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32 Cards in this Set
- Front
- Back
What is the MC form of ARF?
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Pre-renal failure
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Defined as an acute, potentially reversible decrease in renal function following toxic or ischemic injury to the kidneys.
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ATN
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ATN is characterized by destruction of ___________ epithelial cells w/ acute suppression of renal function.
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tubular
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In ATN, what is the urine flow?
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Characteristically there is a period of oliguria, followed by gradually increasing rates of urine flow, culminating in a period of polyuria – however, this is not universal.
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What is the one of the earliest manifestations of tubular damage?
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The inability to concentrate the urine
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w/ ATN, tell how BUN, creatinine, plasma Na, plasma K, GFR is affected?
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BUN & plasma creatinine levels are increased. Na is decreased while K is increased & GFR is decreased.
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In ATN, urine contains _________ ________, reflecting tubular cell necrosis & sloughing.
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Epithelial casts
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Relate GFR restoration in pre-renal failure & ATN?
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GFR does NOT improve w/ RBF restoration in ATN but does improve in pre-renal failure
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What are the major causes of ATN?
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1) nephrotoxic durgs, 2) increased risk of certain drugs w/ pre-existing renal dz
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What are some things that increase of ATN in a person w/ a pre-existing renal dz?
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Sulfonamides, aminoglycosides (gentamicin), cancer agents (cisplatin), methoxylurane, ethylene glycol, Heavy metals - lead mercurial, Radiocontrast dyes, Massive doses of salicylates
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How does cisplatin & gentamicin cause damage?
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They both accumulate in PCT & cisplatin causes mitochondrial damage
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These types of drugs cause necrosis if accompanied w/ dehydration?
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Massive doses of salicylates
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What are some effects from systemic injury or illness that may cause ATN?
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1) severe trauma where there is blood loss or hypotension, 2) heat stroke, 3) heroin or methadone over dosage, 4) myoglobunuria, 5) rhabdomyolysis, 6) major fluid loss such as in sepsis, burns
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what is the most frequent cause of ATN d/t to intratubular obstruction?
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the presence of myoglobin, Hb, uric acid, myeloma light chains or ecess uric acid in the urine.
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how do radiocontrast media induced ATN cause damage? w/c group of people are more likely affected?
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direct tubular toxicity & renal ischemia. greatest in elderly persons & those w/ preexisting kideny dz, volume, depletion, DM, & recent exposure to other nephrotoxic agents.
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when is myeloma cast & urate nephropathy seen?
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in widespread malignancy or massive tumor destruction by therapeutic agents.
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The ischemic injury in ATN occurs where in the kidney?
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Injury mainly affects PCT & DCT, characteristically the BM
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hemoglobinuria results from what?
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blood transfusion rxns & other hemolytic crises.
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Myoglobinuria results from what?
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mm tauma, extreme exertion, hyperthermia, sepsis, prolonged seizures, K or phosphate depletion, alcoholism & drug abuse.
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Pathophysiologic mechanisms causing ATN
– 4 theories |
1. Profound reduction of RBF – lead to ischemia
and tubular anoxia 2. Obstruction of tubular lumen secondary to debris. - Debris could be a result of the damaged tubular cells via the ischemia or the necrosis induced by toxic substances. - Back pressure would decrease GFR. 3. Back-leakage of tubular fluid into the renal interstitial spaces though areas of discontinuity of the tubular walls. 4. Profound reduction in GFR caused by some structural alterations of the glomeruli. |
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The clinical course of ATN can be divided into 3 phases, what are they?
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1) initiation phase, 2) maintenance phase, 3) recovery phase
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What is the initiation phase of ATN?
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It’s the time of precipitation event until tubular injury occurs w/c is usually hours to days
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This phase of ATN is characterized by a marked decrease in GFR?
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maintenance phase
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The clinical course of ATN can be divided into 3 phases, what are they?
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1) initiation phase, 2) maintenance phase, 3) recovery phase
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What is the initiation phase of ATN?
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It’s the time of precipitation event until tubular injury occurs w/c is usually hours to days
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In ATN, what is seen w/n 24-48 hours of initial injury?
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Oliguria & azotemia
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The clinical course of ATN can be divided into 3 phases, what are they?
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1) initiation phase, 2) maintenance phase, 3) recovery phase
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What is the initiation phase of ATN?
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It’s the time of precipitation event until tubular injury occurs w/c is usually hours to days
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In ATN, what is seen w/n 24-48 hours of initial injury?
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Oliguria & azotemia
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T/F: Pre-renal urine is concentrated?
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True
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List 3 difference between pre-renal dz & ATN?
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1) BUN:creatinine ratio, 2) urine to plasma osmolarity is >2:1 in pre-renal while 1:1 in ATN, 3) K is still secreted in pre-renal
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What is important in preventing pre-renal from going to ATN?
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Oliguria in pre-renal must have volume.
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