CKD and renal failure

Question 1

What happens when the homeostatic functions of the kidney fail?

Answer 1

• inc. potassium (due to dec. secretion and acidosis)
• dec. bicarbonate (due to dec. reabsorption)
• dec. pH (metabolic acidosis)
• inc. phosphate
• salt and water imbalance–> usually reduced secretion-leads to hypertension, oedema, pulmonary oedema

Question 2

What happens when the endocrine functions of the kidney fail?

Answer 2

• dec. calcium (due to lack of 1 alpha-hydroxylase vitamin D)
• phosphate retention
• inc. PTH (negative feedback)
• anaemia (due to lack fo erythropoietin) in chronic cases

Question 3

What happens when the excretory functions of the kidney fail?

Answer 3

• inc. urea
• inc. creatinine
• dec. insulin requirement (as they aren’t excreting it)

Question 4

Why might you be tachypneic with normal oxygen sats and clear lungs on auscultation?

Answer 4

increased respiratory rate to compensate for metabolic acidosis (–> CO2 decreases as breathing out more)
‘Kussmaul respiration’
N.B. oxygen might be slightly raised

Question 5

What scan would you do in A+E if someone comes in with kidney failure?

Answer 5

ultrasound- size, obstruction

Question 6

When might you see salt+water loss in kidney failure?

Answer 6

tubulointerstitial disorders- damage to concentrating mechanism –> hypovolemia

Question 7

What might decreased skin turgor indicate?

Answer 7

hypovolemia

Question 8

How does metabolic acidosis in renal failure contribute to hyperkalaemia?

Answer 8

elevated H+–> goes into cells then leaves, through H+/K+ ATPase, so K+ comes in–> into blood

N.B. give bicarbonate to treat hyperkalaemia in acute setting–> so H+ goes down and K+ can go back into cells

Question 9

What causes the anorexia and muscle catabolism in renal failure?

Answer 9

metabolic acidosis

Question 10

What are the symptoms of chronic hyperkalaemia?

Answer 10

• cardiac arrythmias
• neural and muscular activity
• vomiting

Question 11

What ECG can changes occur in arrhythmia due to hyperkalaemia?

Answer 11

• peaked T waves
• P wave broadens, reduces in amplitude, then disappears
• QRS widens
• heart block
• asystole
• ventricular tachycardia, ventricular fibrillation

Question 12

What is the most likely cause of death in a patient with CKD?

Answer 12

cardiovascular disease

Question 13

How do you manage a hypervolaemic patient?

Answer 13

trial diuretics to drive fluid off (but if no bring output, then do dialysis)

Question 14

How do you treat hyperkalaemia?

Answer 14

• drive into cells: give sodium bicarbonate, or give insulin dextrose (but risk of hypoglycaemia)
• drive out of body: give diuretics/dialysis
• stop gut absorption: give lactulose to cause diarrhoea, use potassium binders (so you poo it out)

Question 15

What is the long term management for kidney failure?

Answer 15

• ideal= transplantation (but contraindicated in certain groups)
• conservative treatment:(for elderly): erythropoietin injections/IV iron for anaemia, phosphate binders, low phosphate diet, diuretics to correct salt/water overload, vit D supplements, other symptom management
• dialysis: home- haemodialysis or peritoneal dialysis OR in centre harm-dialysis (4h 3x a week)

Question 16

Why should you avoid transfusion in transplantable patients with kidney disease?

Answer 16

you sensitise them–> they make antibodies–> likely transplant failure

Question 17

When is creatinine used to assess GFR?

Answer 17

to look at the trend over time in a patient (not that useful when comparing different patients, as affected by muscle mass, age, race, sex etc…)

Question 18

What is taken into account in the NICE guidance classification of renal patients?

Answer 18

eGFR and albuminuria (leaking protein)

N.B. greatest risk= severely reduced GFR+ severely increased albuminuria