Lec 5-7 Flashcards
What is periuria?
Inappropriate urination
If you find crystals in a urine sample, does that mean that there are uroliths present?
No
They are microscopic structures which on their own don’t form signs
-After collection urine cools down and struvite crystrals form
What are some factors that can predispose to urolith formation?
Highly concentrated urine
Urine retained for sufficient time
Favourable pH
Nidus/nidi for nucleation/crystallisation
Decreased concentration of crystallisation inhibitors
What percentage of uroliths are found in the kidneys of dogs and cats?
Less than 5%
Most are in the LUT, ureters, bladder, urethra
What are the 2 most common types of uroliths?
Struvite
Calcium oxalate
-Both radiopaque
What is one explanation for why oxalate uroliths are more common now?
Increased use of urine-acidifying diets
After detecting a urolith in an animal, what should you do with it?
Stone analysis
-Optimal management of the case
What are struvite uroliths made up of?
Magnesium ammonium phosphate
Are struvite uroliths seen in infected or uninfected animals?
Both
- Cats usually uninfected
- Dogs usually infected
What are most feline urethral plugs made up of?
Struvite
How do straphylococci and proteus lead to struvite urolith formation?
They produce urease
- Leads to alkaline urine
- Increased phosphate and ammonia
What 2 breeds may have a genetic predisposition to developing struvite urolithiasis?
Cocker Spaniels
Miniature Schnauzers
If you find a urolith that is over 1cm, what is it most likely to be?
Struvite
-Smooth, blunt-edged, faceted, pyramidal
How do you treat a struvite urolith?
If infected
- Remove stones surgically
- Treat the UTI
- Monitor for recurrence
If uninfected
- Remove stones surgically
- Culture stones
- Maintain on hills c/d food or equivalent
- Monitor for recurrence
If instead of removing stones surgically you are instead dissolving them, how long would the animal need to be on antibiotics for?
Entire duration of dissolving can take 2 weeks to 7 months
-Bacteria would have been embedded as the stone grew, so will be slowly released
What are 4 contributing factors to developing calcium oxalate uroliths?
Increased urinary calcium
Increased urinary oxalate
Decreased urinary citrate
Acidic urine - Under pH 6.5
What patients are you more likely to find calcium oxalate uroliths?
Male dogs
Old
Schnauzers, Miniature poodles and other small breeds
Describe treatment principles for calcium oxalate uroliths?
Surgical removal and analysis -Decrease probability of recurrence by Consider feeding Hills u/d Avoiding excessively salty foods \+/- oral potassium citrate \+/- thiazide diuretic
What does giving oral potassium citrate decrease the probability of calcium oxalate uroliths forming?
Slightly alkalinises
Chelates calcium
How do urate uroliths form?
Form readily in acidic urine
Uric acid is derived from purine catabolism and dietary nucleic acid
-Usually uric acid is converted to allantoin
What breed is predisposed to urate uroliths and why?
Dalmatians - 60% of all cases
They produce less allantoin - defect inhepatic transport of uric acid
-Therefore stays as less soluble form of uric acid
What type of urolith is a dog with liver failure most likely to get?
Urate
-Increased excretion of ammonium urate
Describe the treatment principles of urate uroliths?
Remove and analyse stones Diagnose and treat PSS if present Treat any UTI Hills u/d Allopurinol -Xanthine oxidase inhibitor
What animals are more likely to get silicate uroliths?
High dietary intake of silicates
-Corn gluten and soybean husks
Male GSD
Acidic urine
What breeds are predisposed to cystine uroliths?
3-6 year old male Dachshunds
Basset hounds, Bulldogs, Yorkies, Setters, Chihuahuas
What predisposes a dog to getting cystine uroliths?
Inherited defect of renal proximal tubular cystine reabsorption
Form more readily in acidic urine
Describe treatment principles for cystine uroliths?
Hills u/d food
Oral potasium citrate - alkalinises urine
If they get recurrence go on one of these lifelong-
*MPG - reduces cystine in urine
*D-penicillamine - forms disulphide bond to form soluble product - nauseous side effects
Describe what is meant by calcium oxalate uroliths causing ‘big kidney, little kidney’ syndrome
Starts as kidney stone Travels and gets stuck in one ureter Causes pain and increased pressure Eventually the kidney dies -Little kidney -Other kidney unaffected so big kidney -However since only one is affected the creatinine doesn't go up
Why is FLUTD a common term that is used?
Because up to 80% of cats with these signs don’t have a detectable cause - idiopathic
What 3 things can cause a predisposition of a cat developing FLUTD?
Highly concentrated urine -Feed wet food Infrequent voiding -Stress And low secretion of GAG's -Less of a protective layer
How do you treat idiopathic sterile cystitis?
After a thorough workup eliminating other causes -Optimal treatment unknown Increase water intake - canned food Multiple clean litter trays Reduce stress, provide toys, play Pheromone sprays
What is the first thing you do to a patient presented with urethral obstruction?
Give IV fluids
Where does potassium and sodium usually sit in the cells?
Potassium - Intracellular
Sodium - Extracellular
Describe the pathogenesis of urethral obstruction?
Can't excrete Increased potassium is what will kill it first Also dehydrated Anaerobic shock causes lactic acid This increases H+ Goes into the cells Pushes out positive ions Potassium is dominate ion pushed out Goes from intracellular to extracellular
Describe a treatment strategy for a urethral obstruction?
Give IV fluids
Give calcium at the rate for eclampsia to protect the heart
-Affects the depolarisiiton and repolarisation - Bradycardia
Then give glucose
Increases insulin and pushes potassium back into cells
What can the shape of the bladder tell you about a problem?
If it is spherical - acute
If it is a spear - chronic
What are some examples of pseudo-incontinence?
Puppy excitement
Submissive behaivour
Left indoors too long
What are some examples for owners mistaking a disorder for urinary incontinence?
Vulvar discharge
Pollakiuria
Diarrhoea
What can you use to treat bladder atony?
-Contract the detrusor Bethanechol (cholinergic) -Relax the sphincter Phenoxybenzamine (alpha blocker) Diazepam (Skeletal muscle relaxant)
What can you use to treat reflex dyssynergia?
Relax the sphincter -Phenoxybenzamine (alpha blocker) -Prazosin (Alpha blocker) -Diazepam (Skeletal muscle relaxant Contract the detrusor -Bethanechol (cholinergic)
What do you need to remember when using phenoxybenzamine?
It is an alpha blocker
Can cause fainting
What can you use to treat urethral sphincter mechanism incompetence?
Alpha-adrenergic agonists -Phenylpropanolamine -Ephedrine Hormones -Oestriol -Diethylstilbestrol -Testosterone
What can you use to treat dextrusor hyperexcitability?
Treat underlying cause Anticholinergics -Oxybutinin -Imipramine -Amitriptyline
What are some clinical signs of a prostate disease?
Penile discharge at times other than urination Haematuria / dysuria Tenesmus / obstripation 'Ribbon' faeces Stiff gait - Painful \+/- urethral obstruction \+/- fever, sepsis
What is the most common cause of a painful prostate?
Bacterial prostitis
What is the most common cause of an enlarged non-painful prostate?
Benign prostatic hyperplasia
On radiograph how big should the prostate be?
Under 50% width of pelvic inlet on VD
Under 70% pubic-sacral height on lateral
On radoigraph what does a mineralised prostate have a strong correlation with?
Neoplasia - Carcinoma
If you want to get a sample of the prostate for evaluation, how should you try and do it and why?
Transurethrally first
-If it is neoplasia then you will seed the needle track back through the skin
