Urinary Tract Disorders Flashcards
history related to renal system issues
– Nonspecific (eg weight loss, depression, etc)
> May be mistaken as colic
– Volume of water intake, volume of urine produced
– Anuria, oligouria, polyuria vs pollakiuria
– Posture, dysuria or stranguria
– Appearance of urine
what components of the urinary tract can we feel with trans-rectal palpation
– Bladder, region of ureters
– Caudal pole of left kidney
what sampling methods do we use for urinalysis?
– Free catch midstream sample
– Catheterization of bladder
– (Cystocentesis in neonatal foals)
urinalysis - gross appearance considarations
– Colour: straw coloured (may be quite dark yellow)
– Clarity: may be turbid (calcium carbonate crystals and
mucus)
– Odour
should we use our whole urine sample for urinalysis? why?
- Split the sample (for later culture if indicated)
how much renal loss for isosthenuria? what can give false elevations of SG?
– >75% of renal function loss before isosthenuria is
detected
– False elevations in presence of excessive proteinuria
what test to confirm proteinuria? why is this needed?
- False positive trace protein in alkaline urine
- Sulfosalicylic acid (SSA) test to confirm
- Differentiate glomerular disease vs. urinary tract
infection/hemorrhage/inflammation
what dipstick values are unreliable in horse?
– Dipstick leukocytes and specific gravity are unreliable
threshold for glucosuria?
– Glucosuria (renal threshold: 9-10mmol/L)
“blood” in urine may be:
- how to tell?
- Erythrocytes
- Hemoglobin
- Myoglobin
– Evaluate by sediment microscopy and/or protein
electrophoresis
Urinalysis
* Sediment Examination values:
– RBCs < 5/hpf
– WBCs < 5/hpf
– Bacteria: scant only
– Epithelial cells: occasional only
– Crystals > calcium carbonate, struvite, calcium oxalate
– Tubular casts (protein or cellular debris) > evaluate sample soon after collection and frequently
cbc can reveal what urinary tract issues?
– Inflammatory leukogram may be seen with renal
infection (not lower regions of UT)
serum biochem values that help us evaluate urinary system?
– Urea
– Creatinine
– Electrolytes and trace minerals
Urine Fractional Excretions
- what are these for?
Evaluation of renal tubular function
– Simultaneous evaluation of urine electrolytes or trace
minerals and blood values:
* Na, K, Cl, Ca, Mg, Phos
* Need to consider dietary influences
<><><><>
FEa = ([urinea] x [serum creatinine]) x 100/
([seruma] x [urine creatinine])
ultrasonography methods of evaluating the urinary tract, and what they are good for?
- Trans-rectal
> Bladder, prostate, ureters - Trans-abdominal:
> Kidneys: Size, shape, Architecture, echogenicity, corticomedullary differentiation
> Urachus (foals)
how to do a renal biopsy? complications?
- Ultrasound guidance
- Possible complications:
> Subcapsular hemorrhage
> Hematuria
> Intestinal perforation
Water Deprivation Test
- purpose
- what is it? when to do it?
- Evaluates concentrating ability of the kidneys
- Serial evaluation of urine specific gravity in the
presence of induced dehydration
> Choose patients judiciously (not azotemic) and monitor closely during and after the test
> Stop once s.g>1.025 or 5% body weight loss observed
cystoscopy - how to perform? what can we see?
- Sedation
- Sterilization of endoscope
- Clean opening to urethra
- Lots of lube!
- Visualization of:
– Urethra (tears, inflammation, strictures, accessory sex glands)
– Bladder (stones, sabulous debris, neoplasia, ruptures)
– Ureteral openings (assess urine production from each kidney, sample each)
how can we assess bladder integrity?
- Catheterization of bladder to infuse dye, then
abdominocentesis
– eg. ruptured bladder in foals
common disorders of the kidneys in horses
– Renal failure (acute / chronic)
– Diabetes insipidus
– Psychogenic Polydipsia
– Pyelonephritis
common disorders of the ureters in horses
- ectopic ureters
common disorders of the bladder in horses
– Bladder rupture
– Cystitis
– Neoplasia
common disorders of the urethra in horses
– Obstruction, rupture
– Accessory sex glands
acute vs chronic renal failure in horses
- what is the difference?
- Acute RF:
– Loss of renal function occurring over hours to
days
– Toxic or hypoxic/ischemic causes
<><><><> - Chronic RF:
– Loss of renal function occurring over weeks to months
– Uncommon in horses
Acute Renal Failure
* Results in:
– Failure to excrete nitrogenous wastes
– Failure to maintain homeostasis of body fluids and
electrolytes
Causes of ARF:
– Vasomotor (decreased renal perfusion)
* Dehydration, hypotension
<><><><>
– Nephrotoxic compounds:
* Aminoglycosides
* NSAIDs
* Vitamin D
* Pigments: myoglobin, hemoglobin
* Cantharidin (Blister beetle toxicosis)
<><><><>
– Interstitial glomerulonephritis
ARF – Clinical Signs
ARF is usually secondary, and signs are more
related to the primary disorder
– Depression
– Anorexia
– Dehydration, tachycardia
– Hyperemic mucous membranes
– Oliguria or anuria
– Colic?
ARF – Diagnosis
Combine urinalysis with serum biochemistry
– Azotemia without urine concentration
– Blood electrolyte disorders:
* Hyponatremia, hypochloremia
* (Variable potassium)
* Hypocalcemia, hyperphosphatemia
* Metabolic acidosis
– Urine GGT/Creatinine?
+/- Hematuria, proteinuria, glucosuria, pyuria, casts
<><><><>
Trans-rectal palpation
– Caudal pole of L kidney
<><><><>
Ultrasonography
– Loss of corticomedullary differentiation
<><><><>
Monitor urine output
– Anuria, oligouria, polyuria
ARF – Treatment
- Improve renal perfusion: Fluid therapy
– Correct both hypovolemia plus electrolyte disorders
> Physiologic saline
> Treat hyperkalemia (NaHCO3, Ca++ Borogluconate,
dextrose)
<><><><> - Discontinue nephrotoxic drugs or alter dosing
interval (peak and trough drug concentrations)
<><><><>
If anuric/oliguric:
– Diuresis
> Furosemide
> Mannitol
– Renal Vasodilation
> (Dopamine – low dose)
<><><><>
Monitor urine output and blood pressure
– Body weight
– Peripheral edema
<><><><> - Wean off fluids slowly (several days)
- Nutritional support
- Treat underlying disease process
- Peritoneal dialysis?
ARF – Prognosis
Depends on:
– Inciting cause
– Duration of insult
– Response to treatment
> Anuria/oliguria → polyuria
> Monitor serum creatinine
