Kidneys 101

Question 1

3 basic functions of the kidneys?

Answer 1

Filtration of the blood
Regulating blood volume and blood pressure
Producing erythropoietin

Question 2

The PCT reabsorbs what percentage of glucose and amino acids?

Answer 2

100%

Question 3

The DCT is mainly involved in reabsorption of?

Answer 3

Sodium and calcium

Question 4

What two lab values are needed to diagnose and acute kidney injury?

Answer 4

Cr and BUN

Question 5

What are the 3 categories of renal disorders?

Answer 5

Prerenal
Intrarenal
Postrenal

Question 6

AKI criteria?

Answer 6

Only need 1 of the following:
Increase in serum creatinine of >/= 0.3 above baseline within 48 hours
Serum creatinine increases >/= 50% in the past 7 days
Oliguria 6 hours

Question 7

Normal Cr?

Answer 7

0.8-1.2 mg/dL

Question 8

What is the single most valuable lab test in evaluating an AKI?

Answer 8

BMP

Question 9

What other diagnostics are helpful for AKI?

Answer 9

Urinalysis, urine microscopy, measurement of urine output, renal ultrasound.

Question 10

Life threatening complications of AKI?

Answer 10

Hyperkalemia
Fluid overload
Uremia
Metabolic acidosis

Question 11

In what situations is dialysis indicated?

Answer 11

Serum creatinine >5-10
Unresponsive acidosis
Severe electrolyte disorders
Fluid overload
Uremic complications

Question 12

AKI is most commonly due to?

Answer 12

Prerenal failure

Question 13

Prerenal failure is defined as?

Answer 13

Reduced effective blood circulating to kidney

Question 14

Causes of prerenal failure?

Answer 14

Reduction in fluid volume(hemorrhage, dehydration)
Effective volume depletion(CHF, cirrhosis)
Impaired renal blood flow (renal artery stenosis)

Question 15

What lab findings are characteristic of prerenal failure?

Answer 15

Serum BUN:Cr ration >20:1
Urine sodium <20meq/L
Urine specific gravity >1.020

Question 16

Why is urine sodium decreased in prerenal failure?

Answer 16

Kidney tries to increase BP by holding on to sodium and water

Question 17

Treatment for prerenal failure due to CHF?

Answer 17

Diuresis

Question 18

Treatment for prerenal failure due to dehydration?

Answer 18

IVF

Question 19

Treatment for prerenal failure due to hemorrhage?

Answer 19

Blood + fluids

Question 20

What is the least common type of renal failure?

Answer 20

postrenal failure

Question 21

Blockage in what areas causes postrenal failure?

Answer 21

Ureters, bladder, urethra

Question 22

What diagnostic testing would you consider ordering for a patient suspicious for postrenal failure?

Answer 22

Post-void residual, ultrasound or IVP, +/- abdominal CT

Question 23

Treatment for postrenal failure?

Answer 23

Relieve obstruction

Question 24

What is intrinsic renal failure?

Answer 24

One or both kidneys have been damaged and do not work properly

Question 25

Most common cause of intrarenal failure?

Answer 25

Acute tubular necrosis

Question 26

Other causes of intrarenal failure?

Answer 26

Nephrotoxins Interstitial diseases Glomerulonephritis Vascular diseases

Question 27

Labs findings suggestive of intrinsic renal failure?

Answer 27

Serum BUN:Cr ratio 10-15:1 Urine sodium > 40meq/L FENa>2% Urine specific gravity 1.010-1.020

Question 28

3 major causes of acute tubular necrosis?

Answer 28

Renal ischemia Nephrotoxins Sepsis

Question 29

Classic UA of ATN?

Answer 29

Muddy brown granular epithelial cell casts and free renal tubular epithelial cells

Question 30

Treatment for ATN?

Answer 30

Hold nephrotoxins, treat underlying cause, supportive management

Question 31

T/F? Most patients spontaneously recover renal function after ATN.

Answer 31

True

Question 32

What is acute interstitial nephritis?

Answer 32

An immune mediated process of tubulointerstitial injury

Question 33

Most common medications to cause acute interstitial nephritis?

Answer 33

Cephalosporins, penicillins, allopurinol, diuretics, NSAIDs, sulfonamides

Question 34

What are some non-iatrogenic causes of AIN?

Answer 34

illnesses - legionella, CMV, strep, ect

Question 35

UA findings in AIN?

Answer 35

WBCs, white cell casts, eosinophils, protein

Question 36

Treatment for AIN?

Answer 36

Stop offending med | Glucocorticoids

Question 37

What is glomerulonephritis?

Answer 37

Renal glomeruli are damaged by deposition of inflammatory proteins in the glomerular membrane

Question 38

What symptoms are classic for AIN?

Answer 38

Fever, maculopapular rash, eosinophilia

Question 39

Urine findings in glomerulonephritis?

Answer 39

Hematuria, urine may be tea or cola colored. RBCs and RBC casts on UA. Misshapen RBCs Proteinuria

Question 40

Treatment for glomerulonephritis?

Answer 40

Nephrology consult! | Steroids and immunosuppressants.