Week 5 - B - Acute kidney injury lecture (more depth)

Question 1

What did acute kidney injury used to be known as?

Answer 1

Acute renal failre

Question 2

What is acute kidney injury defined as?

Answer 2

Rapid reduction in renal function over hours/days as defined by measuring the serum urea and creatinine

Question 3

What are the measurements for diagnosing acute kidney injury?

Answer 3

Rise in serum creatinine by 26.4micromoles/l in the past 48 hours Serum creatinine level has risen over time (by 50% or more within the past 7 days) Oliguria (less than 0.5ml per kg per hour for more than 6 hours) (less than 400mls per day)

Question 4

is acute kidney injury a description or a ddiagnosis?

Answer 4

Acute kidney injury is a description , not a diagnosis

Question 5

Acute kidney injuries can arise from 3 ways Name the 3 ways?

Answer 5

Pre renal Renal Post renal

Question 6

What are causes of pre renal AKI?

Answer 6

o Hypovolaemia  Major haemorrhage  Volume depletion (diarrhoea + vomiting, burns) Also drugs NSAIDs and ACEi/ARBS

Question 7

What is the name of the syndrome that can also cause AKI?

Answer 7

Hepatorenal syndrome - life-threatening medical condition that consists of rapid deterioration in kidney function in individuals with cirrhosis or fulminant liver failure.

Question 8

How does the liver cirrhosis lead to kidney failure in hepatorenal syndrome? What drug can be given for treatment?

Answer 8

Cirrhosis - causes portal hypertension - causes splanchnic vasodilation Decreases effective arterial blood volume Activation of RAAS system Causes renal vasoconstriction Kidneys become underperfused HEPATORENAL SYNDROME OCCURS -treat wth terlipressin for the kidneys

Question 9

If there is a decrease in renal perfusion, what is the normal physiological response?

Answer 9

Decrease in renal perfusion cuases the RAAS system to act, this causes angiotensin 2 to vasoconstriction the efferent arteriole leading to a minatined GFR

Question 10

If a patient is hypotensive, why would giving an ACE inhibtor precpitate AKI?

Answer 10

Will cause vasodilation of the effernet arteriole leading to a decreased GFR - worsen the oliguria

Question 11

The kidneys are 0.5% of body weight What percentage of the cardiac output do they receive?

Answer 11

Receive 20% of the cardiac output

Question 12

What does untreated AKI lead to?

Answer 12

This will lead to acute tubular necorosis

Question 13

What is the treatment of pre renal acute renal failure?

Answer 13

Control the hypovalaemia by giving IV fluids

Question 14

What are other causes of acute tubular necrosis that isnt hypovalaemia?

Answer 14

Common causes include sepsis and severe dehydration Other important causes include rhabdomyolysis and drug toxicity

Question 15

How does rhabdomyolysis cause acute kidney injury?

Answer 15

Due to eg a woman has fallen and laid on the foor for days, sskeletal muscle breaks down releasing myoglobin, this is toxic to the kidneys and cause acute tubular necrosis causing acute kidney injury

Question 16

Diseases causing inflammation or damage to cells causing AKI This is renal AKI What are some things that can cause this?

Answer 16

Ischaemia to the kidneys, drugs, vasculitis, glomerulonephritis , interstitial nephritis

Question 17

What can cause interstitial nephritis?

Answer 17

NSAID s, infection eg TB and sarcoidosis

Question 18

What are some clues to vascutiis/glomerulonephritis causes?

Answer 18

Sore throat, haemopytisis , join pain

Question 19

What investigation can cause AKI if you do not hydrate the patinet?

Answer 19

Contrast CT scan

Question 20

What type of urinary casts are specific to acute tubular necrosis?

Answer 20

Muddy brown casts

Question 21

What is the most common causes of renal AKI?

Answer 21

wegeners granulomatosis (GPA) and microscopic polyangitis

Question 22

Accelerated hypertension can be a cause of AKI What can this show on histology of the kidney?

Answer 22

• Fibrinoid necrosis is seen in arterioles and in glomerular tufts and multiple cortical petechial haemorrhages

Question 23

What is the commonest cause of renal failure in children under 5years old?

Answer 23

E.Coli 0157

Question 24

What can E.coli 0157 cause that damages the kidneys?

Answer 24

It can release a verotoxinnthat causes haemolytic uuraemic syndrome

Question 25

What is the classic triad of haemolytic uraemic syndrome?

Answer 25

Kidney failure - uraemia, thrombocytopenia (low platelets) and haemolytic anaemia

Question 26

If the patient presents with haemapreoteinuri and haemoptysis What should you test for? What do you think is the cause?

Answer 26

Test for ANCA (c-ANCA PR3) - wegener's granulomatosis and Anti-GBM anitbody - Goodpasture's syndrome

Question 27

What is post renal failure due to?

Answer 27

Obstruction lead to back pressure in the kidneys causing oliguria

Question 28

What is the treatment of post renal causing acute kidney failure?

Answer 28

Catheterisation or Nephrostomy

Question 29

What is it important to check in acute kidney injury?

Answer 29

Check the blood pressure - patinet could require fluid and also check ureas and electrolytes

Question 30

What are examples of things that can cause obstruction in post-renal failure?

Answer 30

Stones, tumours, strinctures

Question 31

Hyperkalaemia Fluid Overload (Pulmonary oedema) Severe Acidosis Uraemic pericardial effusion Severe Uraemia These are life threatening complications of acute kidney injury What pH is the severe acidosis? What level is the uraemia?

Answer 31

Hyperkalaemia Fluid Overload (Pulmonary oedema) Severe Acidosis (pH 40)

Question 32

What is the hyperkalaemia associated with? What concentration of potassium is life threatening?

Answer 32

It is associated with cardiac arrythmias which can lea to cardiac arrest Potassium - \>6.5mmol/l

Question 33

How is the hyperkalaemia seen?

Answer 33

Seen on ECG as tall tented Twaves Muscle weakness

Question 34

What is the medical treatment for hyperkalaemia?

Answer 34

To protect myocardium from arrythmias 10%, 10ml calcium gluconate IV over 2minutes To move potassium back into the cell Give 10 units of actrapid insulin with 50mls50% dextrose Nebulised salbutamol (10mg)

Question 35

The life threatening effects of acute kidney failure require treatment What are the life threatening effects again?

Answer 35

Hyperkalaemia Fluid overload (pulmonary oedema) Severe acidosis (less than 7.15) Uraemic pericardial effusion Severe uraemia - greater than 40

Question 36

What is the treatment for the life threatening effects f AKI?

Answer 36

Give the patinet haemodialysis

Question 37

Mortality AKI alone 10-30% AKI with one other organ dysfunction 30-50% AKI as part of multiorgan failure 70-90% What are the recovery outcomes for acute kidney injury?

Answer 37

Recovery 10-15% do not recover 5-10% recover but have progresssive CKD The rest recover

Question 38

When carrying out an ultrasound in acute kidney injury, this may help determine whether it is an exacerbated unnoticed CKD or actually AKI What would you see on US?

Answer 38

o Suspect chronic disease if patients have small kidneys (\<9cm) on USS – but the only definite sign of chronic disease is previous blood results showing high creatinine/low GFR

Question 39

There is a KDIGO (kidney Disease - Improving Global Outcomes) of acute kidney injuery What is the serum creatinine criteria in stage1?

Answer 39

Increase \>26µmol/L or Increase \> 1.5-1.9 x reference Cr

Question 40

What is the urine output in stage 1 KDIGO classification?

Answer 40

Les sthan 0.5 ml/kg/hr for \>6hours

Question 41

What is the serum creatinine and urine ouput criteria for stage 2 on the KDIGO classifcation?

Answer 41

Increase \> 2 to 2.9 x reference SCr 12 hrs

Question 42

What is the serum creatinine and the urine output for stage 3 classification?

Answer 42

Increase \> 3 x reference SCr or increase to \> 354µmol/L or need for RRT 24hrs or 12 hrs for anuria

Question 43

Which of these is AKI 3 by KDIGO? A – Biochemical kidney injury disappearing after rehydration B – creatinine of 354 C – anuria for 6 hours D – eGFR 60 E – creatinine 2.5 times base line F – urine output 0.5mL/kg/hr for 6 hours G– creatinine increased by 27µmol

Answer 43

B - Creatinine of 354 micromoles or greater Urine output - less than 0.3ml/kg/hr for 24 hours or anuric for 12 hours