Renal

Question 1

What percentage of sodium filtered by the glomerulus is typically excreted in the urine?

Answer 1

~5%

Question 2

What part of the kidney does furosemide act on?

Answer 2

The ascending loop of Henle

Question 3

How does ADH work in the kidney?

Answer 3

Increases aquaporin-2 water channels in the collecting ducts

Question 4

Of the following areas, which is most responsible for concentrating urine: proximal tubule, ascending loop of Henle, distal convoluted tubule, collecting duct

Answer 4

Collecting duct; by the time the filtrate gets to the collecting ducts, the medullary interstitium is very concentrated and the filtrate is hypotonic, allowing for lots of water to move into the interstitium and out of the “urine”

Question 5

How does aldosterone work?

Answer 5

Increases the density of K+ channels and Na/K ATPase enzymes in the cortical collecting duct

Question 6

What is Conn’s Syndrome?

Answer 6

Hyperaldosteronism: hypokalemia

Question 7

What are the effects of angiotensin II?

Answer 7

Causes mesangial cells in the juxtaglomerular apparatus to contract (decreases glomerular blood flow -> increased renin) + increases aldosterone release from adrenal cortex

Question 8

What is the process by which angiotensin II is made?

Answer 8

Renin secreted from juxtaglomerular apparatus of the kidney -> converts angiotensinogen to angiotensin I -> angiotensin I is covered to angiotensin II by ACE in the lungs

Question 9

How does dopamine and fenoldapam affect the kidneys?

Answer 9

Dilates both afferent and efferent arterioles and increases GFR

Question 10

FeNa 2%?

Question 11

BUN/Creatinine > 20?

Answer 11

Pre-renal etiology of renal problems

Question 12

What is a common electrolyte problem seen with rhabdomyolysis?

Answer 12

Hyperkalemia (also hyperphosphatemia)

Question 13

What is the mechanism of action of spirinolactone?

Answer 13

Direct aldosterone receptor antagonist

Question 14

What is the mechanism of action of acetazolamide?

Answer 14

Carbonic anhydrase inhibitor -> decreased bicarbonate uptake

Question 15

What is the mechanism of action of loop diuretics?

Answer 15

Inhibits Na-K-2Cl transporter in the thick ascending limb of the loop of Henle

Question 16

What is the mechanism of action of thiazide diuretics?

Answer 16

Inhibits Na-Cl transporter in the distal convoluted tubules

Question 17

What would muddle brown casts be pathopneumonic for?

Answer 17

Acute tubular necrosis

Question 18

Definition of oliguria in the ICU?

Answer 18

< 0.5cc/kg/hr

Question 19

What electrolyte abnormalities do you see with loop diuretics? Thiazide diuretics?

Answer 19

Loop: hypokalemia, HYPOcalcemia, hypomagnesemia
Thiazide: hypokalemia, hypomagnesemia, HYPERcalcemia

Question 20

Which medication can result in digoxin toxicity if co-administered with digoxin: lisinopril, spironolactone, triamterene, fenoldopam, furosemide?

Answer 20

Furosemide: digoxin competes with K+ on the Na/K ATPase, so if you are hypokalemia (with Lasix), then digoxin further out-competes and leads to toxicity

Question 21

What is the formula for plasma osmolality and what is the normal value?

Answer 21

Plasma osmolality = (2* Na) + (Gluc/18) + (BUN/2.8)

Normal: 290 mOsm/kg H2O

Question 22

What is the correction for hyperglycemia and sodium levels?

Answer 22

For every increase in glucose of 100 mg/dL above 200 mg/dL, add 1.6

Question 23

What is the classic ECG finding for hypokalemia?

Answer 23

U waves (can also see prolonged PR intervals, flattened T wave, and ST depression)

Question 24

How can you treat hypercalcemia?

Answer 24

Fluids + loop diuretic (hypocalcemia)

Question 25

What two electrolyte abnormalities would prolong NMB?

Answer 25

HypoPO4 and hyperMg

Question 26

What are examples of non-gap metabolic acidosis?

Answer 26

``` Renal tubular acidosis (increased plasma Cl-) GI losses (i.e. diarrhea) Excess NS administration ```

Question 27

What is the most common nerve injury?

Answer 27

Ulnar neuropathy

Question 28

What vertebral levels does the obturator nerve derive from?

Answer 28

L2-L4

Question 29

What nerve plexus innervates the general visceral afferent fibers of the bladder?

Answer 29

Hypogastric plexus (from T10)

Question 30

What do you see with TURP syndrome when surgeons are using glycine irrigating solution?

Answer 30

Hyponatremia + hyperammonemia (glycine is metabolized to ammonia) + hyperglycemia + transient blindness

Question 31

To do a cystoscopy under epidural anesthesia, at what level of loss of cold discrimination is needed to cover surgical pain?

Answer 31

T6 (fibers as high as T8 need to be completed blocked for loss of sensation to bladder, ureters, and renal pelvis so 2 levels above that)

Question 32

Most common cause of perioperative renal dysfunction?

Answer 32

Hypovolemia and anemia

Question 33

What causes the release of renin?

Answer 33

Decreased afferent blow flow or sympathetic stimulation