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Flashcards in Path Lower Urinary Tract Deck (36)

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)


Do tumours commonly metastasise to the kidney

YES esp lymphoma (ats and cattle)
- carcinomas and sarcomas
- randomly scattered multiple nodules
- usually BOTH kidneys
> neoplastic cells form sheets of cells within the renal parenchyma


DDX for pyogranulomatous inflammation centred on blood vessels on the kidney capsule in cats?



Ddx for pale foci of tumour growth in cattle kidneys?



Which neoplasms are seen in the LUT?

- retention of urine ^ exposure time to carcinogen (pdf)
> epithelial tumours
- TCC/TCP (pedunculated, trigone of bladder, can cause hydronephrosis, males pdf, mets to local LN/lung/kidney)
- SCC and adenocarcinomas from transitional epithelium
> mesenchymal tumours
- leimyomas (circumscribed pale firm masses, = normal sm mm)
- fibromas from lamina propria
- lymphoma
- rhabdomyosarcoma (rare tumour of skeletal mm, bladder /urethra young large breed dogs, embryonic myoblasts invovled, botyroid masses protrude into bladder lumen, local invasion, occ mets.)


Outline developmental disorders of the kidneys

> renal aplasia (failure one/both kidneys to develop)
> hypoplasia (incomplete development fewer nephrons or incompete development)
> extopic kidneys (pelvic canal/inguinal position, histo structure and funtion normal but malposition of ureters pdf obstruction and 2* hydronephorsis)
> fused kidneys (cranial/caudal pole - horseshoe shape but structurally and functionally normal)
> dysplasia *MOST COMMON* abnormal differentition
- pdf lhasa apso, shutzu, golden retriver
- progressive juvenile nephropathy (familial dz)
- severe bilateral renal fibrosis
- shrunken pale kidneys, pitted surface: DDX FIBROSIS BY.. foetal glomeruli, interstitial inflammation, fibrosis, tubular dilation
> renal cysts (spherical thin walled distension of cortical/medullary tubules, ddx pelvic hydronephrosis where single pelvis enlarged, in this dz multiple cysts throughout cortex and medulla)
- congenital, 2* renal dysplasia or acquired d/t fibrosis or other renal dz, genetic and toxic causes
- polycystic kidney dz (heritable condition in persian cats and bull terriers)
- large cysts can compress adjacent parenchyma and impair renal function


Developmental anomalies of the ureters and urachus

> ureteral aplasia and hypoplasia
- obstruction - hydronephrosis
> ectopic ureters
- empty into urethra, vagina, bladder neck
- pdf obstruction/infection
- urinary incontinence clinical sign
> patent urachus
- foals
- direct channel bladder - umbilicus
- dribbling urine from umbilicus (d/t underlying omphalitis/congenital urethral obstruction ^ bladder pressure)