urinary system notes pt 3

Question 1

Hypoplasia/aplasia of the ureters can result in what?

Answer 1

• if unilateral, usually results in hydronephrosis
  > unless the ipsilateral kidney is also aplastic, in which case it can be clinically silent
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• Bilateral aplasia (or bilateral severe hypoplasia) is obviously not compatible with life

Question 2

arguably the most important developmental abnormality of the ureters

Answer 2

ectopic ureters

Question 3

issues with ectopic ureters

Answer 3

• more prone to obstructions and lack proper vesicoureteral valves (one-way valve found where the ureters normally enter the bladder)
  > animals are predisposed to ascending infection leading to pyelitis and/or pyelonephritis

Question 4

most common abnormality of the lower urinary tract? issues with this?

Answer 4

• patent urachus
  > fetal urachus (connection from bladder to umbilicus) fails to close
• can either rupture (leading to uroperitoneum) or become infected +/- lead to abscess formation (ironically one cause of failure of closure of the urachus is inflammation)
• Urachal patency can also lead to urine dribbling out of the umbilicus in some situations

Question 5

most common urethral abnormalities? issues?

Answer 5

fistulae (urethrorectal or urethrovaginal)
- In males the urethra most commonly communicates with the rectum (and thus dogs pee from the rectum)
- in females it usually opens into the vagina
- altered anatomy increases the risk of urinary tract infections
> but often incidental findings

Question 6

most important condition of the lower urinary tract aside from developmental abnormalities

Answer 6

• inflammation
  > cystitis,
  > ureteritis (usually with systitis)
  > urethritis (usually with obstructive urolithiasis)

Question 7

the common clinical term of cystitis refers to :
(though not really what it should mean)

Answer 7

• clinical syndrome of stranguria and polyuria with or without hematuria
  > There are many causes of disease that result in the clinical signs of ‘cystitis’ without it being infectious or inflammatory

Question 8

bladder - body’s defences for cystitis

Answer 8

• bacteria are usually cleared with the normal flow of urine
• Tamm-Horsfall mucoprotein, which may prevent bacterial adherence by binding to adhesins
• locally produced IgA,
• IgG,
• surface glycosaminoglycans
• urinary oligosaccharides which also interfere with bacterial adherence
• antimicrobial peptides such as cathelicidin
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• desquamation of urothelial cells also helps prevent infection

Question 9

predisposing factors for UTI

Answer 9

• Trauma to the bladder urothelium
• stagnation of urine due to obstruction or incomplete voiding

Question 10

is animal urine a good medium for bacterial growth? why?

Answer 10

• not a good medium for bacterial growth due to its acidity and high osmolality
  > (unlike human urine)

Question 11

The majority of bacteria causing cystitis come from where?

Answer 11

• up the urethra, and most of these are originally from the rectal flora

Question 12

common types of bacteria implicated in cystitis for all species

Answer 12

• E. coli
• Proteus vulgaris,
• streptococci
• staphylococci

Question 13

Feline lower urinary tract disease (FLUTD) can be associated with:

Answer 13

• UTIs (viral, bacterial, or fungal origin)
• uroliths,
• urethral plugs
• congenital or anatomic defects of bladder or urethra
• or iatrogenic

Question 14

Idiopathic cystitis
- what is it? possible pathogenesis?

Answer 14

clinical signs of cystitis without infections, no uroliths (macro or microlithiasis), or history of urethral obstruction
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- Damage to the lining of the bladder and loss of the locally produced glycosaminoglycans that normally stop urine imbibition into the submucosa
> edema and hemorrhage, and erosion of the epithelium
> elf- perpetuation of the process
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- Initial damage may be due to:
> infection (infectious/bacterial cystitis)
> urolithiasis
> urethral obstruction
> chemical (cyclophosphamide, bracken fern)
> unknown
- Grossly, all have a swollen and sometimes hemorrhagic mucosa.

Question 15

Lymphonodular cystitis
- what is this?
- gross appearance

Answer 15

• lymphoid follicular hyperplasia in chronic infectious cystitis
• Grossly, the mucosa is covered with myriad small (~ 1 mm) grey-white nodules that occasionally are surrounded by hyperaemic mucosa
  > nodules are composed of proliferating lymphocytes

Question 16

Polypoid cystitis
- what is it?
- gross appearance?
- possible negative outcomes?

Answer 16

• Chronic cystitis with multiple polyps can be seen commonly in any species
• Grossly the mucosa is folded and/or forms villus-like projections
  > polyps are composed of a core of proliferating connective tissue with numerous mononuclear leukocytes overlain by a layer of epithelium
• if chronic > fibrosis can develop
• chronic insults to polyps can provide background for urothelial cell carcinoma to develop
• lesions can ulcerate > hematuria, obstruction

Question 17

Bovine enzootic hematuria
- what is it?
- what problems does it cause?

Answer 17

• Chronic ingestion of bracken fern > hematuria
  > with a hemorrhagic mucosa (‘cystitis’) and papillomas, fibromas, hemangiomas, and/or their malignant counterparts, urothelial (transitional) cell carcinoma and hemangiosarcoma
  > Malignant forms can be locally invasive, but only 10 % of the epithelial tumours metastasize
  > regionally problematic

Question 18

Lower urinary tract tumours
- how common
- species?
- what type is most likely?
- type of disease / signs caused?

Answer 18

• uncommon
• dogs, cats, and cattle (enzootic hematuria)
• most common = urothelial cell carcinoma (UCC) aka transitional cell carcinoma (TCC)
  > often are invasive and metastatic
  > systemic disease with a silent primary
  > can obstruct (esp in bitch)

Question 19

epithelial tumours of the urinary tract other than UCC

Answer 19

• adenomas
• papillomas
• adenocarcinomas
• squamous cell carcinomas (SCC)

Question 20

urinary SCC’s vs UCC’s - metastasis

Answer 20

Urinary SCCs are reported to be less likely to metastasize than UCCs.

Question 21

Stromal tumours of the urinary tract
- what types
- malignancy?
- who is affected?
- usual signs / issues?

Answer 21

• leiomyomas and fibromas
  > malignant counterparts very rare
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• Botryoid (like a bunch of grapes) rhabdomyosarcoma occurs in the urinary bladder, most commonly in young large breed dogs, especially St. Bernards
  > The tumours often cause obstruction and are usually identified because of the clinical signs of obstruction
  > If not diagnosed early, can metastasize
  > botryoid rhabdomyosarcoma has been associated with hypertrophic osteopathy