Acute Kidney Injury 3 Flashcards
What are the main causes of prerenal AKI?
Hypovolemia, hypervolemia with decreased effective circulating volume, and hypotension.
What are examples of hypovolemic causes of prerenal AKI?
Hemorrhage, GI losses (vomiting, diarrhea), urinary or cutaneous losses.
What conditions cause hypervolemia with decreased effective circulating volume in prerenal AKI?
Nephrotic syndrome, cardiac dysfunction, and liver disease.
What types of shock can lead to prerenal AKI?
Septic and myocardial shock.
How does the body respond to decreased renal perfusion?
Increased sympathetic tone, and hormonal responses such as renin, angiotensin II, aldosterone, and ADH release.
What role do prostaglandins play in prerenal AKI?
They cause afferent arteriole dilation to maintain GFR.
How does angiotensin II affect renal arterioles?
It constricts efferent arterioles to preserve GFR.
Is the renal structure intact in prerenal AKI?
Yes, the glomeruli, interstitium, and tubular structures remain intact.
What happens if hypoperfusion persists in prerenal AKI?
It may progress to intrinsic AKI.
What are key historical features of prerenal AKI?
Hemorrhage, vomiting, diarrhea, fever, weight loss, and decreased urine output.
What physical signs indicate dehydration or hypoperfusion in prerenal AKI?
Tachycardia, hypotension, poor skin turgor, dry mucous membranes, sunken eyes/fontanelle, and prolonged capillary refill (>2 seconds).
What physical finding suggests nephrotic syndrome, cardiac dysfunction, or liver disease in prerenal AKI?
Edema.
What BUN-to-creatinine ratio suggests prerenal AKI?
Greater than 20.
What is the typical urine specific gravity in prerenal AKI?
Greater than 1.020.
What is the typical urine osmolality in prerenal AKI?
Greater than 500 mOsm/kg.
What is the normal urine sodium level in children with prerenal AKI?
Less than 10 mEq/L.
What is the normal urine sodium level in neonates with prerenal AKI?
Less than 20–30 mEq/L.
What is the fractional excretion of sodium (FENa) in children with prerenal AKI?
Less than 1%.
What is the FENa threshold in neonates with prerenal AKI?
Less than 3%.
How is prerenal AKI diagnosis confirmed?
Return of serum creatinine to baseline after volume repletion.
What are the core principles of managing prerenal AKI?
Address the underlying cause, provide volume resuscitation, and maintain adequate renal perfusion.
How does fluid management help in prerenal AKI?
It restores renal perfusion and prevents progression to intrinsic AKI.
What are clinical clues for diagnosing prerenal AKI?
Dehydration signs such as capillary refill >2 seconds, tachycardia, and sunken eyes.
Why is prerenal AKI considered functional?
It results from decreased perfusion without structural kidney damage.
What are common but non-specific findings in prerenal AKI urinalysis?
Hyaline casts.
