Path Lower Urinary Tract Flashcards
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)
