Acute renal failure (AKI and CKD)

Question 1

Define AKI

Answer 1

A rapid (within 7 days) and sustained (>24 hours) reduction in renal failure resulting in oliguria and a rise in serum urea and creatinine

Question 2

NICE criteria for AKI

Answer 2

1. Rise in creatinine of ≥ 25 micromol/L in 48 hours
2. Rise in creatinine of ≥ 50% in 7 days
3. Urine output of < 0.5ml/kg/hour for > 6 hours

Question 3

List 4 risk factors for AKI

Answer 3

1. CKD
2. Heart failure
3. Diabetes
4. Liver disease
5. Age > 65 years
6. Nephrotoxic medications
7. contrast medium during CT scans.

Question 4

List the 3 types of AKI and which is the most common

Answer 4

1. Pre-renal (55%)
2. Intrinsic/ renal (35%)
3. Post- renal (20%)

Question 5

List 3 causes of pre-renal AKI

Answer 5

1. Shock (hypovolaemic, cardiogenic, distributive)
2. Renal artery stenosis
3. Hypovolaemia (diarrhoea/vomiting or dehydration)

Question 6

List 4 causes of intrinsic renal AKI

Answer 6

1. Acute glomerulonephritis
2. ATN
3. Acute interstitial nephritis
4. Rhabdomyolysis

Question 7

List 4 causes of post-renal AKI

Answer 7

1. Kidney stones
2. pelvic or abdominal masses
3. ureteral strictures or compression
4. BPH or prostate cancer

Question 8

How does AKI present?

Answer 8

May be asymptomatic or as renal failure progresses:

1. reduced urine output
2. pulmonary and peripheral oedema
3. arrhythmias (changes in K+ and acid-base balance)
4. features of uraemia (eg. pericarditis or encephalopathy)

Question 9

Investigations for AKI?

Answer 9

1. U&Es
2. Urinalysis
3. Renal ultrasound

Question 10

Management of AKI?

Answer 10

1. ABCDE
2. Identify and treat underlying cause
3. IV fluids in pre-renal AKI
4. Stop nephrotoxic and renally excreted drugs
5. Relieve obstruction in a post-renal AKI

Question 11

List 4 examples of nephrotoxic medications

Answer 11

1. NSAIDs
2. ACEi
3. ARBs
4. Aminoglycosides eg. gentamicin

Question 12

List 2 examples of renal excreted drugs

Answer 12

1. Metformin
2. Lithium
3. Digoxin

Question 13

List 3 treatments for hyperkalaemia?

Answer 13

1. IV calcium gluconate
2. Insulin/dextrose infusion and/or nebulised salbutamol
3. Dialysis.

Question 14

List 4 complications of AKI

Answer 14

1. Hyperkalaemia
2. Fluid overload, heart failure and pulmonary oedema
3. Metabolic acidosis
4. Uraemia can lead to encephalopathy or pericarditis

Question 15

Indications for renal replacement (dialysis) in the acute setting?

Answer 15

• Acidosis
• Electrolytess - hyperkalaemia
• Intoxication (poisoning)
• Oedema - refractory pulmonary oedema
• Uraemia - encephalopathy or pericarditis

Question 16

Why may serum creatinine may not be useful in determining eGFR?

What is used instead?

Answer 16

Due to differences in muscle

Question 17

What is CKD?

Answer 17

Gradual, irreversible decline in kidney function for more than 3 months?

Requires either a decreased GFR (<60) or markers of kidney damage (albuminuria, electrolyte abnormalities etc..)

Question 18

List 4 causes of CKD

Answer 18

1. Diabetes
2. Hypertension
3. Age
4. Glomerulonephritis
5. Polycystic kidney disease
6. Medications such as NSAIDS, proton pump inhibitors and lithium

Question 19

List 4 risk factors for CKD

Answer 19

1. Older age
2. Hypertension
3. Diabetes
4. Smoking
5. Medications that affect the kidneys

Question 20

How does CKD present?

Answer 20

Usually asymptomatic (diagnosed on routine testing) but features may incl

1. Pruritus (itching)
2. Loss of appetite
3. Nausea
4. Oedema
5. Muscle cramps
6. Peripheral neuropathy
7. Pallor
8. Hypertension

Question 21

Investigations for CKD?

Answer 21

1. eGFR: using U&E blood test
2. Proteinuria and Haematuria
3. Albumin:creatinine ratio (ACR) -≥ 3
4. Renal ultrasound

Question 22

How is CKD staged?

Answer 22

G score based on the eGFR:

• G1 = >90
• G2 = 60-89
• G3a = 45-59
• G3b = 30-44
• G4 = 15-29
• G5 = <15 (“end-stage renal failure”)

A score based on the ACR

• A1 = < 3
• A2 = 3 – 30
• A3 = > 30

Question 23

When does NICE recommend CKD should be referred to a specialist?

Answer 23

1. eGFR < 30
2. ACR ≥ 70 mg/mmol
3. Accelerated progression
4. Uncontrolled hypertension despite ≥ 4 antihypertensives

Question 24

Aims of CKD management?

Answer 24

Slow the progression

Reduce risk of CVD

Reduce the risk of complications

Treating complications

Question 25

What medication is offered for primary prevention of CVD?

Answer 25

Atorvastatin 20mg

Question 26

List 4 complications of CKD

Answer 26

1. Anaemia (**↓**EPO) 2. Renal bone disease (CKD-MBD) 3. CVD 4. Peripheral neuropathy 5. Hypertension 6. Dialysis related problems

Question 27

List 4 features of Renal bone disease

Answer 27

1. Osteoporosis 2. Osteomalcia 3. Osteosclerosis 4. 2^o Hyperparathyroidism

Question 28

Pathophysiology of renal bone disease?

Answer 28

1. Descreased Vit D (no 1-alpha hydroxylation in kidneys) 2. ↑ phosphate and **↓** calcium 3. 2^o hyperparathyroidism

Question 29

What x-ray changes are associated with renal bone disease

Answer 29

Spine xray shows sclerosis of both ends of the vertebra and osteomalacia in the centre “Rugger Jersey spine” due to hyperparathyroidism

Question 30

How is renal bone disease treated?

Answer 30

1. Vitamin D (alfacalcidol and calcitriol) 2. Low phosphate diet 3. Bisphosphonates for osteoporosis

Question 31

Pathophysiology of anaemia in CKD?

Answer 31

kidneys produced EPO, which stimulates production of RBCs CKD leads to less EPO and subsequent anaemia

Question 32

Treatment of anaemia in CKD.

Answer 32

1. Iron 2. Exogenous EPO

Question 33

Treatment of metabolic acidosis in CKD?

Answer 33

Oral sodium bicarbonate

Question 34

Treatment of end stage renal failure?

Answer 34

1. Dialysis 2. Transplant

Question 35

Treatment of hypertension in CKD?

Answer 35

ACE inhibitors: Monitor ***serum K+*** as CKD and ACEi both cause ***hyperkalaemia*** Criteria for ACEi: * Diabetes plus ACR \> 3mg/mmol * Hypertension plus ACR \> 30mg/mmol * All patients with ACR \> 70mg/mmol

Question 36

What BP do we aim for in a patient with CKD?

Answer 36

\< 140/90