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1
Q

What are the 3 steps in renal insufficiency at what percentage loss of function occur and what occurs at each stage

A

1) Regulatory failure
- Loss of ≥66% of nephron function
- Failure to concentrate urine→ polyuria
- Metabolic acidosis and electrolyte abnormalities
2) Excretory failure
- Loss of ≥75% of nephron function
- Nitrogen wastes accumulate
3) Biosynthetic failure : Erythropoietin
Non-regenerative Anaemia

2
Q

List 3 causes of primary renal damage and 4 causes of secondary renal damage (decreased tubular function)

A

Primary
1) Toxic insult – ethylene glycol, grapes, lillies
2) Parenchymal damage and fibrosis - inflammation and infectious process
3) Nephritis - inflammation of the kidneys
Secondary
1) Primary diabetes insipidus - failure to excrete ADH
2) Secondary diabetes insipidus
3) Hypercalcemia, Hyperadrenocorticism, Pyometra
4) Loss of medullary concentration gradient – depletion of NaCl and urea
○reversible

3
Q

List the 4 ways renal function is assessed and what is tested within each test

A

1) Excretion of waste products
- Urea and Creatinine in mammals
- Uric acid in birds and reptiles
- SDMA
2) Fluid and electrolyte balance - dehydration
- Urine concentration
- Serum and urine electrolytes
3) Acid-base regulation - Acidosis, alkalosis
- Serum bicarbonate
- Urine pH
- Blood pH and blood gases
4) Production of erythropoietin
- RBC count/PCV/Haemoglobin or measure EPO

4
Q

How do you measure GFR in urinalysis

A

Measurement of Glomerular Filtration Rate (GFR) - don’t measure directly but indirectly through the 4 methods of assessing renal function

5
Q

List 6 uraemias

A

1) Mucosal ulceration
2) Halitosis - bad breath
3) Vomiting
4) Depression
5) Weakness
6) Anorexia

6
Q

Describe the 3 broad causes of azotaemia and examples within

A

Prerenal
Decrease Renal blood flow - something upstream
- Dehydration - reduced blood volume
- Severe haemorrhage
Renal
- decrease in functional nephrons, decrease GFR
Postrenal
Decrease urine output- get leakage of urine into abdomen and contents reabsorbed into circulation
- Tumour, inflammation - nephrosis
- Urinary tract disease
- Obstruction - kidney stones

7
Q

urea filtration, reabsorption where occur and what are the 2 sources of urea

A
  • Sources
    1) Liver protein catabolism → ammonia → urea
    2) Large intestine (small amount)
  • Freely filtered by glomerulus
  • Some tubular reabsorption - especially with slower urine flow
8
Q

What are the two main reasons serum urea increases and give examples within

A

1) ↓ glomerular filtration rate
- Decreased renal perfusion = prerenal
- Loss of nephron function = renal
- Obstruction of urine flow = postrenal
2) ↑ increased protein breakdown - prerenal
- High protein diet
- GI bleeding into the gut - increase protein breakdown in the gut, increase microbe convert to ammonia and liver convert to urea and excret into circulation on its way to the kidney
- Protein losing enterophathy

9
Q

Which is more specific for pre-renal azotaemia urea or creatinine

A

Urea increases more with pre-renal azotaemia than creatinine increases - less specific

10
Q

What are the 3 main downfalls of using urea as a measurement of azotaemia and why

A

1) Less useful in assessing renal function in ruminants and horses - use creatinine mainly
- Ruminants excrete urea via rumen
- horses excrete urea via large intestine
- Excretion depends on nitrogen intake
2) Not useful in birds and reptiles
- Protein catabolism →ammonia → uric acid
3) Increases can reflect dehydration

11
Q

creatine filtration, excretion and reabsorption and why more specific then urea but what animal not used in

A
  • Freely filtered by the glomerulus
  • Small amount excreted in GIT
  • No tubular reabsorption - more specific → better indicator of decreased GFR than urea
  • Concentration not affected by diet
    not used in birds as only see once advanced renal disease
12
Q

List the 3 main reasons see increase serum creatinine and 1 decrease and examples within

A

1) ↑ muscle mass → ↑ creatinine
- Greyhounds are higher than labrador
2) ↑ muscle breakdown → ↑ creatinine
- Training or rhabdomyolysis
- When stable with weight and muscle turnover most effective
3) ↓GFR
- Decreased renal perfusion = prerenal
- Loss of nephron function = renal
- Obstruction of urine flow = postrenal
4) Decreases with generalized muscle wasting
- Could mask kidney disease as if occurring at same time one make go up either decrease so overall no change

13
Q

What is the downside with creatinine

A
  • Little change in creatinine until advanced renal failure
  • normal creatinine doesn’t mean don’t have renal dysfunction
  • need to explore early onset markers
14
Q

uric acid in birds and reptile list 4 things that increase uric acid and why difficult to use

A

1) Renal disease (low sensitivity) - only really see increase in advanced renal disease
2) Profound dehydration - prerenal
3) Ovulation - very hard to know
4) Diet (high protein)
difficult
- Higher levels are seen in carnivorous species
- Hard to get good reference intervals

15
Q

SDMA what does it stand for, when released, when increased levels seen and what causes increase levels

A
  • Symmetrical dimethylarginine
  • Released with proteolysis and excreted through the kidneys
  • Increased levels are seen with ≥ 40% loss of renal function
  • Slightly higher levels are seen in Greyhounds
  • Increases with any cause of decreased GFR
    e. g. dehydration, hypovolaemia (pre-renal)
16
Q

List 3 clinical signs of renal azotaemia and pre-renal azotaemia

A

renal azotaemia
1) Polyuria and polydipsia
2) Anuria or oliguria
3) Inadequately concentrated urine
Pre-renal azotaemia
1) Concentrated urine - actively resorbing water
2) Evidence of dehydration
○ Vomiting, decrease skin turgor, dry tacky membranes, increase in urea and creatinine
3) Evidence of increase protein breakdown in GIT
○ Melena - blood in faeces
○ Increase in urea only, creatinine will be normal

17
Q

Urine Specific gravity what measure with, what is it, what does it indicate and what does it reflect

A
  • Refractometry
    ○ If above 1.000 greater than water (always the case with urine)
    ○ USG is ratio of refractive index of urine compared to water
    ○ Indication of tubular function = ability of tubules to absorb or excrete water
    ○ Reflects urine osmolality
  • High USG = more concentrated urine
  • Low USG = less concentrated urine
18
Q

What are the 3 ways to measure fluid and electrolyte balance

A

1) Urine specific gravity
2) Dipstick reagent pad
3) urine osmolality

19
Q

1) If have azotaemia + concentrated urine =

2) Azotaemia + inadequate urine concentration =

A

1) = dehydration - prerenal

2) = renal

20
Q

List 5 factors that influence urine concentration

A

1) Number of functional nephrons
2) Renal medullary hypertonicity
○ Resorption of NaCl & Urea
○ Renal medullary blood flow
3) ADH secretion and action - RAAS mechanism
- Extra-renal factors
○ Hydration status
○ Serum electrolytes
○ Concurrent diseases - inhibiting ADH function - diabetes insipidus
○ Drug therapy e.g. diuretics
4) renal insufficiency as unable to conserve water and electrolytes and unable to excrete N wastes

21
Q

what are the 3 things that urine concentration does not distinguish

A

1) reversible from irreversible
2) acute from chronic renal disease
3) primary from secondary renal insufficiency

22
Q

Progression of renal insufficiency what do you see:

1) ≥ 40% loss of function →
2) ≥ 66% loss of function →
3) ≥ 75% loss of function →

A

1) ↑ SDMA
2) polyuria
3) azotaemia

23
Q

postrenal azotaemia findings of examination, history and histology

A
  • History – stranguria or dysuria
  • Examination/imaging findings:
    ○ Decreased urine output - leaking into abdomen or banking into the bladder
    ○ Distended bladder - pressure can build back to the kidney causing kidney disease
    ○ Uroabdomen
    Hyperkalaemia - increase in potassium
24
Q

What are the 2 main causes of postrenal azotaemia and examples within

A

1) Obstruction of urine flow
○ Urinary calculi - urinary stones could be suck in urethra
○ Urethral plug
2) Internal urine leakage/uroabdomen
○ Ruptured bladder - can be seen with contrast leaking into abdomen in radiograph
○ Torn ureter / urethra
○ Patent urachus

25
Q

List the other 8 changes with renal insufficiency

A
  • Potassium
    • Phosphate
    • Sodium
    • Chloride
    • Bicarbonate
    • Albumin
    • Anaemia
    • Amylase and Lipase
26
Q

potassium what causes increase and decrease

A
- Hyperkalaemia - Anuric (acute kidney injury), oliguric or obstructive disease (post-renal)
○ Decreased GFR
○ Decreased secretion
○ Associated acidemia
- Hypokalaemia - Polyuric renal disease
○ Increased urine flow rate
○ Reduced tubular function - chronic kidney disease 
→ decreased potassium absorption
27
Q

phosphate what causes with increase and decrease

A
  • Hyperphosphataemia
    ○ Decreased GFR - renal (generally more severe)
    ○ Bone activity (young animals) - also get high ALT
    ○ Sample haemolysis - pre-renal
  • Hypophosphataemia common in horses with chronic kidney disease uncommon in other species
28
Q

calcium what occurs with chronic kidney and acute kidney disease

A

Chronic Kidney Disease
→ Hypocalcaemia in dogs and cats, rarely hypercalcaemia
- secondary to hyperphosphatemia and decreased Vitamin D production
→ Hypercalcaemia in horses and rabbits
- High calcium diet
- Renal excretion controls excess and when get disease hard to keep up with the calcium absorbed from the gut
Acute Kidney Injury
→ Hypercalcaemia or Hypocalcaemia

29
Q

magnesium what occurs with decreases GFR

A

Decreased GFR - Hypermagnesaemia

- Don’t have on a routine biochemistry

30
Q

sodium and cholide when elevated

A
  • Elevated with dehydration
  • Variable level with renal insufficiency
    ○ Depends on water loss vs electrolyte loss
    ○ Changes masked by dehydration
    ○ Selective Cl loss with vomiting
31
Q

bicarbonate what does renal insufficiency cause and what are the two types

A
  • Renal insufficiency causes a metabolic acidosis
    1) Titrational acidosis - ureamic acids +/- Lactic acid
    2) Secretory acidosis – renal loss of bicarb → Hypobicarbonataemia
32
Q

amylase and lipase what are they

A
  • Pancreatic enzymes
  • Excreted by the kidneys
  • Decreased GFR → ↑ amylase and lipase
33
Q

What are the features of acute kidney injury and chronic kidney disease

A

Acute Kidney Injury (AKI) = abrupt decline in renal function (hours to weeks)
- (acute renal insufficiency)
- Have dysfunction but often reversible to the extent that the animal can live a healthy life
- Toxins, infection, drugs
Chronic Kidney Disease (CKD) = progressive decline in renal function over months to years
- (chronic renal insufficiency)
- Tends to be non-reversible

34
Q

List two secondary renal insufficiency causes

A

1) Hyperadrenocorticism - cushings disease dogs
→ impaired tubular response to ADH
2) Diabetes insipidus
→ impaired ADH secretion (central DI)
→ ↓ tubular response to ADH (nephrogenic DI)

35
Q

List 5 causes of urinary protein

A

1) Renal
- Glomerular loss - ↑ filtered protein
- Tubular dysfunction - ↓reabsorbtion
2) Inflammation of urinary tract
- Cystitis
- Pyelonephritis
3) Haemorrhage
4) Genital tract
- Prostatic disease
- Uterine or vaginal disease
5) Prerenal
- Physiologic e.g. dehydration, fever
- Hyperglobulinaemia, haemolysis, myopathy (a disease of muscle tissue)

36
Q

What are the two sources of protein leakage within the kidney and which is more severe

A

1) Glomerular - excess filtration due to leaky glomerulus
○ Often higher level of proteinuria
○ Primarily Albumin
2) Tubular - less severe than glomerular
○ Milder proteinuria
○ Albumin and other proteins eg aminoacids
○ May see other evidence of tubular dysfunction eg renal glycosuria

37
Q

List the 4 ways proteinuria is assessed and what do you need to rule out first before do any of these assessments

A

1) urine dipstick
2) urine sediment examination
3) urine protein:creatinine ratio
4) microallbuminuria
Need to rule out inflammation as a source of the increase in protein first

38
Q

urine dipstick what most sensitive to, what effected by and when use urine sediment examination

A
  • Urine dipstick
    ○ Most sensitive to albumin
    ○ Affected by urine temp, colour, pH, storage, contaminants
  • Urine sediment examination
    ○ Cytology evaluation for haematuria, pyuria (WBC), bacteriuria and casts
39
Q

microallbuminuria when detects, what useful for, why not usually used

A

○ Early detection of renal disease before there is overt proteinuria (i.e. dipstick protein is negative)
○ Useful for screening predisposed breeds
○ Positive with high levels of exercise and so not normally done

40
Q

How to differentiate between acute kidney injury vs chronic kidney disease

A
  • Magnitude of azotaemia does not differentiate
  • Need knowledge of:
    •Duration of clinical signs
    •Urine output
    •Calcium and Potassium levels
    •Other clues eg anaemia (RBC have long half-life so take awhile to see decrease in RBC when erythropoietin has been decrease), weight loss
41
Q

what see in blood and clinical signs of chronic kidney disease

A
  • Hypocalcaemia in dogs and cats (only 5-10% hypercalcaemic)
  • Hypercalcaemia in horses
  • Hypokalaemia common in cats
  • Anaemia occurs with chronic renal failure
    ○ ↓erythropoietin
  • Chronic polyuria and polydipsia
  • May see weight loss
42
Q

what see in blood and clinical sings, history acute kidney injury

A
  • May see hypercalcaemia or hypocalcaemia in dogs and cats
  • Hyperkalaemia if anuric or oliguric
  • Usually not anaemic
  • Acute history of illness
43
Q

What are the 4 routine urinalysis and what are the 2 additional testing

A
Routine urinalysis
1) Direct observation
2) Urine specific gravity (USG)
3) Urine dipstick
4) Urine sediment examination
Additional testing
1) Urine protein:creatinine ratio (UPC)
2) Urine culture
44
Q

what does the following colours of urine indicate

red, brown, dark yellow

A
  • Red = haemoglobin or haemorrhage - can be common in rabbits
  • Brown = Myoglobin, haemorrhage, bilirubin
  • Dark yellow = concentrated or bilirubin
45
Q

what does the clarity of urine indicate and what species has very cloudy urine and why

A

varies with species
Cloudiness can reflect - for
- Mucus
- Cells (pyuria) – leukocytes or epithelial, casts
- Crystals – especially horses and rabbits
- Bacteria
- Storage
horse and rabbit it is crystals and mucus

46
Q

Urine sample storage and handling how long until perform testing, how to store and what to do before testing

A
  • Collection should precede treatment
  • Perform urinalysis within 30 minutes so best in clinic
  • Can refrigerate up to 12 hours
    ○ May introduce crystals and alter pH
    ○ Bring to room temperature before testing
47
Q

List the 4 methods of urine collection and what useful for

A

1) cystocentesis - least likely for contamination useful for dogs and cats
2) catheterisation - must use sterile technique
3) voided (free catch) - not sterile, midstream best, mainly dogs and cats good for USG
4) off the floor/litter tray - useful for USG

48
Q

List the 7 things urine dipsticks assess

A
  • Urobilinogen
    • Protein
    • pH
    • Blood
    • Ketones
    • Bilirubin
      • Glucose
49
Q

Protein on the dipstick when get false positives and when positive results more significant and why

A
  • False positives with alkaline urine (pH > 8.0) - so need to confirm with another test
  • Positive results more significant in dilute urine
    ○ As if detect trace amount of protein means more protein is being lost as large amount of urine
50
Q

What are the 2 other ways of assessing proteinuria if suspect false positive with alkaline urine

A

1) Sulfosalicylic acid precipitation test - detects all proteins - use with alkaline proteinuria
2) UPC

51
Q

causes of glucosuria

A

○ Hyperglycaemia

1) exceeding renal threshold
2) Tubular disease (renal glucosuria)

52
Q

ketones when see in urine, which ketone more sensitive, what one is major in the blood and which first ketonuria or ketonaemia

A
  • Only really see in if catabolic state or ketosis (cattle, horses) and diabetes mellitus (dog and cat)
  • Detects: acetone (most sensitive) and acetoacetic acid
  • Dipstick does not measure β-hydroxybutyrate - measured in the blood
    ○ (Major intermediate in ketosis)
  • Ketonuria often precedes ketonaemia
53
Q

bilirubin is it significant to find in a cat or a dog

A
  • Dogs lower renal threshold - conjugate bilirubin in tubules - not really significant finding
  • Bilirubinuria in cats is always significant
54
Q

blood in the urine what are the 3 possible sources and the 3 ways to differentiate between them

A
  • Reacts with haemoglobin (infection, RBC lysis), myoglobin (muscle breakdown), and intact erythrocytes
  • Differentiation of cause
    1. Sediment exam - is there intact RBCs
    2. Plasma colour & CBC results - myoglobin has brown tinge
    3. CK levels – increased with myopathy
55
Q

urine pH what increases and decreases with normally and what does it affect

A
  • Acidic pH (7.0) vegetable diet
  • Post-prandial “alkaline tide” in dogs and cats
    ○ Straight after eating generally get pH increasing before normalising
  • Affects type of crystals and uroliths
56
Q

urobilinogen how formed, what does presence in urine indicate, is there variation

A
  • Formed in intestine by bacterial breakdown of conjugated bilirubin
  • Presence indicates patent bile duct
  • Correlation of increase and hepatobiliary disease is poor in animals
  • Does vary quite a lot so don’t always use
57
Q

What are the 3 things to ignore on a dipstick

A

1) nitrite
2) leukocytes
3) USG

58
Q

what stain used in urine sediment evaluation

A

Can use Sedi-stain to stain the cells and bacteria however should make one stained and one unstained

59
Q

What are the 6 things you can find within a urine sediment

A

1) cells
2) fat globules
3) casts
4) crystals
5) fungal hyphae
6) parasite eggs

60
Q

what are the 3 types of cells found in urine and types within

A
  • Erythrocytes
    • Leukocytes
    • Epithelial cells
      ○ Urothelial
      ○ Squamous
      ○ Caudate (tubular)
      ○ Sperm
      ○ Prostatic
61
Q

What are the 4 type of casts and types within

A

1) Hyaline cast
2) granular cast
3) waxy cast
4) cellular cast
- epithelial
- erythrocyte
- leukocyte

62
Q

Urinary tract neoplasia name some main ones

A
  • Urothelial (transitional) cell carcinoma - most common and often aggressive
  • Prostatic carcinoma
  • Squamous cell carcinoma - of the bladder or urethra
  • Leiomyoma - arise from bladder
  • Leiomyosarcoma - arise from bladder
63
Q

What occurs to globulin concentration in a dog with hepatic insufficiency, why and when else does this occur and what other changes would you see on biochemistry

A

Decreased serum concentration of globulins
○ Inflammation increase globulins like fibrinogen due to increased risk of infection without liver and kupffer cells removing microbes form the gut
- also see with PSS
Other changes
- decreased albumin, glucose, cholesterol in serum
- increase in bile acid concentration in serum