Lecture 11: Renal I Flashcards
1
Q
What are the basic functions of the kidney
A
- Regulate blood volume
- Acid base and electrolyte balance
- Excrete waste
- Hormone production
2
Q
what hormones are produced by kidney and what are their functions
A
- Renin: blood pressure regulation
- Erythropoietin: RBC production
- Calcitriol- Ca2+ homeostasis
3
Q
what is urine composed of
A
glomerular filtration + tubular reabsorption + tubular secretion
4
Q
what composes glomerular filtration barrier
A
- Capillary endothelium
- Glomerular basement membrane
- Podocytes
5
Q
glomerular filtration barrier allows only __molecules to pass, depends on molecular __ and __
A
small, size, and charge
6
Q
__ is the largest threshold size for passing through glomerular filtration barrier
A
albumin
7
Q
what occurs in PCT
A
Majority of water and solutes reabsorbed
8
Q
how does fluid volume and concentration change in PCT
A
decrease fluid volume, concentration no change
9
Q
what occurs in descending LOH
A
resorb water
10
Q
what happens to volume and concentration of fluid in descending LOH
A
concentrated and volume reduced
11
Q
what occurs in ascending LOH
A
resorb solutes (Na, Cl, K)
12
Q
how does concentration change in ascending loop and what is purpose
A
filtrate becomes dilute, establishes medullary concentration gradient
13
Q
what is resorbed in DCT
A
Na and Cl
14
Q
what is resorbed in collecting duct
A
urea, water if ADH present, Na Cl
15
Q
what is secreted in collecting duct and what controls that
A
K and H+ secreted, controlled by aldosterone
16
Q
describe how the medullary concentration gradient works
A
ascending LOH- resorbed Na and Cl- back into interstitium and CD urea is resorbed creating hypertonic interstitium which then pulls water from filtrate/urine into body to concentrate urine
17
Q
define renal disease
A
presence of morphological renal lesions of any severity OR any biochemical abnormalities related to renal function
18
Q
t or f: clinical signs may or may not be present with renal disease
A
true
19
Q
define renal insufficiency
A
biochemical evidence of renal dysfunction, often without clinical signs
20
Q
define renal failure
A
when clinical signs +/- laboratory abnormalities are observed that are caused by reduced renal function
21
Q
define uremia
A
clinical syndrome associated with renal failure
22
Q
Define GFR
A
rate of fluid moves from plasma to glomerular filtrate
23
Q
what is estimation of renal functional mass
A
GFR
24
Q
what is gold standard test to measure GFR but not practical
A
inulin or iohexol clearance test
25
what are the practical ways to test GFR
1. BUN, creatinine, uric acid
2. SDMA
26
what is main source of BUN
protein catabolism (urea cycle) in liver
27
renal extraction of BUN depends on __ and __, therefore the lower the flow the more __
renal blood flow and tubular function
The lower the flow the more urea reabsorbed in proximal tubules—> increase urea in blood increase BUN
28
what are some extra-renal factors that can increase or decrease BUN
1. High protein diet- increase
2. Liver failure- decrease
3. Bacterial flora in rumen and equine GI that recycle urea into protein can decrease BUN
29
What is the main source of creatinine
muscle metabolism waste product
30
which is more sensitive and specific: creatinine or BUN and why
creatinine, less affected by extra renal factors
31
how can low muscle mass affect creatinine
decrease serum concentration
32
define azotemia
increased BUN or creatinine
33
in renal failure azotemia is seen with __% of functional nephron loss
75%
34
how can high protein diet effect BUN: creatinine ratio
increase because increase protein catabolism
35
what diagnostic test is able to predict renal failure earlier then BUN and creatinine
SDMA
36
which dog breed normally have slightly higher SDMA
greyhounds
37
in avian and reptiles what is the product of protein catabolism
uric acid
38
in avian and reptiles what is the best indicator of renal function
Hyperuricemia
39
how does dehydration affect BUN
increases
40
t or f: creatinine is useful to measure GFR function in reptiles and birds
false- not produced
41
what test do we use to evaluate urine concentrating ability
USG
42
what are USG indicates hypersthenuria (concentrated) values for dogs, cats and large animals
dogs: >1.030
Cats: >1.035
Large: >1.025
43
what USG indicates partially concentrated
1.013
44
what USG indicates isothenuria
1.008-1.012
45
What USG indicates hyposthenuria
<1.008
46
If patients BW shows increase BUN, creatinine , and USG >1.025-1.035. 6% dehydrated. what type of azotemia and what does that tell you about kidneys
pre-renal azotemia- Dehydration
Hypersthenuria USG- kidneys are working and able to concentrate urine
47
hypersthenuria is expected in __patients with normal __
dehydrated with normal renal function
48
isothenuria is abnormal in __ or __ animals. What does that indicate
dehdyrated or azotemia animals
Indicates loss of renal concentrating ability
49
partially concentrated USG is abnormal in __ patients. What are some causes
azotemic patients
Causes: renal disease, extra renal: DM, hypercalcemia, liver failure
50
how would osmotic diuresis effect USG
decrease- preventing water reabsorption
51
what causes central DI
insufficient production of ADH
52
what causes nephrogenic DI
kidney not responding to ADH
53
what are some causes of nephrogenic ADH
1. Hypercalcemia
2. Canine pyometra
3. Liver failure
4. Hypokalemia
54
hyposthenuria may be normal in __ and __
neonatal cattle and horses
55
hyposthenuria is abnormal in __ but not __patients
dehydrated, but not renal failure
56
what type of USG would you expect with Central and nephrogenic DI and why
hyposthenuric
Central DI: ADH deficient- can’t pull water in
Nephrogenic DI: kidneys don’t respond to ADH: can’t pull water in
57
with renal azotemia there is a decrease in functional nephrons by __%
75%
58
how would BUN, creatinine, and USG change with renal azotemia
increase BUN and creatinine, decrease USG (isothenuria or lower)
59
how does urea production change with pre-renal azotemia
increases
60
what can cause increase in urea production
1. High protein diet
2. Increase protein catabolism
3. GI hemorrhage
61
how would BUN, creatinine, and USG change if pre-renal azotemia was caused by increase urea production
1. Increase BUN
2. No change to creatinine or USG
62
what type of azotemia would decrease renal perfusion/GFR due to dehydration or shock cause. How would BUN, creatinine and USG change
pre-renal azotemia
1. Increase BUN
2. Increase creatinine
3. Increase USG (hypersthenuria- kidneys working just dehydrated)
63
how would BUN and creatinine change with high protein diet
increase BUN, no change creatinine
64
how would BUN and creatinine change with hepatic insufficiency
decrease BUN, no change creatinine
65
how would BUN and creatinine change with GI bleeding
increase BUN and no change creatinine
66
how would BUN and creatinine change in ruminating sheep
decrease BUN, no change creatinine
67
how would BUN and creatinine change with dehydration
increase both
68
how would BUN and creatinine change with starvation
BUN increase, creatinine decrease
69
What are some diseases that can cause pre-renal azotemia with extra-renal effect on USG
1. DM
2. DI
3. Addisons
4. Hypercalcemia
70
how would DM, DI, addisons, and hypercalcemia effect BUN, creatinine, and USG
increase BUN and creatinine
Decrease USG: partially concentrated (1.013)
71
what are some causes of post-renal azotemia
1. Urethral obstruction
2. Uroabdomen
72
how does BUN, creatinine and USG change with post-renal azotemia
1. Increase BUN and creatinine
2. USG variable
73
what bloodwork finding is indicative of glomerular dysfunction. Also what finding in UA
hypoalbuminemia, proteinuria
74
hypoalbunemia can lead to __
edema
75
glomerular dysfunction/damage can also lead to lose of __ which can lead to hypercoaguability
antithrombin
76
what is nephrotic syndrome and 4 characteristics
glomerular disease and protein losing nephropathy
1. Proteinuria
2. Hypoalbunemia
3. Fasting hypercholesterolemia
4. Edema (transudate)
77
besides the 4 characteristics of nephrotic syndrome, what are some other changes seen
1. Hypercoaguability
2. Azotemia
3. Hypernatremia
4. Hypertension
78
what are some signs of defective tubular resorption/secretion
1. Glucosuria
2. Proteinuria
3. Acid base abnormalities
4. Electrolyte abnormalities
79
renal tubular dysfunction can lead to impaired __activation
vitamin D
80
renal tubular dysfunction can lead to decreased __production
erythropoietin
81
what acid base abnormality is seen in renal disease
metabolic acidosis
82
why is a metabolic acidosis seen with renal disease
decrease resorption of bicarbonate, retention of Cl- decreased excretion of hydrogen
83
what electrolyte abnormalities are seen with renal disease
1. Hyper or hypokalemia
2. Hyponatremia
3. Hypochloremia
84
when do you see hyperkalemia vs hypokalemia in renal disease
hyperkalemia: acute decrease in urine output
Hypokalemia: increase urine output, decrease K+ intake
85
what would cause hyponatremia or hypochloremia in renal disease
decreased resorption from tubular disease, increased urine output
86
Acute vs chronic kidney disease: normal to increase PCV
acute
87
acute or chronic kidney disease: non-regenerative anemia
chronic
88
acute or chronic kidney disease: hypokalemia or normal
chronic
89
acute or chronic kidney disease: severe metabolic acidosis
acute
90
acute or chronic kidney disease: hyperkalemia or normal K
acute
91
acute or chronic kidney disease: quick, marked increase BUN, creatinine
acute
92
acute or chronic kidney disease: active UA sediment possible
acute
93
what could cause hyperphosphatemia in renal disease
decrease GFR
94
what could cause hypophosphatemia in renal disease
renal failure in horses and post-renal obstruction in goats
95
what could cause hypercalcemia in renal failure
renal failure in horses
96
Describe renal secondary hyperparathyroidism
1. Increase phosphate, decrease vitamin D—> decrease Ca2+
2. Increase PTH
3. Kidney increase phosphate excretion
4. Bone increase calcium resorption
97
what type of anemia is seen with renal disease and chronic renal failure and why
normocytic, normochromic, non-regenerative anemia due to decrease erythropoietin production
98
RBC fragmentation is seen with __
glomerulonephritis
