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Flashcards in Path Lower Urinary Tract Deck (36)
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Diseases of the renal pelvis

> Hydronephrosis

> Pyelonephritis

> Papillary (medullary crest) necrosis


What is hydrnephorosis and what causes it?

- dilation of pelvis d/t obstruction of urine outflow -> atrophy of renal parenchyma d/t interstitial vessels collapsing -> hypoxia and ischemic necorsis
- pdf pyelonephritis if bacteria contaminate
- d/t congenital/urinary calculi/inflam/neoplasia/neurogenic functional disorder
- uni/bi-lateral: if bilateral uraemia can occour before dilation of pelvis


What is pyelonephritis? Which animals is it comonly seen in?

- commonly bilateral, ascending infection (d/t vesicurethral junction failure allowing reflux)
- infection of pelvis with extension into tubules and interstitium (if extends into cortex radially red/grey streaks seen - polar scars)
- endotox form G- bacteria inhibit peristalsis
- cow (sporadic chronic condition) and sow (post-partum 2-3w, acute)
- can extend to surface causing peritonitis


What is seen on histo with pyelonephritis?

- histo: transitional epithelium necrotic and sloughing, bacteria, inflam cells and necrotic shit accumulate in tubular lumen
- if vasa recta obstructed -> papillary necrosis
- extends radially into cortical tubules


What causes papiillary necorsis?

- blood supply comes from cortex through vasa recta so papilla susceptible to ischaemia
- 1* necrosis: NSAID overdose damages medullary interstitial cells d/t v PG synthesis (dehydrated animals and horses especially)
- 2* necrosis: v vasa recta flow d/t glomerular amyloidosis or glomerulosclerosis
- OR compression of vasa recta d/t oedema/fibrosis
- `or compression of renal papilla d/t pelvic calculi, LUT obstruction, pyelonephritis, vesiculoureteral reflux
> necrotic areas can slough and block further down


Disease of the LUT

- developmental
- LUT obstruction
- urolithiasis
- Cystits
- Neoplasia of LUT


What attaches the ureters to the bladder?

- vesiculoureteral valve


How does urine of horses differ to other animals?

- mucous filled causes cloudy urine (rats and rabbits too)


What is the LUT lined by?

Pseudostratified transitional epithelium


How does urine change PM?

- cloudy/red d/t haemolysis


Defence mechanisms of the LUT

- flushing action of urine
- peristalsis to get rid of bacteria with adhesion capabilities
- inhospitable pH
- protective urothelial mucus coating
- innate, humoral and cellular immune repsonses


Responses of the LUT to injury

- dilation and pressure necrosis (onbstruction)
- inflammation
- neoplastic transformation


clinical signs of LUT obstruction

- stranguria
- dysuria
+- haematuria


causes of obstruction

> congenital
- cysts, ureter aplasia, ectopic ureters
> acquired
- calculi
- neoplasia
- trauma/inflam
- circumferential fibrosis
- bladder paralysis
- vaginal/uterine prolapse
- feline urologic syndrome (fine struvite crystals (sand) in mucoid protein matrix fill urethra)


Consequences of obstruction?

- distended/ruptured bladder
- transmural ecchymotic haemorrhage
- mucosal ulceration and hamorrhage
- peritonitis
- inflammation


What is urolithiasis?

- urinary calculi (formed from excretory metabolites in urine, mineral + proteinaceous debris)
- arise at various sites in urinary tract
- urinary obstruction (males)
- larger calculi can form in females
- local pressure necoriss and mucosal ulceration/haemorrhage


Factors that pdf calculus formation?

- urinary pH (struvite and carbonate @ alkaline, oxalates @ acid)
- v water intake
- mineral supersaturiation
- bacterial infection LUT
- structural abnormalities


Where do different species commonly obstruct?

> cattle: proximal sigmoid flexure
- ^ oxalates in pasture
> sheep: urethral process
> dogs: proximal base os penis


Clinical signs of acute cystitis. Most common cause?

- dysuria, stranguria, haematuria
- bacterial infection


Which pathogens are commonly involved in LUT infections?

- uropathogenic E Coli
- Corynebacterium renale in cattl e
- Eubacterium suis in pigs
> Hydrolysis of urea by urease producing bacteria (C renale and E suis) causing ^ ammonia damaging mucosa and ^ urine pH


What is seen at path with acute cystits?

- denuded oedematous mucosa, adherent neutrophils, bacterial colonies, hyperaemia haemorrhage


pdf for acute cystits

- urinary stasis
- infrequent urination
- calculi
- catheterisation
- prolonged Abx use


What are the 3 forms of chornic cystitis?

> diffuse
- thickened mucosa with mononuclear inflam infiltrate
- submucosal fiborsis
- hypertrophy of muscularis
> follicular
- many small red nodules on mucosal surface
- hyperplastic lymphoid cells surrounded by hyperaemia and haemorrhage
- assoc with uroliths
> polypoid
- multiple masses of proliferative connective tissue
- lymphocytes and neutrophils


Which 2 types of serious cystits exist and when are these seen?

> emphysematous cystitis
- in diabtetic animals (glucose enhanes bacterial growth)
- E Coli and C perfringens metabolise, releasing CO2 into bladder
- absorption of gas into lymphatics causes emphysema
> toxic cystitis
- most common cattle following chronic ingestion of bracken fern (ENZOOTIC HAEMATURIA) -> haemorrhage, chronic cystits, bladder neoplasia (transitional cell/sc carcinomas)
- active metabolites of cyclophosphamide (neoplasia and IMD tx)


What 3 types of neoplasia affect the kidney?

- embryonal origin
- mesenchymal
- epithelial


Is neoiplasia of kidney common?

NO rare


How does renal neoplasia present?

- unilateral
- 1* renal tumours highly malignant so usually metastasized by the time you find them


What are tumours of emryonal origin?

- nephroclastomas (common pigs and chicken)
- usually incidental finding at slaughter
- arise from primitive pluripotent tissue in young animals 1


Which types of mesenchymal tumours can occour?

- 1* renal sarcomas rare
- eg. ??fibromas, fibrosarcomas and haemangiosarcomas


Which type of renal tumour is more common?

> epithelial origin
- adenoma (usually incidental at necropsy)
- carcinoma (aggressive, large foci haemorrhage, necoriss, cystic degeneration, usually obliterate ONE POLE of the kidney, paraneoplastic polycythaemia -> ^ EPO)
- transitional cell papilloma/carcinoma (aruse renal pelivs and LUT, can obstruct outflow and invade kidney)