AKI

Question 1

What is AKI?

Answer 1

an abrupt loss of kidney function

Results in retention of urea + other nitrogenous waste products + dysregulation of extracellular volume + electrolytes.

Question 2

Who can develop AKI?

Answer 2

Those with previously normal kidneys or those with pre-existing renal disease

Question 3

Describe the classification of AKI

Answer 3

KDIGO Classification
Increase in serum creatinine > 26 mmol/L within 48 hrs
Increase in serum creatinine to > 1.5X baseline within preceding 7 days
Urine volume < 0.5 ml/kg/hr for 6 hours

Question 4

What are the causes of AKI split into? Which is most common?

Answer 4

Pre-renal 90%
Renal
Post renal

Question 5

List 6 pre renal causes of AKI

Answer 5

Hypovolaemia (e.g. haemorrhage, severe vomiting)
Heart failure
Cirrhosis
Nephrotic syndrome
Hypotension (e.g. shock, sepsis, anaphylaxis)
Renal hypoperfusion (e.g. NSAIDs, ACEi, ARBs, renal artery stenosis)

Question 6

List 5 renal causes of AKI

Answer 6

Glomerular: glomerulonephritis, HUS
Tubular: acute tubular necrosis
Interstitial: acute interstitial nephritis (e.g. NSAIDs, AI)
Vasculitides (e.g. Wegener’s granulomatosis)
Eclampsia

Question 7

What causes post renal AKI? List 4 specific examples

Answer 7

Obstruction
Calculi  
Urethral stricture 
Prostatic hypertrophy or malignancy  
Bladder tumour

Question 8

Give 8 risk factors for developing AKI

Answer 8

Age  
CKD
Comorbidities (e.g. HF)  
Sepsis  
Hypovolaemia 
Use of nephrotoxic medications  
Emergency surgery 
Diabetes mellitus

Question 9

What do symptoms of AKI depend on? List 4 symptoms of AKI

Answer 9

Depends on underlying CAUSE  
Oliguria/ anuria 
N+V  
Dehydration  
Confusion

Question 10

List 5 signs of AKI

Answer 10

HTN
Distended bladder
Dehydration: postural hypotension
Fluid overload (in HF, cirrhosis, nephrotic syndrome): raised JVP, pulmonary + peripheral oedema
Pallor, rash, bruising (vascular disease)

Question 11

What urinalysis investigations do you perform in AKI?

Answer 11

Blood: suggests nephritic (intrinsic) cause
Leukocyte esterase + nitrites: UTI
Glucose (DM= RF)
Protein (high in HTN, DM)
Urine osmolality (high in HF, shock, RAS)

Question 12

What bloods should be taken for AKI?

Answer 12

FBC (infection, anaemia)
Blood film 
U+Es (kidney function)
CRP (infection)
Immunology 
Virology

Question 13

What immunoglobulins should you investigate in AKI?

Answer 13

Serum immunoglobulins + protein electrophoresis: for multiple myeloma (+Bence-Jones proteins in urine)
ANA + anti-dsDNA antibodies: kidney manifestation of SLE
Complement levels low in active disease e.g. SLE
Anti-GBM antibodies: Goodpasture’s syndrome
Antistreptolysin-O antibodies: high after Streptococcal infection

Question 14

Give 2 viral causes of AKI

Answer 14

Hepatitis B or C

HIV nephropathy

Question 15

What imaging would you perform in AKI?

Answer 15

USS: Check for post-renal cause + Look for hydronephrosis
CXR: pulmonary oedema
AXR: renal stones

Question 16

What are the 4 main components of AKI management?

Answer 16

Protect pt from hyperkalaemia (with calcium gluconate)
Optimise fluid balance
Stop nephrotoxic drugs
Consider for dialysis

Question 17

List 4 additional steps to take in management of AKI?

Answer 17

Monitor serum creatinine, Na+, K+, Ca2+, phosphate + glucose
Identify + treat infection
Urgent relief of urinary tract obstruction
Refer to nephrology if intrinsic renal disease is suspected

Question 18

In which 4 situiations is renal replacement therapy considered? (PUSH)

Answer 18

Pulmonary oedema refractory to medical management
Uraemic complications
Severe metabolic acidaemia
Hyperkalaemia refractory to medical management

Question 19

List 6 complications of AKI

Answer 19

Pulmonary oedema  
Acidaemia  
Uraemia  
Hyperkalaemia  
Bleeding 
Increased risk of developing CKD

Question 20

What is the prognosis in AKI? List 5 indicators of poor prognosis

Answer 20

Mortality varies- depends on cause + comorbidities  
Indicators of poor prognosis: 
Age  
Multiple organ failure  
Oliguria 
Hypotension  
CKD

Question 21

Describe the epidemiology of AKI

Answer 21

15% of adults admitted to hospital develop an AKI

Most common in ELDERLY

Question 22

What does abrupt anuria suggest?

Answer 22

Post-renal obstruction