Equine Urinary Tract Flashcards
what does pollakuria mean?
increased frequency of urination
what does dysuria mean?
painful urination
what does stranguria mean?
painful, frequent urination of small volumes
what does oliguria mean?
low urinary output
what does anuria mean?
absence of urination
which urinary tract disorders are horses prone to?
PUPD pigmenturia renal disease neoplasia urolithiasis UTIs developmental disorders
what are the most common problems that owners state in a horse with a urinary disorder?
abnormal urination
weight loss
what is considered polydipsia for a horse?
more than 100ml/kg/day
how should you perform a clinical examination of a horse presenting with urinary issues?
standard clinical exam
rectal exam
penis exam under sedation (a2 agonist and butorphanol PLUS ACP to encourage protrusion of penis)
pass urinary catheter if suspected obstruction
what blood tests can be performed to assess for urinary disease?
haematology - leukocytosis, anaemia (chronic disease/renal failure)
urea/creatinine (azotemia)
when will creatinine levels in the blood increase?
not until >75% nephrons non-functional - little use in evaluation of early/minor changes
what is the relationship between urea/creatinine and kidney function?
once elevated, doubling urea/creatinine = 50% decline in remaining function
how is urine caught for urinalysis?
usually caught midstream (container on a stick) or obtained by catheterisation
most horses will urinate when placed in a freshly bedded stable
can cystocentesis be performed in horses?
no
what urinalysis can be performed?
USG
biochemistry (reagent strip analysis)
sediment analysis (casts)
if pigmenturia, note timing and duration of passage of discoloured urine
what is USG? how do you measure it?
an estimate of urine concentration
measured with a refractometer
what is the term given for urine that is more dilute than serum?
hyposthenuria - low USG (<1.008)
kidney unable to concentrate urine normally
what is the term given for urine with a similar osmolality to serum?
isosthenuria (1.008-1.014)
kidneys cannot form urine with a higher or a lower specific gravity than that of protein-free plasma
what is the term given to urine that is more concentrated than serum?
hypersthenuria (>1.014)
unusually high specific gravity and concentration of solutes, resulting usually from loss or deprivation of water
what is the normal concentration of equine urine?
adults hypersthenuric
foals hyposthenuric
how/why is ultrasonography performed?
transrectally/transabdominally
looking for uroliths in kidneys/bladder
checking size and architecture of kidneys
what is cystoscopy useful for?
very useful for investigation of abnormal urination
what can be examined under cystoscopy?
urethra and bladder
watch urine coming from ureters (may identify a unilateral renal problem)
why might you perform a water deprivation test?
assessment of PUPD - tests for diabetes insipidus/psychogenic polydipsia
what is psychogenic polydipsia?
excessive fluid intake in the absence of physiological stimuli to drink
what parameters should be checked before a water deprivation test?
urea, creatinine and USG
do not proceed if increased (azotemic) or USG>1.008
when should a water deprivation test be stopped?
when 24 hours reached
when USG rises to >1.020
if azotemic
if any clinical signs of dehydration
if loss of 5% BW
how is a modified water deprivation test carried out?
water restricted to 4% BW per day and given in small amounts
why might a horse have myoglobin or haemoglobin in the urine?
myoglobin - myopathy
haemoglobin - haemolysis
why might a horse have haematuria throughout urination?
haemorrhage in kidneys/ureters/bladder
why might a horse have haematuria at the beginning of urination?
bleeding from distal urethra
why might a horse have haematuria at the end of urination?
bleeding from proximal urethra
what are the possible causes of PUPD?
renal failure
diabetes mellitus
pituitary pars intermedia dysfunction (PPID)
primary/psychogenic polydipsia
central/nephrogenic diabetes insipidus
what further tests can be done in horses with PUPD?
look for renal failure - isosthenuria and azotemia
investigate for PPID in older horses
water deprivation test to differentiate between diabetes insipidus and primary polydipsia
what is acute renal failure?
a clinical syndrome associated with abrupt reduction in glomerular filtration
what does acute renal injury lead to?
failure of kidneys to excrete nitrogenous wastes, causing azotemia –> uraemic syndrome
disturbances in fluid/electrolyte/acid-base homeostasis
how does acute renal injury result from pre-renal failure?
decreased renal perfusion without associated cell injury
conditions causing decreased cardiac output / increased renal vascular resistance
e.g. dehydration, diarrhoea, endotoxaemia, septic shock, +/-use of NSAIDs in these cases
how does acute renal injury result from intrarenal failure?
ischaemic or toxic damage to the tubules
tubular obstruction (e.g. from casts)
acute glomerulonephritis
tubulointerstitial inflammation
how does acute renal injury result from post-renal failure?
obstruction or disruption of urinary outflow tract (e.g. uroliths)
what are the clinical signs of acute renal failure?
lethargy
inappetence
dehydration
signs of the primary problem e.g. colic
vague and non-specific signs
how is ARF diagnosed?
oliguria
azotemia
USG
casts in urine - show damage
rule in/out prerenal and postrenal causes, if not is intrarenal
if intra-renal, US, biopsy
how is ARF treated?
reverse underlying cause
correct fluid and electrolyte imbalances
dopamine infusion to improve renal blood flow
diuretics to increase urine production
stop aminoglycosides where possible (if not, monitor serum concentrations)
what are the nursing considerations for ARF?
fluid therapy
monitor urine output and signs of oedema, digital pulses
encourage appetite - variety of feeds, in-hand grazing
monitor for complications e.g. laminitis, thrombophlebitis, swelling/heat at catheter sites
what is the prognosis for ARF?
depends on underlying cause, duration, response to treatment, and development of complications
can live long-term but usually polyuric - must always have access to water
what are the possible causes of chronic renal failure (CRF)?
glomerulonephritis (most common) immune-mediated ischaemia toxic insults infection
what are the clinical signs of CRF?
lethargy (anaemia) anorexia weight loss (common) PUPD dental tartar azotemia and inability to concentrate urine
signs present late in disease course
what are the nursing considerations for CRF?
fluid therapy to rule out ARF - monitor urine output and signs of oedema
access to water always
encourage eating
diet - reduce protein (avoid alfalfa)
what is the most common sign of UTI in horses?
dysuria
are UTIs common in horses?
no - usually secondary to another issue (e.g, urolithiasis)
how can you diagnose a UTI?
mid-stream urine sample for bacteriology
investigate for underlying causes
what types of neoplasia are common in horses?
penile - usually squamous cell carcinoma (older geldings)
can have melanoma, sarcoid, papilloma
what are the signs of penile squamous cell carcinoma?
no signs early on
malodourous/swollen sheath
haematuria if distal urethra involved
obstruction is uncommon unless tumours are large
how is penile SC treated?
local excision and penile resection
penile resection plus urethrostomy
what is the prognosis for penile SCC?
high rate of recurrence but slow metastasis (inguinal lymph nodes)
which horses are more likely to develop uroliths?
male adults (mean age 10)
shorter, wider urethra makes it easier for mares to pass small caliculi
what is the most common site for uroliths to form?
bladder
what is the least common site for uroliths to form?
urethra
what are the 2 types of uroliths?
type 1 - most common, yellow and spiculated, easily fragment
type 2 - grey and smooth
what are all uroliths made of in horses?
calcium carbonate
what is a sabulous urolithiasis?
accumulation of urine sediment in the ventral bladder
what are cystic caliculi?
bladder stones
what are the signs of cystic caliculi?
dysuria haematuria stranguria incontinence signs especially at/after exercise
how are cystic caliculi diagnosed?
rectal exam, endoscopy of bladder, US (must empty the bladder)
how are cystic caliculi treated?
laparotomy and cystotomy
why can’t cystic caliculi be dissolved?
horses have alkaline urine due to diet - difficult to alter diet to make urine acidic enough to dissolve stones
which horses usually suffer from cystic caliculi?
usually males
what are urethral caliculi?
usually small cystoliths that have passed into the urethra
what are the signs of urethral caliculi?
dysuria
colic, post-renal ARF and risk of rupture if blocked
how are urethral caliculi treated?
perineal urethrotomy
how can recurrence of urolithiasis be avoided?
avoid predisposing factors
no supplementary electrolytes
no alfalfa/lucerne
check for UTI
what are the signs of urinary incontinence in horses?
similar signs to urolithiasis, which is more common, so more beneficial to check for uroliths
what can cause urinary incontinence?
upper motor neuron diseases (equine herpes virus, myeloencephalitis)
lower motor neuron diseases
myogenic disorders
sabulous urolithiasis
what are the nursing considerations for urolithiasis/urinary incontinence?
cleaning of the perineum/hindlimbs
protection from urine scalding
management of urinary catheter
monitoring urine output and quality
which developmental urinary diseases can affect foals?
patent urachus
ruptured bladder
what is patent urachus?
developmental malformation
congenital patent urachus - failure to close at birth means urine passes out of umbilicus
how is patent urachus treated?
prophylactic antibiotics, usually closes with time
some may require surgical resection
when does bladder rupture occur in foals?
occurs during parturition, usually in males
what does a bladder rupture result in?
electrolyte imbalance (hyperkalaemia)
urine accumulation free in the abdomen
how is bladder rupture treated?
fluid support then surgery to correct
