AKI Flashcards
Define AKI.
Abrupt decline in renal function manifesting as reversible acute inc in nitrogenous wastes over hours to weeks
What 6 conditions are at a higher risk for developing AKI?
(1) HTN
(2) congestive cardiac failure
(3) diabetes
(4) multiple myeloma
(5) chronic infection
(6) myeloproliferative disorders
What are the 3 big etiologies of AKI?
1) renal blood flow (prerenal azotemia): MAP <80mmHg then steep decline in GFR
2) intrinsic renal diseases-affecting small vessels, interstitium, glomeruli or tubules
Toxic, ischemic, obstructive acute tubular necrosis
3) postrenal processes-obstruction to urine flow in ureters, bladder, or urethra
What are 4 etiologies of prerenal AKI?
(1) hypovolemia
(2) dec CO
(3) dec effective circulating volume
(4) impaired renal autoregulation
T/F: prerenal injuries are the most common cause of renal failure.
True
What is the BUN:Creatinine ratio in prerenal injuries?
> 20:1
What does a urinalysis often reveal in prerenal injuries?
hyaline casts
What does a FeNA <1% suggest?
Prerenal azotemia
What does a FeNA >1% suggest?
Intrinsic renal failure
What does a FeNA >4% suggest?
Postrenal failure
What is influenced by diuretics, FeNa or FeUrea?
FeNa (FeUrea is not)
What does a FeUrea < 35% or FeUA < 9-10% suggest?
Prerenal etiology
What does a FeUrea > 50% or FeUA > 10-12% suggest?
ATN (acute tubular necrosis)
What are 3 findings on prerenal labs?
(1) volume depletion (hemoconcentration, elevated Na, BUN, Cr)
(2) dec CO/effective arterial volume (edema, low Na, albumin)
(3) urine output altered (oliguria or anuria, high specific gravity, normal sediment or hyaline casts, low urine Na)
How do you tx volume depletion in prerenal injury?
Free water deficit in L
How do you tx dec CO/effective circulating volume in prerenal injury?
Diuretics, nitrates, dobutamine
What are 7 types of intrinsic renal diseases?
(1) AIN
(2) ATN
(3) glomerular diseases
(4) pyelonephritis
(5) multiple myeloma
(6) renal artery thrombus/embolism
(7) vasculitis
What is acute interstitial nephritis (AIN) caused by most commonly?
Allergic reaction to medication
What are 5 findings of classic presentation of AIN?
(1) recent new drug exposure
(2) fever
(3) oliguria
(4) skin rash
(5) peripheral eosiniophilia
What are 4 classes of medications (and the drug names) that are associated with AIN?
(1) antibiotics: vancomycin, beta-lactams, sulfonamides, rifampin, erythromycin
(2) acyclovir
(3) NSAIDs
(4) anticonvulsants (phenytoin, valproate, carbamazepine)
What are 2 findings on UA of AIN?
(1) pyuria- WBCs (2) hematuria
What are 2 tx for AIN?
(1) d/c offending agent (2) glucocorticoid therapy-may accelerate renal recovery
What is acute tubular necrosis (ATN) and its causes?
Acute tubular cell injury that is usually reversible unless severe and prolonged; ischemia, sepsis and toxins (exogenous and endogenous nephrotoxins)
What are 3 endogenous nephrotoxins associated with ATN?
(1) myoglobinuria
(2) hemoglobinuria
(3) uric acid