The oliguric patient

Question 1

What is anuria, oliguria and non-oliguria?

Answer 1

– Anuric: <100 mL/day
– Oliguric: 100-500 mL/day
– Non-oliguric: >500 mL/day

Question 2

Define acute kidney injury.

Answer 2

A rapid reduction in kidney function over hours to days, as measured by serum urea and creatinine, and leading to a failure to maintain fluid, electrolyte and acid–base homeostasis

Question 3

What are the 3 characteristics of AKI?

Answer 3

• by a rise in serum creatinine concentration or
• by azotemia = a rise in blood urea nitrogen [BUN]
  concentration
• oliguria

Question 4

Besides the kidney, what else does AKI affect? (4)

Answer 4

• Increased infection risk
• Increases time to wean from a ventilator
• Affects the metabolism of drugs
• Increases risk of CKD

Question 5

What causes pre-renal AKI? (5)

Answer 5

• Renal hypoperfusion
  – Hypovolaemia –fluid losses, bleeding, malnutrition
  – Sepsis - systemic vasodilatation
  – Severe anaemia
  – Heart/liver disease
  – Medicines: NSAIDs, cyclosporine, ACE-inhibitors
• Reduced renal artery flow
  – Stenosis, NSAID

Question 6

What cause intra-renal AKI? (3)

Answer 6

• acute tubular necrosis (ATN) from = TUBULAR
  – prolonged ischemia, drugs, toxins, cytokines,
  infection itself
• primary glomerular diseases = GLOMERULAR
  – glomerulonephritis
• vascular lesions = VASCULAR
  – TTP/HUS, vasculitis, malignant hypertension

Question 7

Give 4 causes of post-renal AKI.

Answer 7

• ureteric – stones, tumour
• bladder – carcinoma
• urethral – prostatic hypertrophy
• Schistosoma
• TB

Question 8

Which urinalysis findings suggests glomerulonephritis or vasculitis? (2)

Answer 8

– Hematuria and proteinuria are prominent

Question 9

Which urinalysis findings suggest hemolysis or rhabdomyolysis? (2)

Answer 9

Blood-positive urine in the absence of
erythrocytes

Question 10

Name 5 investigations to do in AKI.

Answer 10

• Creatinine (or urea – both not needed)
• Potassium and sodium
• Blood gases – acidosis?
• FBC – anemia, trombocytopenia?
• RBS
• Kidney ultrasound – postrenal?
• Chest x-ray – fluid overload?

Question 11

Give 5 indications for dialysis.

Answer 11

• Persistent hyperkalaemia
• Fluid overloaded (+anuria)
• Uremic Pericarditis
• Severe acidosis (HCO3 <12)
• Symptomatic uremia – nausea, vomiting,
  tremor, cognitive impairment

Question 12

What things are specific in primary survey for AKI? (7)

Answer 12

– Airway
– Breathing - acidotic breathing, respiratory distress
from pulmonary edema,
– Circulation - severe hypertension secondary to AKI,
cardiac arrhythmias from electrolyte abnormalities
– Disability - confusion from hyperuremia or
electrolyte imbalance
– Exposure - hypo/hyperthemia