Acute Kidney Injury

Question 1

Acute kidney injury (AKI) describes a a rapid reduction in renal function following an insult to the kidneys. What % of all hospital admissions have AKI?

1 - 1-2%
2 - 15-20%
3 - 30-40%
4 - 70-80%

Answer 1

2 - 15-20%

Carries a 30% mortality in hospital

Question 2

What is the key marker that determines if a patient has an acute kidney injury?

1 - urea
2 - hematuria
3 - creatinine
4 - Na+

Answer 2

3 - creatinine

Creatinine and urea filtered by the kidneys comes from amino acid metabolism

Question 3

Accoridng to NICE guidelines, which of the following are diagnostic of acute kidney injury can be made using all of the following, EXCEPT which one?

1 - rise in creatinine of more than 25 micromol/L in 48 hours
2 - <0.5ml/kg/hour urine output >6 hours
3 - reduction in eGFR function by >50%
4 - rise in creatinine by 50% in 7 days

Answer 3

3 - reduction in eGFR function by >50%

• eGFR is not typically a good measure of AKI

Staging of AKI is seen in the image

Question 4

Which 2 of the following is an AKI most likley to occur in?

1 - older patients
2 - infected patients
3 - post-surgery
4 - female gender

Answer 4

2 - infected patients
3 - post-surgery

Question 5

Which of the following are risk factors for developing AKI?

1 - Older age >65 years
2 - Sepsis
3 - Chronic kidney disease
4 - Heart failure
5 - Diabetes
6 - Liver disease
7 - Cognitive impairment (reduced fluid intake)
8 - Radiocontrast agents (e.g., used during CT scans)
9 - all of the above

Answer 5

9 - all of the above

Question 6

All of the following medications can increase the risk of an AKI, EXCEPT which one?

1 - Ibuprofen
2 - Ramipril or Losartan
3 - Warfarin
4 - Gentamicin
5 - Indapamide

Answer 6

3 - Warfarin

• NSAIDs
• Diuretics
• ACE-I and ARB-II
• Diuretics

Some drugs in these classes are better than others though

Question 7

How can NSAIDs cause AKI?

1 - induce vasoconstriction of efferent arterioles
2 - inhibit prostaglandin, inducing vasoconstriction of afferent arterioles
3 - increase prostaglandin and therefore increase eGFR
4 - all of the above

Answer 7

2 - inhibit prostaglandin, inducing vasoconstriction of afferent arterioles
- vasoconstriction causes hypoperfusion of kidneys

• prostaglandin induce vasodilation of afferent arterioles to maintain eGFR

Question 8

How can ACE and ARB-I cause AKI?

1 - induce vasoconstriction of efferent arterioles
2 - inhibit prostaglandin, inducing vasoconstriction of afferent arterioles
3 - increase prostaglandin and therefore increase eGFR
4 - induce vasodilation of efferent arterioles

Answer 8

4 - induce vasodilation of efferent arterioles
- reduces blood flow and eGFR due to hypoperfusion

Question 9

Are ACE inhibitors nephrotoxic?

Answer 9

• No
• Should be stopped in AKI due to reducing the filtration pressure
• ACE inhibitors have a protective effect on the kidneys long-term and can protect the kidneys, but in AKI they should NOT be used

Question 10

Acute kidney injury (AKI) can be categorised as:

• pre-renal
• renal
• post renal

Which of these categories is the most common?

Answer 10

• pre-renal

Question 11

Acute kidney injury (AKI) can be categorised as:

• pre-renal
• renal
• post renal

Which of the following is NOT a pre-renal cause of AKI?

1 - Dehydration
2 - Renal calculi
3 - Shock (sepsis, anaphylaxis, acute blood loss)
4 - Heart failure

Answer 11

2 - Renal calculi
This is a post-renal issue

Pre-renal causes are typically due to hypoperfusion if the kidneys

Question 12

Acute kidney injury is defined as an abrupt decline in kidney function. Which blood vessels supplies the kidneys?

1 - abdominal artery
2 - renal artery
3 - superior mesenteric artery
4 - inferior mesenteric artery

Answer 12

2 - renal artery
- branch from abdominal aorta
- renal vein drains the kidneys

Question 13

Acute kidney injury (AKI) can be categorised as:

• pre-renal
• renal
• post renal

Renal causes of AKI are intrinsic to the kidneys and accounts for 10% of all AKIs. Which of the following is NOT a renal cause of AKI?

1 - Acute tubular necrosis (ATN)
2 - Glomerulonephritis
3 - Acute interstitial nephritis (AIN)
4 - Shock (e.g., sepsis or acute blood loss)
5 - Haemolytic uraemic syndrome
6 - Rhabdomyolysis

Answer 13

4 - Shock (e.g., sepsis or acute blood loss)

Nephron = whole unit
Tubules = part of the nephron that filter
Glomerulus = network of small blood vessels that filters waste into the tubules

• ATN = ischaemia due to pre-renal, or toxins, drugs, contrast, rhabdomyolysis
• AIN = Typically drug-induced, but can also be infections or autoimmune diseases

Glomerular: Rapidly progressive glomerulonephritis or other glomerulopathies

Question 14

All of the following can cause intra-renal AKI, but which is most common?

1 - Acute tubular necrosis (ATN)
2 - Glomerulonephritis
3 - Acute interstitial nephritis (AIN)
4 - Haemolytic uraemic syndrome
5 - Rhabdomyolysis

Answer 14

1 - Acute tubular necrosis (ATN)

Relates to damage and death of the epithelial cells of the collecting tubules of the nephrons.

Question 15

Acute tubular necrosis (ATN) is the most common cause of intra-renal AKI. All of the following can cause ATN, EXCEPT which one?

1 - ibuprofen
2 - gentamicin
3 - secondary ischaemia (pre-renal)
4 - renal calculi
5 - radiology contrasts

Answer 15

4 - renal calculi

Secondary ischaemia (pre-renal):
- hypoperfusion/shock
- sepsis
- dehydration

Question 16

Acute tubular necrosis (ATN) is the most common cause of intra-renal AKI. Is ATN reversible?

Answer 16

• Yes

Typically takes 7-21 days for epithelial cells to regenerate

Look for Muddy brown casts on urinalysis

Question 17

Nephrotic and nephritic syndrome are both intra-renal kidney conditions that affect the glomeruli.

• Nephrotic syndrome = loss/reduced function of podocyte and foot processes and/or basement membrane
• Nephritic syndrome = immune complexes become deposited in glomerular capillaries causing immune response against capillaires

Which of these syndromes presents with the following?

• proteinuria >3.5g/day
• systemic oedema due to lost intravascular protein (mainly albumin)
• frothy urine
• hyperlipidaemia (liver attempts to compensate)
• antithrombin 3 lost in urine (prevents excessive clotting) so patients have hypercoaguable state

Answer 17

• NephrOtic syndrome
  Think O in nephrOtic = Open podocytes

Loss of antithrombin III increases risk of thromboembolism in the renal vein that can cause a blood clot travelling to the lungs

Question 18

Nephrotic and nephritic syndrome are both intra-renal kidney conditions that affect the glomeruli.

• Nephrotic syndrome = loss/reduced function of podocyte and foot processes
• Nephritic syndrome = immune complexes become deposited in glomerular capillaries causing immune response against capillaires

Which of these syndromes presents with the following?

• proteinuria <3.5g/day
• haematuria and RBC casts may cause cola coloured urine
• pyuria (WBCs) in the urine
• mild oedema
• hypertension with low eGFR
• oliguria as glomerulus is damaged and cannot filter urine

Answer 18

• Nephritic syndrome
  Also called Glomerulonephritis

This is a cause of intra-renal AKI called Acute interstitial nephritis

Antigen-antibody complexes (AAC) (type III hypersensitivity) inside the glomerulus capillaries cause:

• AACs infiltrate glomerula and block capillaries
• WBCs are recruited causing inflammation
• inflammation damages the glomerulus basement membrane, causing podocytes to spread out
• blood and protein can leak into urine

Question 19

In patients with AKI due to Acute interstitial nephritis (AIN), which of the following may also be present in addition to the AKI?

1 - Rash
2 - Fever
3 - Flank pain
4 - Eosinophilia (high levels)
5 - all of the above

Answer 19

5 - all of the above

Steroids can be useful when treating AIN

Question 20

Post-renal causes of AKI involve obstruction to the outflow of urine away from the kidney, causing back-pressure into the kidney and reduced kidney function. This is called an obstructive uropathy. Obstruction can be caused by which of the following?

1 - Kidney stones
2 - Tumours
3 - Strictures of the ureters or urethra
4 - Benign prostatic hyperplasia
5 - Neurogenic bladder
6 - all of the above

Answer 20

6 - all of the above

Question 21

When trying to diagnose the AKI, all of the following can be performed, but which is typically 1st line?

1 - Blood samples
2 - Urinalysis
3 - Imaging
4 - Autoimmune profiling

Answer 21

2 - Urinalysis

• Leucocytes and nitrites suggest infection
• Protein and blood suggest acute nephritis (but can be positive in infection)
• Glucose suggests diabetes

Microscopy, culture and sensitivity MC&S may be needed if any evidence of UTI on the urine dipstick

Question 22

If acute glomerularnephritis is suspected, which of the following should be calculated?

1 - urea : creatiine ratio
2 - protein : creatinine ratio
3 - blood : creatinine ratio
4 - glucose : creatinine ratio

Answer 22

2 - protein : creatinine ratio

Question 23

U&Es is important to measure in a patient with AKI. Which of the following derangement is most common in AKI?

1 - hyperkalemia and hyponatremia
2 - hypokalemia and hyponatremia
3 - hypercalcaemia and hyponatremia
4 - hypomagnesium and hyponatremia

Answer 23

1 - hyperkalemia and hyponatremia

Typically kidneys retain Na+ and excrete K+ to maintain body fluid balance

Question 24

What is the 1st line imaging for AKI?

1 - ultrasound
2 - MRI
3 - CT
4 - X-ray

Answer 24

1 - ultrasound

Mainly used in post-renal

Question 25

Which of the following approaches should be used in an attempt to reduce AKI? 1 - Avoiding/stop nephrotoxic medications 2 - adequate fluid intake oral and IV 3 - Additional fluids before and after radiocontrast agents 4 - all of the above

Answer 25

4 - all of the above

Question 26

All of the following are effective in various causes of AKI (main cause needs to be identified), EXCEPT which one? 1 - IV fluids for dehydration and hypovolaemia 2 - administer ACE inhibitors to protect kidney function 3 - Stop/adjust medications that may accumulate with reduced renal function (e.g., metformin and opiates) 4 - Relieve the obstruction in a post-renal AKI 5 - Dialysis may be required in severe cases

Answer 26

2 - administer ACE inhibitors to protect kidney function Good long term Must be stopped in AKI

Question 27

Which of the following is NOT a common complication of AKI? 1 - Fluid overload, heart failure and pulmonary oedema 2 - Hyperkalaemia 3 - Metabolic alkalosis 4 - Uraemia (high urea), which can lead to encephalopathy and pericarditis

Answer 27

3 - Metabolic alkalosis Commonly causes metabolic acidosis due to less HCO3- being produced

Question 28

Hyperkalaemia is a complication of AKI. At what concentration does this need to be treated URGENTLY? 1 - >3.5mmol/L 2 - >4.5mmol/L 3 - >5.5mmol/L 4 - >6.5mmol/L

Answer 28

4 - >6.5mmol/L - OR if ECG changes are present

Question 29

Vasculitis is an autoimmune inflammatory condition where immune cells mistake antigens on the endothelium for foreign antigens called molecular mimicry. Which of the following vasculitis conditions matches the following: - IgA antiibodies involved - skin, kidneys and GIT involved - purpuric rash in legs and bum of children - inflammation in vasculature due to IgA antibodies 1 - IgA nephropathy 2 - Henoch Schonlein purpura 3 - Lupus 4 - Leukaemia

Answer 29

2 - Henoch Schonlein purpura IgA nephropathy affects just the kidneys and occurs 1-3 days post infection

Question 30

Henoch Schonlein purpura is a form of vasculitis affecting the skin, kidneys and GIT. IgA antibodies enter affected tissues in blood vessels and lead to inflammation. This affects children of what age? 1 - newborns 2 - children <5 3 - children <10 4 - children <15

Answer 30

3 - children <10 - typically occurs following gastroenteritis or upper airway infection

Question 31

Which of the following is NOT one of the 4 classic signs in Henoch Schonlein purpura, a form of vasculitis affecting the skin, kidneys and GIT? 1 - purpura (100% of children) 2 - pericarditis (60% of children) 3 - joint pain (75% 4 - abdominal pain (50% of children) 5 - kidney impairment ((50% of children)

Answer 31

2 - pericarditis (60% of children)

Question 32

Purpura, which occurs in 100% of children is a classic sign in Henoch Schonlein purpura. Is this rash blanching or non-blanching?

Answer 32

- non-blanching - it says red when you apply pressure - purpura is blood from small blood vessels - palpable on the skin

Question 33

Henoch Schonlein purpura is a form of vasculitis affecting the skin, kidneys and GIT. IgA antibodies enter affected tissues in blood vessels and lead to inflammation. Does this cause nephritis or nephrotic syndrome?

Answer 33

- nephritis syndrome - causes haematuria and proteinuria - BUT if patient has ++ protein, they have developed nephrotic syndrome

Question 34

Henoch Schonlein purpura is a form of vasculitis affecting the skin, kidneys and GIT. IgA antibodies enter affected tissues in blood vessels and lead to inflammation. How are these patients diagnosed? 1 - FBC and blood film 2 - renal profile 3 - serum albumin 4 - CRP and blood culture (sepsis) 5 - urine dipstick (proteinuria, ACR) 6 - BP 7 - all of the above

Answer 34

7 - all of the above - FBC and blood film = rules out sepsis, leukaemia and thrombocytopenic - serum albumin = rule out nephrotic syndrome

Question 35

What is another condition that can cause pulmonary-renal syndrome? 1 - TB 2 - Good Pastures Syndrome 3 - SLE 4 - Infective endocarditis

Answer 35

2 - Good Pastures Syndrome - autoimmune inflammatory condition affecting the lungs and kidneys - causes haemoptysis in lungs and haematuria in the kidneys - typically triggered by infection or agent

Question 36

Good pastures syndrome (GPS) is able to cause pulmonary-renal syndrome. What is the trigger for GPS? 1 - IgE from mast cells is released and binds to type IV collagen 2 - IgG/IgM antibodies bind to type IV collagen 3 - antibody-immune complexes forms on type IV collagen 4 - cytotoxic T cells target and begin to degrade type IV collagen

Answer 36

2 - IgG/IgM antibodies bind to type IV collagen - type 2 hypersensitivity that triggers the complement pathway - type IV collagen is present in abundance in the basement membranes of the glomerulus and alveolar basement membranes

Question 37

In good pastures syndrome (GPS), which can causes pulmonary-renal syndrome, the Fab region of the antibody binds to type IV collagen. The Fc portion then binds with what to trigger the complement pathway? 1 - C1 2 - C2 3 - C3 4 - C4

Answer 37

1 - C1 - complement pathway is then activated

Question 38

In good pastures syndrome (GPS), which can causes pulmonary-renal syndrome, once the complement pathway is activated, C3a, 4a and 5a act as chemotactic agents and attract which cell? 1 - basophils 2 - cytotoxic T cells 3 - B cells 4 - neutrophils

Answer 38

4 - neutrophils

Question 39

In good pastures syndrome (GPS), which can causes pulmonary-renal syndrome, once the complement pathway is activated, C3a, 4a and 5a act as chemotactic agents and attract neutrophils. What do the neutrophils then release that damages the collagen and therefore the basement membranes? 1 - peroxidase 2 - myeloperoxidase 3 - proteinase-3 4 - all of the above

Answer 39

4 - all of the above - all cause free oxygen radicals that form and damage the basement membranes

Question 40

Which of the following is NOT a common symptom in good pastures syndrome (GPS)? 1 - dysponea/cough 2 - glomerularnephritis 3 - proteinuria >3.5g 4 - haemoptysis

Answer 40

3 - proteinuria >3.5g

Question 41

Which of the following antibody can be screened for to diagnose good pastures syndrome (GPS)? 1 - anti-glomerular basement (GBM) 2 - anti-neutrophil cytoplasmic antibodies (ANCA) 3 - cytoplasmic-ANCA 4 - proteinase 3-ANCA

Answer 41

1 - anti-glomerular basement (GBM)

Question 42

How is good pastures syndrome (GPS) typically treated? 1 - high dose of steroids 2 - cyclophosphamide 3 - plasmapheresis 4 - all of the above

Answer 42

4 - all of the above - typically does not relapse and is a 1 hit wonder Steroid is methylprednisolone, if this fails then use cyclophosphamide

Question 43

Calculate AKI stage. Patient is 50kg and has 240ml urine output in 24h. What stage AKI are they? 1 - stage 1 2 - stage 2 3 - stage 3

Answer 43

3 - stage 3 Minimum in UK = 0.5 ml/kg/h - (50kg x 0.5 = 25ml/h) x 24 = 600ml Here calculation is: - (240/24 = 10ml/h) / 50kg = 0.2ml/h