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Pathoma LAH > Renal: 12.2: Acute Renal Failure > Flashcards

Renal: 12.2: Acute Renal Failure Flashcards

1
Q

BUN:Cr ratio is greater than 15:1. Dx?

A

prerenal azotemia

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2
Q

How does acute interstitial nephritis present?

A
  • Days to week after starting a drug:
    • oliguria
    • fever
    • rash
    • hematuria
    • CVA tenderness
    • Eos in the urine
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3
Q

What are the clinical features of acute tubular necrosis?

A
  • oliguria with brown, granular casts
  • elevated BUN and Cr
  • Hyperkalemia
  • Metabolic acidosis
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4
Q

Why does acute tubular necrosis cause hyperkalemia?

A

decreased renal excretion of K+

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5
Q

What are the consequences of renal failure?

A

MAD HUNGER

  • Metabolic Acidosis
  • ƒƒDyslipidemia (esp. triglycerides) ƒƒ
  • Hyperkalemia ƒƒ
  • Uremia ƒƒ
  • Na+/H2O retention (HF, pulmonary edema, HTN) ƒƒ
  • Growth retardation and developmental delay
  • ƒƒErythropoietin failure (anemia) ƒƒ
  • Renal osteodystrophy
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6
Q

What do all of the following have in common?:

  • Chronic analgesic use (ie phenacetin, aspirin, NSAIDs)
  • Diabetes mellitus
  • Sickle cell trait or disease
  • Severe acute pyelonephritis
A

they can cause renal papillary necrosis

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7
Q

What is the most common cause of acute renal failure?

A

acute tubular necrosis

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8
Q

What are the 2 major causes of acute tubular necrosis?

A
  1. ischemia
  2. nephrotoxic
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9
Q

What is allopurinol used for?

A
  • to prevent uremia/tumor lysis syndrome kidney damage
  • tx for gout
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10
Q

Which parts of the kidney are particularly susceptible to toxins?

A

proximal tubule

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11
Q

What is the ratio of BUN:Cr in acute tubular necrosis?

A

less than 15

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12
Q

What items are very nephrotoxic?

A
  • aminoglycosides
  • heavy metals (ie lead)
  • myoglobinuria (ie crush injury)
  • ethylene glycol (antifreeze)
  • radiocontrast dye
  • urate/uric acid (ie tumor lysis syndrome)
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13
Q

What is azotemia? How is it measured?

A
  • an increase of nitrogenous waste products in the blood
  • increased BUN and Cr
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14
Q

What is post-renal azotemia?

A

obstruction of the urinary tract downstream from the kidney

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15
Q

Which parts of the kidney are particularly susceptible to ischemia?

A
  • proximal tubule
  • medullary segment of the thick ascending limb
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16
Q

What happens to the tubular function in acute tubular necrosis? What will the tests of tubular function show?

A
  • decreased
  • FENa greater than 2%
  • urine osm less than 500
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17
Q

What does post-renal azotemia do to the GFR?

A

decreases it

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18
Q

What is prerenal azotemia?

A

decreased blood flow to the kidney

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19
Q

What does pre-renal azotemia do to the GFR?

A

decreases it

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20
Q

What happens to the tubular function in prerenal azotemia? What will the tests of tubular function show?

A
  • it’s normal
  • FENa = less than 1%
  • urine osm = greater than 500
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21
Q

What is renal papillary necrosis?

A

necrosis of the renal papillae –> sloughing –> gross hematuria and proteinuria

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22
Q

What happens to the tubular function in post-renal azotemia? What will the tests of tubular function show?

A
  • early: remains intact
    • FENa = less than 1%
    • urine osm = greater than 500
  • late: decreased resorption of Na
    • FENa greater than 2%
    • urine osm less than 500
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23
Q

How can acute tubular necrosis be reversed?

A
  • tubular cells can regenerate (although slowly)
  • often req’s supportive dialysis
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24
Q

What is oliguria?

A

low urine production

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25
How does renal papillary necrosis present?
* gross hematuria * flank pain * proteinuria
26
What kind of casts are seen in acute tubular necrosis?
brown, granular
27
How is acute interstitial nephritis treated?
cessation of the drug
28
What is found in the urine in acute interstitial nephritis?
Eosinophils
29
What happens to the GFR in acute tubular necrosis?
it decreases
30
What is the hallmark of acute renal failure?
azotemia
31
This is a drug-induced hypersensitivity rxn of the interstitium and tubules (inflammation).
acute interstitial nephritis
32
Dx? * Days to week after starting a drug: * oliguria * fever * rash * hematuria * CVA tenderness * Eos in the urine
acute interstitial nephritis
33
What is the ratio of BUN:Cr in post-renal azotemia?
* early: BUN:Cr greater than 15 * late: BUN:Cr less than 15 * \*\*\* Late = LESS than
34
This is an increase of nitrogenous waste products in the blood.
azotemia
35
What is acute interstitial nephritis?
a drug-induced hypersensitivity rxn of the interstitium and tubules (inflammation)
36
What are the s/s of uremia?
* increased BUN ƒƒ * Nausea and anorexia ƒƒ * Pericarditis ƒƒ * Asterixis ƒƒ * Encephalopathy * ƒƒPlatelet dysfunction
37
This is necrosis of the renal papillae --\> sloughing --\> gross hematuria and proteinuria.
renal papillary necrosis
38
What causes renal papillary necrosis?
* Chronic analgesic use (ie phenacetin, aspirin, NSAIDs) * Diabetes mellitus * Sickle cell trait or disease * Severe acute pyelonephritis
39
What category of azotemia is acute tubular necrosis?
intrarenal azotemia
40
Dx? * injury of tubular epi cells --\> necrosis --\> plug tubules with brown, granular casts --\> decreased GFR
acute tubular necrosis
41
What does acute interstitial nephritis cause?
intrarenal acute renal failure
42
Is acute tubular necrosis fatal? Why/why not?
* it can be * electrolyte imbalances
43
Dx? * oxalate crystals in the urine
ethylene glycol poisoning
44
What is acute tubular necrosis?
injury of tubular epi cells --\> necrosis --\> plug tubules with brown, granular casts --\> decreased GFR
45
What is the ratio of BUN:Cr in prerenal azotemia?
greater than 15:1
46
What is Fomepizole? What is it used to treat?
* an alcohol dehydrogenase inhibitor * tx for methanol or ethylene glycol poisoning
47
What is the tx for ethylene glycol poisoning?
Fomepizole
48
Pts that have ingested ethylene glycol often have _____ in their urine.
oxalate crystals
49
What do the following drugs have in common?: * NSAIDs * penicillin * diuretics * PPIs * sulfonamides * rifampin
they all can cause acute interstitial nephritis
50
Are BUN and Cr reabsorbed?
only BUN is
51
What is asterixis?
a recurrent flapping tremor of the arms, like the action of a bird's wings
52
This is a recurrent flapping tremor of the arms, like the action of a bird's wings. When is it seen?
* asterixis * hyperammonemia (liver or kidney dysfunction)
53
What is the normal ratio of BUN:Cr?
15:1
54
How is tumor lysis syndrome prevented?
* hydration * allopurinol
55
How is tubular function measured? What are the normal values?
* FENa = less than 1% * urine osm = greater than 500
56
What do all these items have in common?: * aminoglycosides * heavy metals (ie lead) * myoglobinuria (ie crush injury) * ethylene glycol * radiocontrast dye * urate (ie tumor lysis syndrome)
they're all nephrotoxic
57
Is acute tubular necrosis reversible?
yes
58
What causes acute interstitial nephritis?
* drugs, including: * NSAIDs * penicillin * diuretics * PPIs * sulfonamides * rifampin
59
Why does acute tubular necrosis cause metabolic acidosis? What kind of metabolic acidosis is it?
* decreased excretion of organic acids * anion gap metabolic acidosis
60
What can acute interstitial nephritis progress to?
renal papillary necrosis

Pathoma LAH (77 decks)

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