersensitivity, develop antigen-antibody complex
  macro = granulomas/pyogranuloma in lungs, kidney + brain, wet = accumulation of viscous yellow transudate
• micro = phlebitis
• consequence = granulomatous pneumonia

Question 55

sarcoid

Answer 55

• caused by papillomavirus
• BPV 1+ 2
• locally aggressive, non metastatic fibrobalstic tumour of horse
• frequently in areas subjected to trauma
• occuli - slow growing, slightly thickened, rough alopecia
• verrucous - slow growing, wart-like
• nodular = firm masses
• fibroblastic = raised, ulcerated surface -proud flesh like
• mixed = more than 1 clinical form, can become more aggreisve
• malevolent = deeply invasive + aggressive
• micro = biphase tumour, epidermal and dermal components

Question 56

equine infections anaemia

Answer 56

• cause = EIA virus of family lentivirus mechanically transmitted by biting flies
  1. virus infects monocytes which then become macrophage
  2. macrophage produce inflammatory chemo+cytokines
  3. arrival of new monocytes and lymphocytes then infected/destroyed
• macro = anaemia, jaundice, hepatomegaly
• micro = sub capsular bleeding, phagocytose RBC, hemosiderin
• consequence = acute period of fever, depress + thrombocytopenia potentially fatal but usually subsides within a year + then horse becomes lifelong carrier

Question 57

immune mediate myositis

Answer 57

polymyositis
- cause = no specific maybe ehrichia Canis
- signs = pain and increase serum muscle enzyme
- temporal + masticatory muscles most obviously affected
- micro = inflame cells - lymphocytes, necrotic fibres
masticatory myositis of dogs
- progressive destruction of masticatory muscles within eventual fixation of jaw.
- cause = humoral antibody response against type 2 myosin
- lesions are bilateral symm
- acute = swelling and areas of haem,
- chronic = atrophy + fibrosis
extra ocular muscle myostisi
- immune mediated attack directed speficially at extra ocular muscles
- acute onset of bilateral exophalmos
- golden retriever’s presupposed

Question 58

photosensitisation

Answer 58

• caused by UV ray
• activation of photodynamic sub in skin with UVA -> ROS formation + mast cell degranulation -> inflammation mediators + damage of cell membranes, nucleic acids, proteins and orgaellles
• type 1 = ingestion of photodynamic substance in platns/ medicine. Most commonly effects herbivores, plants contain hypericin which turned into photo reactive products in intestine - St John Wart
• type 2 = abnormal metabolism of porphyrin - so accumulation
• type 3 = hepatogenous - decrease liver cap to exclude phylooerythrin occurs secondary to liver damage (toxic plants) mostly herb
• macro = areas of unpigmented skin ,parachute developemed
• micro = coagulative necrosis of epidermis, fibrinoid vascular degeneration and secondary bacterial infection

Question 59

juvenile panhypopituitarism

Answer 59

• GSD, spitz, toy pinshcer
• autosomal recessive disease in GSD
• defect in LHx3 gene depletion in exon 5 -> low GH, TSH, prolactin + gonadotropin, ACTH, normal or low
• low activity of IGF and somatomedin
• symptoms = slow/subnormal growth, retention of wooly puppy coat, bilaterally symmetrical alopecia

Question 60

equine recurrent uveitis (moon blindness)

Answer 60

• repeated episodes of uveitis - periods of active inflammation alternate with periods of quiescence
• cause = unknown, correlation btwn disease + leptospirosis infect
  1. antibodies against leptospirosis cross react with equine cornea, lens and retina
  2. episode spreading occurs when immune-mediated damage to tissue exposes antigens previously unrecognised
  macro = glaucoma/cataracts
  micro = primary lymphoplasmacytic uveitis, secondary = cataract and retainal ablataion
• consequence = glaucoma and blindess
• episodes of uveitis tend to increase in severity leading to cumulative damage

Question 61

BVD

Answer 61

• cause = pestivirus
• young adults - sporadic, high mortality
• if infected in utero with non-cytopathic biotype = mummification, abortion, congenital abnormalitlies
• infected with NCP after 4 m gestation of v. early in life = persis infected calf due to immunotolerance, if exposed CP = mucosal disease
• macro = multifocal, sharply demarcated ulcers in tongue, palate, esophagus, rumen + coronary bands of hoof
• micro = foci of necrosis in epi over GALT, ulcers, lymphoplysis
• signs = anorexia, watery diarrhoea, pyrexia
• calves affected in utero = cerebellar hypoplasia, cataracts
• consequence = more susceptible to mannhiemosis - transmission = inhalation, ingestion

Question 62

rickets and osteomalacia

Answer 62

• failure of mineralisation with subsequent bone deformities in young (rickets) and old animals (osteomalacia)
• caused Vit D deficiency, phosphorus deficiency
• consequence = bone pain, path fracture + deformities

rickets
= osteoid formed but no mineral deposited, v. long growth plates and fibrous tissue
- macro = growth plate enlarged and widedned

osteomalacia
= osteoid laid but doesn’t mineralise ,cortical bone soft and deformed
- micro = excessive osteoid

Question 63

wallerianc degeneration

Answer 63

• changes occurring in nerve after axon transection/breakdown in PNS and CNS
• changes proximal to site of injury = central chromatolysis
• changes distal from injury site: wallerian degeneration
• axonal swelling + fragmentation of myelin
• CNS = process is slower, very limited regernation
• PNS = not too much gap between occlusion and if endoneural tubes are preserved there’s good prospects for regeneration

Question 64

leptospirsosis

Answer 64

• haemolytic anaemia in calves, lambs and pigs
• L. interogans servers pomona + icterohemorrhagiae
• immune- mediated hemolysis- > extravaccular hemo
• phospholipase from bacteria -> intravascular hemolysis
• infection through skin/mm -> leptospirosis -> localisation of bacteria in kidneys/ pregnant uterus
• dogs - differential diagnosis from babesia

Question 65

uremia

Answer 65

• pathologic manifestation of renal failue
• pre-renal (decreased renal perfusion, decreased blood flow, systemic circulatory disorder), intrarenal (infection + toxins), post renal (urinary obstruction)
• presence of urinary products in blood and toxic condition caused by these
• these animals would be azotemic
• non-renal lesions = endothelial degeneration + necrosis >infarct + secondary thrombosis -> ulcer formation
• cause = renal secondary hyperparathyroidism + renal osteodystrophy

Question 66

infectious feline rhinotracheitis

Answer 66

• FeHV-1
• spread by sneezing or contaminated objects. Multiplies in nasal cavity and upper respiratory -> loss of cilia in trachea
• macro = mouth sores, inflammation of cornea

Question 67

tumour in CNS

Answer 67

1. embryonal/primitive neoplasia
2. medulloblastoma
3. astrocytoma
4. choroid plexus papilloma and carcinoma
5. ependymoma
6. oligodendroglioma
7. meningioma
8. peripheral nerve sheath tumour

Question 68

feline calicivirus

Answer 68

• upper resp tract
• virus infected and replicated in mucosal epithelial cells, then spreading via lymph vessels, then spread to pulmonary alveolar macro + synovial macrophage
• macro = mucopurulent conjunctivitis, rhinitis
• spread by sneezing or contaminated objects

Question 69

liver cirrhosis

Answer 69

• end stage liver - irreversible change characterised by diffuse fibrosis
• causes = chronic toxicity, chronic congestion + abnormal metabolism of copper
• macro = loss of hepatic parenchyma, distorted nodules separated by fibrous bands
• micro = capillarisation of sinusoids and acquired portosystemic shunt
• consequences = hepatic failure

Question 70

renal fibrosis

Answer 70

• replacement of renal parenchyma with mature fibrous CT
• cause = infarction, glomerulonephritis + TI
  = macro = pale, shrunken and pitted kdiney
• micro = increase in interstitial CT, absence of renal tubules
• consequence = fibrous osteodystrophy and renal secondary hyperparathyroidism

Question 71

Epitheliogenesis imperfecta

Answer 71

• incomplete development of skin epithelium
• cause = inherited genetic mutation
• macro = sharply demarcated areas without epidermis > exposed, red, moist dermis
• micro = no epidermis
• consequence = tissue is easily traumatised leading to bacterial infection and bacteremia > death from infection of dehydration and electrolyte imbalance

Question 72

Malignant catarrhal fever

Answer 72

• cause = rhadinoviruses, ovine herpes 2
• transmission = aerosol
• lesions = erosions/ulceration of mucosa, corneal opacity lymphadenomrgaly
• consequence = fatal

Question 73

Free Martin

Answer 73

• blood vessels from placentas from 2 different Fetus fuse and exchange blood between 2 fetuses, so each becomes haematopoietic chimera
• free Martin = female out of a set of male and female twins
• macro = small ovaries, hypo plastic vagina, vestibule and vulva
• micro = Sertoli cells + seminiferous cordlike structures in ovaries

Question 74

Ocular neoplasm

Answer 74

• feline diffuse iris melanoma
• feline post traumatic ocular sarcoma
• equine intraocular melanocytic neoplasia
• canine uveal melanocyte neoplasia
• irridocilliary adenoma
• meibomian gland adenoma/ epithelioma

Question 75

swine dysentery

Answer 75

• cause = brachyspira hyodysentenae + anaerobic bacteria
• macro = bloody faeces, haemorrhage, fibronecrotic pseudo membrane in intestines
• micro = spirochetes in lumen of intestine

Question 76

Feline calcivirus

Answer 76

• upper resp tract
• virus infects + replicates in mucosal epithelial cells, then spreading via lymph vessels, then spread to pulmonary alveolar macro and synovial macrophage
• macro = mucopurulent conjunctivitis, rhinitis
• spread by sneezing or contaminated objects

Question 77

Adenomyosis

Answer 77

• presence of endometrium within myometrium
• cause = forced in by pregnancy/pyometra/soo migrates
• macro = localised thickening of myometrium
• micro = endometrial gland within myometrium

Question 78

Classic swine fever

Answer 78

• hog cholera
• cause = pesto virus (RNa virus)
• patho
  1. Virus inhaled from direct contact with infected pigs or ingestion of undercooked infected pork
  2. Virus selectively damages endo cells of immune system and epi
  3. Haemorrhaged lesions due to increased vascular permeability, DIC
• macro = widespread petechial haemorrhage, spleen, skin and L.N, button ulcers on colonic mucosa
• micro = hydrophilic degeneration of endoethelial cells, fibrinoid necrosis + fibrin deposition
• consequence = death

Question 79

Malignant hyperthermia

Answer 79

• porcine stress syndrome
• cause = autosomal recessive inherited trait
• patho
  1. Genetic defect, causes abnormal activity of Ryanodine receptor
  2. Uncontrolled intracytoplasnkc calcium receptor
  3. Leads to excessive contract and heat produced > triggered by halothane anaesthesia or stress
• macro = increase body temp and severe muscle rigidity
• consequence = pale, soft, swollen muscles - appear cooked (PsE pork)

Question 80

Hydranencephaly

Answer 80

• formation of large fluid filled cavities in the brain
• cause = BVD, orbivirus (blue tongue), Rift Valley fever
• path - virus infects and destroys differentiating neuro lasts and neuro glial cells indevelop Fetus in uterus
• macro = thin walled, fluid filled cysts in cerebral hemisphere
• micro = necrosis of undifferentiated cells surrounding the fluid filled cavities
• consequence = dennervation atrophy of limb muscles, arthrogryposis and non suppurative encephalitis