Urinary Tract Flashcards
Normal kidney anatomy:
right kidney more cranial and in contact with the caudate process of the caudate lobe of the liver
Kidney structures:
Where are the kidneys normally found in the canine patient? What is their size like? Shape?
- L = T13-L2
- R = more cranial and under the ribs, T10-13 with visibility dependent on body fat
2.5-3.5x length of L2 on VD
kidney bead shape with smooth, well-defined margins
How does the feline kidney compare to canine?
- left and right kidneys at approximately at the same level, caudal to the ribs
- rounder shape
- 2-3x length of L2 on VD
How is renal size measured?
measure on VD views only, where they will be equidistant from the detector and have equal magnification
Describe the kidneys in these radiographs.
- both are small
- L is more irregular and has a flattened caudal pole, indicative of chronic scarring (likely CKD)
Where are the kidneys found in the regional approach to the abdomen?
retroperitoneum
- kidneys
- adrenal glands
- ovaries
Differential diagnoses for renal disease:
When are the ureters visible on radiographs?
- containing ureteroliths
- dilated with obstruction or chronic infection (can be mistaken for GI segments)
not normally visible!
What are the 3 causes of visibility of the ureters on radiographs?
- LUMINAL - ureteroliths, cells, debris
- MURAL - neoplasia (TCC), infection, inflammation
- EXTRAMURAL - ligation, compression
What is seen on this radiograph?
uroliths within the kidneys and ureters
What fake out can look like a ureterolith?
deep circumflex iliac artery/vein
What is the normal anatomy of the adrenal glands?
- R = near caudal vena cava
- L = near ascending aorta
- both craniomedial to kidneys
not seen if normal
What contrast is commonly used for excretory urography?
POSITIVE metal opaque iodinated contrast media
- safe IV injection
What are 3 contraindications for performing excretory urography?
- dehydration = contrast-induced renal failure
- renal disease = BUN > 75 results in poor opacification
- anaphylaxis
How excretory urography be performed in patients with renal disease? Why is this not common?
can increase dose 2x
- can further reduce renal function
- can increase risk of renal toxicity and systemic reactions
What are the phases of excretory urography?
NEPHROGRAM
- vascular phase where the cortext of the kidney is more opaque than the medulla (5-10 s)
- tubular phase where the kidney quickly becomes uniformlu opaque
PYELOGRAM - opacification of the collecting system (pelvic diverticulae, renal pelvis, ureter)
What option for excretory urography is safest?
non-ionic iodine - less hyperosmolar, less movement of water into the vascular space
What occurs after administering contrast for excretory urography?
- IV injection
- excreted by functional kidneys
- concentrated in renal parenchyma
- excreted through renal pelvis and ureters
- collects in urinary bladder
What 4 things does excretory urography allow us to visualize?
- renal size, locations, and shape
- filling defects
- crude estimate of renal function
- ureteral location
Interpret this excretory urogram sequence.
- nephrogram vascular phase - vessels well-visualized
- nephrogram tubular phase - kidney cortex more opaque
- early pyelogram - renal pelvis and ureter more opaque
- delayed pyelogram - kidney less opaque, contrast in collecting system
Interpret the function of the kidney based on this excretory urogram.
- difficult to observe kidney
- kidney becomes ore opaque in the beginning of the nephrogram
- reduction in kidney opacity with more accumulation of contrast in pelvis
- reduction in kidney opacity with more accumulation of contrast in ureters
- larger decrease in kidney and collecting system opacity
normal function, contrast is moving through the renal system and being excreted
How is hydronephrosis seen on excretory urograms?
dilation of collecting system (diverticular, pelvis, and ureter) typically due to ureteral obstruction
How does pyelonephritis appear on excretory urograms?
chronic infections seen as irregular renal margins with mild pelvic dilation
- not as intense as hydronephrosis
What is seen on this excretory urogram?
- ureter dilation and tortuosity
- likely due to obstruction due to the ectopic nature of the L ureter - connection not at trigone, more caudal within the pelvis
What are possible causes of bilaterally enlarged kidneys?
- bilateral obstruction: uteretoliths
- lymphoma: markedly enlarged, round, smooth, well-defined
- FIP: mildly enlarged
- polycystic kidney disease: irregular marginated with lobular borders
- pyelonephritis
What are possible causes of bilaterally small kidneys?
- CKD: cats, older patients
- congenital hypoplasia/dysplasia/ aplasia: young patients
What are possible causes of unilaterally small kidneys?
- chronic infarction: irregular margins, scarring (CKD)
- hypoplastic/dysplastic: smooth, well-defined
What are possible causes of unilaterally enlarged kidneys?
GENERALIZED
- ureteral obstruction, hydronephrosis
- stricture
- TCC
- suture
- retrocaval ureter
FOCAL
- neoplasia: renal carcinoma
- renal abscess
Urinary bladder Roentgen signs:
Locate the urinary bladder and prostate.
- UB cranial within caudal abdomen
- both cranial to pelvic rim
What are the 4 most common urinary bladder abnormalities?
- wall thickening by masses or neoplasia - typically not seen due to border effacement by urine
- polyps
- abnormal contents - calculi
- herniation
What is the normal thickness of the canine and feline urinary bladder when it’s filled?
DOGS - 1-4 mm
CATS - 1-2 mm
(not possible to see on plain radiographs - U/S)
How does location of urinary bladder thickening aid with diagnosis?
- CRANIOVENTRAL = cystitis secondary to calculi
- TRIGONE = TCC
- DIFFUSE = infiltrative neoplasia or cystitis
What are the 4 most common urethral abnormalities?
- thickening - TCC, urethritis
- calculi
- dilation
- obstruction
What types of calculi are visible on radiography? Which are not visible?
struvite and calcium oxalate are visible
cystine and urate are not visible (I can’t CU)
In what patients is it uncommon to find the prostate? Where is it normally found?
those neutered by 1 y/o
depends on UB - large bladder can pull it forward into the caudal abdomen
What is being pointed to in this radiograph? Is it pathological?
mineralization of an enlarged prostate gland
- highly suggestive of prostatic neoplasia in NEUTERED male dogs
- non-specific sign in INTACT males, possibly due to neoplasia, chronic prostatitis, or benign prostatic hyperplasia
Prostate, Roentgen signs:
What is occuring in these radiographs?
CAUDAL ABDOMINAL MASS - oval to lobular soft tissue opaque
- dorsal displacement of the colon
- ventral and right displacement of the UB
likely prostatomegaly
What are the 5 major differentials for prostatomegaly?
- DEGENERATIVE: cystic degeneration, chronic inflammation (asymmetrical)
- ANOMALOUS: paraprostatic cysts from the Mullerian duct
- NEOPLASIA: TCC, prostatic adenocarcinoma - look for mineralization and examine LNs and pelvic limbs for metastasis
- METABOLIC: benign prostatic hyperplasia in intact male dogs
- INFECTION: prostatitis +/- mineralization, no osseous involvement
