Dogs and Cats 22 Flashcards
General history of a blocked cat and what need to differentiate
- Most have dysuria/stranguria ○ But sometimes owners haven’t noticed - Owners cannot differentiate between ○ Dysuria or dyschezia? ○ Stranguria vs. pollakiuria, polyuria, incontinence or behavioural? ○ NEED TO ASK QUESTIONS TO DETERMINE - Urethral obstruction or just cystitis?
Talking to owners with a blocked cat what need to keep informed and their options
Three levels of care - keep informed - without highest level of care increase risk of recurrence
1) Unblock and home - (Ugh!)
2) Hospitalisation for one day
○ Catheterisation
○ Indwelling catheter
○ IV fluids
3) Hospitalisation as long as it takes
○ Catheterisation
○ Indwelling catheter until urine is clear
○ IV fluids
○ At least one day in hospital after catheter removal - majority are dysuric after this point - need to ensure inflammation NOT REBLOCKED
Is azotaemia prognostic use for a blocked cat
- Magnitude of azotaemia is of no prognostic use - generally doesn’t have renal failure afterwards
○ Azotaemia takes days to resolve
unblock the cat in treating a blocked cat preparation and equipment needed
- GA -> if sick - opioid and benzo, not sick - ketamine
- Equipment
○ Unblocking catheter
○ Sterile lube
○ Flush solution and syringe
○ Lidocaine
○ Indwelling catheter
○ Tape
○ Nylon on a straight needle
○ Adapter for urinary catheter
○ Empty fluid bag with IV tubing
○ Two people
unblocking a blocked cat preference for unblocking and indwelling
- My preference for unblocking
○ Kendall Sovereign Sterile Tom Cat Catheter
○ 5 ½ inch
○ Open ended - My preference for indwelling
○ Kendall Sovereign Sterile Feeding Tube and Urethral Catheter - doesn’t kink
○ 5 French (3 ½ only if you are desperate)
Unblokcing the cat technique up to draining the bladder
a. Dorsal or lateral recumbency with hip flexion -> dorsal best as can visualise
b. Get someone else to extrude penis
§ If cyanotic (chronic obstruction down into penis) -> squeeze and twist may just unblock
c. Massage penis and urethra
d. Pass lubricated urinary catheter 3-4 mm into tip of penis at first
e. Allow penis to return into prepuce then pull prepuce caudally and dorsally to straighten urethra - TO AVOID URETHRAL WALL
f. Twist and gently advance catheter
g. Attach extension set to catheter
h. Short, sharp flushes with 20ml syringe while twisting and advancing catheter - want to dilate the urethra
Cystocentesis? - NO -> some cats can get uroabdomen - RISK
Unblocking the cat from draining the bladder
i. Fully drain bladder
j. Flush bladder repeatedly with isotonic electrolyte solution until urine is as clear as possible
k. Palpate bladder while flushing to evacuate sediment
l. Inject 0.5 ml lignocaine while withdrawing catheter (don’t overdo it!)
m. Fully drain bladder
n. Pass 5F flexible urinary catheter (indwelling catheter) (flush while advancing)
§ 2-4cm passed the pelvic brim
o. Secure with tape butterfly & mattress suture either side of prepuce
p. Secure catheter to tail (tape to catheter then tape to tail)
q. Attach to closed collection system or IV tubing and attach to empty IV fluid bag
r. E collar always
Further treatment and monitoring after unblocking a cat
- Fluid therapy:
○ Initially 5-10 ml/kg/hr if euvolaemic & no contraindications
○ Then modify on the basis of urine output, PCV/TS, electrolytes and PE hydration status
○ Modify IV fluid rate to exceed urine output by maintenance and replacement requirements - MBS parameters q 2-12 hrs
- Urine output q 4-6 hrs
- PCV/TS/electrolytes q 2-12 hrs
- Consider need for analgesia and anti-inflammatory drugs
○ Personally I don’t want NSAIDs anywhere near possibly sick kidneys - Initially no antibiotics, prolonged corticosteroids or bethanechol - predispose to infection
After unblocking the cat what to do with catheter and after removal what to do
- Leave urinary catheter in >24 hrs or until urine is clear (well kinda!)
- After catheter removal consider:
○ Wait 24 hours - cystocentesis, urine analysis (dipstick and sediment) - see if have signs of infection - THEN TREAT ANTIBIOTICS
○ +/- culture
§ Prazosin > phenoxybenzamine, ?dantrolene
§ Prob. not diazepam
what are the basics in treatment for blocked cat
- Major body system assessment first
- ALWAYS stabilise before unblocking
- There is NO contraindication to rapid fluids
- Treat severe hyperkalaemia aggressively
○ Calcium gluconate is treatment of choice
○ Treat the patient not the number
Blocked dogs how to diagnose and remove
Radiograph
- Ensure the legs are pulled forward to see the
- Fabella often sit where urethra is
Retrohydropulsion
- Anesthetise the dog
- Catheter in of penis, hold of end of penis
Someone else feel ventral area of urethra (through rectum) and compress and lift off -> moves calculi into bladder
Uroliths do they cause obstruction, common and less common types, crystalluria what is it, is it normal, treatment needed
Uroliths
- Can cause urethral and rarely ureteral obstruction
- Multiple types
- Can be mixed / compound
- Common: Struvite, Calcium oxalate, ammonium urate (dogs)
- Less common : Cystine, calcium phosphate
Crystalluria
- Urolith vs. Crystals
- Can be normal
- Crystals ≠ Urolithiasis or stone forming tendency
- Alone does not justify treatment
- May be “in vitro”
What are the 5 main factors affecting urolith formation
- Supersaturation of urine
- +/- Presence of an organic nidus - suture material within bladder urine -> crystals can precipitate out onto and come together
- Reduced solubility (urine pH)
- Presence of crystalization inhibitors or promoters
- Retention of crystals within urinary tract
What are the main causes of uroliths and signs
- Genetics [breed]
- Diet
- Infectious agents (UTI)
- Life style
- Systemic disease
Signs
○ Subclinical (e.g. nephrolith)
○ Mild: LUT signs
○ Severe
○ Life threatening : obstruction
What are the main ways to diagnose uroliths
- History
- Clinical signs (palpation) - can be small - may not be able to palpate
- Plain radiology +/- contrast
- Ultrasound
- Urinalysis
○ Fresh & non-refrigeration, in-house - Stone analysis
What are some factors that help you guess urolith type and which types are common
- Age ○ young - urates (liver shunting, liver disease) ○ Older - Calcium oxalates - Breed - Gender ○ Female - struvite ○ Male - calcium oxalates - UTI - Crystals - pH ○ High - struvite ○ Low - calcium oxalate - Radiographic density ○ Calcium oxalate - show up well on radiographs - Size & number - Serum abnormalities
Feline urethral plugs structure, what leads to and most common
- Typically > 50% matrix
- Mucoprotein gel ‘traps crystals’ -> rigid plug -> obstruction
- MOST COMMONLY STUVITE in LUT
Treatment of uroliths
- Identify and treat any predisposing causes
○ Renal - nephroliths -> hard to treat, generally leave unless issue
○ Ureteral - harder due to stricture issues - stenting works well
○ Bladder -> multiple options, laparoscope,
Send stones / urethral plugs for quantitative analysis
Key points of treatment of all uroliths
- Increased risk with bacterial UTI and in genetically predisposed individuals
- Therapy aims to reduce risk of recurrence
- Increased water intake, decrease USG
- Encourage urination - wet food diets, water fountains
- Avoid predisposing causes
- Treat all infections > 3 weeks and up to 3 months - may
- If UTI, re-culture urine 1 week post antibiotics (treat like complicated UTI)
Dog struvite signalment, prediposing cause and what need to investigate
- Females > Males
- Tend to be small white fluffy dogs
- 3-8 years
- Most infected - main predisposing cause
○ Urease producing
○ Gold standard to culturing bladder wall, often just do urine or urolith - Radiodence, smooth
- Urine pH > 7
- Investigate for predisposing causes of infection
○ Underlying incontinence, prostatitis
Struvite treatment
- Baseline plain radiographs ○ Number, size, location, density - Antibiotics ○ 3-4 weeks past dissolution - Diet (acidify the urine - C/D) ○ 3-4 weeks past clear radiographs - Urinalysis ○ Every 2 weeks - Monitor radiographs ○ Monthly - Time to dissolve - can be as quick as 2 weeks, 6 months within kidney ○ Within urethra or ureters CANNOT DISSOLVE
Struvite prevention and when get recurrence
- Treat UTI
- (Feed preventative diet) -> don’t normally need - just treating underlying infection
- Monitoring: Aim pH 6 – 6.5, low USG, sediment
- Reoccurrence : - 40-55% without changing management (1% with C/D)
○ UTI
○ Poor monitoring
○ Poor owner compliance
○ Lack of removal of all stones surgically
Calcium oxalate signalment, recurrence, predisposing, diagnosis and treatment options
- Male > Female
- Average 5 – 12 years old
- High reoccurrence rate as genetically driven generally
- May be metabolic / genetic factors
- Check for ↑[Ca]
- Treatment
○ Surgery
○ Voiding Uro-hydropropulsion
○ Lithotripsy
○ Cannot dissolve with diet once formed!
Treatment of calcium oxalate uroliths and monitoring
- Reduce crystal forming substances ○ Calcium ○ Oxalate ○ Increase pH ○ Lower USG - makes a large difference - Diet - Rx concurrent disease Monitoring ○ pH 7 – 7.5 (+/- K citrate) ○ USG < 1.020 to reduce risk of formation ○ Sediment ○ Radiographs every 3-6 months
Calcium oxalate recurrence and how to prevent
- High recurrence rate especially 6 months – 3 years
- Even with ideal prevention
- Consider Vitamin B6 supplementation
- Consider Hydrochlorothiazide diuretics
Urate uroliths what made of, form within, look, causes and dissolution
- Ammonium urate, uric acid, sodium urate
- Form in acid urine
- Radiolucent, smooth, round or oval
- Dalmatians
○ Genetic
○ Often male, 1-5 years old - Others
○ Liver: shunts, dysplasia, failure - Urate crystalluria in Dalmatians
- Dissolution: Low success rate
Urate uroliths treatment/prevention and monitoring in dalmatians
- Diet - reduce protein and purines -> U/D diet
- Allopurinol (xanthine oxidase inhibitor) - for dalmatians to block formation of uroliths
- Monitor
○ Rx UTI
○ pH 7 – 7.5
○ USG < 1.020
○ Ultrasound / contrast radiographs every 2-3 months as dissolving
○ [TP], [Alb] q 6 months -> should be coming down to ensure dietary therapy is successful
○ +/- Surgery
Urate uroliths treatment/prevention and recurrence with other breeds
- Liver disease – hepatic diets (e.g. L/D)
- No detectable liver pathology (e.g. hepatic / renal diets)
- Recurrence
○ 30-50% within one year of Sx
○ Lower risk if > 9 year (14%) vs. < 5 years (60%)
Cystine uroliths signalement, look like, forms in what urine and causes
- 100% males
- Relatively radiolucent, round, smooth
- Age 3 – 8 years
- Staffy, Australian cattle dogs, Rottweilers
- Formes in acid urine
- Inherited proximal tubule defect - RECURENCE NORMAL
- Abnormal transport of cystine by renal tubules
○ +/- other amino acids
Cystine uroliths treatment/prevention and recurrence
- Reduce protein (cysteine, methionine) ○ Diet – Hill’s u/d - Increase pH ≥ 7.5 (K citrate - add this to get there) - USG < 1.020 - Low Na diet - (2-MPG if available) - Penicillamine ○ Increased solubility of cystine - Recurrence in 2-12 months unless take steps to prevent ○ Less recurrence if > 5 years old
cat uroliths what associated with most common, which form plugs and dietary aims for prevention
- 15 – 23% of FLUTD cases
- Uroliths: Struvite > Calcium oxalate
- Plugs : Most Struvite
- Dietary aims
○ Control urine pH
§ more important when comes to struvite - average 2 weeks for dissolution
○ Minimise building blocks of stone
§ Struvite dissolution / prevention: ↓Mg ,↓ P
§ Calcium oxalate prevention : ↓Ca, ↓Oxalate
○ Increase water intake -> ↓ USG
Define oliguria, anuria and polyuria
Oliguria - less than expected urine output, can be physiologic, pathologic or caused by partial urinary tract obstruction or rupture, various values have been used to define, in a hydrated, well-perfused patient, less than 1ml/kg/hr can be considered absolute and 1-2ml/kg/hr can be considered relative oliguria
Anuria - essentially no urine production, never physiologic and indicates the most severe form of renal disease or complete urinary obstruction
Polyuria - is generally defined as being above 2ml/kg/hr unless recieveing IV fluids above maintenance rates
Risk factors for developing acute kidney injury, what all lead to
- Shock
- Pre-existing renal insufficiency
- Concurrent cardiovascular disease
- Sepsis
- Use of diuretic and potentially nephrotoxic drugs
They all lead to hypotension and therefore hypoperfusion of the kidney
What are the 3 main life threatening problems from acute renal disease and how to treat
1) bradycardia, hyperkalaemia (and hypoperfusion) - calcium gluconate
2) presumptive hypocolaemia
3) metabolic acidosis
all acute resuscitative fluid therapy
What are the 3 main pathogenic changes in acute kidney injury and what clinical manifestations then occur
- Vascular dysfunction
○ Decreased RBF, GFR, oligoanuria
§ Azotaemia, hyperphosphataemia, hyperkalemia - Glomerular dysfunction
○ Decreased GFR, oligoanuria
§ Azotaemia, hyperphosphataemia, hyperkalemia - Renal tubular epithelial injury
○ Casts, proteinuria, glucosuria, oliguria
§ Loss of regulation of water, lytes, acid-base
What are the principles of treatment of acute kidney injury
- Damage is done
- Support them through the complications associated with loss of renal functions
- Wait for recovery phase
- Potentially chronic kidney disease - is owner okay to manage this medically
What are the 8 steps in the treatment of acute renal injury
- Correction of perfusion abnormalities and fluid deficit
- Correction of acid-base and metabolic emergencies (hyperkalaemia and acidaemia)
- Determination of pre-vs. renal vs. post-renal injury (or a combination thereof)
- Determination of UOP, establishing urine production
- Discontinue substances with nephrotoxic potential
- Treating any treatable etiologies
- Provide intensive supportive care and nutritional support and
- Renal replacement therapies such as dialysis - not really available in Australia
Acute kidney injury correction of perfusion abnormalities, acid-base, metabolic emergencies (first 2 steps) how done
1) fluid therapy
- Goal is to stabilize animal and determine UOP, THEN to maintain a neutral fluid balance
- Acute resuscitative fluid therapy –your normal approach -> balanced isotonic crystalloids
- After resuscitation and rehydration, “maintenance” could be anything… depends on UOP:
Generally -> dehydration x body weight in kg = deficit to be replaced over 4-6 hours
2) Correction of metabolic derangements
- Main issue if blocked - hyperkalaemia
○ Indications include: measurement of serum potassium, detection of inappropriate bradycardia (or normal) in very sick Hypoperfused animal -> suggests this
How to avoid overhydration when giving fluid therapy for acute renal injury
- Recognize safety limits ○ Central venous pressure ○ Body weight ○ Respiratory effort ○ Oedema - mainly pulmonary oedema - If occurs all fluid therapy must be stopped
Other metabolic derangements besides hyperkalaemia to correct for acute renal injury
- Metabolic acidosis… fluids will help A LOT… may need to consider sodium bicarbonate
○ Risks include: metabolic alkalosis, hypernatremia, paradoxic cerebral acidosis - Sodium can be anywhere… rate of change is imp
- Phosphorus. Typically high. Can cause Hypocalcemia
- Magnesium. Typically high. Can cause hypokalaemia.
- Calcium. Can be anywhere. Use as little as possible (but use it prn)
- Hypertension. Treat but avoid precipitous decline.
