SA neutering, urinary Flashcards
What neoplasia are a higher risk with neutering?
Osteosarcomas in Rottweilers (esp if spayed <1y)
Haemangiosarcoma and MCT in Viszlas (spayed any age)
TCC and cardiac tumours in spayed animals
What age to neuter animals?
Kittens from 4 months (pre-pubertal) - but GA risk with maturity of liver and kidneys, hypothermia risk (small glycogen reserves) etc
Puppies:
- benefits of prior to first season = reduced mamary neoplasia risk, uterine/ovarian vessels small, reduced inconvenience to owner
- disadvantages of prior to first season = anaesthetic considerations
- contraindications to prior to first season = juvenile vaginitis, juvenile urethral sphincter mechanism incompetence
- if after first season, always in anoestrus (>12 weeks after oestrus), >6-8 weeks postpartum (preferably >3 weeks post weaning)
- can do combined with caesarean
Medical options for neutering?
GnRH agonists
GnRH vaccine, antagonists - implant, injection
Pros and cons of surgical neutering?
Pros:
- permanent
- perioperative pain
- 100% effective
- eliminates neoplasia of repro tract
Cons:
- more expensive
- GA
Pros and cons of medical neutering?
Pros:
- quick
- cheaper in short run
- no anaesthetic
Cons:
- temporary
- pain on injection
- never 100% effective
- repro tract neoplasia still possible
- unknown effect on USMI etc
When not to neuter based on clinical exam?
Lactation False pregnancy (can make it permanent) In heat (uterus more engorged and friable) Skin pyoderma (post-op infection)
Open technique for dog castration?
Incise vaginal tunic and pop out testicle
Divide testicle and tunic - use clamp
Ligate vas deference and blood vessels individually, then together
Haemostat distal to ligatures, then divide
Check for haemorrhage
Close vaginal tunics, s/c tissue, skin
Closed castration technique for dog castration?
Keep testicle within tunic, ease out of incision
Place one encircling and one transfixing ligature around the entire spermatic cord and tunics
Haemostat distal to ligatures, then divide
Check for haemorrhage
Close vaginal tunics, s/c tissue and skin
Complications of dog castrations? How to avoid?
Urethra - vulnerable at first cut and when closing (make sure to push testicle forward)
Scrotum - dermatitis (care with clipping and scrubbing)
Scrotum - haematoma (care with haemostats)
Cryptorchids - Why are they a problem? How to find them? Where are they?
Vulnerable to torsion, higher risk of neoplasia (13.6x greater risk of seminoma or SCT), may or may not be functional
Often small/soft/misshapen
Palpation, US, exploratory laparotomy
Inguinal - may be able to ease down to normal incision or if not do separate inguinal incision
Abdominal - can be anywhere, exploratory laparotomy, follow ductus deferens
Bilateral castration recommended (sex linked autosomal recessive trait)
Keep the testicle!!
Bitch spay - How big an incision? How to locate ovaries? How to exteriorise the ovaries?
Incise from umbilicus to last pair of nipples (larger if deep chested, obese or large breed
Locate ovary by duodenal (right) and colonic (left) manoeuvres
Exteriorise ovary - stretch (pull ovary caudally, break with other hand) or cut suspensory ligament
How to ligate the ovarian pedicle?
3 clamp technique At least 2 ligatures Encircling and transfixing Or two encircling Or encircling and Miller's Ligate broad ligament as appropriate - ranges from barely existent to full of fat and blood vessels (make a window in an area without vessels)
How to ligate the cervix?
Traction everything cranially
Transfixing and encircling ligatures
Clamp and cut cranial to ligatures
Check for bleeding
How much blood is too much blood?
Check gutters and cervix Check broad ligament Use suction or swab to see Wait Muscle ooze?
Ovariectomy - Benefits?
Quicker Pyometra unlikely (exogenous progestins required) But no difference in pain score, surgical time, haemorrhage, short or long term complications
Bitch spay closure?
Simple continuous for muscle - less suture material, quicker, weakest point is knot
Skin - intradermal or cruciate/interrupted or staples
Flank cat spay technique?
Retriece uterus with finger or spay hook
Find an ovary on one end and bifurcation on other
Ligate pedicle - single ligature often fine
Traction on uterus to find other horn
Care clamping uterus - may tear, ligate caudal to tear
What drugs to use for neutering?
Antibiotics not indicated
Analgesia:
- LA - lidocaine (pedicles, midline, testicles, incision)
- full mu agonist in premed e.g. methadone
- NSAID if not contraindicated (renal/GI disease, receiving steroids)
- consider paracetamol
- 3-5d home pain relief
Comfortable animals don’t chew wounds or cry and settle at home = happy owner
Post op care for neutering?
Pain relief
Exercise - midline require strict rest policy, lead only walks for one month, avoid stairs, jumping, climbing
Owner to monitor wound for swelling, redness, discharge, pain
Deeding - reduced exercise so need less calories, reduced metabolism, so reduce ration by 20% when not exercising
What must all closing sutures of a bitch spay involve?
All bites must have strength holding layer = fascia of rectus abdominus
What late post op neutering complications are there?
Ovarian remnant: - signs of in heat - more common on right side - more common in dogs - check ovary in surgery to ensure completely excised Stump pyometra: - only if progestogen exposure and remaining uterine tissue Granulomas: - use of non absorbable suture material - poor tissue handling and aseptic technique - excessive devitalised tissue left Urethral sphincter mechanism incompetence: - multifactorial - exclude other causes (especially UTI) - 90% respond to phenylpropanolamine - second line ephedrine or estriol - surgical options
What innervation controls filling and emptying of the bladder?
Filling and storage
- mostly sympathetic via hypogastric nerve
- B receptors in detrusor muscle for relaxation
- A receptors in urethral smooth muscle and trigone for contraction
- also somatic via pudendal nerve - urethral striated muscle contraction and inhibition of detrusor reflex
Emptying:
- mostly parasympathetic via pelvic nerve
- stimulates stretch receptors in bladder wall
- contraction of detrusor muscle
- relaxation of urethral muscle
- = detrusor reflex
What allows urinary continence?
Brainstem micturition centre integrates urethral and detrusor function
Cerebral cortex gives voluntary control by over-riding the detrusor reflex
How to investigate urinary incontinence?
Detailed history - e.g. bed wetting, dribbling urine, constant or when excited etc, thirst (could just be PUPD)
Clinical exam (if puppy dripping urine every min etc likely ectopic ureter)
Biochemistry and haematology (check for UTIs etc)
FeLV test in cats
Urinalysis
Urine culture and sensitivity
Observe patient urinating
Plain abdominal radiographs - screen for calculi etc
IV urogram/CT angiography - to check for ectopic ureters
Retrograde (vagino) urethrogram
US exam of urinary tract
Urethroscopy/cytoscopy
Typical findings of abnormalities of the bladder filling phase?
Can urinate and empty bladder normally
Dribble urine between urinations
Often have reduced bladder capacity (likely due to the incontinence, not the cause)
Ddx of abnormalities of the bladder filling phase?
Ectopic ureter - congenital or acquired Reduced pressure at bladder neck: - congenital USMI - acquired USMI - intrapelvic/caudal bladder, short urethra, hypo plastic bladder (probably all part of USMI) - bladder neck mass (polyp, neoplasia, cystic calculus) - urethral dysplasia in female cats Involuntary contractions/urge incontinence: - bacterial infection - cystic calculus - drug induced - FeLV +ve cats - neoplasia of bladder neck
Typical findings of abnormalities of bladder emptying phase?
Distended bladder
Poss constant dribbling of urine
Often no normal urination
Ddx of abnormalities of bladder emptying phase?
Partial/complete urethral obstruction Chronic distension of bladder: - urethral obstruction - pelvic trauma - intervertebral disc protrusion - feline dysautonomia Dyssynergia
What is USMI in female dogs? Signs? Forms? Aetiology?
Urethral sphincter mechanism incompetence
Commonest cause of incontinence in bitch
Intermittent involuntary passage of urine
Incontinence usually whilst dog is relaxed (lying down/sleeping)
Do not constantly dribble urine, can urinate normally
Acquired:
- usually medium/large breeds (Dobermans, Boxers, Irish Setters, OESD)
- usually neutered females (but no proof spaying actually causes it)
Congenital:
- juvenile bitches (prior to first season
- 50% resolve after first season
- ectopic ureter in main ddx (both conditions can be present)
Aetiology:
- low urethral tone
- hormonal influence - spayed bitches, prior to first season
- obesity
Treatment for USMI in female dogs?
Medical: - increase muscle tone with phenylpropanolamine or ephedrine, or estriol - weight loss - treat secondary UTI Surgical: - colposuspension - urethropexy -hydraulic occluder
Presentation USMI in male dogs? Treatment?
Uncommon Usually older, castrated medium/large breeds Usually overweight Treatment: - phenylpropanolamine or ephedrine - oestrogen based drugs? - weight loss - surgery: vas deferensopexy, prostatopexy, hydraulic occluder
What are ectopic ureters? What may happen/be present at the same time? Which dogs is it more common in?
Congenital anomaly, ureter bypasses bladder to empty into urethra, vagina or rectum
Congenital USMI or hypo plastic bladder may co-exist
Secondary UTIs common (cystitis, hydroureter, pyelonephritis)
Most are unilateral
Intramural more common
Female:male 20:1
Golden/Lab retrievers, skye terriers, siberian huskies - greater incidence
Treatment for ectopic ureters?
Treatment of associated UTI
Early surgical management before irreversible secondary changes - referral
Exploratory coeliotomy
Cystotomy to assess trigone area
Uteronephrectomy - for unilateral ectopia, severe hydronephrosis
Ureteral transection and re-implantation - for extramural ectopia
Intravesical repair - for intramural ectopia
What is IV urography (IVU)? What is needed for a diagnostic study?
IV injection of iodine based contrast medium and documentation of its transition through the kidneys, ureters and into the bladder with multiple radiographs
Need:
- adequate renal function and hydration
- good patient prep (fasting, enema)
- GA/heavy sedation
- multiple VD and lateral radiographs at short intervals
What are the phases of IV urography (IVU)?
Start with a plain study (2 orthogonal views)
Rapid IV injection of contrast (iodine based)
Immediate radiograph (angiogram) - homogenous enhancement of kidneys and renal vessels
2 mins = nephrogram - enhancement of kidneys and renal pelvis
5 mins = pyelogram +/- ureters - enhancement of kidneys, renal pelvis and ureters
10 mins = ureters
20 mins - ureters +/- bladder - fading in the kidneys
40 mins = bladder
How to do cystography?
Catheterise and empty bladder
Instill/insufflate with contrast medium (air/gas or iodine based contrast) until reasonably distended
How to do retrograde urethrogram/vaginourethrogram?
Catheterise, empty bladder, inflate bladder moderately full with air/gas (creating back pressure)
Place catheter tip in tip of penis/just within vulva and clamp
Inject iodine based contrast and expose at end of injection
When would you use IVU, cystography and retrograde urehtrograms?
IVU:
- good for ureters and kidneys
- indicated for suspected ectopic ureter, uteroliths, ureteral stenosis, renomegaly, integrity
Cystography:
- good for bladder
- indicated for radiolucent calculi, bladder masses, bladder rupture
Retrograde urethrogram:
- good for urethra, (bladder)
- indicated for stranguria (urethrolith, stenosis, inflammation, neoplasia), integrity
Need GA for all
Need adequate renal function and hydration for IVU
Normal location, opacity, shape, margination and size of the kidneys on radiography?
Location:retroperitoneal space, left more caudal
Opacity: homogenous ST opacity +/- fat at hilus
Shape: bean shaped in dog, slightly more rounded in cat
Margination: sharp and smooth
Size:
- best assessed on VD
- dog: length = 2.5-3.5 x length of L2 vertebral body
- cat: length = 2-3 x length of L2
Normal appearance of the kidney cortex, medulla and pelvis on ultrasound?
Cortex - echoic, similar or hypoechoic to liver
Medulla - near anechoic, least echogenicity of all organs
Renal pelvis and diverticula (renal sinus) - hyperechoic (bright), should not contain any urine (anechoic)
Causes of unilateral and bilateral focal and generalised renomegaly?
Unilateral focal renomegaly: - neoplasia - cysts - abscess - haematoma Bilateral focal renomegaly: - neoplasia/metastasis - PKD - FIP Unilateral generalised renomegaly: - neoplasia - hydronephrosis - perinephric pseudocyst Bilateral generalised renomegaly: - AKI - pyelonephritis - lymphoma - FIP
Causes of microrenale?
CKD - uni or bilateral
Dysplasia - uni or bilateral
Atrophy (chronic obstruction) - unilateral
How do the kidneys look with CKD on radiography and US?
Non specific changes - poor correlation with function
Variable, may appear normal in early stages
Classic end stage - small and irregular, but may be smooth
US - poor corticomedullary definition, small, irregular
How do renal cysts appear on US?
May be solitary (can develop as part of CKD) If multiple indicate PKD Thin walled Mostly unicameral Distal acoustic enhancement May distort surface
Define pyelectasia and hydronephrosis?
Pyelectasia = mild to moderate dilation of the renal pelvis secondary to diuresis (IVFT, furosemide) or inflammation (pyelonephritis) Hydronephrosis = moderate to severe pelvic dilation often secondary to obstruction (ureteral calculi, masses) with overall enlargement of the kidney
Normal appearance of ureters on radiography, US and IVU?
Radiography and US - not usually visible
IVU:
- location: retroperitoneum, lateral the spine on VD
- size: 1-2mm, peristalsis
- ureterovesicular junction: J shaped, in the trigonal region, ureteral jets (US)
How do ureteroliths appear on radiography and US?
Radiography - mineral opacity structures in region of ureters
US - dilation of ureter lumen, hyperechoic (shadowing) structure within the lumen
Normal location, shape, margination, size and opacity of the bladder on radiography?
Location: caudoventral abdomen, just cranial to pelvic inlet, caudal extremity is retroperitoneal
Shape: divided into body and neck, pear-shaped in dogs, ellipsoid in cats, long thin bladder neck in cats
Margination: smooth and sharp
Size (and position): varies with volume of urine
Opacity: homogeneous ST opacity
Normal appearance of bladder on US?
Pear shaped organ in caudal abdomen with anechoic contents
Wall thickening depends on the filling status but should be thin and smooth
In trigonal region (neck), ureteral papillae sometimes visible (jets)
How does cystitis appear with imaging?
Not visible on plain radiographs Cystography: - thickened (cranioventral) wall - irregular mucosa - blood clots Double contrast media - can see calculi and blood clots
How do bladder calculi appear on radiography and US?
Radiography:
- accumulate in most dependent part of bladder (ventrally)
- visibility dependent on radiopacity and size
- struvite, oxalate, calcium phosphate moderate to marked
- silicate moderate
- cystine and rate non opaque to faint
US:
- hyperechoic structures in dependent part of bladder
- strong distal shadowing (unless tiny)
How do bladder masses appear on radiography and US?
Radiography: - not visible on plain radiographs - will create a defect in contrast pool or as a ST opacity on pneumocystogram - predilection site: trigonum, dorsal bladder wall US: - most commonly TCC - sessile, polypoid echoic mass - trigonal region or bladder neck
Can bladder rupture be seen by radiography and US?
Not visible on plain radiographs, but may see loss of serosal detail (free fluid) and small bladder
If suspected, do positive contrast cystography - leakage of contrast
US rarely able to show defect, but will see free fluid
What is the only method of accurately assessing the urethra? How does it compare in males and females?
Retrograde (vagino)urethrogram
Males - prostatic urethra, membranous or pelvic urethra, penile urethra
Females - shorter and wider than males, entirely intrapelvic
Smoothly marginated
Can the uterus and ovaries normally be seen by radiography? US? Position?
Not unless greatly enlarged
Ovaries - in dorsal middle aspect of peritoneal space, caudal and ventral to each kidney
Uterus:
- width must be at least 2x width of small bowel to be detected
- US: identification of normal horns can be difficult, the body is located between the urinary bladder ventrally and the descending colon dorsally
How does canine cystic endometrial hyperplasia-pyometra complex appear on radiography and US?
Radiography:
- dilated, soft tissue opacity loops originating between bladder and colon
- mass effect displacing the intestines cranially and dorsally
Ultrasound:
- fluid dilation of uterine horns and body
- uterine wall appearance is variable and depends on degree of dilation and if hyperplasia is concurrently present
Normal location, size, shape and opacity of the prostate on radiography?
Location: caudal to the bladder, may be partly within the pelvic canal
Size: dependent on neutering status (rule of thumb <70% height of pelvic inlet)
Shape: symmetrical, ovoid to round, urethra centrally
Opacity: homogenous soft tissue opacity
Appearance of the prostate by US in neutered and intact dogs?
Neutered dogs:
- intrapelvic
- small and homogeneously hypoechoic
- round on transverse images and enveloping the urethra
- fusiform on sagittal images
Intact male dogs:
- ovoid, symmetrical and smoothly marginated
- significantly larger than in castrated dogs
- homogeneously to mildly heterogeneously hyperechoic
Causes of prostatomegaly? How do each appear?
Benign prostatic hyperplasia: - symmetrical enlargement - ST opacity - normal in entire older dogs Prostatitis (entire dogs): - regular or irregular shape - may see mineralisation - sometimes loss of serosal detail Prostatic neoplasia: - often irregular shape - often mineralisation (very specific for neoplasia in neutered dogs: carcinoma, TCC) - often loss of serosal detail - dorsal displacement of colon/rectum - may see metastatic disease to medial iliac lymph nodes and lumbar vertebrae (periosteal reaction, lysis)
What is AKI?
A spectrum of disease associated with a sudden onset of renal parenchymal injury
Results in:
- abnormal GFR, tubular function and urine production
- sudden inability to maintain fluid, acid-base and electrolyte balance
- possibly azotaemia
Causes of AKI?
Decreased renal blood flow: - hypovolaemia - dehydration - hypotension - renal vasoconstriction (PG inhibitors) - thrombi, DIC Toxins: - antibacterials e.g. aminoglycosides - chemotherapy drugs e.g. cisplatin - radiographic contrast media - NSAIDs - organic compounds e.g. ethylene glycol - lilies (cats) - grapes (dogs) Infectious: - Leptospirosis - FIP - Leishmania Pyelonephritis, septic emboli Glomerulonephritis Trauma Systemic diseases: - multiple organ failure - polycythaemia - lymphoma - hyercalcaemia
What are the 4 stages of AKI?
Initiation phase: - damage starts Extension phase: - ischaemia - hypoxia - inflammatory response - ongoing cellular injury - cell death Maintenance phase: - stabilisation of GFR - typically see azotaemia, uraemia - urine production variable Recovery phase: - azotaemia improves - tubules undergo repair - can be marked polyuria
Initiation and extension phases may be clinically silent
History/clinical signs of AKI?
Non specific!
Recent onset of anorexia, polydipsia, vomiting, diarrhoea
May get CNS signs in cases of ethylene glycol ingestion
Known toxin exposure?
Nephrotoxic drugs?
Signs of infection or previous UTI?
Ischaemic episode?
Check vaccination status - leptospirosis?
Physical exam of AKI?
Usually in good condition Dehydration Uraemic breath Hypothermia (unless infection) Ulceration of tongue/buccal mucosa Occasional neurological signs \+/- Kidney pain or enlargement Tachycardia if dehydrated Bradycardia if hyperkalaemia
Diagnosis of AKI?
Blood sample:
- azotaemia
- increased iP
- hyperkalaemia if oliguric (normal or hypo if polyuric)
- calcium variable (low with ethylene glycol, high with Vit D intoxication and neoplasia)
- metabolic acidosis
- increased PCV, TP (dehydration)
Urinalysis:
- isosthenuric (1.008-1.012)
- may be glucosuria, haematuria, proteinuria
- look at sediment for casts, WBCs, bacteriuria, crystals
Radiography - size, shape, opacity
Ultrasound - size, parenchyma, echogenicity
Differentiating between CKD and AKI?
CKD:
- weight loss
- previous history of PUPD/poor appetite/GI signs
- non regenerative anaemia
- kidneys typically small, firm and irregular
- often surprisingly well for degree of azotaemia
- normal or low K
- poor hair coat
AKI:
- good body condition
- acute onset of signs
- +/- history of toxin exposure
- kidneys may be enlarged or painful
- may be disproportionately sick for the degree of azotaemia
- +/- hyperkalaemia
- urine sediment may show casts
- good hair coat
Specific treatments for AKI?
Induce vomiting if recent toxin ingestion (antifreeze, lilies) - need early recognition Ethylene glycol: - 4 methylpyrazole (fomepizole) - ethanol (needs to be given within 8h) Leptospirosis or pyelonephritis: - antibiotics
What is seen in the urine with ethylene glycol toxicity? Prognosis?
Calcium oxalate monohydrate crystals
Poor prognosis if already azotaemic or oliguric
Fluids for AKI? How much? Monitoring?
Correct hydration status, acid-base status and electrolytes
Monitor hydration with MM, CRT, HR, RR, ABP, PCV and biochemistry
Don’t overload - no evidence that aggressive IVFT is better than restoration of normal perfusion
Give just enough but not too much
Measure BW accurately at least twice per day
What to do if rehydrated an animal with AKI but is oliguric? Define oliguric?
Oliguric = urine flow <1ml/kg/hr normally but <2ml/kg/hr if hydrated and well perfused
Give 3-5% BW in IVFT if not overhydrated
Reassess hydration, BP - reduce IVFT, place urinary catheter, start treatment to increase urine output
- furosemide (increases urine output but doesn’t improve GFR or outcome), initial 1-2mg/kg IV bolus, then 0.5-1mg/kg/hr CRI
- mannitol
How to correct hyperkalaemia with AKI?
Fluid therapy (0.9% NaCl or Hartmans)
Calcium gluconate 10% - antagonist of cardiac effects, monitor ECG
Dextrose - stimulates insulin secretion (glucose and potassium share a carrier)
Insulin
Sodium bicarbonate - K+ into intracellular space in exchange for H+
Treatment for vomiting and hypertension with AKI?
Vomiting: - H2 antagonists, PPIs - maropitant, metaclopramide Hypertension: - exacerbated by overdydration - reduce ICFT - diuretics - if persistent can use antihypertensives: nitroprusside, hydralazine, amlodipine
Dialysis for AKI?
If can’t induce diuresis consider euthanasia or dialysis
Removes toxic wastes
Allows time for kidneys to repair
Haemodialysis available at some referral centres
Peritoneal dialysis - expensive, time consuming, complications common, often poor response
Prognosis of AKI and how long to treat for?
If renal function returns to normal or improves and stabilises but not normal levels - taper fluids off
If renal function worsens or doesn’t improve sufficiently ro be managed at home - renal replacement therapy (dialysis) or euthanasia
