Renal and Urology Flashcards
(85 cards)
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 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
What are the three places renal calculi can cause an obstruction?
- Ureteropelvic junction
- Pelvic brim
- Vesicoureteric junction
What are the types of stones formed?
- Calcium Oxalate (most common - 80%)
- Struvite
- Uric acid (not visible on X-Ray)
- Hydroxyapatite
What are the diagnostic factors for renal calculi?
- May be asymptomatic until obstruction
- Acute severe loin to groin pain (renal colic)
- N + V
- Unable to lie still/writhing in pain
- Urinary symptoms (urgency, frequency, haematuria)
What are the risk factors of renal calculi?
- Dehydration
- High protein intake
- High salt intake
- Structural abnormalities
- Previous kidney stones
- FHx of kidney stones
What are the investigations of renal calculi?
- Non-contrast CT KUB
- Urine Dipstick (blood + infection)
- Blood test (calcium, infection, kidney function)
- Abdominal X-Ray
- US KUB for pregnant women and children
What is the management for renal calculi?
- NSAIDs (diclofenac)
- IV Paracetamol
- Antiemetics for N + V (ondansetron)
- IV Antibiotics if infection
What is the surgical management based on renal stone size?
- Stone less than 10mm : offer SWL and consider URS if there is contradiction for SWL
- Stone between 10 and 20mm : consider URS or SWL or PCNL if both of those fail
- Stone larger than 20mm (incl. staghorn) : Offer PCNL or URS if PCNL is not an option
What are the surgical options for renal calculi?
- Shockwave lithotripsy SWL
- Ureteroscopy URS
- Percutaneous nephrolithotomy PCNL
- Open Surgery