Acute kidney injury Flashcards
What is acute kidney injury
acute decline in renal filtration function characterized by rise in serum creatinine or fall in urine output
What are some pre-renal causes of AKI
impaired renal perfusion
hypovolemia
heart failure
excess afferent vasoconstriction
renal artery stenosis
What are some renal/intrinsic causes of AKI
structural injury - acute tubular necrosis
glomerulonephritis
acute interstitial nephritis
What are some post renal causes of AKI
obstruction of collecting system from renal pelvis to urethra
ureteric obstruction in lumen, in wall or external compression
bladder flow obstruction
BPH
kidney stones
What are some key diagnostic factors
hypotension/ hypovolamiea
kidney insults
oliguria (<0.5ml/kg/hour for at least 6 consecutive hours )
lower UTI symptoms -urgency,frequency, hesitancy
What are some other diagnostic factors
arrhythmias
dizziness and orthostatic symptoms
uremic - pericarditis, encephalopathy
pulmonary and peripheral oedema
What are risk factors
advanced age - >65
underlying kidney disease
DM
sepsis
iodinated contrast
nephrotoxins - ACEI, NSAIDs
surgery, trauma, haemorrhage
pancreatitis
malignant hypertension
What are the 1st investigations to consider
U&E’s- urea, creatinine, potassium
FBC
CRO
urinalysis and output monitoring
CXR
ECG
What investigations should be considered
renal ultrasound if no identifiable cause for deterioration/ at risk of urinary tract obstruction within 24 hours of assessment
When should one diagnoses AKI
-Increase in serum Cr by 26umol/L or more within 48 hours
-Increase in serum Cr by 50% or more in past 7 days
- fall in urine output to less than 0.5ml/kg/hour for 6 hours
What is management if patient is hypovolemic
- fluid resuscitation
-review meds and stop nephrotoxins
stop NSAIDs, aminoglycosides, ACEI, ARBs, diuretics - identify and treat underlying cause
-consider vasopressor if patient remains severely hypotensive
- if refractory/complications - consider renal replacement therapy
What is management if patient is hypervolaemic
-loop diuretic and sodium restriction
-identify and treat underlying cause
-consider renal replacement therapy
How to treat hyperkalemia in a patient
IV calcium gluconate
combined insulin/dextrose infusion
nebulised salbutamol
calcium resonium, loop diuretics, dialysis ( to remove potassium )
What medications should be stopped if someone has AKI
ACEI as it can worsen renal function and provoke hyperkalaemia
-ARBs
NSAIDs
diuretics
aminoglycosides
What drugs may have to be stopped in AKI due to increased risk of toxicity
Metformin
Lithium
Digoxin
