L81 - Biochemical Investigation of Urogenital Diseases II Flashcards Preview

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Flashcards in L81 - Biochemical Investigation of Urogenital Diseases II Deck (70):
1

Major urinary proteins?

IAABRC

-IgG

-Albumin

-a1-Microglobulin

-Retinol Binding
Protein (RBP)

-Cystatin C

-B2-Microglobulin

2

Filtration of protein in down to which metrics?

molecular size (20 - 40A)

protein molecular mass ( 30 - 70kDa)

Charge

3

How does charge influence protein filtration?

Negatively charged molecules have lower permeability

4

Proportion of Albumin relationship with severity of proteinuria?

proportion of Albumin increases with increasing severity of proteinuria

5

Normal daily excretion of protein? What protein makes up 40-50% excretion?

< 150 mg;

about 40 - 50% is Albumin

6

3 types of proteinuria?

Glomerular

Tubular

Overflow

7

What causes glomerular proteinuria?

Increased glomerular permeability

8

What causes overflow proteinuria?

Increased plasma concentration of
relatively freely filtered proteins

9

What is the consequence of glomerular proteinuria?

Progressively increasing excretion
of higher molecular weight proteins

because permeability increases

10

Give 5 CAUSES of tubular proteinuria?

1) PCT damage
2) DCT damage
3) Decreased nephron number

4) Orthostatic proteinuria
5) Transient proteinuria

11

What is the consequence of PCT damage in Tubular proteinuria?

decreased tubular reabsorptive capacity and/or release of intracellular components

12

What is the consequence of damaged nephron number in Tubular proteinuria?

Decreased nephron number:
increased filtered load per nephron

13

Give examples of proteins excreted due to overflow proteinuria?

-Bence Jones protein (BJP)

-Lysozyme

-Myoglobin (not haematuria but due to breakdown)

14

What is orthostatic proteinuria?

Protein excretion varies with posture,

increasing on standing/
prolonged upright posture

15

What is transient proteinuria?

Mild to moderate proteinuria

due to systemic illnesses apparently not related to the kidneys

16

Give examples of causes of transient proteinuria?

-high fever,
-congestive heart failure,
-seizures

-strenuous exercise
-urinary tract infection

17

What is the normal urinary albumin: creatinine ratio in male and female?

≤2.5 (males)
≤3.5 (females)

18

Normal Urine Reagent
Strip (‘dipstick’) reading?

Negative

19

Normal Urine Protein:
Creatinine ratio mg/mmol?

<15 mg/mmol

20

Normal Urine Total
Protein Excretion g/24h?

<0.15 g/24h

21

Urinary protein measurements should be taken in What new discovered changes in blood metrics?

raised serum creatinine / reduced GFR

haematuria (esp. microscopic haematuria)

22

What is urinary protein measurement for?

Assessment of severity of known kidney disease

(e.g.Structural renal tract disease, recurrent renal calculi)

23

Urinary protein measurement should be included when initially assessing which patients?

patients with hypertension

patients with newly diagnosed type 2 diabetes

Family history/ hereditary stage 5 CKD

Suspected multisystem disease, e.g., SLE

24

2 methods to collect urine protein specimen? (think timing)

Timed: 24-hour, 12-hour overnight, 4-hour

Random: assess Urine Protein / Creatinine ratio

25

Dipstick method for urrine protein is sensitive to what protein? The dipstick is poort for detecting what?

• Most sensitive to albumin

• Poor method for detecting tubular proteinuria

26

Name of reagent in dipstick and colour change in detecting protein?

Tetrabromphenol blue

green in the presence
of protein

yellow in its absence

27

Why is Dipstick a Poor method for detecting tubular proteinuria?

less sensitive to globulins, Bence Jones protein, mucoproteins, and hemoglobin

28

How does Sulfosalicylic acid change with increasing protein concentration?

Increasing turbidity/ opaqueness

More and more precipitated until Flocculent precipitate

29

Name some drug that can cause false positive proteinuria in urine dipstick or Sulfosalicylic acid?

Sulfonamide

High levels of penicillin or cephalosporin

Radiocontrast media

Urine pH > 8

30

How to collect 24h urine sample?

First void of the day should be discarded


all urine passed in the next 24 hours collected

31

2 main Disadvantages of timed urine collection?

inconvenient for patients

significant inaccuracies: incomplete collection, timing errors, intra-individual
variation

32

Spot urine specimen usually done when?

Can choose random spot specimen or first morning spot specimen

UACR test most accurate with morning spot test

33

Which method is used: timed 24 hours or Spot urine Pr/Cr ratio ?

Spot urine Pr/Cr ratio

34

In individuals with large muscle mass, how does the UPCR or UACR test result chnage?

creatinine excretion may be much higher than
average population

>> UPCR (or UACR) will
underestimate proteinuria

35

Cachectic patient or a patient with small muscle mass, how does the UPCR or UACR test result chnage?

creatinine excretion may be much lower than average population

>> UPCR (or UACR)
will overestimate proteinuria

36

What is UPCR and UACR?

Urine protein: creatinine ratio

Urine albumin: creatinine ratio

37

Factors affecting urinary albumin: creatinine ratio?

Transient elevation in
albuminuria (e.g. exercise, posture, UTI)

Intraindividual variability

Non-renal causes of
variability (e.g. age, race, gender)

38

What is urine albumin a marker for?

marker of the risk of development of renal damage in diabetic patients

39

Elevated urine albumin is an established marker of What?

cardiovascular risk in the diabetic and nondiabetic
populations

40

What does microalbuminuria indicate?

increase in urinary excretion of
albumin

above the reference interval for healthy
nondiabetic subjects

41

What is the 24h urinary albumin for microalbuminuria and macroalbuminuria?

Micro = 30-300mg/day

Macro = >300mg/day

42

How does albumin exretion rate change with time for a type I DM patient?

Steadily increases until it overtakes GFR which steadily drops >> renal failure

43

What is the initial compensation mechanism of increased albumin loss?

Hyperfiltration

44

Serum creatinine starts rising at which stage of CKD?

After stage 2

When eGFR is lower than 60

45

Microalbuminuria starts at which stage of CKD?

Stage 1

>90 eGFR

46

Why should albuminuria be confirmed on at least 2 occasions?

high biological variability and nonrenal influences

47

Measurement of what allows the use of spot sample?

Urine albumin-to-creatinine ratio

48

What is the triad of nephrotic syndromes in relation to serum protein?

triad of heavy proteinuria, hypoalbuminemia,
and edema

49

Criteria of proteinuria for nephrotic syndrome?

Proteinuria > 3.5 gm/day/1.73 m2

50

Explain what occurs in rhabdomyolysis?

Large amounts of myoglobin are released into the plasma,

saturating the tubular reabsorptive mechanism

51

What happens to myoglobin in kidney normally?

catabolized by endocytosis and proteolysis

in PCT

52

What can myoglobinuria cuase?

directly toxic to the renal tubules

acute tubular necrosis with acute kidney injury

53

What are the 2 diagnostic tests for myoglobinuria?

plasma creatine kinase, urine myoglobin

(Positive reaction with hemoglobin reagent
strip tests)

54

What are some physical and chemical promoters of renal stone formation?

Chemical = calcium, urate, sodium

Physical = urinary tract obstruction, stasis

55

What 3 factors cause supersaturated solution of salt which can form renal stone?

Urinary volume decrease

Excess excretion of stone components

pH increase

56

What are some predisposing factors for renal stones?

Metabolic disorders

Hot climate

Protein rich diet

57

Why know the type of renal tone helps?

helps delineate
the best treatment option + identification of risk factors = prevent
recurrence

e.g. Targeted therapeutic intervention or medical prophylaxis for recurrence

58

Does renal stone analysis reflect the functional status of the
kidneys?

no

59

Name some high risk conditions for recurrent renal stone formation?

Residual stone fragments

Uric acid and urate stones

Hyperparathyroidism

Nephrocalcinosis (increase Ca)

Family history of stones/ genetic determined stones

60

Name some genetic determined stones?

- Xanthine
- Cystic fibrosis
- Cystinuria

61

What are the 3 analysis needed for treating renal stones?

Renal stone analysis

Blood and urine analysis

62

What are the 5 common types of stones?

CPC MAP CUACO

Calcium Phosphate/Carbonate

Magnesium, Ammonium and Phosphate (Struvite
stones)

Calcium Oxalate

Uric acid

Cystine

63

What causes Calcium Phosphate/Carbonate stones?

primary hyperparathyroidism or renal tubular acidosis

64

What causes Magnesium, Ammonium and Phosphate (Struvite
stones) stones?

urinary tract infections >> urease-producing organisms

>> (e.g. staghorn
calculus)

65

What causes Calcium Oxalate stones?

aetiology often obscure

e.g. idiopathic hypercalciuria, excess calcium ingestion, hyperparathyroidism

66

Which renal stone is the most common?

Calcium oxalate

67

What causes Uric acid stones?

consequence of hyperuricaemia

68

What causes Cystine stones?

very rare, associated with cystinuria

69

What biochemical markers are checked in lab investigation of renal stones?

24h Urine sample:
check volume, and all the ions in diff. types of stones

Early morning urine: pH, amino acids, microscopy and culture

Blood:
check ions in stones

70

What techniques are replacing biochemical investigation of renal stones?

infrared spectroscopic study and diffraction
crystallography

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