AKI (Part IV)

Question 1

What is AKI?

Answer 1

This is syndrome characterized by rapid decrease is renal function

Question 2

What are the pitfalls in using creatinine and urine as criteria for diagnosing AKI ?

Answer 2

See attached image

Question 3

Diagnostics for AKI?

Answer 3

see image attached

Abbreviations:

AKI = acute kidney injury
ANCA = anti-neutrophil cytoplasmic antibody
ANA = anti-nuclear antibody
Anti-ds-DNA = anti-double stranded DNA
anti-GBM = anti glomerular basement membrane
C3 = complement component 3
C4 = complement component 4
CK = creatine kinase
CK-MB = creatine kinase MB fraction
CRP = C-reactive protein
ENA = extractable nuclear antigen
HIV = human immunodeficiency virus
HUS = haemolytic uraemic syndrome
NT-proBNP = N-terminal pro-brain natriuretic peptide
TTP = thrombotic thrombocytopenic purpura

Question 4

Urine dipstick in AKI ?

Answer 4

• Glomerulonephritis (with haematuria and proteinuria)
• Acute pyelonephritis (with pyuria/ leucocyturia and nitrites in urine)
• Interstitial nephritis (occasionally with eosinophiluria)

Question 5

Urinary microscopy in AKI?

Answer 5

• presence of red cell casts or dysmorphic red cells supports the diagnosis of glomerular disease
• ethylene glycol poisoning where oxalate crystals may be seen
• tumour lysis syndrome where urate crystals may be present.

Question 6

Intra-abdominal compartment syndrome in AKI?

Answer 6

Any pressure > 20mmHg is consistent with compartment syndrome

Question 7

Pathologic proteinuria ?

Answer 7

> 3g/day is pathologic

Question 8

Renal biopsy ?

Answer 8

Transjugular approach might be safest

Question 9

Other laboratory tests in AKI diagnosis?

Answer 9

• lactate dehydrogenase (LDH) (in case of suspected thrombotic thrombocytopenic purpura (TTP))
• serum creatine kinase and myoglobin (in case of suspected rhabdomyolysis)
• fragmentocytes (in case of possible TTP / haemolytic uraemic syndrome (HUS))
• N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin (in case of suspected cardio-renal syndrome)
• serum / urine protein electrophoresis (in case of suspected myeloma kidney)

Question 10

What are the most common causes of AKI in critically unwell patients?

Answer 10

• Sepsis
• Heart failure
• Haemodynamic instability
• Hypovolaemia
• Nephrotoxic substances