Acute Tubular Necrosis/Acute Renal Failure

Question 1

Acute interstitial renal inflammation with eosinophils* in the urine?

Answer 1

Drug induced interstitial nephritis

Question 2

Most drugs take _________ to develop Drug induced interstitial nephritis but NSAIDS take __________

Answer 2

1-2 weeks

Months

Question 3

Acute generalized cortical infarction of both kidneys?

Answer 3

Diffuse cortical necrosis

Question 4

MCC of acute injury in hospitalized patients?

Answer 4

Acute tubular necrosis (ATN)

Question 5

With ATN, there will be increased?

Answer 5

FENa

Question 6

What will you see in the urine? Why?

Answer 6

granular (“muddy brown”) casts

Tubular cells die and plug the nephron=>intrinsic azotemia=>granular casts

Question 7

There are 3 stages to ATN; they are?

Answer 7

1. Inciting event
2. Maintenance phase—oliguric; lasts 1–3 weeks;
3. Recovery phase—polyuric;

Question 8

During the maintenance phase you could get?

Answer 8

Risk of hyperkalemia, metabolic acidosis,
uremia Why? there is oligouria

Low urine, low urine K+, Low urine H+ and Low urine Urea

Question 9

During the Recovery phase you could get?

Answer 9

BUN and serum creatinine fall; risk of hypokalemia Why? there is polyuria

Question 10

In ischemic tubular necrosis, what part of the kidney is most susceptible to injury?

Answer 10

PCT and thick ascending limb

Question 11

In Toxic tubular necrosis, what part of the kidney is most susceptible to injury?

Answer 11

PCT=>lots to absorb

Question 12

What are 3 common ways that Toxic tubular necrosis happens?

Answer 12

1. Leukemia=>chemo
2. Ethylene glycol=>oxalate crystals
3. Crush Injury

Question 13

How does a patient with leukemia get toxic tubular necrosis?

Answer 13

Leukemia=>chemo=>tumor lysis=>increased uric acid

Question 14

After 4-6 weeks, ATN cells are able to regenerate. Why?

Answer 14

Tubular cells are stable cells (G0=>G1)

Hepatocytes and lymphocytes

Question 15

Sloughing of necrotic renal papillae with gross hematuria and proteinuria? Dx?

Answer 15

Renal papillary necrosis

Question 16

Renal papillary necrosis causes?

Answer 16

SAAD papa with papillary necrosis: 
Sickle cell disease or trait
Acute pyelonephritis
Analgesics (NSAIDs)
Diabetes mellitus

Question 17

What is acute renal failure?

Answer 17

Increased creatinine and BUN due to oligouria=>azotemia

Question 18

Prerenal azotemia is due to?

Answer 18

=>decreased RBF=>Decreased GFR=>Increased renin=> More BUN is reabsorbed but creatinine is NOT

Question 19

Prerenal azotemia what are the numbers

Answer 19

BUN: C=> 20:1

Urine Na+ b/c you are reabsorbing
FENab/c you are reabsorbing
Urine osmolarity= >500

500 20 1

Question 20

Postrenal/Intrinsic azotemia what are the numbers?

Answer 20

Decreased tubular function

Urine Na+ >40
FENa >2
Urine osmolarity= 350

350 40 2

Question 21

Postrenal vs Intrinsic Azotemia

Answer 21

Intrinisic BUN:C=

Question 22

What is the problem in post renal azotemia?

Answer 22

There is backpressure, pushing BUN into the tubular cells but they are damaged

Question 23

Another name for Intrisinic Azotemia?

Answer 23

Acute Tubular Necrosis

Tubular cells die=>cannot reabsorb

Question 24

Consequences of Renal Failure?

Answer 24

Retention of everything
MAD HUNGER:
ƒ Metabolic Acidosis
ƒ Dyslipidemia (especially 􏰀 triglycerides)
ƒ Hyperkalemia
ƒ Uremia—clinical syndrome marked by
􏰀BUN:
ƒ Nausea and anorexia ƒ Pericarditis
ƒ Asterixis
ƒ Encephalopathy
ƒ Platelet dysfunction
ƒ Na+/H2O retention (HF, pulmonary edema, hypertension)
ƒ Growth retardation and developmental delay
ƒ Erythropoietin failure (anemia)
ƒ Renal osteodystrophy (Hyperphosphatemia)

Question 25

EPO is made by?

Answer 25

Renal Peritubular Intersitial cells

Question 26

Patients with chronic renal failure get cysts how?

Answer 26

CRF=>Shrunken kidney=>dialysis=>cysts

Question 27

Renal Failing patients have increased risk of?

Answer 27

RCC

Question 28

Tumors that secrete EPO?

Answer 28

• Pheochromocytoma
• Renal cell carcinoma
• Hepatocellular carcinoma
• Hemangioblastoma