Urinary tract surgery - investigation of UT dx

Where are the kidneys located?

• Sit in the retroperitoneal space

• R more cranial than left

• Both covered by thin capsule

What history would you take when investigating urinary disease?

• Complete history incl. signalment & prev. tx

• Onset/duration of clinical signs

• Progression of clinical signs

• Drinking and urination changes

• Previous therapy (response)

What are the clinical manifestations of urinary disease?

• Haematuria                              

• PU/PD

• Dysuria (pain on urination)

• Pollakiuria (multiple frequent urination)

• Stranguria (straining to urinate)

• Oliguria (reduced urine output)

• Anuria (absence of urine)

• Nocturia (getting up in the night to urinate)

• Incontinence

• Lethargy

• Collapse

• Pyrexia

• Weight loss

• Vomiting or diarrhoea

• Abdominal or lumbar pain

What imaging techniques can you use when investigating urinary disease?

• Radiography

• Contrast radiographic studies (using air / radiopaque contrasts)

• Ultrasound

• Advanced Imaging

  • CT, MRI

  • Cystoscopy

What is assessed in plain radiography?

• 2 orthogonal views —> R or L lateral + ventrodorsal

• Size

• Shape

• Location

• Number

• Margination

• Opacity

Describe the features of the kidney in survey radiography

• Retroperitoneal

• R more cranially (cranial pole T13)

• L L1-L3

• Length

• Dogs —> 2.5-3.5 x L2 length

• Cats —> 2.4-3 x L2 length

Describe the features of the bladder in a dog or cat in survey radiography

• Dogs

  • Entirely intraabdominal, or intrapelvic neck (females may be more likely to have urinary incontinane)

  • Os penis present

• Cats

  • Consistently intrabdominal neck

What is being shown in this radiograph and what are the possible causes?

• Enlarged kidney —> increased soft tissue opacity in kidney

• DDX = Cysts, haemorrage, abscess, neoplasia, granulomatous inflam, hydronephrosis

• Metastasis of neoplasia (smaller circles)

What is being shown on this radiograph?

• Mineralised calculi opacities present within the bladder lumen

• Urethra has been collimated out of the radiograph —> retake radiograph to see if mineralised calculi is along length of urethra

What is being shown on this radiograph?

Enlarged prostate (benign prostatic hyperplasia?)

What are examples of negative contrast agents?

• Make things more black

• Room air

• Carbon dioxide (ideally —> don't cause an embolism)

What are examples of positive contrast agents?

• Make things more radiopaque

• Iodine-based

When carrying out retrograde urethrography/vaginourethrography, why do you need to collect the urine sample first?

What else should you do prior?

Will change urine results otherwise

(starve patient and give enema 2-3hrs before)

When would you carry out intravenous urography?

• Evaluation of kidneys and ureters

• Indirect assessment of renal function

• Investigation of uroabdomen

• Investigation of urinary incontinence

• Investigations of upper tract haematuria

What is the process of intravenous urography and when would you not use it?

• Inject contrast agent through cannula and take radiographs sequentially (would go into kidney first)

• Renal failure

• Dehydration

• Hypotension

• Hypovolaemia

What is being shown here after the use of Intravenous Urography?

Ectopic ureter —> the ureter is dilated and is inserting into the urethra rather than the trigone of the bladder

When would you utilise contrast cystography?

• Haematuria

• Dysuria

• Urine retention

• Incontinence

What information does contrast cystography tell you?

• Bladder location and integrity

• Assessment of bladder wall and mucosa (only if double contrast)

• Presence of calculi (depending on opacity)

How is pneumocystography carried out?

• Urinary catheter placement

• Room air or Carbon dioxide injected into the bladder (5-10ml/kg in dogs, 25ml in cats)

• Left lateral recum

• Gently palpate bladder while injecting, stop injecting when bladder feels moderately distended, obtain radiograph —> don’t over-distend bladder!

  

When should you NOT perform a pneumocystography?

If bladder is ruptured, mucosal trauma or haemorrhage —> use positive contrast as more definitive to see

What is being shown here?

Intrapelvic bladder —> irregularly shaped due to surrounding tissues compressing

What is being shown here?

There is a thickened irregular wall —> the bladder hasn’t distended evenly due to fibrosis and chronic cystitis.

When and how would you carry out Positive contrast cystography?

• To localize the bladder and assess integrity (obscures caliculi and we cannot see mucosal detail)

• Place urinary catheter and inject 5-10ml/kg of contrast medium

• Conc. of contrast medium = 150mg/ml, dilute with saline

• Reflux of contrast into ureters due to pressure = normal finding

What is being shown in this Positive contrast cystography radiograph?

• Bladder is small and is caudally positioned

• Mineralised opacity of contrast medium

• Contrast leaking into the abdomen (rupture)

What is being shown in this positive contrast cystography radiograph?

You can see that bladder is abnormally positioned —> due to perineal hernia and the bladder had herniated through the pelvic diaphragm

How do you carry out double contrast cystography?

• Urinary catheter placement

• Empty bladder

• 2-5ml (small patient) 10-20 ml (large patient) of diluted contrast medium (150mg/ml) - important not to inject too much

• Inject gas as for pneumocystography

• Highlights mucosal detail —> can recognise lesions not seen with gas or contrast medium alone

Why would you carry out double contrast cystography?

• Assessment of mucosal lining and looking for radiolucent calculi

• Best assessment of mucosal detail, can recognise lesions not seen with gas or contrast medium alone

What is the double contrast cystography showing here?

• Growth of polyps from bladder wall —> polypoid cystitis

  • Soft tissue of polyps outlined by contrast

• Using folley urinary catheter —> has balloon on end, stops catheter dislodging from UT —> gets stuck @ neck of bladder

What is retrograde urethrography used to investigate?

• Urethral, prostatic, vaginal and penile disease

  • Stranguria or dysuria

    • calculi in urethra?

    • narrowing of urethra? = stricture

    • Urinary obstraction / RTA? —> urethra damaged

How do you carry out retrograde urethrography?

• Catheterise urethra and empty bladder (if possible)

• Pneumocystogram should ideally be performed first. This aids with retention of the contrast in the urethra.

• Prefilled urinary cath with contrast medium, tto remove air bubbles (will look like false filling defect)

• Tip of the foley catheter in the penile urethra

• Take radiographs while injecting (5-10ml, 150mg/ml)

• Take radiographs while injecting

Describe this retrograde urethrography radiograph (dog)?

• Membranous urethra is wider (normal)

• Fabella of femur can look like caliculi so pull legs forward

• No contrast leakage

Describe this retrograde urethrography radiograph (cat)?

• Narrowing

• Strong hollow contrast leading to bladder

• Ureters would have been clearer with IVU

What is being shown here?

• RTA —> femoral #

• Bladder rupture —> leakage of urine into the peripheral tissues

  • cannot see clear bladder outline

  • gas obacity in abdomen, consistent with ruptured ureter

What would you use retrograde vaginourethrogram to investigate?

• Used for females as difficult to catheterise

• Stranguria (e.g. neoplasia, proliferative urethritis)

• Mass lesions within pelvis or vagina

• Urinary incontinence

• Ectopic ureters

How do you perform a vaginourethrogram?

• Insert a Foley catheter into the vulva and dilate the balloon

• Clamp the lips of the vulva using atraumatic forceps

• Inject radiographic contrast material

• Take the radiograph as injecting contrast

What do you identify about the kidneys in an ultrasound?

• Size, shape, internal architecture, renal perfusion (doppler —> highlights blood flow)

• Clear demarcation between cortex and medulla (normal)

• (ureters not normally identified)

• (urethra challenging due to intrapelvic location)

  

What do you identify about the bladder in an ultrasound?

• Wall thickness and layering

• Presence of mass lesions

• Calculi

What is being shown here?

• R = Dilated renal pelvis

• Bottom = dilalted proximal ureter

• L = ureters dilated by couple mms —> obstruction of urinary outflow

What is being shown in this bladder?

Cystolith (bladder stone) —> casting acoustic shadow

What is being shown in these bladders?

L —> thickened wall with a hyperechoic lesion arising from the wall —> consistent with a bladder wall mass

R —> thickened and within the lumen we can see hyperechoic areas which may be a mass or could be blood clots.

How do you use a doppler to tell the difference between a blood clot vs a tumour?

Blood clot has no blood flow, tumour does

What is being shown on this ultrasound?

Normal prostate

What can cystoscopy be used for?

• Diagnosis and treatment of ectopic ureters and other developmental conditions

• Can also be used for removal of bladder stones or to acquire biopsies

What are the advantages and disadvantages of cystoscopy?

+

• Minimally invasive —> patient can go home same day (no surgery required)

• Excellent visualization of urethra and bladder

• Allows simultaneous treatment

-

• Requires additional equipment

• Requires advanced skill —> could overfill bladder or camera could go through bladder

What are the options for biopsies?

• Fine needle aspirates with or without U/S guidance

  • avoid for masses → could leave trail of neoplastic cells in abdomen when needle withdrawn

• Catheter suction samples from the bladder, urethra or prostate

• Surgical —> incisional (part of lesion) or excisional (whole thing)