RENAL FAILURE

Question 1

a sudden decrease in kidney function.

characterized as an increase in serum creatinine.

Answer 1

Acute Kidney Injury (AKI)

Question 2

AKI results in

Answer 2

an inability to maintain acid- base, fluid, and electrolyte balance and to
excrete nitrogenous wastes.

Question 3

AKI can be divided into three categories:

Answer 3

(a) Prerenal
1) Kidney hypoperfusion (low blood flow or pressure) leading to decreased GFR
(b) Intrinsic kidney disease
(c) Postrenal
1) Obstructive uropathy

Question 4

MOST common etiology of AKI

Answer 4

Prerenal

Question 5

If hypoperfusion persists it can lead to

Answer 5

a secondary intrinsic kidney injury

Question 6

(e) Decreased renal perfusion occurs in several ways

1) Decrease in intravascular volume

Answer 6

a) Hemorrhage
b) GI losses

c) Dehydration
d) Excessive diuresis

Question 7

(e) Decreased renal perfusion occurs in several ways

Change in vascular resistance

Answer 7

a) Sepsis
b) Anaphylaxis

c) Anesthesia and other medications including
1 ACE inhibitors
2 NSAIDS
3 Epinephrine

Question 8

(e) Decreased renal perfusion occurs in several ways

Low cardiac output

Answer 8

a) Cardiogenic shock
b) Heart failure
c) Pulmonary embolism
d) Pericardial tamponade
e) Arrhythmia

Question 9

(e) Decreased renal perfusion occurs in several ways

Postrenal

Answer 9

a) Least common cause (5-10%)
b) Important to detect because they are reversible

c) Causes include:
 1 Urethral obstruction (Stones, strictures)
 2 Bladder dysfunction or obstruction 
3 Obstruction of both ureters/renal pelvises
 4 BPH (most common cause in males)
 5 Cancer (bladder, prostate, and cervical)

Question 10

(e) Decreased renal perfusion occurs in several ways

Intrinsic

Answer 10

a) Up to 50% of cases
b) Considered after prerenal and postrenal causes are ruled out

c) Sites of injury include:
 1 Tubules
 2 Interstitium
 3 Vasculature
 4 Glomeruli

Question 11

Pertinent anatomy

Answer 11

(1) Kidneys
(2) Ureters
(3) Bladder
(4) Prostate
(5) Urethra

Question 12

Signs and symptoms

Answer 12

(1)Buildup of waste products can sometimes cause nonspecific symptoms and signs
collectively termed uremia
(a) Nausea, vomiting, altered sensorium, pericarditis, malaise
(2)Pericardial effusion leading to tamponade and friction rub
(3)Arrhythmias
(4)Rales in hypervolemia
(5)Nonspecific diffuse abdominal pain and ileus
(6)May experience symptoms and signs of the underlying disease process causing their AKI.
(7)May be hyper or hypovolemic depending on underling disease process.

Question 13

Differential diagnosis

Answer 13

Consideration for the underlying causes

Question 14

Laboratory findings

Answer 14

(1) Blood Urea Nitrogen (BUN)
(2) Creatinine

(a) Ratio of BUN:Cr can help determine prerenal, postrenal or intrinsic
(3) Urinalysis

(a) Looking for red blood cells, casts or white blood cells

Question 15

Imaging

Answer 15

Renal ultrasound

Question 16

Treatment

(1)Prerenal

Answer 16

(a) Depends entirely on the cause
1) Achieving euvolemia
2) Restoring renal perfusion
(b) Avoiding nephrotoxic drugs

Question 17

Treatment

Postrenal

Answer 17

(a) Bladder catheterization

(b) Relieve underlying cause

Question 18

Treatment

Intrinsic

Answer 18

(a) Usually self-limited

(b) Managed by nephrology

Question 19

Complications

Answer 19

(1) Need for dialysis
(2) Arrhythmias secondary to electrolyte abnormalities
(3) Bleeding/clotting disorders
(4) Encephalopathy
(5) Cardiac tamponade

Question 20

Follow up

Answer 20

(1) Most patients will be a MEDEVAC
(2) Depending on the underlying cause

(a) Prerenal
1) May be referred to Emergency medicine, cardiology, or internal medicine
(b) Postrenal
1) Urology referral to relieve obstruction
(c) Intrinsic
(d) Nephrologist