Acute Kidney Injury Flashcards
Definition of acute kidney injury?
Sudden acute drop in kidney function
How is acute kidney injury diagnosed?
Measuring serum creatinine
What is AKI characterized by?
-Rapid increase in blood urea & creatinine concentration caused by decreased glomerular filtration rate
Criteria for AKI?
- Rise in creatinine of >26.4micromol/L in 48 hours
- Rise in creatinine of >50%
- Urine output of <0.5ml/kg/hour for more than 6 hours
Who can commonly get AKI?
Common for patients already in hospital
Risk factors for AKI?
- CKD
- Heart fialure
- Diabetes
- Liver diseasse
- Older age (>65)
- Cognitive impairment
- Nephrotoxic medications: lithium, haldol
Classifying causes of acute renal injury?
Pre-renal
Renal/Intrarenal
Post-renal
Which is the most common type of cause of AKI?
Pre-renal
What is pre-renal caused AKI due to?
Inadequate supply to kidneys reducing filtration of blood
What can cause the inadequate blood supply resulting in pre-renal AKI?
- Dehydration
- Hypotension (shock/volume depletion)
- Heart failure (reduced effective circulating volume)
- Renal artery stenosis
- Renal hyperfusion
- Pharmacological (NSAIDs, ACEi)
What is renal AKI?
Where intrinsic disease in kidney is leading to reduced filtration of blood
Possible causes of Renal AKI?
- Ischaemic injury
- Nephrotoxic injury
- Immune-mediated injury
- Vasculitis/vascular disease
- Interstitial nephritis
- Glomerulonephritis
- Acute tubular necrosis
What is the cause of post-renal AKI?
Obstruction to outflow of urine from kidney, causing back-pressure into kidney and reduced kidney function
What is the cause of post-renal AKI called?
Obstructive uropathy
What can renal obstruction be caused by?
- Kidney stones
- Blood clots
- AAA
- Masses eg cancer (usually retroperitoneal)
- Ureter or ureteral strictures
- Enlarged prostate/prostate cancer
- Bladder issues (malignancy, blood clot)
- strictures
Signs/symptoms of AKI?
Non-specific:
- Anorexia, wt loss, fatigue, lethargy
- N/V
- Itch
- Fluid overload
Signs:
- Uraemia including itch
- Pericarditis
- Oliguria
What may pre-renal AKI presnet with?
- Hypovolaemia
- Hypotension
What does hypotension/hypovolaemia present as?
- Thirst
- Dizziness
- Weakness
- Diarrhoea
Investigations for AKI?
- Urinalysis: protein, blood, glucose, nitrates
- U&Es
- FBC and coags
- Immunology: ANA, ANCAM, GBM
- Protein electrophoresis