Acute Kidney injury AKI

Question 1

AKI?

Answer 1

An abrupt loss of kidney function resulting in the retention of urea and other nitrogenous waste products and the dysregulation of extracellular volume and electrolytes. Increase in serum creatinine > 26 μmol/L within 48 hrs

Question 2

AKI Aetiology, 3 groups?

Answer 2

Question 3

AKI aetiology pre-renal?

Answer 3

Hypovolaemia (haemorrhage, severe vomiting), heart failure, cirrhosis, nephrotic syndrome, hypotension, renal hypoperfusion (NSAIDs, ACE inhibitors, ARBs, renal artery stenosis)

Question 4

AKI aetiology Intrinsic renal?

Answer 4

Glomerular (glomerulonephritis, haemolytic uraemic syndrome) Tubular (acute tubular necrosis) Interstitial (acute interstitial nephritis from NSAIDs or autoimmune) Vasculitides (e.g. Wegener’s granulomatosis) Eclampsia

Question 5

AKI aetiology post-renal?

Answer 5

(due to obstruction) calculi, urethral stricture, prostatic hypertrophy or malignancy, bladder tumour.

Question 6

AKI risk factors (8)?

Answer 6

Age

Chronic kidney disease
Comorbidities (e.g. heart failure)

Sepsis
Hypovolaemia
Use of nephrotoxic medications

Emergency surgery
Diabetes mellitus

Question 7

AKI epidemiology?

Answer 7

Most common in elderly, 15% of adults in hospital.

Question 8

AKI symptoms?

Answer 8

Can depend on underlying cause,

Oliguria/anuria,

nausea and vomiting,

dehydration,

confusion.

Question 9

AKI signs?

Answer 9

Hypertension, distended bladder, dehydration (postural hypotension), fluid overload (raised JVP, pulmonary and peripheral oedema), pallor, rash, bruising.

Question 10

AKI investigations urinalysis?

Answer 10

blood suggests nephritic cause,

Leucocyte esterase and nitrates suggest UTI,

glucose,

protein,

urine osmolality

Question 11

AKI investigations bloods?

Answer 11

1. FBC,
2. blood film,
3. U&Es,
4. clotting,
5. CRP,
6. immunology (serum immunoglobulins and protein electrophoresis for multiple myeloma, ANA associated with SLE, complement levels are low in active lupus, Anti-GBM antibodies in goodpastures syndrome),
7. virology (hep and HIV).

Question 12

AKI investigations USS?

Answer 12

Check for post-renal cause,

look for hydronephrosis

Question 13

AKI investigations imaging?

Answer 13

CXR for pulmonary oedema, AXR for renal stones.

image shows renal stones with black arrows

Question 14

AKI management?

Answer 14

protect patient from hyperkalaemia (calcium gluconate),

optimise fluid balance,

stop nephrotoxic drugs,

consider for dialysis.

Identify and treat infection

Question 15

When to consider renal replacement therapy (RRT)?

Answer 15

hyperkalaemia or pulmonary oedema refractory to medical management, severe metabolic acidaemia

Question 16

AKI complications (5)?

Answer 16

pulmonary oedema, acidaemia, uraemia, hyperkalaemia, bleeding