Acute Kidney Injury- AKI Flashcards
Kidney functions (6)
- Remove waste products from the body
- Remove drugs from the body
- Fluid balance
- Release hormones that regulate BP renin, aldosterone
- Produce an active form of vit D
- Control production of RBC’s EPO
what is an AKI?
Abrupt decrease in kidney function, resulting in the retention of urea and other nitrogenous waste products and in the dysregulation of extracellular volume and electrolytes.
What is the spectrum of an AKI? How is this measured?
Between a minor change in creatinine all the way to failure of renal function and requirement for renal replacement.
AKI’s are measured with biochemical parameters (serum creatinine) and/ or urine output.
how do you categorise the causes of AKI?
Pre-renal
Renal (intrinsic)
Post renal
what are the pre-renal causes of AKI?
-
Hypovolaemia
- Sepsis, haemorrhage, burns, vomiting/ diarrhoea, diuretics
- Reduced cardiac output
- Decreased effective circulatory volume (CHF, liver failure,)
- Hypotension, fluid overload
-
Impaired renal regulation
- NSAIDs, ACEi
renal/ intrinsic causes of an AKI
Divide by the areas of nephron affected:
- Glomerulonephritis- nephritic syndrome
- Tubular- acute tubular necrosis (prolonged ischaemia from pre-renal AKI), infection, nephrotoxins, haemolysis
- Interstitial- acute interstitial nephritis (ischaemia, infections etc.)
- Vascular- vasculitis, MAHA, HUS
post renal causes of an AKI
- Renal/ ureteric calculi
- Prostatic hypertrophy
- Tumours
- Retroperitoneal fibrosis
- Rhabdomyolysis???
who is at risk of an AKI?
Any patient is at risk of an AKI therefore all patients admitted to hospital should have urea, creatinine and electrolytes checked.
High risk groups:
What percentage of hospitalised patients have an AKI?
5%
how do i manage an AKI
- Commence AKI bundle
- Involve senior clinician
- ABC assessment
- Assess fluid status (HR, BP, JVP, cap refill time, RR, oedema, fluid balance, skin turgor, mucous membranes)
- Optimise blood pressure
- Review medications–> stop agents that drive AKI
- Treat sepsis
- Treat obstruction- catheterisation will manage bladder outflow obstruction
What are the initial investigations for AKI?
- Urea, creatinine, electrolytes and bicarbonate
- ABG if bicarbonate is low
- FBC
- LFTs
- Calcium/ phosphate
- Creatinine kinase
- Blood cultures
- Urinalysis
- Ultrasound of renal tract and bladder
What common drugs should I think about that can cause of drive AKI?
- ACE inhibitors/ A2RB’s
- NSAIDs
- Diuretics
- Aminoglycosides
- Metformin
- Radiocontrast
Name 3 complications of an AKI and how to manage them
-
Hyperkalaemia
- Consider cause, ECG
- Calcium
- Insulin dextrose
- Critical care referral
-
Acidosis
- Consider IV sodium bicarbonate- senior advice/ supervision advised
- Uraemic encephalopathy
-
Uraemic encephalopathy or pericarditis
- Renal replacement therapy
When to refer to nephrology
- Cause of AKI unclear
- Stage 3 AKI
- Inadequate response to treatment
- Complications
- Stage 4 or 5 CKD
- Renal transplant
- Possible diagnosis requiring specialist input (e.g., vasculitis or glomerulonephritis)
when to start considering rare diagnoses?
- Blood and protein on urinalysis (not explained by UTI)
- Creatinine proportionately higher than urea
- Multisystem involvement
- Not getting better
