Renal 3) Acid-base and electrolyte disturbances

Question 1

What is urea?

Answer 1

Produced by liver from excretion of ammonia and breakdown products of amino acids
Excreted in urine

Question 2

What can increase urea levels?

Answer 2

Intravascular depletion
Blood
Food
Renal failure

Question 3

What are the normal serum urea levels?

Answer 3

1.7-8.3mmol/L

Question 4

What symptoms occur when urea is above 20?

Answer 4

Nausea
Decreased appetite
Itchiness
Tiredness
Smelly breath
Metallic taste in mouth

Question 5

What symptoms occur when urea is above 60?

Answer 5

Extreme uraemia frost
Uraemic pericarditis
Encephalopathy

Question 6

What is creatinine?

Answer 6

Breakdown product of creatinine phosphate in muscle

Question 7

What are normal creatinine levels?

Answer 7

62-106umol/L depending on muscle mass

Question 8

What is the MDRD formula for eGFR?

Answer 8

186 x (creatinine /88.4)^-1.154 x (age)^-0.203 x (0.742 if female) x (1.210 if black)

Question 9

What is the normal eGFR?

Answer 9

> 90mls/min

Question 10

What is the eGFR in CKD stage 1?

Answer 10

> 90mls/min

Question 11

What is the eGFR in CKD stage 2?

Answer 11

> 60mls/min

Question 12

What is the eGFR in CKD stage 3a?

Answer 12

> 45mls/min

Question 13

What is the eGFR in CKD stage 3b?

Answer 13

> 30mls/min

Question 14

What is the CKD stage if eGFR is >15mls

Answer 14

Stage 4

Question 15

What is the CKD stage if eGFR is <15mls?

Answer 15

Stage 5

Question 16

What is the average eGFR when starting dialysis in UK?

Answer 16

8

Question 17

What are the 3 factors that can cause hyponatraemia?

Answer 17

Intra-renal factors
Defect with NaCl transporter out of thick ascending limb / distal convoluted tubule
Continued secretion of ADH stimulated by non-osmotic mechanisms

Question 18

What can decrease glomerular filtration?

Answer 18

Age
Renal disease
Congestive heart failure
Cirrhosis
Nephrotic syndromes
Volume depletion

Question 19

What can reduce NaCl reabsorption in the TAL and DCT?

Answer 19

Loop diuretics
Osmotic
Diuretics
Interstitial disease
Thiazide diuretics (DCT only)

Question 20

What can increase permeability of the collecting duct?

Answer 20

Vasopressin

Drugs

Question 21

What are normal serum K levels?

Answer 21

3.2-5.1mmol/L

Question 22

What are the causes of hypokalaemia?

Answer 22

Redistribution
Non-renal loss
Poor diet
Renal loss >20mmol/L

Question 23

What can cause a renal loss of potassium?

Answer 23

Drugs - diuretics, ahminoglycosides, amphotericin
Renal tubular acidosis or metabolic acidosis
Low BP in Bartter’s or Gitelman’s
High BP
High /low aldosterone

Question 24

What are the complications of chronic hypokalaemia?

Answer 24

Cardiovascular
 - hypertension
 - ventricular tachyarrhythmias
Endocrine - impairs insulin activity and sensitivity
Muscular - impairs muscle contraction
Renal
 - mild tubulointerstitial fibrosis
 - renal cyst formation
 - metabolic alkalosis
 - polyuria
Liver - increases renal ammonia production

Question 25

What are the causes of hyperkalaemia?

Answer 25

``` Impaired renal excretion - drugs impairing secretion - increased K load Increased intake Pseudohyperkalaemia + haemolysis ```

Question 26

What drugs can impair renal excretion of K?

Answer 26

Spironolactone Amiloride ACEi ARB

Question 27

What can increase K load?

Answer 27

Rhabdomyolysis Haemolysis GI bleed

Question 28

What is the treatment of hyperkalaemia?

Answer 28

``` Put K back into cells: - salbutamol - insulin and dextrose - sodium bicarbonate Stabilisation - calcium gluconate Removal - IV fluids and diuretics, dialysis ```

Question 29

What are the causes of metabolic alkalosis?

Answer 29

Excess alkali K+ depletion Cl- depletion

Question 30

What are the normal levels of serum calcium?

Answer 30

2.2-2.6mmol/L

Question 31

Where in the kidneys is calcium reabsorbed?

Answer 31

Loop of Henle | Distal tubule

Question 32

What hormone controls calcium levels?

Answer 32

Parathyroid hormone

Question 33

What are the normal levels of phosphate?

Answer 33

0.85-1.6mmol/L

Question 34

Describe electrolyte levels in an AKI

Answer 34

``` Normal Na High K Low bicarb Low pH High urea High creatinine Normal Ca, phosphate, PTh ```

Question 35

Describe electrolyte levels in CKD

Answer 35

``` Normal Na High K Low Bicab Normal pH High urea High creatinine High calcium, phosphate and PTH levels ```