electrolyte and acid base talk

Question 1

what is the normal level of urea?

Answer 1

»Serum Urea 1.7- 8.3 mmol/l

Question 2

when is urea decreased?

Answer 2

liver disease

Question 3

when is uread increased?

Answer 3

• intravascular depletion
• blood meal
• renal failure

Question 4

what symptoms will you get if urea >20

Answer 4

Nausea,

decreased appetite,

itchiness,

tiredness,

smelly breath,

metallic taste in mouth,

Question 5

what symptoms do you get if urea>60

Answer 5

extreme ureamic frost,

uraemic pericarditis,

encephalopathy

Question 6

how are ckds characterised in terms of EGFR?

Answer 6

»CKD 1 eGFR >90mls

»CKD 2 eGFR >60mls

»CKD 3a eGFR >45mls

»CKD3b eGFR > 30mls

»CKD 4 eGFR > 15mls

»CKD 5 eGFR < 15mls

Question 7

What is the average EGFR fpr starting dialysis in the uk?

Answer 7

8

Question 8

what can cause hyponatraemia?

Answer 8

Intra-renal factors

Defect with Na/Cl transport out of TAL/DCT

Continued secretion of ADH, stimulated by non-osmotic mechanism

Question 9

what is the serum k level normally?

Answer 9

»Serum K = 3.2-5.1 mmol/L

Question 10

which things cause hypokalaemia by redistributing potassium back into the cells?

Answer 10

˃insulin, theophylline, adrenergic use- like salbutamol

Question 11

what things can cause potassium loss >20mmol/l?

Answer 11

• Drugs, diuretics, aminoglycosides, amphotericin- antibiotics and antifungals
• RTA or metabolic acidosis
• Low BP Bartter’s or Gittlemans- structural glomerular issues
• High BP
• High Aldosterone normal Cortisol – hyperaldoseronism
• Low Aldersterone normal cortisol - Liddle’s
• Low Aldersterone high Cortisol – Cushings Syndrome

Question 12

what are chronic cardiac complications of hypokalaemia?

Answer 12

˃Cardiovascular

+Hypertension

+Ventricular tachyarrhythmias

Question 13

what are endcrine complications of chronc hypokalaemia?

Answer 13

˃Endocrine

+Impairs insulin activity & sensitivity

Question 14

what effect does chronic hypokalaemia have on muscles?

Answer 14

+Impairs muscle contraction (weakness)

Question 15

what effects does long term hypokalaemia have on the kidneys?

Answer 15

+Mild tubulointerstitial fibrosis

+Renal cyst formation

+Metabolic alkalosis (increased net renal acid excretion)

+Polyuria

Question 16

what is the effect og chronic hypokalaemia on the liver?

Answer 16

+Increases renal ammonia production which may worsen hepatic encephalopathy

Question 17

what is the cause of hyperkalaemia?

Answer 17

1) Impaired renal excretion- CKD4/5

+Drugs impairing secretion – Spironolactone, amiloride, ACE-I, ARB

+Increased K load – rhabdomyolysis, haemolysis, GI bleed

2) Increased intake
3) Pseudohyperkalaemia

+haemolysis

–during blood collection/storage

–Rheumatoid/infectious mononucleosis

Any increase in plasma (or serum) potassium resulting from in vivo hemolysis is true hyperkalemia. By contrast, in vitro hemolysis is a process that only occurs in blood removed from the body and is due to mechanical disruption of erythrocytes induced by the process of blood collection and handling.

Question 18

what are the 3 strategies for treating hyperkalaemia?

Answer 18

1. Back into cells

˃Salbutamol, insulin and dextrose, sodium bicarbonate( if acidotic)

2. Stabilisation

˃Calcium gluconate- stabilises the cardiac membrane

3. Removal

˃If passing urine, Pee it out, iv fluids and diuretics

˃dialysis

Question 19

what is the treatment of metabolic acidosis when it is severe <7.2

Answer 19

»isotonic NaHCO3 1.26%

Question 20

what is a risk of giving exogenous sodium during metabolic acidosis?

Answer 20

»Exogenous Na load can exacerbate fluid overload & Htn

Question 21

how does the kidney respond to metabolic alkalosis?

Answer 21

˃K+ depletion

˃Cl- depletion

Question 22

where is calcium reabsorbed?

Answer 22

loop of Henle and distal tubule

Question 23

what is the normal serum calcium

Answer 23

2.2-2.6mmol/l

Question 24

what is normal serum phsphate?

Answer 24

»0.85 to 1.6mmol/l

Question 25

what is the effect of CKD on phosphate?

Answer 25

• less activation of vitamin D
• stimulates PTH
• causes release of potassium and calcium from bones