acute kidney injury Flashcards
what is the definition of acute kidney injury?
An abrupt (<48hrs) reduction in kidney
function defined as
– an absolute increase in serum creatinine by
>26.4μmol/l
– OR increase in creatinine by >50%
– OR a reduction in UO
what are some risk factors for AKI?
- Older Age
- CKD
- Diabetes
- Cardiac Failure * Liver Disease
- PVD
- Previous AKI
- Hypotension
- Hypovoleamia
- Sepsis
- Deteriorating NEWS
- Recent Contrast
- Exposure to Certain Medications
what are some pre renal causes of AKI?
- hypovolaemia- haemorrhage, D&V, burns
- hypotension- cardiogenic shock, sepsis, anaphylaxis
- renal hypoperfusion - NSAIDs/ COX-2, ACEis / ARBs, hepatorenal syndrome
what are the signs of pre-renal AKI?
reversible volume depletion leading to oliguria (<0.5ml/kg/hr) and increased creatinine
what is the commonest form of AKI in hospital?
acute tubular necrosis - commonly caused by sepsis and severe dehydration
what is the treatment of pre-renal AKI?
assess for hydration- clinical obs, JVP, cap refill, pulmonary oedema
- fluid challenge for hypovolaemia - crystalloid (0.9% NaCl) or colloid (gelofusion) NOT dextrose
give bolus then reassess
if >1L necessary with no improvement seek help
what are vascular causes of renal AKI?
vasculitis or renovascular disease
what is the cause of glomerular renal AKI?
glomerulonephritis
what are causes of interstitial renal AKI?
drugs (e.g. antibiotics, ppis, NSAIDs), infection (TB), systemic (sarcoid)
what are causes of tubular injury leading to renal AKI?
ischaemia, drugs (gentamicin), contrast, rhabdomyolysis
what are the signs and symptoms of AKI?
non-specific symptoms- anorexia, weight loss, fatigue, nausea and vomiting, itch, oedema and SOB, uraemia, pericarditis, oliguria
what are clues to renal cause of AKI?
sore throat (strep), rash, joint pains, D&V, haemoptysis, eosinophilia (interstitial nephritis), CK (rhabdomyolysis), vascular bruits
what are the initial investigations in AKI?
U&Es, FBC and coagulation screen, urinalysis, USS, immunology, protein electrophoresis
what causes 1 big and 1 small kidney?
renal artery stenosis
what are the life threatening complications of AKI?
hyperkalaemia
fluid overload (pulmonary oedema)
severe acidosis - pH <7.15
uraemic pericardial effusion
severe uraemia (Ur >40)
what are the levels of hyperkalaemia from normal to life threatening?
- Normal K = 3.5-5.0
- Hyperkalaemia = >5.5
- Life threatening hyperkalaemia = >6.5
how do you assess hyperkalemia?
ECG- peaked T waves, no P waves
what is the treatment of hyperkalaemia?
Cardiac Monitor & IV access Protect myocardium
– 10mls 10% calcium gluconate (2-3mins) Move K+ back into the cells
– Insulin (actrapid 10units) with 50mls 50% dextrose (30 mins)
– Salbutamol Nebs (90 mins)
Prevent absorption from GI tract
– Calcium resonium (NOT in the acute setting)
what are urgent indications for haemodialysis?
- hyperkalaemia >7 or >6.5 & unresponsive to medical therapy
- severe acidosis (pH < 7.15)
- fluid overload
- urea > 40, pericardial rub / effusion
what are risk factors for contrast induced nephropathy?
renal impairment - +/- diabetes mellitus
dehydration
congestive heart failure
LV ejection fraction < 40%
acute MI (within 24 hours)
nephrotoxic drugs
what is the management of contrast induced nephropathy?
Give either Sodium Chloride or Sodium Bicarbonate as follows:
IV 0.9% Sodium Chloride
1000ml at 83ml/hour 12 hours before and 12 hours after the scan
IV 1.26% Sodium Bicarbonate
500ml at 71ml/hour Starting 1 hour before and continuing for 6 hours after
