Acute Renal Failure

Question 0

Anurea? Differential diagnosis should include?

Answer 0

Less than 50 mL of urine output 24 hours. Acute obstruction, cortical necrosis, and vascular catastrophes (aortic dissection)

Question 1

Acute renal failure? Indicator?

Answer 1

Abrupt decline in GFR, Indicated by increases in creatinine

Question 2

Oligurea?

Answer 2

Less than 400 mL of urine output 24 hours (physiologically the lowest amount of urine person on a normal diet can make)

Question 3

Uremia Sx?

Answer 3

/fatigue, nausea/vomiting, itchiness, confusion, pericarditis due to retention waste products.

Question 4

Azotemia?

Answer 4

Elevated BUN without symptoms

Question 5

BUN to creatinine ratio in prerenal azotemia

Answer 5

20+

Question 6

Causes of prerenal azotemia?

Answer 6

1. Volume depletion (blood loss, G.I. loss, renal loss)
2. Reduced effective blood volume (nephrotic syndrome, cirrhosis, SIRS, burns)
3. Drugs (ACE inhibitors, NSAIDs)
4. Decreased cardiac output (tamponade, CHF)

Question 7

Most common causes of postrenal azotemia?

Answer 7

1. Prostatic obstruction

2. Uterine obstruction due to malignancy

Question 8

Causes of intrinsic acute renal failure?

Answer 8

1. Acute tubular necrosis
2. Glomerulonephritis
3. Tubulointerstitial nephritis

Question 9

Causes of acute tubular necrosis?

Answer 9

1. Nephrotoxic agents (aminoglycosides, radiocontrast, chemo)
2. Ischemic (hypertension, vascular catastrophe)

Question 10

Causes of glomerulonephritis?

Answer 10

1. Postinfectious
2. Vasculitis
3. Immune complex diseases
4. Cholesterol emboli
5. HUS/TTPo

Question 11

Causes of tubulointerstitial nephritis?

Answer 11

1. Drugs (cephalosporins, methicillin, rifampin)

2. Infection (pyelonephritis, HIV)

Question 12

Specific gravity and microscopic findings in:

1. Prerenal failure
2. postrenal failure

Answer 12

1. High specific gravity and normal microscopic findings

2. Unable to concentrate urine (isosthenuria) and various microscopic findings

Question 13

Microscopic findings if postrenal azotemia is caused by:

1. Stones or crystals
2. Prosthetic hypertrophy
3. Extrinsic compression from a tumor

Answer 13

1. Hematuria
2. Leukocytes
3. No change

Question 14

Tubulointerstitial nephritis – see what in urine?

Answer 14

1. Mild proteinuria
2. Leukocytes and white Cell Casts
3. Urinary eosinophils

Question 15

FEna<20? UA will show?

Answer 15

1. Prerenal failure. Concentrated urine with normal sediment

2. Early post-renal failure

Question 16

FEna>1% and Una>20? UA will show?

Answer 16

1. ATN. Isosthenuria with muddy brown casts
2. Interstitial nephritis. Proteinuria with RBCs, WBCs and RBC casts
3. Late post renal failure. Variable.

Question 17

FEna<1% and variable Una? UA will show?

Answer 17

Glomerulonephritis. Severe proteinuria with RBCs and RBC casts

Question 18

EKG shows peaked T waves. Cause? Transient Treatment?

Answer 18

Hyperkalemia.

1. Intravenous calcium. Calcium will oppose the effects of high potassium in the heart
2. Insulin. Drives potassium into ( also can use Beta agonist like albuterol)
3. Intravenous sodium bicarbonate

Question 19

Definitive treatment of hyperkalemia (as opposed to transient treatment)?

Answer 19

1. Diuretic
2. Kayexalate (Cationic exchange resin that exchanges Na for K in colon)
3. Emergency dialysis

Question 20

Indications for dialysis?

Answer 20

AEIOU
Acidosis
Electrolyte disturbances (hyperK, hyperPO4)
Ingestions
Overload (fluid, pulmonary edema)
Uremia and Uremic pericarditis

Question 21

Drugs to use in the clinical treatment of hyperkalemia?

Answer 21

C BIG K
Calcium
HCO3/beta agonist
Insulin
Glucose
Kayexalate

Question 22

Recap - FENa/UNa and UA findings in:

1. GN
2. Tubular interstitial nephritis
3. Prerenal
4. ATN

Answer 22

1. Low/variable ; protein with RBCs and RBC casts
2. High/high; protein WBCs with eosinophils, RBCs and WBC/RBC casts
3. low/low normal sediment
4. High/high; Isosthenuria with muddy brown casts