AKI

Question 1

What are prerenal causes of AKI?

Answer 1

Hypoperfusion of the kidney
-Hypovolaemia (haemorrhage, severe D+V, burns)
-Oedema (cardiac failure, cirrhosis, nephrotic syndrome)
-Hypotension (cariogenic shock, sepsis, anaphylaxis)
-Cardiovascular (severe cardiac failure, arrhythmias)
-Renal hypo perfusion (eg NSAIDs, AAA, renal artery stenosis)

Question 2

What are renal causes of AKI?

Answer 2

Intrinsic renal disease
-Glomerular (glomerulonephritis, acute tubular necrosis)
-Interstitial (drug reaction, infection, infiltration)
-Vessels (vasculitis, DIC)

Question 3

What are post-renal causes of AKI?

Answer 3

Obstruction to the urine
-Within renal tract (stone, renal tract malignancy, urethral stricture, clot)
-Extrinsic compression (pelvic malignancy, prostatic hypertrophy, retroperitoneal fibrosis)

Question 4

How is AKI diagnosed?

Answer 4

-Rise in serum creatinine of 26umol/L or more within 48hr
OR
-50% increase in serum creatinine within the preceding 7 days
AND/OR
-A fall in urine output to less than 0.5ml/kg for >6hr

Question 5

What investigations would you order for someone with AKI?

Answer 5

-FBC, U+Es, creatinine, CRP, LFTs, clotting
-ABG (metabolic acidosis)
-Catheterisation to measure urine output
-CXR (?pulmonary oedema)
-USS (?obstruction)

Question 6

How should you manage an AKI?

Answer 6

-A-E approach
-Mostly supportive treatment
-Treat cause ie stop nephrotoxic drugs, infection, obstruction
-Fluids - maintenance or 500ml over 15min if acutely unwell
-Regular creatinine and UO monitoring
-Treat complications eg acidosis, oedema, hyperK+