Acute Kidney Injury Flashcards
Define Acute Kidney Injury (AKI)
Sudden, often REVERSIBLE loss of function. Developed within days/weeks. Accompanied by reduction in urine volume. Rapid loss of glomerular filtration & tubular function over days.
What are the three subtypes of AKI?
Pre-Renal (Most common)
Renal (Rare)
Post-Renal (Common and usually curable)
What is pre-renal AKI?
- Perfusion to the kidney is reduced
- Reduced perfusion = decreased GFR
- Uncorrected, can lead to Acute Tubular Necrosis
What can cause reduced perfusion to kidney?
- Congestive heart failure
- Sepsis
- Blood Loss (acute setting such as burns)
- Dehydration
- Vascular Occlusion
- ARB/Diuretic Usage
- NSAID / ACEi Usage
What histological findings would you see in pre-renal AKI?
Inflammatory changes
Interstitial Oedema
Focal breaks in tubular basement membrane
Symptoms of pre-renal AKI?
- Vomiting
- Diarrhoea
- Haemorrhage
- Jaundice
- Postural hypotension
Signs of pre-renal AKI
- Hypotension
- Tachycardia
- Weight Loss
- Incr. skin turgor
- Delayed capillary refill
- JVP not visible
What is Renal AKI?
- Primary insult that directly affects kidney function i.e. glomerulonephritis or nephrotic drugs or inflammatory disease/infection.
- Untreated pre-renal AKI can cause Acute Tubular Necrosis which is a direct insult to kidney.
Signs of Renal AKI
- Hypertension
- Oedema
- Purpuric rash (suggesting glomerulonephritis)
- Fever/rash (suggesting interstitial nephritis)
What drugs can cause Renal AKI?
PPI
NSAIDs
Antibiotics
What is Post-renal AKI?
Obstruction of urine flow from ureter/tubule to urethra.
This causes in intraluminal uretal pressure, which can in turn affet nephron pressure.
If obstruction is not relieved, Angiotensin II will maintain the low GFR
What can cause a obstructed outflow from tubules?
- Urinary calculi
- Retroperitoneal fibrosis
- BPE
- Bladder cancer
- Prostate cancer
- Urethral stricture
What is the main sign of post-renal AKI?
Distended bladder.
What investigations do we do for AKI?
• Bloods:
- U & Es
- FBC
- Bicarbonate
- IgA
- ABG
- CREATININE (Diagnostic)
• Urinalysis
- Dipstick (looking for blood and protein)
- PCR
- Ultrasound
- Renal Biopsy
Management of AKI
STOP Protocol
S - Sepsis management
T - Toxin stoppage
O - Optimisation of BP (we just love acronyms init)
P - Prevent harm