Pathology of the Renal System: Lower Urinary Tract Flashcards
What structures make up the lower urinary system?
- PAIRED URETERS
- URINARY BLADDER
- URETHRA
Most diseases of the LUT are associated with?
- Obstruction and Infection ( can occur at the same time)
What are males more predisposed to when it comes to the urinary system? Why is this?
Males are more prone to obstruction due to urethral anatomy ( long and has sharp turns) Urethra narrows
What are females more predisposed to when it comes to the urinary system? Why is this?
Females are more prone to infection this is due to its proximity to the external environment and proximity to the rectum.
What are the most prominent locations in the male anatomy where urinary obstruction can occur?
- Sigmoid Flexure
- Urethral Process
- Os penis
What is the most important ureteral anomoly?
Extopic ureter
What is an ectopic ureter?
Rather than terminating at the trigone of the bladder, it terminates at the urethra or vagina
How are ectopic ureters usually diagnosed?
Incidental Finding
What does a ectopic ureter predispose the patient to?
-> predisposes them to ascending infection and compression of ureter. This causes an obstruction of the ureter, distention of the renal pelvis, hydronephrosis and UTI-pyelonephritis from the ascending infection.
What is seen in this image?
What is urolithiasis?
Presence of calculi (uroliths or stones) in the urinary passages
What is the most important urinary pathology?
Urolithiasis
What is calculi made of ?
Calculi are aggregates of precipitated urinary solutes, urinary proteins and
proteinaceous debris
Are all cases of urolithiasis related to stones?
No it could be from stones or a plug( urethral debris)
What is calculi?
- Calculi: minerals predominate, round/spherical hard structures
What are urethral plugs?
- Urethral plugs: masses of sandy sludge with a much higher organic component
Will calculi have a higher organic component or would urethral plugs?
Urethral plugs
What causes urolith formation?
Cystitis-> desquamation of epithelium. This sloughed off epithelium is what starts urolith formation.
What are the causes of urolithiasis?
- Defective meabolism of substance (i.e dalmations and urate stones)
- Metabolic diseases (i.e hyperparathyroid/ hypercalecemia)
- High levels of a substance in the diet (sillicic acid in native pastures -> ruminants)
- Infection
- other factors: pH, decreased water intake, urine supersaturation, foreign body (suture, grass awn, catheter)
What are examples of urolith formation due to defective substance metabolism?
- Uric Acid in Dalmations -> urate calculi
- Cystine ( defective proximal tubular resorption from GF)
How do cystine stones occur?
- defective proximal tubular resorption from GF causes high levels of cystine in the bladder which causese calculi formation and sedimentation.
What are examples of metabolic diseases that cause urolithiasis?
Metabolic diseases
- Hyperpathyroidism, hypercalcemia: Calcium oxalate
- Severe liver disease(liver fibrosis)/portosystemic shunts: Ammonium biurate calculi (ammonia not metabolized by liver thus ending up in the urinary bladder and forming stones)
What are examples of high levels of substances in diets that cause urolithiasis?
- High levels of a substance in the diet
- Silicic acid in native pastures, ruminants - Mineral imbalance (calcium, phosphorus, magnesium)
If you have a ruminant (cattle or small ruminants) with urolithiasis then check for diet imbalance.
What is the typical crystals/ stones that form due to infection? What are the animals that are usually affected by this?
Struvite
Dogs ++++++
and Cats
What other factors can affect predisposition to stone formation?
Certain factors are more or less important: urinary pH, reduced water intake, urine supersaturation, foreign body (suture, grass awn, catheter)
If you have a bull with urolithiasis, within the urinary bladder what is most likely your cause?
- High level of a substance
Which dog would be more predisposed to urolithiasis?
a.) Intact female
b.) Spayed female
c.) Intact male
d.) Neutered male
d.) Neutered male
Staph and proteus secrete _____ to induce supersaturation?
(Ureases from Staph/Proteus induce
supersaturation)
Which animal is more likely to be affected by urolithiasis?
a.) horses
b.) cats
c.) pigs
d.) sheep
b.) cats
What breeds of dogs are predisposed to urolithiasis?
Predisposed breeds in dogs: Dachshunds, Dalmations, Cocker
spaniels, Basset Hounds, Poodles, Schnauzers, and small terriers
Where can calcili form in the urinary system?
a.) urethra
b.) renal pelvis
c.) ureter
d.) bladder
e.) all of the above
e.) all of the above
Can form anywhere from the renal pelvis to the urethra
Where is the most common site of lodgement of urethral calculi in cattle?
Cattle: at the ischial arch and at the proximal end of the sigmoid flexure
Where is the most common site of lodgement of urethral calculi in rams?
Rams: at the urethral process (vermiform appendage)
Where is the most common site of lodgement of urethral calculi in dogs?
Dogs: at proximal to the base of the os penis
Where is the most common site of lodgement of urethral calculi in cats?
Cats: along the entire length of the urethra
What occurs to the tissue at the site of calculi lodgement? What can this cause?
At the site in which calculi lodge, there is local pressure necrosis, ulceration of the mucosa, and acute hemorrhagic urethritis/cystitis
Causes: Hematuria and dysuria (straining to urinate)
What can be a risk factor/ result during medical intervention of a urinary obstruction in the urethra ? Why does this occur?
Urethral tear
- Damage to mucosa makes it more friable.
What is seen in this image?
Nephrolith ( goat)
What is seen in this image?
uroliths in bladder of dog
What is seen in this image? What is indicated by the teal, aqua, and sage circles?
Teal: Hemorrhage
Aqua: Calculi, sludge/ sand, and uroliths
Sage: Hydronephrosis
What is seen in this image? What is indicated by the teal, aqua, and sage circles?
Teal: Hematuria
Sage: Hemorrhage and ulceration
Aqua: Calculi
What is the most common crystals in dogs? What is the cause?
Struvite most common in dogs. This is due to infection/ bacteria
What do stones cause on the mucosa of the bladder?
Causes direct damage to epithelium resulting in ulceration and hemorrhage.
What is seen in this image? What is indicated by the teal, aqua, and sage circles?
Sage Line: Ulceration
Aqua: Uroliths
Teal: Hemorrhage
What is seen in this image? What is indicated by the teal, aqua, and sage circles/ lines? What is the likely stone composition if this is a dalmation?
most likely urate calculi due to dalmations defect in uric acid metabolism.
Aqua: urate calculi
Sage: Hemorrhage ( likely more apparent underneath stones)
Teal: Cystitis / ulceration
What is seen in this image? What is indicated by the sage and aqua circles?
Necrosis of the urethral process
Aqua: calculi in the vermiform appendage/ urethral process of a small ruminant
Sage: Gangrenous Necrosis
What is a common complication of cows with a urethral obstruction?
Rupture of the urethra with accumulation of urine in the subcutis
What is seen in this image?
What is seen in this image? What is indicated by the light blue, aqua, purple and seage circles?
This is a goat with a urethral obstruction
Purple: areas of inflammation -> neutrophils -> indicating a suppurative pyelonephritis ascending infection
Sage: distended ureter (hydroureter)
Aqua: pyelonephritis ( exudate present in renal pelvis)
Light blue: Hydronephrosis
What is seen in this image? What is a likely consequence related to the urinary system for animals with this condition?
This is a portosystemic shunt. you can see the hepatic portal vein ( circled in teal) and the new vessels created to help bypass the liver.
The condition that they are at risk for is developing ammonium biurate crystals.
What is the pathogenesis for ammonium biurate crystal formation for pathients with acquired portosystemic shunts?
Quick N dirty: Liver fibrosis -> compression of portal vein -> portal hypertenison -> shunt formed to bypass liver -> shunt connects portal vein to vensa cava to bypass liver -> NH3+ in blood not metabolized (from here there are two consequences) -> NH3 + crosses bbb and causes hepatic encephalopathy, and NH3+ in urine casue ammonium biurate stones.
What are the normal antibacterial properties of the bladder?
- Repeated voiding
- Protective urothelial mucus coating
- Mucosal IgA
- High urea and organic acids
What are the risk factors for infection within the bladder?
- Stagnation of urine (obstruction of urinary flow).
- Incomplete voiding (spinal cord lesions)
- Urothelial trauma
What animal and species is more prone to bacterial cystitis?
Females -> due to closeness of vagina to the rectum/ outside environment
What are the causes of cystitis?
- Bacterial (♀ - ↑cystitis)
- Chemicals (cyclophosphamide)
- Urolithiasis
- Trauma
What is the most common bacteria that causes cystitis?
What are specifc renal pathogens of cattle, pigs, and horses?
What is a chemical cause of cystitis in horses fed hay?
What is the likely cause of the cystitis in this hay fed horse whose bladder is shown below?
What chemotherapy agent has a common side effect of causing hemorrhagic ulcerative cystitis?
Cyclophosphamide
What is the cause of feline lower urinary tract disease?
- Multifactorial condition
- Multiple causes:
- Feline idiopathic (interstitial) cystitis
- Infection
- Uroliths/urethral obstruction
What is seen in this image? What is the cause of these lesions ? ( hint Cat)
What is the risk factors for feline lower urinary tract disease?
Risk factors:
* Middle-aged and neutered cats
* Over-weight and cats which take little exercise
* Cats with little or no access outside
* Cats that eat a dry diet
* Multiple animal households
* STRESS
What is the number one cause of feline cystitis? What is it caused by?
Struvites caused by idiopathic cystitis.
What are the 2 types of chronic cystitis?
- Follicular: Disseminated submucosal lymphoid nodules
- Polypoid: Polyps composed of connective tissue mixed with mononuclear cells
What is the kind of chronic cystitis seen in this image?
follicular
What is the kind of chronic cystitis seen in this image?
Raised from fiberous connective tissue/ Make sure to distinguish polyp vs. mass
What is seen in this image?
Emphysematous cystitis
What is emphysematous cystitis? What is it associated with?
What are the neoplasms of the urinary bladder?
What is the most common neoplasia of the urinary tract?
Transitional cell carcinoma
Where is transitional cell carcinoma typically found in the urinary bladder
Most common is urinary bladder neck and trigone.
What animals are transitional cell carcinomas more common in?
Dogs.
What tumors can be seen in cattle with chronic bracken fern poisoning?
Transitional cell carcinomas, hemangiomas,
hemangiosarcomas
Can see multiple at the same time.
What breed of dog has a predisposition for transitional cell carcinoma? What is it linked to?
Scottish terriers ( any terriers really) linked to lawn pesticides
What percent of these tumors have already metastasized by the time of clinical diagnosis?
40% of these tumors have metastasized by the time of clinical diagnosis
Where do transitional cell carcinomas metastasize to?
Lymph nodes, lung and bone
What are the classifications of TCC? Which has the worst prognosis/ why? Which has the best?
1) Papillary and non-infiltrating - no invasion of the stroma ( Better prognosis)
2) Papillary and infiltrating (most common)
- Rupture of basement membrane leads to invasion of blood vessels and mets.
3) Non-papillary and non-infiltrating (carcinoma in- situ)
- Malignant only in the mucosa. Not infiltrating the sub mucosa.
4) Non-papillary and infiltrating – most common to metastasize (not as good prognosis)
What classification of TCC is being indicated in this image?
Papillary and non-infiltrating
What classification of TCC is being indicated in this image?
Invasive papillary Carcinoma
What classification of TCC is being indicated in this image?
Flat non invasive carcinoma
What classification of TCC is being indicated in this image?
Flat invasive carcinoma
What is seen in this image? What is being indicated by the teal circles?
What is seen in this image?
What is seen in this image? What kind is it?
Transitional cell carcinoma - papillary
What is seen in this image? What is the distribution?
What is the mechanism for the tumor formation from bracken fern posioning?
What virus is involved in tumor formation for bracken fern posioning?
Bovine papilloma virus - 2
What is the toxic principle of bracken fern posioning?
Toxic principle: Ptaquiloside (carcinogenic and immunosuppressive)
What is the most common clinical sign of bracken fern posioning?
Hematuria
What is seen in this image?
What is seen in this image?
What is seen in this image?
What is a botryoid rhabdomyosarcoma? What animals do you usually see them in?
What breed are botryoid rhabdomyosarcomas overrepresented in?
St. Benard
Where does a botryoid rhabdomyosarcoma arise from? what is its origin cells?
Arise at the trigone or bladder neck from embryonic
myoblasts
What can you see clinically with patients with botryoid rhabdomyosarcoma??????????????????
Clinically cause obstruction (In one case - hypertrophic
osteopathy in a dog)
What is seen in this image? (Hint: young dog)
Botryoid Rhabdomyosarcoma
What is seen in this image? (Hint: young dog)
Botryoid Rhabdomyosarcoma
