25 – Urinary II Flashcards
1
Q
Urinalysis
A
- Use a fresh, non-refrigerated urine sample
- Physical, chemical and sedimentation evaluation
- Less ambiguity with a cystocentesis sample
2
Q
Urinalysis: physical analysis
A
- Colour
- Clarity
- Smell
- Measurement of urine concentration
- USG (usually use refractometer)
- Can do urine osmolality (not readily available)
3
Q
*USG values
A
- No true normal USG
- Must decide if it is appropriate for the patient in question
o Assess hydration status
o Use your history - Varies with: diet, water intake, extrarenal diseases
4
Q
Urinalysis: chemical dipstick analysis
A
- pH (don’t over interpret)
- glucose
- ketones (human dipsticks not great for animals)
- protein
- urobilirubin
- leukocytes/nitrites
- specific gravity (not accurate)
- bilirubin
5
Q
When might you get acidic urine?
A
- Meat-based diet
- Systemic acidosis
- Catabolic state
- Administration of acidifying drugs
6
Q
When might you get alkaline urine?
A
- Old stored urine
- UTI from a urease producing organism
- Vegetarian diet
- Systemic alkalosis
- Administration of alkalinizing drugs
7
Q
pH
A
- affected by what they eat
- don’t get excited unless
o if need to modify it to promote excretion of toxic
o uroliths
o true hematuria or pigmenturia
8
Q
Bilirubin in cat urine
A
- ANY in cat is abnormal
- Dog 1+ can be normal
9
Q
Urinalysis: sediment analysis
A
- Method of collection will influence the sediment findings (consider the interpretation of results)
- If collected by cystocentesis: urine should be sterile
- RBC: 0-5
- WBC: low numbers
- Squamous cells: low numbers
- Transitional cells: high number=mucosal disruption from inflammation or neoplasia
- Sperm: intact males
10
Q
Casts in urine
A
- Cylindrical molds of renal tubules: aggregated proteins and/or cells
- Low number=normal
- Best IDed at lower power with the condenser lowered
- Absence does NOT rule out tubular injury
- *cylindruria localizes disease to the kidneys
11
Q
Lipiduria
A
- Common in cat urine and normal
12
Q
When does crystallization occur?
A
- When urine composition (pH, SG, mineral composition) favors oversaturation of certain minerals
o most have unique appearance and solubility characteristics - Visualize also depends on pH, solubility of the crystals and temperature of the urine
- May form with refrigeration and be an artifact
- Significance depends on type of crystal and other clinical findings
13
Q
Crystalluria: uric acid
A
- In born error of metabolism in some breeds (ex. Dalamations)
- Liver disease
- Normal in acidic urine left on a counter
14
Q
Crystalluria: bilirubin
A
- Can be normal in male DOGS with highly concentrated urine or signify bilribinuria
15
Q
Crystalluria: struvite
A
- Often normal but significant if UTI induced or in a stone former
- Looks less structed when dissolving
16
Q
Crystalluria: CaOx Monohydrate
A
- EG toxicity
- Oxalate rich foods (ex. peanut butter, sweet potatoes)
17
Q
Crystalluria: CaOx Dihydrate
A
- Can be normal
- Seen with EG, but less commonly than monohydrates
18
Q
Crystalluria: Melamine
A
- AKI from contaminated dog food
19
Q
Crystalluria: cholesterol
A
- Suggests membrane breakdown
- Has been seen with renal disease and proteinuria
20
Q
Crystalluria: cystine
A
- Inborn error in metabolism
- *always significant
- Newfoundland, English bulldogs, and others
21
Q
Crystalluria: amorphous crystals
A
- Phosphate or uric acids salts
- NOT clinically significant but can form cast like structures and increased with refrigeration
22
Q
What can proteinuria result from?
A
- Prerenal
o Bence-jones with multiple myeloma
o IMHA, platelet problem - Renal
o Neoplasia
o Glomerulonephritis
o Amyloidosis - Postrenal
o Neoplasia
o UTI
o Urolithiasis
23
Q
How do you evaluate proteinuria?
A
- Interpret in light of USG and urine sediment exam
- Trace or 1+ may be normal if urine concentrated
- Urine dipsticks do NOT detect Bence-Jones
- Quantification with inactive sediment
- *UPC <0.4 cat and <0.5 dog
24
Q
How do you evaluate tubular function?
A
- Assessment of urine concentrating ability: USG and osmolality
- No ‘normal’ USG since concentrating ability is affected by non-renal factors
o Ex. diet, water intake, many disease other than primary renal disease - Provocative testing of urine concentrating ability through a modified water deprivation test
- Assessment of tubular reabsorption of electrolytes and other solutes
25
Urine culture and sensitivity
- Get a cystocentesis sample
- For best results: culture within 6hrs of collection
- False negatives occur if urine refrigeration is prolonged
- Quantitative vs. qualitative
- Sensitivity: Kirby Bauer, MIC
26
Radiographs: kidneys
- Assess size on V/D
- Normal kidneys have a smooth outline
- No abnormalities does NOT rule out renal disease (AKI, pyelonephritis)
- Renomegaly
27
Radiographs: urinary bladder
- Assess size and displacement
- Nonvisual: empty, ruptured, displaced due to hernia or mass
- Enlarged: normal, urine retention, urethral obstruction
- Small bladder: normal, anuria, tear, ectopic ureters, nondistensible
- Abnormal shape: diverticula
- Radiopaque calculi
- Dystrophic mineralization
- Emphysematous cystitis
- Normal urethra NOT visible
28
Excretory urography
- Useful for evaluating the renal pelvis and ureters
- US: better for evaluating parenchyma
- Angiogram
- Nephrogram
- Pyelgram
29
What are the indications for a contrast study?
- Evaluate abnormalities in renal size, shape and location
- Assess renal perfusion and patency of excretory pathway
- If suspect tears
- Investigate congential anomalies
- Detect radiolucent uroliths
- Dilation, distortion and filling defects (hydronehprosis, calculi, pyelonephrotoxic drug)
30
What are some contraindications to a contrast study (IV pyelography)
- Dehydrated patients
- Patients receiving other nephrotoxic drugs
- Patients with known sensitivity to contrast media
31
Retrograde contrast
- Used to investigate location, integrity, wall thickness, luminal filling deficits and mucosal detail of lower urinary and genital tract
- Can do pneumocystography, positive contrast
32
What can retrograde contrast be helpful to investigate?
- Urinary obstruction
- Excretory pathway rupture
- Congential abnormalities (fistula)
- Mucosal or mural lesions
- Non-radiopaque uroliths
- Strictures of urethra, extramural compression
33
Ultrasound
- Allows you to look at TEXTURE and parenchyma of kidneys and bladders
o Focal parenchyma: cysts, neoplasia
o Diffuse parenchyma: inflammation, AKI
- Normal ureters NOT visible
o If do see on=hydronephrosis with ectopic ureters, stricture, uroliths, neoplasia
- Evaluate for local extension or metastasis
- Limited evaluation of proximal urethra/prostate
34
Advanced or specialized imaging of urinary tract
- Fluoroscopy for interventional procedures
- CT (ex. ureterocele)
- 3T MRI
- **indications: characterize disease prior for surgical planning or interventional approaches
35
Cytology and Histology
- Traumatic urethral catheterization
- Renal biopsy: percutaneously US guided vs. surgical
- Bladder wall biopsy: surgical vs. cystoscopic
36
What are some indications for renal biopsy?
- Differentiation of glomerulonephritis from amyloidosis, suspected neoplasia
- To determine prognosis for ARF, for definitive diagnosis of other renal disorders
37
What are some complications of renal biopsy?
- Hemorrhage, infarction (significant problem in cats)
- Rarely: hydronephrosis if blood clot obstructs the renal pelvis
38
What are some contraindications for renal biopsy?
- Solitary kidney
- Coagulopathy
- Severe systemic hypertension
- Renal lesions associated with fluid accumulation (cyst, abscess)
- End stage kidney disease unless doing a transplant
39
Urethroscopy/cystoscopy
- Assessment of chronic LUTD
- Hematuria
- Incontinence
- Recurrent UTIs
- Biopsy of bladder mass
- Remove stones
- Injection of urethral bulking agents
40
What are interventional radiology procedures?
- Ballooning or stenting urethral strictures
- Lithotripsy
- Schlerotherapy
41
What are some urodynamic procedures?
- Urethral sphincter mechanism incompetence
- Detrusor hyperreflexia
- Reflex dyssynergia
