LUT Pathology Flashcards
components of the LUT
bladder - stores urine
urethra - controls bladder emptying
LUT histological layers
mucosa
muscularis
adventitia/serosa
LUT mucosa
transitional epithelium + lamina propria
transitional epithelium
non-keratinized, stratified epithelium lining the renal pelvis, ureters, bladder, and urethra
distensible - stretches while remaining impermeable
variable cell layers depending on stretch/relaxation
is muscularis layer smooth or skeletal muscle
smooth muscle (detrusor muscle)
LUT muscularis
inner longitudinal
outer circular
outer longitudinal (only in bladder)
LUT adventitia vs serosa
fibrous connective tissue
adventitia: surrounds retroperitoneal structures
serosa: surrounds peritoneal structures
LUT developmental disorders
- duplicated ureters
- ectopic ureters
- patent urachus
- urethrorectal/rectovaginal fistula
duplicated ureters
ureters from the cranial and caudal pole of the kidney do not fuse into one
causes two ureters to exit a single kidney
cranial ureter often ectopic
ectopic ureters
congenital abnormality where the ureter doesn’t terminate at the trigone of the bladder
can be intra or extramural
ID’d in young (3-6 months) animals
clinical sign: urinary incontinence
intramural ectopic ureter
ureter enters at the trigone but tunnels through the bladder wall and terminates in the urethra
extramural ectopic ureter
ureter bypasses the trigone entirely and terminates directly into the urethra
patent urachus
urachus (the tube between the bladder and umbilicus during fetal development) does not close after birth, creating a channel between the bladder apex and the umbilicus
urine drains out of umbilicus
predisposes to infection and rupture (uroperitoneum)
partial closure –> urachal cysts w/ metaplasia
urethroectal/rectovaginal fistula
abnormal connection between the urethra and rectum or rectum and vagina causing urination from the rectum
urolithiasis
solid formations composed of organic and mineral matrix (calculi, stones, uroliths) along the urinary tract
risk factors for uroliths
diet
mineral accumulations in forage
infection
breeds
urine pH
water intake
anatomic barriers
what can urolithiasis and hydronephrosis predispose an animal to
pyelonephritis
urethral obstruction
blockage in the urethra
are urethral obstructions more common in males or females
males - longer urethra
what can urethral obstructions/uroliths cause
- pressure necrosis leading to ischemia
- ulceration of the mucosa
- cystitis and pyelonephritis (due to urinary stasis)
- hydronephrosis + hydroureter
vermiform appendage
narrowing of the distal urethra in small ruminants
frequent site of obstructions in goats
what are most common sites of obstruction in goats
vermiform appendage
sigmoid flexures
nephroliths
kidney stones
cystoliths
bladder stones
what are some consequences of UT obstruction
- severe cystitis (necrotic, hemorrhagic, inflammation, ulceration)
- ruptured bladder
- uroabdomen
- hydronephrosis (can be caused by any obstruction, not just uroliths)
- progressive renal atrophy
types of LUT inflammation
ureteritis
cystitis
ureteritis
inflammation of the ureters
(rare w/o concurrent cystitis)
caused by calculi in bladder
cystitis
inflammation of the bladder (main site of LUT inflammation)
causes: bacterial, fungal, viral, drugs
does cystitis occur more in males or females
females due to shorter urethra
what type of cells predominate in acute cystitis
neutrophils
what type of cells predominate in chronic cystitis
mononuclear cells
follicular cystitis
proliferation of lymphoid tissue
polypoid cystitis
overgrowth/folds of mucosa into bladder lumen
emphysematous cystitis
gas filled inflammation of the bladder caused by gas production by glucose-consuming bacteria
occurs with diabetes mellitus (causes glucosuria)
bladder defense against infection
micturition
hydro kinetic washout
peristalsis in ureters
urine pH
glycosaminoglycan coating
urothelial cell shedding
immunoglobulins
what is the most common LUT neoplasia
transitional cell carcinoma
(epithelial)
transitional cell carcinoma
urothelial cell carcinoma; proliferation of the transitional cell layer
can be infiltrative or non-infiltrative
bracken fern toxicosis mechanism
bracken fern contains ptaquiloside toxin
chronic consumption of bracken fern –> hemorrhagic cystitis –> persistent hematuria, anemia, UT neoplasia
ptaquiloside
glycoside toxin
myelodysplastic and carcinogenic
what species does bracken fern toxicosis occur in
cattle
some sheep
what type of calculus gives sabulous cystitis its sand-like texture
Calcium carbonate in horses
most common site of LUT obstruction in cats
within penis
most common site of LUT obstruction in cattle
sigmoid flexure
ischial arch
most common site of LUT obstruction in dogs
proximal os penis
most common site of LUT obstruction in horses
kidney
urinary bladder (sand-like cystitis)
most common site of LUT obstruction in pigs
kidney
most common site of LUT obstruction in sheep/goats
urethral process (vermiform appendage)
sigmoid flexure
what type of epithelium lines the LUT
transitional epithelium
urine dribbling from the umbilical remnant of a neonate likely has what developmental abnormality
patent urachus
a neonate with urinary incontinence is likely to have what developmental abnormality
ectopic ureter
where should the ureter enter the bladder
trigone
LUT defense mechanisms
micturition
hydro kinetic washout
peristalsis in ureters
urine pH
shedding urothelial cells
LUT risk factors
glycosuria
corticosteroid administration
obstruction
catheterization
what lesions can cause hydronephrosis
urolithiasis
prostatic carcinoma
ureter ligation during spay
trigonitis
urethral stricture
all cause obstruction of the urethra –> hydronephrosis
acute cystitis gross appearance
hemorrhagic, swollen
follicular cystitis gross appearance
small, diffuse nodules
histology: dark blue lymph aggregate
polypoid cystitis
white/suppurative discharge
histology: folds of mucosa into the lumen
what renal function controls the amount of urea entering the proximal tubule
glomerular filtration rate
what stain is used to detect amyloid
congo red
what does basement membrane thickening cause
proteinuria
