Acute kidney injury

Question 1

What is acute kidney injury?

Answer 1

Rapid reduction in kidney function. No specific symptoms (ex stones). Recognises a spectrum of injury.

Question 2

What are the potential mediators of AKI?

Answer 2

Uraemic toxins, cytokines and leukocytes.

Question 3

What percentage of hospital admissions have AKI?

Answer 3

18%

Question 4

What percentage of ICU admissions have AKI?

Answer 4

30-80%

Question 5

What is intrinsic AKI?

Answer 5

Acute tubular injury (sepsis, hypotension, nephrotoxins (NSAIDs), contrast, rhabdomyolysis, myeloma and snake bites)

Tubulointerstitial injury

Glomerulonephritis

Vasculitis

Question 6

What is post-renal AKI?

Answer 6

Kidney stones

Prostatic hyperthrophy

Retroperitoneal fibrosis

Cervical Ca

Uretral stricture

Intra-abdominal hypertension

Obstructed urinary catheter

Question 7

What is pre-renal AKI?

Answer 7

Sepsis

Hypotension - hypovolaemia (vomiting, diarrhoea, haemorrhage), MI, cardiac failure, liver cirrhosis

Drugs - diuretics and ACEi

Question 8

What is the clinical presentation of AKI?

Answer 8

Poor fluid intake - nausea/vomiting etc

Excessive fluid loss - fever, diuretics, diarrhoea, high stoma output

History - stones, prostate disease, haematuria

Drug history - nephrotoxic drugs, iodinated contrast

Low BP

Absent pulse

Rash - vasculitis, nephritis

Joint swelling - vasculitis

Question 9

What are the complications of AKI?

Answer 9

Hyperkalaemia

Acidaemia

Pulmonary oedema

Uraemia - pericarditis, encepalopathy

GI - gastritis, malnutrition, ulceration

Haematological - anaemia, bleeding

Question 10

What investigations are relevant in AKI?

Answer 10

FBCs, U&Es, LFTs, bone, urinalysis, immunology, creatinine kinase, US, CT KUB, biopsy

Question 11

What is the prevention algorithm for AKI?

Answer 11

• Sepsis – treat promptly
• Toxins – avoid/stop nephrotoxic medications, minimise volume of iodinated contrast
• Optimise blood pressure – consider fluids, hold antihypertensive drugs, consider vasopressors
• Prevent harm – review medications

Question 12

How do you optimise blood pressure?

Answer 12

Fluids:

-Crysalloids - 0.9% NaCl/Hartmann’s (contains k)

Question 13

What is hyperklaemia?

Answer 13

• 30mls 10% Calcium gluconate over 5-10 min
• 50mls 50% glucose + 10units soluble insulin
• Stop drugs causing ­ K+
• Sodium Bicarbonate
• Salbutamol nebulisers
• Renal Replacement Therapy

Question 14

What would you do in pulmonary oedema?

Answer 14

•Sit up
•O2 high flow via reservoir mask
•(High dose furosemide)
–only if volume replete
–do not persist if unresponsive
•Intravenous nitrates
–specific situations
•Renal Replacement Therapy

Question 15

Which drugs have reduced renal clearance in AKI?

Answer 15

Cephalosporins, penicillins, fluconazole, opioids, diazepam, digoxin

Question 16

What medications are nephrotoxic?

Answer 16

Aminoglycosides, gentamicin, NSAIDs

Question 17

What are the indications for renal replacement therapy?

Answer 17

–AKI - progressive
–rising urea
–oliguria
– K unresponsive to medical therapy
–pulmonary oedema unresponsive to medical therapy
–severe acidosis pH < 7.1
–uraemic complications