Clinical Biochemistry 2

Question 1

What function of kidneys?

Answer 1

Passive filters

Question 2

Describe renin-angiotensin-aldosterone system

Answer 2

Renin acts on angiotensinogen + converts it to angiotensin 1
ACE from lungs convert 1 to 2
2 increases sympathetic activity, increases aldosterone secretion = increases H2O retention, increases vasoconstriction = increase blood pressure + ADH release = increase H2O absorption

Question 3

How to measure renal function?

Answer 3

Creatinine used as proxy marker for GFR = filtered by kidneys + not reabsorbed
= measurement of creatinine clearance

Question 4

How do we calculate creatinine clearance?

Answer 4

                             SrCr

Question 5

What is mild impairment for creatinine clearance?

Answer 5

50-20ml/mins

Question 6

What is moderate impairment for creatinine clearance?

Answer 6

20-10ml/min

Question 7

What is severe impairment for creatinine clearance?

Answer 7

<10ml/min

Question 8

When is it inherently inaccurate?

Answer 8

Significant muscle wastage present
Patients with low muscle mass
Cachexic patients
Rapidly changing serum creatinine levels

Question 9

MORD EQUATION

Answer 9

LOOK AT NOTES

Question 10

What is problem is MORD equation?

Answer 10

Not validated in all racial groups, children, pregnant, kidney transplant, diabetic + those with reduced muscle mass

Question 11

When is urea produced?

Answer 11

In liver following deamination of amino acids

Question 12

What is urea cleared by?

Answer 12

GF

Question 13

Why is urea important?

Answer 13

Major source of nitrogen for the body

Question 14

What is some urea reabsorbed by?

Answer 14

Passive tubular reabsorption

Question 15

How much that is filtered by GF reabsorbed?

Answer 15

50%

Question 16

When does urea increase?

Answer 16

Infection, gastric blood loss, dehydration

Question 17

When does urea decrease?

Answer 17

Low protein diet, dialysis, loss of hepatic function + pregnancy

Question 18

What is 90% of potassium available for?

Answer 18

Exchange

Question 19

Where is other 10% of K+?

Answer 19

Bound to RBCs + other tissues

Question 20

How is K+ obtained?

Answer 20

Diet + reabsorption in kidneys

Question 21

Why are serum K+ levels important?

Answer 21

Influence membrane potential

Question 22

What can happen in acidosis?

Answer 22

= hyperkalaemia

Question 23

What can happen in alkalosis?

Answer 23

= hypokalaemia

Question 24

What is aldosterone + renin-angiotensin aldosterone system important for?

Answer 24

K+ haemostasis

Question 25

How are Na+ + K+ closely related?

Answer 25

Na+ actively reabsorbed, K+ moves into filtrate to balance membrane potential

Question 26

What is 70% of Na+ available for?

Answer 26

Exchange

Question 27

Where is the other 30% of Na+?

Answer 27

Held in bones

Question 28

What link between Na+ + H2O?

Answer 28

H2O never lost without Na+ - vice-versa

Question 29

What is hyponatremia?

Answer 29

Serum Na+ < 135mmol/L | Excess H2O relative to Na+

Question 30

What is hyponatremia due to?

Answer 30

Defective homeostatic mechanisms

Question 31

What do you need yo develop hyponatremia?

Answer 31

Source of free H2O Impaired ability of urine to excrete dilute urine Reduced solute intake Poor renal function

Question 32

What are the symptoms of hyponatremia?

Answer 32

``` Cerebral oedema Confusion Seizures Coma Brain herniation ```

Question 33

What is hypernatremia?

Answer 33

Decrease in H2O relative to Na+

Question 34

What does there have to be for hypernatremia?

Answer 34

Impaired thirst mechanisms or lack of access to H2O

Question 35

What can hypernatremia be caused by?

Answer 35

Drugs or drinking sea water

Question 36

What is microalbuminuria?

Answer 36

Loss of albumin >30mg/L

Question 37

What does total protein loss reflect?

Answer 37

Greater % of albumin rate | = reflective of nephrotic syndrome