Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Clinical Biochemistry & Endocrinology 3 > Disorders of Renal Function > Flashcards

Disorders of Renal Function Flashcards

1
Q

Define plasma and serum

A

plasma: fluid surrounding blood
serum: fluid remaining after clotted cells removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is hypovoloemia?

A

volume depletion, decreased intravascular volume to salt and water or blood loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the Gold Standard?

A

reference method against which other methods are compared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is standardisation?

A

to conform to a standard (e..g. all routine methods standardised against the gold standard)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is tumour lysis syndrome?

A

potentially life threatening condition that occurs usually during cancer treatment of blood tumours due to rapid cancer cell death, leading to toxic levels of cellular material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an MI?

A

heart attack due to death heart tissue not receiving enough blood/oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is meant by nephrotoxic?

A

substance that is damaging to the kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some non-biochemical tests to asses the renal and urinary system?

A

patient history, physical examination, urine for culture/sensitivity (UTI), imaging, renal biopsy (invasive)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are biochemical tests crucial for?

A

detect renal dysfunction
indicate extent of severity
monitor disease progression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is AKI?

A

acute kidney injury
causes include hypovoloemia, renal stones/obstruction, medications, infections, TLS’s, renal insult on top of CKD (many causes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is CKD?

A

chronic kidney disease

causes: diabetes, CVD, hypertension, others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the features of an ideal biochemical marker for renal disease?

A 
simple
quick to analyse
widely available
cheap
undetectable/stable in health
correlates with degree of disease
accurate reflection of changes in disease
detects AKI/CKD early
applicable to all groups in society (age, gender, ethnicity)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the glomerulus and its function?

A

part of the nephron - interfact between blood plasma and kidney
filters blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The rate at which kidneys filter blood is defined as the

A

glomerular filtration rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the equation to calculate GFR and hence clearance (you’re gonna have to rearrange)

A

GFR*plasma = urine * rate of urine formation

clearance or GFR = urine*rate of formation/plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is clearance?

A

volume of blood plasma from which a substance is completely removed by GFR/time
(note: volume not amount of plasma passing through kidney as substance not removed by single pass through kidney)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is inulin?

A

a non-endogenous fructose polymer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is inulin used as a marker?

A

administered intravenously, is freely filtered - measured in urine and then GFR calculated using:
GFR = (inulin in urine)*rate of urine formation/inulin in plasma
Used as the gold standard - annoying to do in practice due to IV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is an issue of creatinine clearance as a marker?

A

Active creatinine secretion into urine occurs which can slightly overestimate GFR

20
Q

What are some general issues with creatinine clearance measurments?

A

urine collection - inaccurate, inconvenient, slow

based on four measurements (urine and serum creatinine, time, volume) each with their own inaccuracy

21
Q

How are single plasma creatinine measurements used to estimate GFR?

A

Creatinine concentration in blood is inversely proportional to it’s clearance (inverse standard curve)
can be used to infer clearance and GFR

22
Q

What are the advantages of using a single blood measurement of creatinine?

A

creatinine levels fairly constant in adult life
as good as urine clearance measurements
detects renal disease
quick
better than urine clearance to follow disease progression

23
Q

What are the disadvantages of using a single blood measurement of creatinine?

A

creatinine is a muscle produced compound - levels reflect renal clearance and muscle production

lower in children and women, and people with low muscle

higher in men, bodybuilders, athletes, people with high meat intake, or those taking supplements

need to use different reference ranges

24
Q

What is regression analysis

A

an equation that predicts GFR using creatinine levels and other metrics

25
Q

What is the issue with Cockcroft-Gault’s equation?

A

Uses old methods

overestimates GFR at low levels - falsely reassuring

26
Q

What is the issue with MDRD equation?

A

imprecision, underestimates GFR at high levels

doesn’t consider body weight

27
Q

What are the advantages of the MDRD equation?

A

allowed for standardisation
validated for CKD staging
uses only one biochemical marker (creatinine)

28
Q

Why is the CKD-EPI equation used clinically?

A

superior than MDRD - shows less deviance

29
Q

What is an issue with the CKD-EPI equation?

A

doesn’t consider ethnicity (which is difficult to define using a computer system)

30
Q

What are issues with estimating GFR using single blood measurements?

A

based on creatinine as a filtration marker

age, gender, ethnicity only account for some non-kidney reasons for disease

derive average relationship between variables (there will always be outlying patients)

31
Q

What are the 2 radiolabelled substances that can be used as markers - outline process?

A

51Cr-EDTA, 125I -iodothalamate
injected, blood samples taken at regular intervals over short period, GFR calculated from rate of disappearance
not convenient, useful in children (chemo), timed urine not needed

32
Q

What is urea?

A

Less toxic product of ammonia which is produced by protein catabolism (liver) and excreted in the urine (kidney)

33
Q

When GFR is low, urea levels….

A

increase

34
Q

If urea and creatinine are both high it means…

A

high chance of AKI and CKD

35
Q

Reasons for urea being significantly higher than creatinine are:

A

higher protein turnover

increased kidney reabsorption

36
Q

Why might kidney reabsorption of urea be increased?

A

reduced blood flow

outflow obstruction

37
Q

What might be a reason for increased protein turnover leading to high urea?

A

gastrointestinal bleed leading to blood in the stomach (blood meal)

38
Q

What is cystatin C?

A

cysteine protease inhibitor synthesised by all cells

39
Q

Why is cystatin C a good marker?

A

unaffected by muscle mass, diet, gender
freely filtered
levels increase and GFR drops
more accurate and reliable than creatinine

40
Q

What is NGAL?

A

neutrophil gelatinase-associated lipocalin

41
Q

Why is NGAL used as a test?

A

BGAL released due to tissue inflammation and injury
so high NGAL in blood or urine indicates insult to kidney as a result of inflammation (AKI)
may rise earlier than other markers

42
Q

What is an issue with urinalysis?

A

subjective due to colour being judged by eye
need to check use-by date
time sample collection (morning)

43
Q

What are the 3 types of proteinuria?

A

overflow: raised plasma concentration of low MWT proteins, exceeding resoprtive capacity of tubules
glomerular: increased permeability of glomerulus
tubular: decreased resorption

44
Q

Why is dipstick protein measured as a ratio alongside creatinine?

A

to account for variation in urine concentration

45
Q

What is microalbuminura?

A

Albumin higher than normal in urine due to glomerular proteinuria, but too low to be tested by dipstick

46
Q

How many stages of AKI are there and how are they decided/diagnosed?

A

3
increasing serum creatinine
decreasing urine output/anuria

47
Q

How is CKD diagnosed?

A

eGFR from CKD-EPI equation
albumin:creatinine ratio
use of cystatin C in patients with mild/moderate renal impairment

Clinical Biochemistry & Endocrinology 3 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions