Acute kidney injury

Question 1

What is AKI?

Answer 1

Sudden, potentially reversible, reduction in renal function. Oliguria (<0.5ml/kg/h) is usually present

Question 2

Classifications of AKI?

Answer 2

• prerenal
• renal
• post-renal

Question 3

What is prerenal failure?

Answer 3

Most common of AKI cause in children

• suggested by hypovolaemia
• needs to be urgently corrected with fluid replacement and circulatory support to avoid acute tubular injury and necrosis

Question 4

What is renal failure?

Answer 4

Salt and water retention; blood, protein and casts often present in urine; may be symptoms specific to an accompanying disease
- haemolytic uraemic syndrome and acute tubular necrosis (multisystem failure) are the most common causes in UK

• restriction of fluid intake and diuretic to increase urine output
• high calorie, normal protein feed to decrease catabolism, uraemia and hyperkalaemia
• emergency management of metabolic acidosis, hyperkalaemia and hyperphosphataemia
• Renal biopsy if cause not obvious

Question 5

What is postrenal failure?

Answer 5

from urinary obstruction
- requires assessment of the site of obstruction and relief by nephrostomy or bladder catheterisation and surgery once medical correction

Question 6

Clinical presentation of acute-on-chronic renal failure?

Answer 6

• growth failure
• anaemia
• disordered bone mineralisation

Question 7

Management of acute renal failure

Answer 7

• monitor circulation and fluid balance
• USS investigation to identify obstruction of the urinary tract, small kidneys of CKD, or large bright kidneys with loss of cortical medullary differentiation typical of an acute process

Question 8

When is dialysis indicated in AKI?

Answer 8

• failure of conservative management
• hyperkalaemia
• severe hyponaturaemia or hypernaturaemia
• pulmonary oedema or severe hypertension due to volume overload
• severe metabolic acidosis
• multisystem failure

Question 9

What is haemolytic uraemic syndrome?

Answer 9

Triad of acute renal failure, microangiopathic haemolytic anaemia and thrombocytopoenia

Question 10

Causes of HUS?

Answer 10

Typically secondary to GI infection with verocytoxin producing E.coli O157:H7
- acquired through contact with farm animals or eating uncooked beef
Less often Shigella

Question 11

Clinical presentation of HUS?

Answer 11

Bloody diarrhoea

Question 12

Prognosis of typical diarrhoea-associated HUS?

Answer 12

Usually good, long term follow up is necessary to monitor for persistent proteinuria etc HTN etc CKD

Question 13

Prognosis of atypical non-diarrhoea-associated HUS

Answer 13

May be familial and frequently relapses. High risk of HTN and progressive CKD with a high mortality.

Eculizumab has greatly improved the prognosis but is v expensive.