[EMed] Acute Renal Failure Flashcards
what can causes of acute renal failure (ARF) be classified into?
- pre-renal
- post-renal (obstructive)
- renal
what are pre-renal causes of ARF?
- hypovolaemia
- shock: cardiogenic, anaphylactic
- heart failure
- renal vasoconstriction / stenosis
*most AKIs are pre-renal in nature
what are post-renal (obstructive) causes of ARF?
- calculi
- tumour
- retention
- prolapse
what are renal causes of ARF?
specific: myeloma, GN
non-specific:
- ischaemia (e.g. emboli, clot)
- toxins (e.g. nephrotoxic drugs. rhabdomyolysis)
- infection / inflammation (e.g. sepsis)
what do you do if you suspect a pt has an AKI?
- hx + exam
- assess fluid status
- basic blood panel
- urine dip
- stage AKI
what is the 1st line ix for AKI?
U+Es for serum creatinine, eGFR and creatinine clearance
what does AKI severity depend on?
rise in baseline creatinine
what is the serum creatinine (µmol/L) for AKI stage 1?
1.5-1.9x baseline
Cr rise >20 in 24 hours
what is the urine output (ml/kg/hr) for AKI stage 1?
<0.5 for 6-12 hours
what is the serum creatinine (µmol/L) for AKI stage 2?
2.0-2.9x baseline
what is the urine output (ml/kg/hr) for AKI stage 2?
<0.5 for >12 hours
what is the serum creatinine (µmol/L) for AKI stage 3?
> 3.0x baseline
Cr rise to >300
initiation of RRT!
what is the urine output (ml/kg/hr) for AKI stage 3?
<0.3 >24 hours
anuria for >12 hours
what will aid in resolving an AKI?
addressing the underlying cause
what can be considered if the AKI is refractory to rx?
renal replacement therapy (RRT)
what is the base criteria for consideration of RRT?
- hyperkalaemia (refractory)
- metabolic acidosis (pH<7.2)
- resistant pulmonary oedema
- uraemia with encephalopathy
- specific toxicology reversal
what is the mx for AKI?
- stop any nephrotoxic drugs and commence IVIs
- start a strict fluid balance chart (including catheterisation)
- regular monitoring of U+Es
- address any electrolyte or pH imbalances
- nephrology input, if the AKI is resistant to rx for RRT assessment
indications for dialysis?
AEIOU
A - acidosis pH<7.2
E - electrolyte: hyperkalaemia (refractory)
I - intoxications: toxicology (very selective)
O - oedema (pulmonary)
U - uraemia: hyperuraemia
what are the risk factors for CKD?
- HTN
- DM
- chronic NSAID use
- prolonged AKI
- untreated outflow obstruction
- cardiovascular disease
what is the progression of CKD?
sustained decrease in eGFR over 12 months
what are the complications of CKD?
- anaemia
- mineral and bone disorders (osteodystrophy)
- acute-on-chronic kidney injury
- fluid overload
- hyperkalaemia
- acidosis
what is the eGFR for stage 1 CKD?
> 90
what is the eGFR for stage 2 CKD?
60-89
what is the eGFR for stage 3a CKD?
45-49
