Acute Kidney Disease

Question 1

timeline for kidney disease

Answer 1

AKI- hours to days
AKD- less than 3 months
CKD- over 3 months

Question 2

echo findings w/ CKD

Answer 2

small echogenic kidneys

Question 3

3 types of AKD

Answer 3

• pre renal: reduced renal perfusion
• intrarenal: vascular, glomerular, tubular, interstitial injury
• post renal: obstructed kidney

Question 4

causes of pre renal pathology (2 broad causes)

Answer 4

low renal perfusion:

1. low ECF volume from GI loss, hemorrhage, diuretics
2. altered renal blood flow: sepsis, HF, cirrhosis, hypercalcemia, meds, vascular disease

Question 5

3 broad categories of intra renal

Answer 5

vascular

(renal parenchymal):
tubulointerstitial- AIN, ATN, tubular obstruction

glomerular disease

Question 6

causes of ATN (acute tubular necrosis)

Answer 6

decreased renal perfusion (prolonged pre renal) causes ischemic tubular injury

nephrotoxins cause tubular injury

• meds like aminoglycosides
• heme pigments like w/ rhabdo
• iodinated contrast from CT scans

Question 7

3 phases of ATN

Answer 7

1. inititating- hours to day, inciting event until injury occurs
2. maintenance- 1-3 weeks, marked decrease in GFR and risk of electrolyte imbalance
3. recovery- repair of renal tissue, BUN and Cr back to normal

Question 8

possible post renal causes

Answer 8

obstruction: large prostate, kidney stone, tumor

increased pressure transmitted to nephrons- must effect both kidneys to have marked GFR reduction

Question 9

how to exclude post renal

Answer 9

foley cath (would have improvement if post renal), renal ultrasound

Question 10

3 types of abnormal urine sediment, w/ DDx

Answer 10

1. RBC, RBC casts, proteinuria: GN, vasculitis, thrombotic microangiopathy
2. WBC, WBC casts, eos: pyelonephritis, interstitial nephritis
3. RTE cells, pigmented casts (granular muddy brown): ATN

Question 11

meaning of hyaline cast

Answer 11

pre renal causes, can be in normal kidney (no cellular filtration)

Question 12

FENa equation

Answer 12

(UNa x Scr/ Ucr x SNa) x 100

Question 13

interpret FENA

Answer 13

less than 1%= likely pre renal, Na avid state

over 2%= likely ATN

Question 14

fractional excretion of urea equation

Answer 14

(Uurea x Scr/ Ucr x BUN) x100

Question 15

interpret FEurea

Answer 15

less than 35% likely pre renal

over 50 likely ATN- loss of urea reabsorption

Question 16

effect of NSAIDs on GFR/kidney fn

Answer 16

inhibit intra renal prostaglandins- block afferent dilation and cause reduction in GFR (pre renal)

Question 17

what to think w/ AKI following cardiac cath

Answer 17

radiocontrast induced ATN nephropathy

less common is atheroembolic disease- can also present w/ livedo reticularis rash, eosinophilia, low C3

Question 18

course of action with drug induced AIN

Answer 18

remove offending drug, steroids can speed recovery

Question 19

define renal papillary necrosis

Answer 19

necrosis and sloughing of papillae from lack of blood flow

Question 20

causes/ tx of renal papillary necrosis

Answer 20

associated w/ NSAIDs, DM, SCD