acute kidney injury Flashcards
what is acute kidney infection?
an abrupt (<48hours) reduction in kidney function defined as:
- an absolute increase in serum creatinine by >26.4 micro mols/l
- OR increase in creatinine by >50%%
- OR a reduction in UO <0.5mL/kg/hr for >6 consecutive hours
what is the staging for AKI?
KDIGO
-either serum Cr criteria or urine output criteria
what are risk factors for AKI?
- older age
- CKD
- diabetes
- cardiac failure
- liver disease
- PVD
- previous AKI
- hypotension
- hypovoleamia
- sepsis
- deteriorating NEW
- recent contrast
- exposure to certain meds
what are some pre renal causes of AKI?
anything that causes a reduction in the perfusion to the kidneys
Hypovolaemia:
- haemorrhage
- volume depletion (e.g. D&V, burns)
Hypotension:
- cardiogenic shock
- distributive shock (e.g. sepsis, anaphylaxis)
Renal Hypoperfusion:
- NSAIDs/ COX-2
- ACEI/ ARBs
- hepatorenal syndrome
what may cause hypovalaemia leading to pre renal AKI?
- haemorrage
- volume depletion (e.g. D&V, burns)
what may cause hypotension leading to pre renal cause of AKI?
- cardiogenic shock
- distributive shock (e.g. sepsis, anaphylaxis)
what may cause renal hypoperfusion leading to a pre renal cause of AKI?
- NSAIDs/ COX-2
- ACEI/ ARBs
- hepatorenal syndrome
how can you define a pre renal AKI?
-reversible volume depletion leading to oliguria and increase in creatinine
what does untreated pre renal AKI lead to?
acute tubular necrosis
what is acute tubular necrosis?
- the commonest form of AKI in hospitals due to a combination of factors leading to decreased renal perfusion
- commonest causes include sepsis, severe dehydration, rhabdomyolysis and drug toxicity
what is the treatment for pre renal AKI?
Assess for hydration:
- clinical observations (BP, HR, UO)
- JVP, capillary refill time, oedema
- pulmonary oedema
Fluid challenge for hypovolaemia:
- Crystalloid (0.9% NaCl) or Colloid (Gelofusion)
- do not use 5% dextrose!!
- give bolus of fluid then reassess and repeat if necessary (give max 1L)
what causes renal AKI?
Diseases causing inflammation or damage to cells causing AKI
Vascular:
- vasculitis
- renovascular disease
Glomerular:
-glomerulonephritis
Interstitial Nephritis:
- drugs
- infection (TB)
- systemic (sarcoidosis)
Tubular Injury:
- Ischaemia
- drugs (gentamycin)
- contrast
- rhabdomyolysis
what are vascular causes of renal AKI?
- vasculitis
- renovascular disease
what are glomerular causes of renal AKI?
-glomerulonephritis
what are interstitial nephritis causes of renal AKI?
- drugs
- infection (TB)
- systemic (sarcoidosis)
what are tubular injury causes of renal AKI?
- ischaemia
- drugs (gentamycin)
- contrast
- rhabdomyolysis
what are some signs and symptoms of AKI?
- anorexia
- weight loss
- fatigue
- lethargy
- nausea + vomiting
- itch
- fluid overload (oedema, SOB)
SIGNS:
- fluid overload (HTN, oedema, pulmonary effusion, pleural effusion, pulmonary oedema)
- uraemia (itch, pericarditis)
- oliguria
what are the initial investigations for AKI?
- U&Es
- FBC and coagulation screen
- urinalysis (haematoproteinuria)
- USS (incase of obstruction)
- immunology (ANA, ANCAm GBM)
- protein electrophoresis and BJP
what is the cause of post renal AKI?
AKI due to obstruction of urine flow lading to back pressure and thus loss of concentrating ability
- stones
- cancers
- strictures
- extrinsic pressure
what can cause cardiac arrhythmias in AKI?
hyperkalaemia
what is treatment for hyperkalaemia?
- cardiac monitor and IV access
- protect myocardium (10mls 10% calcium gluconate for 2/3 mins)
- Move K+ back into the cell (insulin actrapid 10 units with 50 mls 50% dextrose for 30 mins and nebulised salbutamol for 90 mins)
- prevent absorption from GI tract using calcium resonium (NOT in an acute setting)
what are indications for HD (hemodialysis)?
- hyperkalaemia >7 or >6.5 if patient unresponsive to medical therapy
- severe acidosis pH <7.15
- fluid overload
- urea >40, pericardial rub/effusion
- B
- A
- C
- D
Furosemide does not- it causes lower potassium
Calcium gluconate
elevated creatinine on its own is not an indication
