Renal and Urology Flashcards
What is the definition of an Acute Kidney Injury?
Acute decline in renal filtration function characterised by a rise in serum creatinine or a fall in urine output
What are the three types of AKI?
Pre-renal
Intrinsic Renal
Post-renal
Causes of Pre-renal AKI
Impaired renal perfusion
Hypovolaemia
Heart Failure
Excess afferent vasoconstriction
Causes of Intrinsic Renal AKI
Structural Injury (Acute Tubular Necrosis)
Glomerulonephritis
Acute Interstitial Nephritis
Causes of Post-renal AKI
Obstruction between renal pelvis and urethra
Ureteric obstruction in lumen, in wall or by compression
Bladder outflow obstruction
What is the KDIGO criteria for AKI?
- Stage 1 : Serum creatinine baseline x1.5 - 1.9 or greater than 26 micromol/L increase OR less than 0.5mL/kg/h for 6-12hrs
- Stage 2 : Serum creatinine baseline x2 - 2.9 or greater than OR less than 0.5mL/kg/h for 12hrs
- Stage 3 : Serum creatinine baseline x3 or over or greater than 354 micromol/L increase OR less than 0.3mL/kg/h for 24hrs or anuria
Symptoms of AKI
- N + V
- Dehydration
- Confusion
- Reduced urine output or changes to urine colour
- High BP
- Abdominal Pain
- Slight Backache
- Oedema
Other Diagnostic Factors of AKI
- Arrhythmias
- Dizziness and other orthostatic symptoms
- Uraemia (pericarditis, encephalopathy)
- Pulmonary and peripheral oedema
Risk Factors of AKI
- Advanced age
- Underlying kidney disease
- Diabetes Mellitus
- Sepsis
- Iodinated contrast
- Surgery, trauma, haemorrhage
- Pancreatitis
- Malignant Hypertension
Primary Investigation to order for AKI
Urinalysis - Perform urine dipstick testing for blood, protein, leukocytes, nitrites and glucoses as soon as AKI suspected
U&Es - urea, creatinine, potassium
What is the diagnostic criteria for AKI?
- Increase in serum Cr by 26 umol/L or more within 48 hours
- Increase in serum Cr by 50% or more in the last week
- Fall in urine output to less than 0.5 ml/kg/hr for 6 hours
Management of AKI if patient is hypovolaemic?
- Fluid resuscitation
- Review medications and stop nephrotoxins
- Identify and treat underlying cause
- Consider vasopressor if patient remains severely hypotensive
- If refractory or complications, consider renal replacement therapy
What are the nephrotoxic medications to stop?
- D - diuretics
- A - ACEi, ARBs, Antibiotics
- M - metformin
- N - NSAIDs
Management of AKI if patient is hypervolaemic?
- Loop diuretic (under specialist supervision) and sodium restriction
- Identify and treat underlying cause
- Consider renal replacement therapy
How is hyperkalaemia treated?
- IV calcium gluconate (stabilise cardiac membrane)
- Combined insulin/dextrose infusion, Nebulised salbutamol (move K+ from extracellular to intracellular compartment)
- Calcium, loop diuretics, dialysis (remove potassium)
What is Renal Calculi and what are the other names for it?
- Presence of calculi within urinary system
- AKA urilithiosis, nephrolithiosis