Week 4 - C - Acute kidney injury and Chronic kidney disease

Question 1

Acute kidney injury may be due to pre renal, intrinsic renal or post renal causes What was acute kindey injury previously known as?

Answer 1

Acute kidney injury was previously known as acute renal failure

Question 2

What is acute injury defined as?

Answer 2

o Acute kidney injury is defined as a rapid reduction in renal function over hours/days, as measured by serum urea and creatinine – leading to failure to maintain fluid, electrolyte and acid-base homeostasis

Question 3

What is the measured blood creatinine in acute kidney injury for diagnosis? What happens to the urine output in acute kidney injury?

Answer 3

blood creatinine level has risen from the baseline value for that person (by 26 micromoles per litre or more within 48 hours)

blood creatinine level has risen over time (by 50% or more within the past 7 days)

The urine output greatly decreses in acute kidney injury

Question 4

• Pre-renal are those which reduce renal perfusion – this is the most common cause (40-70%) Give some example causes? (give some non drug examples which can cause the renal hypoperfusion)

Answer 4

They include major haemorrhage, hypovolaemia due to severe diarrhoea, reduced renal perfusion associated with severe sepsis, and hypotension due to cardiac causes eg. Myocardial infarction

Question 5

Renal hypoperfusion is especially worse in patients with renal artery stenosis How is renal artery stenosis diagnosed? What is heard on ausculatation during a renal examination?

Answer 5

Renal artery stenosis is diagnosed by US for blood flow to the kidneys

But gold standard is by carrying out CT angiogram

Listen for renal bruits on auscultation suggesting turbulent blood flow due to the stenosis

Question 6

Still on pre renal causes of acute kidney injury, what drugs are contraindicated? And which is contrainidcated in bilateral renal artery stenosis?

Answer 6

Do not give NSAIDs as this constricts the afferent arteriole and this could lead to even more underperfusion

Do not give ACEI/ARBs in renal artery stenosis -

o Due to reduced ATII so efferent arteriolar vasodilation - fall in GFR - increased serum creatinine

Question 7

o If renal perfusion is restored in time, renal function recovers quickly – it is reversible If renal function is not restored, what will happen?

Answer 7

Patient will undergo inrtinsic failure due to acute tubular necrosis

Question 8

What are the two main causes of acute tubular necorisis?

Answer 8

A low blood pressure causing prolonged renal hypoperfusion and nephrotoxic drugs

Question 9

What type of cast are basically always showing acute tubular necrosis?

Answer 9

Muddy brown casts

Question 10

Give an example of a nephrotoxic drug?

Answer 10

Gentamicin

Question 11

What are two other causes of intrinsic actue kidney injury?

Answer 11

Can have glomerulonephritis and acute interstitial nephritis

Question 12

destruction of large volume of skeletal muscle causing myoglobin protein to be present in renal tubules – toxic! What is this condition?

Answer 12

Rhabdomyolysis

Question 13

Post-renal AKI is due to obstruction of the urinary tract. If the patient previously had normal renal function, and has 2 kidneys, both must be obstructed to cause AKI Where must the obstuction be to cause AKI if post renal?

Answer 13

Obstruction present in the bladder or urthra to cause bilateral AKI

Question 14

What is the treatment of post-renal AKI?

Answer 14

Catheter - can go with nephrostomy

(artificial opening between kindey and skin to drain urine)

Question 15

NSAIDs as stated can cause intrinisc kidney injury they cause vasocontriction of the affterent arteriole Are NSAIDs linked to glomerulonephritis or intersitital nephritis? Whcih other drugs cause it?

Answer 15

They are linked to interstitial nephritis

Also caused by PPIs

Question 16

Acute kidney injury can lead to a patient entering hyperkalaemia as the kidney fails to secrete acid and therefore tries to compensate What is the treatment for hyperkalaemia? urgent treatment

Answer 16

Give 10ml calcium gluconate 10% intravenously.

This doesn’t lower serum potassium, but protects the heart against arrhythmias.

Give 10 units Actrapid insulin with 50ml glucose 50% intravenously.

Insulin causes potassium to move into cells.

Glucose must be given with insulin to prevent hypoglycaemia, and blood glucose level monitored.

Give 10mg salbutamol by nebuliser. β-agonists also cause potassium to enter cells.

Question 17

What type of action is the insulin analogue ActRapid? What is the chemical name for act rapid?

Answer 17

This is a short acting insulin action

Chemical name = soluble insulin

Question 18

Give the brand name of 2 rapid acting insulin analogues?

Answer 18

Novorapid and humalog

Question 19

WHat is the chemical name for Novorapid? What is the chemical name for humalog?

Answer 19

Novorapid - insulin aspart

Humalog - insulin lispro

Question 20

What is the brand name for insulin glargine? What is its type of action?

Answer 20

Brand name - Lantus

Type of action - long acting

Question 21

Give the chemical and brand name of 2 rapid and short acting insulin drugs Give the chemical and brand name of one long acting?

Answer 21

• Rapid -
  
  • Insulin lispro- Humalog
  • Insulin aspart - Novorapid
• Short -
  
  • Soluble insulin - ActRapid or
  • Humulin S
• Long acting - Insulin glargine - Lantus

Question 22

For meals, usually a rapid acting insulin is given and a long acting is given at the start of the day This is the basal bolus regime Name the options for the basal dose and the bolus doses? Bolus is given with meals

Answer 22

Basal dose - long acting -

• Insulin glargine - Lantus

Bolus dose - rapid acting -

• Insulin aspart - Novorapid
• Insulin lispro - Humalog

Question 23

What would the ECG show in signs of hyperkalaemia?

Answer 23

Peaked or ‘tall-tented’ T waves (occurs first)

Loss of P waves

Broad QRS complexes

Sinusoidal wave pattern

Ventricular fibrillation

There would be associated muscle weakness also

Question 24

In acute kidney injury, why can a person enter hyperkalaemia?

Answer 24

The kidney is failing to secrete acid and this is leading to a build up of acid in the blood causing a metabolic acidosis

The kdiney therefore tries to exchange potassium for hydrogen ions to fix the matabolic acidosis

Check ECG and bloods for life threatening hyperkalaemia

Question 25

In hyperkalaemia, none of the measures actively remove potassium from the body so what is likely to be required?

Answer 25

Haemodialysyis is likely to be required

Question 26

Arrange an ultrasound scan of the kidneys if suspected AKI. Ultrasound is needed (1) to check for obstruction (2) to check the size of the kidneys What will the size of the kidneys tell you about in chronic kidney disease vs acute kidney injury?

Answer 26

In chronic kidney disease the kidneys would have been scarred and therefore become atrophic so on ultrasound it will look small

Question 27

What is the prevalence of chronic kidney disease? (what percentage of the population is affected)

Answer 27

Approximately 11% of the population is affected

Question 28

There a 5 stages of chronic kidney disease with different eGFR values for each stage What are the eGFR values for each stage?

Answer 28

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Question 29

Which stages of chronic kidney disease is evidence of kidney damage required? What kind of evidence could this be?

Answer 29

Stages 1 and 2 Stage 1 - eGFR normal/ >90 Stage 2 - eGFR 60-90 This evidence may be proteinuria, or abnormalities on scanning.

Question 30

Examples: A patient with polycystic kidneys, identified on ultrasound, with a GFR of 100ml/min, would have which stage of CKD?

Answer 30

This would be stage 1 CKD

Question 31

A patient with scarring seen on ultrasound, caused by reflux nephropathy, and a GFR of 66ml/min, would have which stage of CKD?

Answer 31

Stage 2 CKD

Question 32

A patient with hypertension, proteinuria 1.2G/day, and a GFR of 78ml/min, would have which stage of CKD?

Answer 32

This would again be stage 2 CKD

Question 33

An 82 year old lady with a GFR of 76ml/min, normal urinalysis and a normal ultrasound scan, would have which stage of CKD?

Answer 33

This patient would not have CKD as they have no evidence of kidney damage

Question 34

After the age of 40, GFR declines by about 0.75ml/min/yr Which stages are defined by GFR values alone?

Answer 34

This would be stages 3-5

Question 35

Note that mild to moderate (Stages 1-3) CKD is common, whereas severe (stages 4-5) CKD is not. It is clear from this that most patients with early CKD DO NOT PROGRESS to advanced CKD, and never need dialysis or a renal transplant. However, almost all patients who are on dialysis did at some time have early CKD

Why is stage 3 CKD important?

Answer 35

This is because it increases the risk of cardiovascular mortality

Question 36

Patients do not suffer from symptoms due to reduced GFR until the GFR Is very low Usually below what levels before they begin to suffer from symptoms?

Answer 36

Usually a GFR below 20ml/min

Question 37

When suspecting CKD in practice What tests is carried out initially?

Answer 37

Carry out urinalysis

Question 38

proteinuria increases the risk of progression of CKD; haematuria may indicate renal disease or a lesion of the lower urinary tract

If proteinuria is present, what must be carried out to quantify the amount?

Answer 38

Carry out either a 24hour protein output or Protein: creatinine ratio test

Question 39

Can chronic kidney disease be diagnosed from one urine creatinine measurement? When may creatinine go up or down physiologically and therefore is not reliable as an indicator of renal function?

Answer 39

Needs multiple emasurememnts over a long period of time

Creatinine may go up or down physiologically

Up - very muscular perosn

Down - decreases with age as GFR decreases by about 0.75ml/min/year

Question 40

What is a complication of CKD in regards to red blood cell count and how?

Answer 40

Can lead to renal anaemia

Kidneys produce erythropoetin which causes the bone marrow to begin erythropoeisis (RBC production)

Therefore if the kidneys are damaged this will cause anaemic

Question 41

What is a complication of CKD in regards to bone disease and how? What type of hyperparathyroidism is this describing?

Answer 41

IF the kidneys ar not working they canot convert calcidiol (25OHVitamin D3) to calcitriol (1,25, diOH vitamin D3)

Therefore calcium is not absorbed from the intestines leading to an increased PTH in response to the hypocalcaemia, this causes increased bone resoprtion causing hyperphosphataemia and increasing the calcium

CKD leads to secondary hypeparathyroidism

Question 42

Stage 3 CKD with urine PCR >100mg/mmol Stage 3 CKD with progression (GFR falling by >20% over 6 months) Stage 3 CKD in younger people (age 100mg/mmol mean

Answer 42

Nephrotic syndrome

Protein:creatinine ratio >100mg/mmol

Question 43

What is the primary option for treatment of end sage renal failure?

Answer 43

Renal replacement therapy - transplant if able

Dialysis if not

Question 44

What groups of people are more likely to have chronic kidney failure?

Answer 44

Those with diabetes, hypertension, glomerulonephritis, reflux nephropathy, polycystic kidneys

Question 45

What are the symptoms of chronic kidney disease? Usually arise very late

Answer 45

These would be tirendess, poor appetite and itchy

Question 46

 Slow progression, reduce cardiovascular risk, identify and treat complications of CKD, and prepare for renal replacement therapy Which drugs will reduce the blood pressure and the proteinuria in CKD?

Answer 46

• ACEI and ARBs reduce BP and proteinuria, also evidence for spironolactone

Question 47

What may there be an initial change in when giving ACEinhibtors and is therefore important to monitor?

Answer 47

There may be an initial decrease in GFR due to the ACEI/ARBS causing vasodilation of the afferent arteriole

May also be hyperkalaemia - the decreased GFR will mean more acid meaning potassium isnt secreted