Acute Kidney Injury Flashcards
What is AKI?
a rapid reduction in kidney function over hours or days as measured by serum creatinine or urea levels
What does it cause?
It results in a failure to maintain fluid balance, electrolytes and acid-base homeostasis
What is the criteria for AKI? (3)
- A rise in creatinine >26umol/L in 48 hours
- Rise in creatinine 1.5x baseline
- Urine output <0.5ml/kg/hour for 6 consecutive hours
What are the pre-renal causes? (1)
Renal hypoperfusion e.g Renal artery stenosis, ACE inhibitors, or hypovolaemia (e.g sepsis, blood loss etc)
How common are pre-renal causes?
They account for 40-70% of AKIs
What are the intrinsic causes? (4)
Acute tubular damage e.g Aminoglycosides, CT contrast, Myoglobinuria; Glomerular damage e.g SLE, infection, glomerulonephritis; Interstitial damage e.g lymphoma, infection, tumour lysis syndrome; Vascular e.g vasculitis, thrombus, hypertension
How common are the intrinsic causes?
They account for 10-50% of AKIS
What are the post-renal causes? (1)
Urinary Tract Obstruction
How common are the post-renal causes?
They account for 10-25% of AKIs
Is AKI common?
Yes, 15% of adults in hospital develop an AKI, 500 million affected in the UK
Who does it particularly affect?
The elderly because their kidney function is usually already reduced
What are the risk factors? (9)
> 65y/o, CKD, eGFR <60, previous AKI, Co-existing illness, hypovolaemia, urological obstruction, iodinated contrast agents, nephrotoxic drugs e.g NSAIDs, Ramipril, Aminoglycosides
Symptoms (6)
Olig/anuria, polyuria, nausea, vomiting, dehydration, confusion
Signs (5)
Hypertension, urinary retention, raised JVP, pulmonary and peripheral oedema, petechial bruising
What investigations ought to be carried out? (15)
Thorough history and examination, urinalysis, FBC U&E and Creatinine, Coagulation studies, Creatine kinase and Myoglobinuria, CRP, Immunology and Virology, Ultrasound of kidneys, Chest Xray, abdo xray, doppler of renal artery, MRI angiography
