Equine Urinary Tract Flashcards
what are the main urinary tract disorders in horses?
PUPD pigmenturia renal disease neoplasia urolithiasis UTI developmental disorders
what history taking is needed when investigating equine urinary problems?
standard history abnormal urination abnormal colour any other problems measure water intake over 24hrs
what water intake is classed as polydipsia in horses?
> 100ml/kg/day
what will owners of horses with urinary issues most often confuse?
polyuria (increased volume)
pollakuria (increased frequency)
what are the most common problems associated with urinary issues?
abnormal urination
weight loss
what is involved in the clinical exam of a horse with urinary issues?
standard
rectal
examination of penis
passing of urinary catheter
what is a rectal exam used for in the urinary patient?
bladder: size, wall thickness, uroliths (bladder stones), masses
caudal pole of left kidney
how should the horse be restrained for examination of the penis?
sedate with alpha 2 agonist
ACP to encourage protrusion
when should a urinary catheter be passed in horses?
if obstruction suspected
what blood tests will be performed on equine urinary patients?
haematology
biochem
what is found on haematology that may indicate UTI or infection?
leukocytosis
what would anaemia in the urinary patient indicate?
chronic disease
chronic renal failure leading to reduction in production of erythropoetin (EPO)
what does raised urea and creatinine indicate?
azotemai
when will urea and creatinine levels increase?
once 75% of nephrons are non-functional
is urea/creatinine useful in early kidney disease?
no
what is indicated by a doubling of urea and creatinine values once they are elevated?
50% decline in remaining kidney function
how is a urine sample obtained from a horse for urinalysis?
caught midstream (container on a stick) catheterisation
is cystocentesis performed in horses?
no
what can be done to encourage horses to urinate?
freshly bedded stable
what should be noted if pigmenturia is present?
timing
duration of passage
what is involved in urinalysis?
USG
dip stick (biochemistry)
sediment analysis of casts
what is USG a measure of?
urine concentration
what is used to measure USG?
refractometer
what is hyposthenuria?
urine that is more dilute than serum (<1.008)
what is isosthenuria?
urine and serum have similar osmolality - indicates kidney is unable to have any effect on urine
>1.008-1.014
what is hypersthenuria?
urine more concentrated than serum
what is the concentration of normal horse and foal urine like?
adult normally concentrated
foal dilute
what can ultrasonography be used for in urinary diagnosis?
uroliths in kidney and sometimes bladder
size and architecture of kidneys
what is cystoscopy useful for?
investigation of abnormal urination
what can be examined during cystoscopy?
urethra
bladder
watching and sampling urine from ureters
what will sedation for cystoscopy need to include if patient is male?
ACP
what is a water deprivation test used for?
test for diabetes insipidus or psychogenic polydipsia once all other causes of PUPD are ruled out
what must be checked before a water deprivation test is performed?
urea and creatinine
USG
weight
when should you not proceed with a water deprivation test?
if urea and creatinine increased
USG >1.008
how is a water deprivation test performed?
weighed
water is removed
USG, urea and creatinine checked regularly
monitor for signs of dehydration
when is a water deprivation test stopped?
24 hours reached USG rises to above 1.020 Azotaemia Clinical signs of dehydration Loss of 5% BW
what is involved in the modified water deprivation test?
water is restricted to 4% of BW over 24 hours rather than being totally removed
what are the main types of haematuria seen?
myoglobin
haemoglobin
haematuria
what does myoglobin in urine indicate?
myopathy
what does haemoglobin in urine indicate?
haemolysis
what does haematuria throughout urination suggest?
haemorrhage from kidneys, ureters or bladder
what does haematuria at the beginning of urination suggest?
haemorrhage from distal urethra
what does haematuria at the end of urination suggest?
haemorrhage in proximal urethra
what can cause PUPD in horses?
renal failure PPID primary/psychogenic polydipsia central nephrogenic diabetes insipidus DM
what is diabetes insipidus caused by?
lack of ADH
what should you look for on the bloods of a horse with PUPD?
renal failure
isosthenuria
azotemia
PPID in older horses
when is water deprivation testing only performed?
if other causes ruled out
if not azotaemic
USG of >1.008
what is acute renal failure?
clinical syndrome associated with abrupt reduction in glomerular filtration
what does acute renal failure lead to?
failure of kidneys to excrete nitrogenous wastes causing azotaemia
disturbances in fluid, electrolyte and acid-base homeostasis
what does azotaemia present as?
uraemic syndrome - manifestation of clinical signs of azoteamia
what are the 3 reasons for acute renal failure?
pre-renal
renal
post renal
how does AKI result from a pre-renal cause?
decreased renal perfusion without associated cell injury
from conditions the decrease cardiac output or increase renal vascular resistance
what are some of the reasons for pre-renal AKI?
dehydration diarrhoea endotoxaemia septic shock NSAID use
what causes intrarenal AKI?
Ischaemic or toxic damage to the tubules, tubular obstruction (e.g. from casts), acute glomerulonephritis, tubulointerstitial inflammation
what causes post renal AKI?
Obstruction or disruption of urinary outflow tract (e.g. uroliths)
what are the clinical signs of AKI?
Lethargy Inappetence Signs of the primary problem e.g. colic Dehydration Vague and non specific
how is AKI diagnosed?
presence of oliguria/anuria
Azotaemia
Urine specific gravity
“Casts” in urine – show damage
how can cause of AKI be diagnosed?
Rule in/out prerenal and postrenal causes, if not is intrarenal
If intrarenal, ultrasound and attempt biopsy
how is AKI in horses treated?
Reverse underlying cause
Correct fluid and electrolyte imbalances
diuretics to improve urine production
stop NSAIDs where possible
what should be done if it is not possible to stop NSAIDs in an AKI patient?
monitor serum concentrations
what can be done if the AKI patient does not respond sufficiently to IVFT?
dopamine infusion to improve renal blood flow
what does the prognosis of AKI depend on?
Underlying cause
Duration
Response to treatment
Development of complications like thrombophlebitis, laminitis
what will often happen to patients who survive AKI?
can live long term
often polyuric
must have access to water at all times
what causes chronic kidney disease?
glomerulonephritis
what are the main causes of glomerulonephritis?
Immune-mediated
Ischaemia
Toxic insults
Infection
when do CKD patients often present?
late on in disease
what are the signs of CKD?
Lethargy due to anaemia Anorexia Weight loss** (main) PU/PD Dental tartar Azotaemia + inability to concentrate urine
what is the prognosis of CKD like in horses?
poor due to number of nephrons destroyed before patient shows signs
what are the nursing considerations for CKD?
Fluid therapy – to rule out ARF.
Access to water
Encourage eating
Diet
what should be monitored when a patient is on IVFT?
urine output
signs of volume overload (oedema)
how should the diet of CKD patients be altered to support them?
reduce protein (avoid alfalfa)
why should alfalfa be avoided in CKD patients?
high protein and calcium levels
are UTIs common in horses?
no - and will be underlying issue if present
what are the presenting signs of UTI in horses?
dysuria
how is UTI diagnosed?
midstream urine sample with biochemistry
investigation of underlying causes
is neoplasia of the urinary tract common in horses?
not really other than penile
what are the main types of penile cancer in horses?
melanoma
sarcoid
papilloma
what is the main neoplasia of the penis seen in older geldings?
squamous cell carcinoma
what are the signs of penile squamous cell carcinoma?
malodourous / swollen sheath
haematuria if distal urethra involved
early on no signs
is urinary tract obstruction often seen with penile squamous cell carcinoma?
uncommon unless tumor is large
what does treatment of penile squamous cell carcinoma depend on?
position and extent of tumor
what are the main treatment methods for penile squamous cell carcinoma?
local excision
penile resection
urethrostomy (major surgery)
how likely is penile squamous cell carcinoma to reoccur?
high rate of recurrence but metastasis is slow
where should be checked to look for local invasion of penile squamous cell carcinoma?
inguinal lymph nodes through rectal exam
in what horses is urolithiosis more common?
males
adults (mean age 10)
why are males more prone to urolithiosis?
shorter and wider urethra makes it easier for mares to pass small calculi
where are uroliths most commonly seen?
bladder
what are all uroliths in horses formed from?
calcium carbonate
what are the most common types of calcium carbonate urolith?
type 1 -
yellow
spiked
what are type 2 uroliths like?
grey
smooth
what is sabulous urolithiosis?
accumulation of urine sediment in the ventral bladder
what are the clinical signs of cystic calculi?
Dysuria Haematuria Stranguria Incontinence Especially at/after exercise
how are cystic calculi diagnosed?
Rectal, endoscopy, ultrasound
(must empty the bladder)
how is cystic calculi treated surgically?
laparotomy and cystotomy
what are the long term complications associated with cystic calculi?
low
where are urethral calculi commonly seen?
males
what are urethral calcui often formed from?
small cystoliths that have passed into the urethra
what are the signs of urethral calculi that have caused urethral obstruction?
Colic
ARF (postrenal)
Risk of rupture
what can repeated, temporary blockage caused by urethral calculi lead to?
CRF
what surgical procedure can be used to treat repeated urethral calculi?
perineal urthrotomy
does urolithiosis often reccurr?
low recurrence rate
is dietary treatment of urolithiosis in horses possible?
no - cannot acidify urine
how can urolithiosis be prevented?
avoid predisposing factors
no supplementary electrolytes
no alfalfa or lucerne due to high Ca2+
what should you check for it urolithiosis is recurring?
UTI
is urinary incontinence common in horses?
no
what are signs of incontinence exacerbated by?
coughing exercise
what are the signs of urinary incontinence?
similar to urolithiosis which is more common so should be checked for
what conditions make urinary incontinence likely?
Upper motor neuron (incl. Equine Herpes Virus (EHV) myeloencephalitis), lower motor neuron or myogenic disorders
Sabulous urolithiasis
what is bladder paralysis a feature of?
neurological diseases (cauda equina syndrome), herpes virus.
what are the signs of bladder paralysis?
Urinary incontinence, scalding, loss of anal/tail muscle tone
what are the nursing considerations for patients with urinary issues?
Cleaning of the perineum/hindlimbs to provide protection from urine scalding
Management of urinary catheter (if necessary)
Nursing considerations as colic surgery if abdominal surgery (e.g. cystotomy)
Monitoring of urine output
Monitoring urination
what urinary tract issues are seen in foals?
Patent urachus
Ruptured bladder
what is the most common developmental malformation in horses?
patent urachus
how does patent urachus occur?
Normally, urachus closes at time of parturition
in a congenital patent urachus there is failure to close at birth (tension during parturition a possible cause)
what is the urachus?
in the foetus urine passes from bladder to allantoic cavity via the urachus
what is the sign of a patent urachus?
Drip urine from umbilicus
how should patent urachus be treated?
prophylactic antibiotics, usually close with time
surgical resection if doesn’t resolve
when does bladder rupture often occur in foals?
Occurs during parturition, usually in males
what are the signs of bladder rupture?
progressive dullness over first 72 hours
what does bladder rupture cause?
Results in electrolyte imbalance (hyperkalaemia)
Urine accumulation free in the abdomen
how is bladder rupture treated?
fluid support then surgery to correct
