acute kidney injury (AKI)

Question 1

definition

Answer 1

Acute kidney injury (AKI), previously known as acute renal failure (ARF), is an acute decline in kidney function, leading to a rise in serum creatinine and/or a fall in urine output.[1] The change in terminology emphasises that kidney injury presents as a disease spectrum from mild kidney injury to severe kidney failure.[1][2][3] A standardised definition is important to facilitate clinical care and research.[4] AKI may be due to various insults such as impaired kidney perfusion, exposure to nephrotoxins, outflow obstruction, or intrinsic kidney disease. The resulting effects include impaired clearance and regulation of metabolic homeostasis, altered acid/base and electrolyte regulation, and impaired volume regulation.

Question 2

symptoms

Answer 2

Malaise, anorexia, nausea, vomiting, pruritus, drowsiness, convulsions, coma (caused by uraemia).
Symptoms of the cause or complications usually dominate (see below).

Question 3

signs

Answer 3

oedema, hypotension, reduced urine production, abnormal urine, palpable bladder/abdominal distension/enlarged prostate (based on the cause), abdominal pain/flank pain

Question 4

investigations

Answer 4

1st investigations:

• ABG/VBG
• U&Es
• basic metabolic profile: serum creatinine, serum potassium, LFTs
• FBC
• bicarbonate
• CRP
• blood culture (check for sepsis)
• urine culture (bacteria check, antibiotic sensitivity check)
• urine output monitoring
• fluid challenge (good response to fluid challenge -> pre renal AKI)
• CXR
• ECG
• FeNa

Question 5

complications

Answer 5

• uremic pericarditis (associated with AKI and severe uraemia) -> pleural rub
• hyperkalemia
• uraemia
• chronic progressive kidney disease
• end stage renal disease

Question 6

treatment

Answer 6

hypovolaemic:
1. fluid resus
+ review medications and stop nephrotoxins
+ identify and treat underlying cause of AKI

hypervolaemic
1. loop diuretic (furosemide) + sodium restriction