what are reasons for an enlarged kidney
FLUID:
- hydronephrosis
- cyst
- perirenal fluid accumulation
SOFT TISSUE:
- hematoma
- neoplasia
MIXED:
- abscess
- hematoma/hemorrhage
what are reasons for a small kidney
- congenital
- acquired (degenerative kidneys)
what are reasons for an indented kidney margin
scarring from an infarction
what are reasons for an expanded kidney margin
- cyst
- tissue proliferation
what are causes of a mildly enlarged, smooth margin kidney
a) UNILATERAL
b) BILATERAL
UNILATERAL
- subcapsular abscess/hemorrhage
- renal neoplasia (- lymphoma)
- compensatory hyperplasia
BILATERAL
- AKI
- acute pyelonephrosis
- amyloidosis
- congenital PSS
- acromegaly
what are causes of a markedly enlarged, smooth margin kidney
a) UNILATERAL
b) BILATERAL
UNILATERAL
- hydronephrosis
- renal tumor
- subcapsular hemorrhage/abscess
BILATERAL
- hydronephrosis
- renal lymphoma
- FIP
- feline perinephric pseudocyst
what are causes of an enlarged kidney with irregular margins:
a) UNILATERAL
b) BILATERAL
UNILATERAL:
- abscess
- hematoma
- granuloma
- cyst
- primary neoplasia
- metastatic neoplasia
BILATERAL:
- polycystic kidney disease
- FIP
- metastatic neoplasia
what are causes of a small kidney:
a) UNILATERAL
b) BILATERAL
UNILATERAL:
- atrophy secondary to obstruction
- CKD
BILATERAL:
- CKD
- developmental hypoplasia/dysplasia
what are the next steps after a tentative diagnosis of kidney disease on radiographs
- US
- CBC
- CHEM
- UA
- UPC
- culture
anytime you see irregular margins in the kidney suspect
infarction
what are DDx for mineralization in the kidneys
- nephroliths
- dystrophic mineralization
what is the normal kidney size on ULTRASOUND in:
- cats
- dogs
CATS: 3-4.3 cm
DOGS: 3-10 cm
what are differentials for a bladder that is not visible
- rupture
- decreased serosal contrast
what are differentials for a displaced bladder
- cranially displaced by an enlarged prostate
- hernia: inguinal, ventral abdominal, perirenal
what are differentials for a bladder with the following opacity changes:
- mineralization
- gas
mineralization: calculi
gas: iatrogenic, gas producing bacteria
what are characteristics of urinary calculi on ultrasound
- intense hyperechoic interface with urine
- generates acoustic shadowing
- generates twinkle artifact
- gravity-dependent
when are you more likely to see twinkle artifact with bladder uroliths
- large stone
- irregular stone
- cysteine
- calcium oxalate
- urate
what are the following types of cystograms best for detecting:
a) positive
b) negative
c) double-contrast
POSITIVE:
- location of bladder
- detecting ruptures
NEGATIVE
- suitable for uroliths
DOUBLE
- mucosal lesions
- intraluminal filling defects
what is a potential complication of doing a negative or double contrast cystogram
gas ascending into bloodstream resulting in an air emboli
when doing a negative or double contrast cystogram how should you position the patient to prevent the risk of an air embolism and why?
left lateral
in right lateral the air with end up sitting at the right ventricular outflow tract and will go to the lungs; in left lateral the air bounces around the right atria which is okay
what are the differential diagnoses for bladder wall lesions and the typical appearance? why can’t we diagnose these on regular radiographs?
a) Inflammation: usually diffuse but if focal will be cranioventrally distributed
b) neoplasia: usually focal and caudodorsal with TCC classically at the neck
both inflammation and neoplasia are soft tissue opacity and therefore silhouette with urine
what view should you take in all male dogs with lower urinary signs
flexed leg lateral projection (butt shot!)
what are indications for doing a urethral contrast study
- stranguria
- cannot pass urinary catheter
- suspected urethral rupture (pelvic fracture, traumatic catheterization)
- hemorrhage when placing catheter
what should not be used when doing a retrograde urethrogram in male or female animals
air or gas -> extravasates into cavernous tissue and makes visualization really challengin
