Acute kidney injury Flashcards
What is Acute Kidney Injury (AKI)?
AKI is defined as any of the following:
* Increase in serum creatinine by > 26.5 μmols/L in 48 hours
* Increase in serum creatinine by > 1.5x baseline creatinine within last 7 days
* Urine volume < 0.5ml/kg/hr for 6 hours
Defined by KDIGO Clinical Practice Guidelines for Acute Kidney Injury 2012.
Why is AKI important?
AKI is COMMON (affects ~7% of hospital inpatients) and has adverse consequences:
* Increased length of stay in hospital
* Increased morbidity
* Increased in hospital & post-discharge mortality
* Very costly (~£500 million/annum)
Highlights the significance of AKI in healthcare.
What are the stages of AKI according to AKIN?
Stages are defined as:
* AKIN 1: SCr > 26.5 μmol/L in 48 hrs OR SCr > 1.5-1.9 fold over baseline
* AKIN 2: SCr > 2-2.9 fold over baseline
* AKIN 3: SCr > 3 fold over baseline OR SCr > 394 μmol/L OR Started on Dialysis
SCr stands for serum creatinine.
What is the inpatient mortality rate for AKIN Stage 3?
43.6%
Reflects the severity of AKI at this stage.
What are the three categories of causes for AKI?
The categories are:
* Pre-renal
* Renal
* Post-renal
Important for differential diagnosis.
What are common pre-renal causes of AKI?
Common pre-renal causes include:
* Hypovolaemia (e.g. bleeding, fluid losses)
* Hypotension (e.g. sepsis, cardiogenic shock)
* Reduced renal blood supply (e.g. renovascular disease)
Emphasizes the importance of blood volume and pressure.
What is the most common cause of AKI in hospitals?
Acute tubular injury (ATI)
Highlights the prevalence of tubular injury as a cause.
What are the renal causes of AKI?
Renal causes include:
* Tubulointerstitial injury
* Glomerular disease
* Blood vessel issues
Indicates the various internal factors contributing to AKI.
What is Acute Tubular Necrosis (ATN)?
ATN is characterized by sloughed cell debris in granular casts and is a common cause of AKI.
Often results from tubular toxins or renal hypoperfusion.
What is the significance of renal ultrasound in AKI?
All patients with significant acute kidney injury MUST have an ultrasound scan to exclude or demonstrate obstruction to the renal tract.
Essential for diagnosing post-renal causes.
What are the clinical steps to take when assessing a patient with severe AKI?
Steps include:
* Take a clinical history
* Perform a clinical examination
* Request appropriate investigations
A systematic approach to patient assessment.
What investigations are crucial in AKI?
Key investigations include:
* Urine dipstick
* Urine culture
* Renal ultrasound
* Blood tests (FBC, biochemistry)
Helps in identifying the cause of AKI.
What are the general treatment options for AKI?
General treatments include:
* Optimise fluid balance and circulation
* Stop exacerbating factors (nephrotoxic drugs)
* Supportive treatment (dialysis, nutrition)
Focus on stabilization and support.
What specific treatment is required for obstruction in AKI?
Drain renal tract (e.g. catheter, nephrostomies)
Addresses the need for immediate intervention.
What is a critical indication for dialysis in AKI?
Severe ‘uraemia’ with no prospect of immediate improvement
Indicates the severity of the condition necessitating dialysis.
True or False: AKI is a formal diagnosis.
False
AKI is considered a syndrome, not a standalone diagnosis.
