AKI Flashcards
how is AKI defined v CKD
AKI- change in serum creatinine over days, CKD- change in eGFR over months
what is AKI defined as (KDIGO) guidelines
increase in serum creatinine by over 50% from baseline or urine output 26umol/l in 48 hours.
what is stage 1 AKI (KDIGO)
incr creatinine 1.5x baseline. urine 6 consec hours
what is stage 2 AKI (KDIGO)
increase 2-2.9 x baseline. urine 12 hours
what is stage 3 AKI (KDIGO)
increase >3 x baseline. urine 24hour or anuria for 12hour
what are the risk factors for developing AKI
age >75, CKD, cardiac failure, peripheral vascular disease, chronic liver disease, diabetes, sepsis, drugs, poor fluid intake/increased losses, history of urinary symptoms
what are the commonest causes AKI
ischaemia, nephrotoxins and sepsis
what are the causes split into and % of AKI
pre renal (40-70%), intrinsic renal (10-50%), post renal (10-25%)
what are the pre renal causes due to
renal hypoperfusion- hypotension (hypovolaemia, sepsis), renal artery stenosis +- ACEi
what are the intrinsic renal causes due to
tubular- acute tubular necrosis (commonest), crystal damage, myeloma. glomerular- autoimmune SLE, HSP, drugs, infections. Interstitial- drugs, infiltration. vascular- vasculitis, malignant BP, thrombus chol emboli, HUS/TTP
what are the post renal causes due to
luminal- stones, clots; mural- malignancy, BPH, strictures. extrinsic compression- malignancy, retroperitoneal fibrosis
what can be found on examination
palpable bladder, palpable kidneys, abdominal/pelvic masses, renal bruits, rashes
blood tests
U&E, FBC, LFT, clotting, CK, ESR, CRP. ABG? cultures if signs infection.
what auto antibodies can be tested
ANCA, ANA, anti-GBM)
what imaging can be used
renal USS- distinguish obstruction and hydronephrosis
is complete anuria common or rare
rare- in AKI suggests obstructive cause
what shows that it is chronic kidney
small kidneys- <9cm on USS, anaemia, low Ca2+, high PO43-, only definite sign is high creatinine/low eGFR
what are the indications for dialysis
pulmonary oedema, persistent hyperkalaemia, severe metabolic acidosis, encephalopathy, uraemic pericarditis, drug overdose
what are the general measures in management
assess vol status, aim for euvolaemia, stop nephrotoxic drugs, monitoring, nutrition
what do incr bp, incr jvp, lung creps, peripheral oesema, gallop rhythm on auscultation indicate
fluid overload
what drugs are nephrotoxic
NSAIDs, ACEi, gentamicin, amphotericin
when do you need to stop metformin
if creatinine >150mmol/L
treat underlying cause- pre renal
correct volume depletion- fluids, treat sepsis- antibiotics
treat underlying cause- post renal
catheterise, CT of renal tract, cystoscopy or retrograde stents
what are the complications
hyperkalaemia, pulm oedema, uraemia, acidaemia
what complications can arise from uraemia
encephalopathy, pericarditis
what options are there in renal replacement therapy
haemodialysis and haemofiltration
what are the ECG changes for hyperkalaemia
tall T waves, small or absent p wave, incr PR interval, widened QRS, asystole
how to treat hyperkalaemia
10mL 10% calcium gluconate over 2 min (cardioprotective); IV insulin and glucose; salbutamol nebs (high doses); IV sodium bicarb
how does insulin work to treat hyperkalaemia
insulin stimulates intracellular uptake of K+. salbutamol has a similar effect as insulin/glucose
how to treat pulmonary oedema
sit up give high flow O2. venous vasodilator eg diamorphine 2.5mg IV. furosemide 80-250mg. haemodialysis or haemofiltration. CPAP. IV nitrates
how to prevent AKI
review drugs- withhold/avoid: diuretics, ACEi, anti hypertensives if bp low, NSAIDs, nephrotoxic antibiotics. use opiates with caution. so contrast CT scans and procedures. ensure pt well hydrates- 1L 0.9% saline over 12 hours.
