Final Exam - Equine Urinary Tract Disease Flashcards
what are the typical presenting complaints seen with urinary tract disease in horses?
ADR, weight loss, abnormal urination, decreased performance, & recurrent colic
why are chronic renal disease horses anemic?
there is decreased erythropoietin production & a shorter RBC lifespan
what lab values are most commonly used to interpret renal function in horses? how long does it take for disease to affect these values?
BUN & creatinine
75% of nephrons must be non-functional before values are increased! once elevated, a doubling of BUN & creatinine = 50% decline of remaining nephrons!!!
what electrolyte abnormalities do you expect to see in a foal with uroperitoneum?
HYPERkalemia
HYPOnatremia
HYPOchloremia
increased BUN & creatinine, increased lactate, decreased bicarb (metabolic acidosis)
what do you expect the USG of horse urine to look like after water has been deprived for 24 hours?
1.045
T/F: suckling foals are naturally hyposthenuric
true
can a suckling foal concentrate its urine?
yes - when dehydrated or hypovolemic
is urine usually alkaline or acidic in horses?
alkaline
what indicates proteinuria in a horse?
urine protein: urine creatinine ratio > 1 = proteinuria
what is the renal threshold of glucose in the horse?
170 mg/dl
if you get a positive dipstick for blood, what all could that potentially indicate? how do you further classify this?
hematuria, hemoglobinuria, or myoglobinuria
need to centrifuge it down!
what is endoscopy used for in horses with urinary disease?
used to visualize the urethra, bladder mucosa, & ureter openings
where is the left kidney located on ultrasound?
left kidney is deep to the spleen which is adjacent to the body wall
what would the kidneys look like on ultrasound if a horse had an AKI?
kidneys appear normal, peri-renal edema, & loss of corticomedullary junction
what would the kidneys look like on ultrasound if a horse had CKD?
decreased kidney size, irregular shape/margins, & increased echogenicity
what defines acute renal failure in horses? can this be fixed?
sudden reduction in GFR
usually reversible if caught early!
what damage is done to the urinary system of a horse with an AKI?
damage to tubules, tubular obstruction, acute glomerulonephritis, & edema
azotemia is most often pre-renal or renal in origin due to hemodynamic insult
what is the most common classification of azotemia seen in horses? what defines it?
pre-renal - reversible increase in BUN & creatinine associated with hypovolemia & renal hypoperfusion
concentrating ability is maintained - USG stays above 1.014 & urine osmolality above 500 mOsm/kg
what is decompensation of the kidneys of a horse defined as in regards to pre-renal azotemia?
persistence of azotemia after correction of hypovolemia
can progress to acute renal failure!!!
what defines renal azotemia?
urine concentrating ability is lost in the face of dehydration or hypovolemia - urine is often isosthenuric
fractional sodium clearance is > 1%
urine to serum creatinine ratio is < 37:1
what is an example of post-renal azotemia in horses?
obstruction or disruption of post-renal urinary tract!
dysuria/pollakiuria, renal colic
progressive abdominal distension - leads to bladder rupture & development of uroperitoneum
how do you diagnose uroperitoneum in a neonatal foal?
ultrasound - look for free anechoic fluid in the abdomen & get a sample
uroperitoneum confirmed by peritoneal fluid creatinine concentration >/= 2X serum creatinine concentration
is a ruptured bladder in a foal a surgical or medical emergency? why?
medical - hyperkalemia must be addressed first
hyperkalemia - severely affects the heart
what would you expect the BUN to creatinine ratio to be in prerenal, renal, & postrenal azotemia?
pre-renal: higher ratio due to increased reabsorption of urea with low tubule flow rates
renal: values are non-discriminatory
postrenal: ratio should be higher due to preferential diffusion of urea across peritoneal membranes in cases of uroperitoneum
