AKI and CKD

Question 1

list some risk factors for AKI

Answer 1

CKD (eGFR <60 and/or hx of proteinuria)
age >75yrs
HF
Liver disease
CVD (previous MI, stroke, PVD)
DM
recent use of nephrotoxins

Question 2

List the 2 things that can be measured to stage AKI

Answer 2

• serum creatinine

- urine output

Question 3

in the KDIGO staging system for AKI, what would stage 1 be defined as?

Answer 3

• rise of >26 micromol/L within 48hrs
  or
• rise of >1.5 - 1.9x baseline serum creatinine
  or
• <0.5mL/Kg/hr urine output for >6 consecutive hrs

Question 4

list 4 common causes of AKI

Answer 4

• sepsis
• hypoperfusion
• medications
• obstruction

Question 5

on examination what could you do to test teh fluid status of a pt?

Answer 5

• cap refill (<3s)
• PR
• BP
• skin turgor
• JVP
• Oedema
• fluid balance charts
• daily weights

Question 6

List 5 complications of AKI

Answer 6

• hyperkalaemia
• acidosis
• acute confusion (uraemic encephalopathy)
• pulmonary oedema
• pericarditis

Question 7

What would you want to be looking for in the biochemistry profile of a person with AKI?

Answer 7

Urea
LFTs
electrolytes
Glucose
Creatinine
Bone profile
Bicarbonate

Question 8

what would you be looking for in a full blood count in someone with AKI?

Answer 8

looking for evidence of haemorrhage or sepsis.

low platelets may occur with sepsis or haemolytic uraemic syndrome/thrombotic thrombocytopenic purpura

Question 9

why would you do urinalysis on someone with AKI?

Answer 9

to check for abnormal protein or blood.

to rule out UTI

Question 10

A pt comes in with AKI and has previous cardiovascular problems which he takes medication for and he has a low BP. what immediate therapy would you do?

Answer 10

IV fluid therapy – fluid challenge = 500 mL 0.9% NaCl over fifteen minutes
Withdrawal of nephrotoxins
Withholding of hypotensive agents and diuretics
Withhold atorvastatin

Question 11

a mnemonic for remembering some nephrotoxic drugs is SADMANGON - list the drug classes

Answer 11

Sulphonylureas
ACEi/ARBs
Diuretics
Metformine
Aldosterone inhibitors
NSAIDs
Gabapentin
Opioids
NOACs (fractionated heparins)

NB penicillin-based abx, aminoglycosides and aciclovir are also nephrotoxic

Question 12

Name 3 principles of managing AKI

Answer 12

1. optimise intra-vascular fluid volume - IV fluids
2. optimise BP - withhold drugs that interfere with renal autoregulation (ACEi. ARBs), temporarily stop all drugs that induce hypotension (hypertensives)
3. Prescribe appropriately - stop and avoid nephrotoxic drugs

Question 13

why does serum potassium sometimes increase in AKI?

Answer 13

mainly due to reduced renal potassium excretion due to AKI combined with the actions of potassium sparing drugs (e.g. spironolactone) and ACEi whcih reduce the effect of aldosterone.

Question 14

what effect does NSAIDs and ACEi have on the kidney arterioles?

Answer 14

NSAIDs cause vasoconstriction of afferent arteriole.

ACEi’s cause vasodilation of efferent arteriole so together they reduce eGFR.

Question 15

what symptoms can you get with hyperkalaemia?

Answer 15

usually asymptomatic.

can get weakness, paraesthesia, palpitations

Question 16

what are the signs on an ECG of hyperkalaemia?

Answer 16

• peaked T-waves
• prolonged PR interval and eventual loss of p-wave
• QRS widening
• AV dissociation
• VF or VT

Question 17

How do you treat mild hyperkalaemia caused by AKI?

Answer 17

treat the cause of AKI

Question 18

when should you treat hyperkalaemia in AKI?

Answer 18

if K>6.5 mmol/L or if there are ECG changes

Question 19

what is the immediate treatment of hyperkalaemia if K+ is >6.5mmol/L or there are ECG changes?

Answer 19

IV 10ml 10% calcium gluconate over 2-5mins.

note that this is to stabilise the myocardium but has no effect on serum potassium conc.

Question 20

what cells in the kidney tubules are responsible for responding to changes in the rate of flow and the composition of tubule fluid?

Answer 20

Macula densa cells

Question 21

hypokalaemia can increase the effects and toxicity of certain drugs. name 2 classes

Answer 21

cardiac glycosides (digoxin).
class III antidysrhythmic drugs

Question 22

which class of diuretics are considered the most powerful? Give 2 examples

Answer 22

loop diuretics e.g. furosemide, bumetanide

Question 23

name some adverse effects of look diuretics

Answer 23

• hypovolaemia and hypotension
• hypokalaemia and metabolic acidosis
• hyperuricaemia whcih can ppt gout
• reduced renal perfusion and pre-renal impairment

Question 24

in what situation would you give IV furosemide rather than oral?

Answer 24

for urgent situations e.g. acute pulmonary oedema

or when intestinal absorption is impaired.

Question 25

what equation can be used to measure the creatinine clearance?

Answer 25

Cockcroft-Gault

Question 26

renal funciton measured in terms of GFR is calculated from a formula derived from what study?

Answer 26

the Modification of Diet in Renal Disease study (‘MDRD formula’)

Question 27

For most people, eGFR can be used to adjust drug doses. in what situations would you use creatinine clearance calculated from teh Cockcroft and Gault formula to adjust drug dosages?

Answer 27

1. for potentially toxic drugs with a small safety margin

2. in pts at both extremes of weight (BMI <18.5 or >30

Question 28

What drugs, metabolised and excreted by the kidneys, need to be dose adjusted for in a pt with an eGFR of <10?

Answer 28

MAPS OF:
Metformin
Aciclovir
pencillin-based abx
Sulfonylureas
Opiates
Fractionated heparins

Question 29

Name 3 drugs that require close monitoring in someone with renal failure

Answer 29

1. Warfarin
2. Aminoglycosides - e.g. gentamicin, tobramycin
3. Lithium

Question 30

Name 3 drugs that aggravate hyperkalaemia by blocking renal excretion of potassium

Answer 30

1. Trimethoprim
2. Spironolactone
3. Amiloride (potassium-sparing diuretic)

Question 31

Name 4 things you would do in an initial assessment when suspecting AKI

Answer 31

1. ABCDE assessment
2. observations - check NEWS score
3. look for signs of sepsis
4. Abdominal palpation to look for full bladder