CR Billy the dalmation Flashcards
- Billy is a 6 year old male neutered Dalmation
- He has been coming to your practice regularly since he was a puppy for all his routine treatments (worming, microchipping, vaccination).
- Previous history:
- occasional bouts of vomiting and diarrhoea
- some skin problems
- He weighs 22 kg (BCS 3/5)
What is the owners complaint?
Owner complaint: “Billy’s been straining to wee for a few days. Sometimes nothing much comes out. He seems really uncomfortable.”
What did Billy’s clinical exam show?
Clinical exam
- All major body systems WNL
- You think you can feel Billy’s bladder which is approximately 20cm diameter
- Penis normal
- Gait and reflexes normal
Use the SOAP format to record your thoughts on Billy’s case so far:
S: Straining to urinate over the last few days with discomfort
Dysuria (difficult or painful urination)
Pollakiuria (voiding small quantities of urine with increased frequency)
O: We do not have a lot of objective information available from Billy’s physical exam. Students need to discuss the significance of the bladder palpation (20 cm diameter)- how confident are they about bladder palpation in dogs? Does this rule anything in or out? Straining with an empty bladder suggests inflammation (+/or infection), straining with a full bladder suggests obstruction.
A: Students should be considering lower urinary tract disease but may also consider neurogenic dysuria
- D:
- A: perineal rupture/retroflexed bladder, inguinal hernia
- M: conditions predisposing to uroliths (Dalmatians very susceptible to urate stones)
- N: bladder, prostate or urethral tumour (start to think about what types of cancer occur at these sites eg transitional cell carcinoma, prostatic adenocarcinoma)
- I: bacterial cystitis, uroliths (cystic calculi, urethral calculi)- obstructive/non obstructive, (sterile cystitis/urethritis uncommon in dogs cf cats), prostatitis (non neoplastic prostatic disease uncommon in neutered dogs)
- T: trauma/dysfunction to the pelvis or the nerves that control the bladder (neurogenic dysuria), urethral stricture (from previous stone or attempts to pass a urethral catheter)
- V: haemorrhage-blood clots causing urethral obstruction
If you decide Billy needs some investigations…
- which tests will you do?
- explain why you want to do each test
- what order will you do these in and why?
Rectal exam
- perineal rupture?
- prostate?
- urethral thickening/calculus
Urethral catheter (r/o obstruction)
- sterile, lubrication, careful
- collect urine sample
- stix, SG, sediment, culture
Diagnostic imaging
- ultrasound?
- x-rays?
- retrograde urethrogram?
If you decide to treat Billy now…
- what will you treat him with?
- when should his owners notice an improvement?
- will you want to see Billy again and if so when?
- only appropriate if happy there is no urethral obstruction
- presume UTI?
- antibiotics
- NSAIDs/pain relief?
- increase water intake?
- owners to monitor closely and call ASAP if no urine passed
- see 2-3 days?- time not critical but must re-ex
Crystals in urine are common and often occur without any stones (uroliths, calculi) being present. Crystalluria is often found in normal dogs and cats.
Dalmatians typically have?
Radiolucent stones (urate calculi) which would be missed on plain x-rays. They might be detected on ultrasound but are easily missed if stones are small and vets are not experienced with ultrasound. Although many Dalmatians with urate stones will have urate crystals found on urine sediment exam this is not always the case.
The only way to effectively image the male urethra is with a positive contrast retrograde urethrogram. Ultrasound is not helpful for the urethra in male dogs.
- The main differentials are:
- uroliths (+/- urethral obstruction or intermittent urethral obstruction)
- urinary tract infection
- Mrs Wallace is keen to avoid any investigations if possible. You take Billy outside & he passes a good stream of urine.
- Urinalysis on this sample shows: pH 7, protein 1+, SG 1.026 no crystals but perhaps a few bacteria were seen on sediment exam You decide to treat Billy for a possible urinary tract infection
- 14 x Synulox (amoxycillin/clavulanic acid) 500mg 1 tablet twice daily
- 14 x Norocarp (carprophen) 50mg 1 tablet twice daily with food
- You ask to see Billy again in 7 days but advise Mrs Wallace she must let the practice know immediately if he is not passing urine or is off his food or vomiting
- Observing a good urine stream is enough to ensure there is no current urethral obstruction but this could change rapidly
- Treating for a UTI might be a “head in the sand” approach here but would be a very common starting point especially with a reluctant owner. A few bacteria on a free catch urine sample could be normal contaminants or significant. This could be a discussion point at the end of the case if time allows. Students should be aware that there are not always clear “right or wrong” approaches but they must be able to justify their clinical reasoning/decision making for their cases
- The owners must be informed about what would constitute an emergency for Billy: urethral obstruction is painful and can cause vomiting associated with acute kidney injury/failure and/or bladder rupture
- Billy’s clinical signs of dysuria have continued. Last night he seemed uncomfortable. This morning he strained but passed only a few drops of urine. He refused his breakfast. His caudal abdomen is painful and very tense.
- His owner managed to collect a small urine sample first thing this morning. Urinalysis shows pH is 6.5, trace of blood, ++ protein and no crystals or bacteria.
- After some discussion with Mrs Wallace (she is a bit worried about costs) Billy is admitted for investigations.
Create a second SOAP entry. What has changed?
S: Still straining to urinate, abdominal pain, too tense to palpate bladder
O: Has anything changed? urinalysis shows pH is 6.5, trace of blood, ++ protein and no crystals
A: What’s your top differential? Most likely diagnosis is now urolithiasis (no bacteria, failure to respond to antibiotic therapy, pH acidic, breed disposition to urate). Risk of urethral obstruction.
P: What needs to be done first? -try to pass a urethral catheter. What imaging is required? What are you looking for? Students should develop their plans for diagnostic imaging further bearing in mind that urate stones are radiolucent. They should think carefully about how to assess the urethra in this dog- where might urethral calculi lodge in a male dog?
where will calculi mainly lodge?
UTI is usually associated with an alkaline pH. Urate stones are found in acidic urine.
Bladder calculi are not always easy to see on ultrasound scans- be careful not to miss these.
Calculi lodge most commonly at the os penis in the distal urethra where there is physical narrowing. The urethra is also more narrow at the ischial arch but this is not such a common site of obstruction.
- Billy is well behaved and calm
- You gently try to pass a well lubricated sterile urethral catheter
- A 6 gauge French catheter can only be passed about 7-8 cm up Billy’s urethra before meeting a blockage
- Billy is well hydrated with good cardiovascular signs (HR 112). You anaesthetise him with propofol and isofluorane
- Even when he is anaesthetised you are unable to pass the catheter any further
You decide to take a right lateral abdominal radiograph
- what radiographic technique has been performed?
- are Billy’s hind legs positioned correctly?
- are there any abnormal findings?
- do you need to do an ultrasound scan?
Facilitator notes:
Positive contrast agent (iodine based agent) has been forced round the urethral calculi which have lodged/accumulated because they are unable to get through the relatively narrow section of urethra at the os penis. Sometimes the legs can be superimposed over the region of interest- for urethra we usually pull the HLs forward rather than backwards as we do for most abdominal radiographs. This specifically means the urethral is easier to assess.
Urethrostomy sites: scrotal urethrostomy preferred because wide point of the urethra and less risk of complications due to infection/urine scalding seen with perineal urethrostomy. Alternative is a low urethrostomy proximal to the os penis- scrotal urethrostomy tends to be preferred.
Because ultrasound gives no useful information about the urethra and we know there are bladder calculi from the x-ray study, ultrasound is not likely to change treatment options in this case and therefore likely to be an unnecessary/unjustifiable expense.
Create a third SOAP file updated to include your interpretation of the results so far
- S
- O: what additional information do you have?
- A: what does the new information mean?
- P: what do you need to discuss with Mrs Wallace and what is your immediate plan for Billy while he is still anaesthetised?
- S: n/a
- O: unable to pass catheter = urethral obstruction. Spasm unlikely because persists when anaesthetised. Are there any radiographic abnormalities? -plain film basically normal, ?prominent spleen (not uncommon under GA), no radiopaque stones. +ve contrast retrograde urethrogram shows multiple radioloucent stones in the penis and likely in the bladder.
- A: urethral obstruction associated with multiple uroliths. The most likely cause is urate stones (radiolucent, breed, acidic urine)
- Plan: options to consider
- retrograde hydropulsion & cystotomy with stone analysis
- urethrostomy (permanent opening in the urethra to allow calculi to pass especially if new ones form in the future). What sites are there for this surgery?
- retrograde hydropulsion and medical treatment to dissolve presumed urate stones?
- Mrs Wallace agrees to go ahead with surgery for Billy
- You manage to flush the stones lodged in the urethra back into the bladder
- A cystotomy is performed and numerous stones varying in size from 1-7mm are removed
- The stones are sent to an external laboratory for analysis.
- Billy’s recovery from surgery is uneventful apart from some haematuria the following day and he is sent home.
Write a surgical report for the cystotomy (this will need to include details of what suture materials and patterns you used and what procedure you used for the cystotomy)?
Billy Wallace: cystotomy report 4.27.5.11
Things to consider for a surgical report for Billy (ie a male dog cystotomy for cystic calculi) include:
- Place a urethral urinary catheter into penile urethra
- Ventral midline and parapenile (probably on right side if right-handed surgeon) skin incision. The cranial limit variable but likely to be 3-5 cm cranial to prepuce.
- Combination of sharp and blunt dissection through subcutaneous fat to expose the linea alba.
- Linear incision through the linea alba (initial stab incision with a scalpel blade and then extended using straight Mayo scissors).
- Locate the bladder and place three stay sutures (3-0/2 metric or 2-0/3 metric polypropylene) to help manipulate bladder during surgery - one in cranial pole and remaining two ventrolateral (left and right sides)
- Exteriorise the bladder and pack-off from abdomen using sterile saline soaked laparotomy swabs
- Make a ventral midline incision into bladder (using scalpel blade) and drain urine with the aid of surgical suction
- Extend the incision (longitudinal, ventral midline) using scissors
- Remove visible uroliths with atraumatic forceps, fingers or a sterile spoon
- Use an assistant to retroflush the urethra (with catheter positioned just within penile urethra) with copious quantities of sterile saline. Use surgical suction to remove flushed saline and uroliths from bladder.
- Use fingers to check trigone, bladder neck and cranial recesses of the bladder for hidden uroliths
- Repeat the flushing process at least 4-5 times - each time pushing the urethral catheter further into the urethra so eventually it appears within the lumen of the bladder
- Remove catheter until it is again positioned in penile urethra and repeat flushing at least one more time
- Be absolutely convinced that all ‘stones’ have be removed- it is very common to inadvertently leave calculi behind and this can cause major problems. It takes time and a conscientious approach to complete the “flushing and checking” part of this procedure.
- Close the urinary bladder using monofilament absorbable suture (3-0/2 metric or 2-0/3 metric) - either polydioxanone (PDS), Glycomer 631 (Biosyn) or polyglyconate (Maxon)
- Either simple interrupted or simple continuous - generally, one layer closure although two layer might be acceptable (second layer might be inverting; e’g. Cushing or Lembert. No knots should be present within the bladder lumen because these can act as a nidus for infection and stone formation post operatively.
- Omentalise the site of the bladder incision - drape omentalise or tack in place with interrupted suture
- Perform a swab count
- Close the linea alba with simple continuous or simple interrupted closure – 0/3.5 metric or 2-0/3 metric PDS or Maxon
- Subcutaneous closure using absorbable monofilament simple continuous/simple interrupted closure
- Routine closure of the skin - intradermal or interrupted skin sutures
- Perform a further swab count if not done so already
- Work out a plan for post op analgesia/perioperative antibiotics/observation of urination
****Last and definitely not least….SEND SOME STONES FOR ANALYSIS AND CULTURE****
What post operative instructions should Mrs Wallace be given?
- Hospitalise overnight?-an opportunity to continue iv fluids, monitor analgesia, observe urination, TPR checks
- Discharge instructions: Owner instructions – consider rechecks, stitches out, things to look for (wound), blood in urine? General demeanour? Should Billy have a Buster collar?
- Should the owner worry if Billy has blood in his urine? (no – normal post op for a few days)
- LEAVING SOME STONES BEHIND AT SURGERY IS A COMMON PROBLEM WITH MAJOR IMPLICATIONS
- The external laboratory calculi analysis takes a while –sometimes several weeks
- When the report arrives it says:
On examination by X-ray diffraction analysis composition of the urolith(s) submitted was as follows:
AMMONIUM URATE - 25%
SODIUM URATE - 75%
Other Urates present
Why does Billy have urate stones?
Dalmatians have a genetic predisposition to forming urate stones. They cannot metabolise uric acid to allantoin predisposing them to form stones containing uric acid. The underlying genetic abnormality in Dalmatians (and some other breeds) has now been identified and a genetic test is available. This problem is also seen in other breeds (English Bulldog, Russian black terrier)
What do you need to discuss with Mrs Wallace about prognosis and long term treatment?
- There are general principles behind medical management of all uroliths. This is important because Billy will form more stones in the future.
- Increase water intake/urine volume
- Manipulate urine pH (aiming for neutral to alkaline pH for urate stones)
- Decrease concentration of components (protein restricted diet will reduce the tendency for purine to be converted to uric acid therefore useful for urate stones. Not all dogs tolerate severe protein restriction)
