tubulointerstitial disease

Question 1

what are the major causes associated with acute renal injury ?

Answer 1

poor renal perfusion
acute tubular necrosis

Question 2

what is acute tubular necrosis ?

Answer 2

sudden damage to tubular epithelial cells
either due to ischemia
drugs and toxins

Question 3

what is the pathology associated with ischemic ATN ?

Answer 3

ischemia means there is vasoconstriction meaning a decrease in GFR , in cases of ischemia the sodium potassium pump moves to the luminal side releasing more sodium in the urine

Question 4

what are the causes of ischemic ATN ?

Answer 4

anything that lowers the perfusion

Question 5

what are the drugs that are responsible for causing tubular ATN ?

Answer 5

aminoglycosides
contrast dye
uric acid
myoglobin
lead
cisplatin
ethylene glycol

Question 6

how is urine flow obstructed in tubulointerstitial nephritis ?

Answer 6

tubular epithelial cells slough off into the urine and cause obstruction - leading to intrinsic renal failure

Question 7

what type of casts are associated with acute tubular necrosis ?

Answer 7

granular casts
muddy brown casts

Question 8

what are the pathology findings associated with ATN ?

Answer 8

patchy focal necrosis of the nephron

Question 9

what part of the nephron is affected by ischemic injury vs toxic injury ?

Answer 9

ischemic injury affects the PCT and the thick ascending
toxic injury affects the proximal tubule

Question 10

what area of the nephron is the most commonly affected by ATN ?

Answer 10

the proximal tubule

Question 11

what are the phases associated with ATN ?

Answer 11

phase 1 - where the injury occurs
phase 2 - maintenance phase
phase 3 - recovery

Question 12

what are the features of stage 1 ATN ?

Answer 12

slight decline in urine output

Question 13

what are the features of stage 3 ATN ?

Answer 13

associated with a higher risk of hypokalemia
associated with polyuria

Question 13

what are the features of stage 2 ATN ?

Answer 13

oliguria
hyperkalemia
AG metabolic acidosis

Question 15

what is acute tubulointerstitial nephritis ?

Answer 15

inflammation of the interstitial , it is a hypersensitivity reaction mediated by eosinophils

Question 15

what is the main clinical feature associated with AIN ?

Answer 15

renal failure with absence of nephritic and nephrotic syndrome

Question 15

generally what are the causes of acute interstitial nephritis ?

Answer 15

DRAINS
diuretics
rifampin
ab - penicillins and cephalosporins
PPI
NSAIDS
sulfa drugs

Question 16

what are the other secondary causes associated with acute interstitial nephritis ?

Answer 16

may be due to systemic infections
like mycoplasma
or autoimmune diseases , sjogren syndrome, SLE, Sarcoidosis

Question 17

what are the classic findings associated with AIN ?

Answer 17

exposed to a trigger in the past few days
maculopapular rash usually associated
renal failure
WBC in urine - no cystitis
fever

Question 18

what are the hallmark findings in the urine associated with AIN ?

Answer 18

sterile pyuria
WBC casts with no signs of cystitis
urine eosinophils

Question 19

what can AIN progress to ?

Answer 19

papillary necrosis

Question 20

what is the pathology associated with chronic interstitial nephritis ?

Answer 20

mononuclear cell infiltration
fibrosis and atrophy of tubules

Question 21

what is the most common scenario associated with chronic interstitial nephritis ?

Answer 21

patients with longstanding use of NSAIDS
mild increase in BUN/Cr
renal function improves after stopping the drug

Question 22

how do NSAIDS cause ATN ?

Answer 22

the lead to ischemia because they block the vasodilatory effect of prostaglandins on the afferent arteriole

Question 23

what is papillary necrosis ?

Answer 23

coagulative necrosis of renal papillae leads to sloughing of tissue gross hematuria that is often painless

Question 24

what are the classic causes of papillary necrosis ?

Answer 24

consequence of untreated AIN chronic phenacetin use diabetes acute pyelonephritis sickle cell anemia SAAD sickle cell anemia acute pyelonephritis analgesics diabetes melllitus

Question 25

what is the classic case associated with papillary necrosis ?

Answer 25

patient presenting with a typical trigger gross hematuria painless normal renal function

Question 26

what is the most dangerous phase associated with acute tubular necrosis ?

Answer 26

the initial oliguric phase

Question 27

what is diffuse cortical necrosis ?

Answer 27

cause by ischemia of the renal cortex - usually due to a combination of vasospasm and DIC

Question 28

what kind of catastrophes are more associated with diffuse cortical necrosis ?

Answer 28

obstetric problems

Question 29

what are the consequences of renal failure ?

Answer 29

MAD HUNGER metabolic acidosis dyslipidemia high potassium uremia sodium and water retention growth retardation epo deficiency renal osteodystrophy

Question 30

a patient that has just started treatment for endocarditis with new onset oliguria ?

Answer 30

treated with genatmicin and now has acute tubular necrosis

Question 31

what results are seen with rhabdomyolsis ?

Answer 31

false positive RBC in urine dipstick hyperkalemia increased CK levels after exersice

Question 32

why is there swelling in acute ischemic ATN ?

Answer 32

due to decreased activity of the sodium ATPase pump

Question 33

woman in surgery who had 30 second episode intra operativley of low blood pressure , what is the cause ?

Answer 33

ATN

Question 34

in acute exacerbations of heart failure

Answer 34

decreased renal blood flow leading to ischemia leading to ATN

Question 35

patient with dark red urine who also has sickle cell ?

Answer 35

most likley due to renal papillary necrosis but if the patient has a renal condition with no blood in the urine that is FSGS

Question 36

where is the injury in interstitial nephritis ?

Answer 36

renal tubule

Question 37

what drug can prevent renal failure in TLS and what is the MOA ?

Answer 37

allopurinol the MOA : xanthine oxidase inhibitor