Renal System & Urologic Surgery

Question 0

The kidneys and ureters are located in what space and at what spinal level?

Answer 0

Retroperitoneal space, centered at the L2 vertebral body

Question 1

Perioperative renal dysfunction can occur as a result of what 3 things?

Answer 1

surgical or medical disease, prolonged reduction in renal oxygen delivery, or nephrotoxin insult. (or all 3)

Question 2

Renal pain is conveyed by sympathetic fibers back to what spinal cord segments? This sympathetic innervation is supplied by preganglionic fibers from what spinal cord segment?

Answer 2

Pain conveyed back to T10-L1. Innervation supplied from T8-L1

Question 3

What nerve supplies the parasympathetic innervation to the kidneys?

Answer 3

vagus nerve

Question 4

Innervation of the ureters is supplied from what spinal cord segments?

Answer 4

S2-S4

Question 5

Where is the bladder located?

Answer 5

retroperitoneal space

Question 6

What spinal level is needed for regional anesthesia for bladder surgery?

Answer 6

T10

Question 7

Sympathetic innervation of the bladder, which conduct pain, touch and temperature sensations, originate from what spinal cord segment?

Answer 7

T11-T12

Question 8

Bladder stretch sensation is transmitted via what?

Answer 8

Parasympathetic fibers from S2-S4

Question 9

Does the SNS or PSNS provide most of the motor innervation to the bladder?

Answer 9

Parasympathetic nervous system

Question 10

SNS and PSNS innervation of the prostate, penile urethra, and penis originate in what spinal cord semments?

Answer 10

SNS = T11-T12
PSNS = S2-S4

Question 11

What is the pudendal nerve?

Answer 11

it provides pain sensations to the penis via the dorsal nerve of the penis

Question 12

What level is needed for spinal anesthesia for testicular surgery?

Answer 12

Thoracic level - testicular sensation is conducted to the lower thoracic and upper lumbar segments

Question 13

What is the microscopic functional unit of the kidney? What two roles does it carry out?

Answer 13

Nephron. carries out excretory and regulatory roles

Question 14

Within the nephron, what is the capillary network that acts as the basic filtering unit called?

Answer 14

the Glomerulus

Question 15

What is the name for the initial segment of the renal tubular system which envelopes the glomerulus and acts as the initial receptacle of the filtrate?

Answer 15

Bowman’s Capsule

Question 16

List the 7 things filtered through the glomerulus.

Answer 16

water, electrolytes, glucose, amino acids, urea, uric acid, and creatinine

Question 17

Kindeys receive what % of cardiac output and what percent of this volume gets filtered by the glomerulus?

Answer 17

20% of C.O. and 10% of this gets filtered to produce glomerular filtrate

Question 18

How many L/day of glomerular filtrate is produced, and what % of this filtered fluid gets reabsorbed into circulation?

Answer 18

180L/day and 99% gets reabsorbed into circulation - resulting in 1-2L of urine output per day

Question 19

GFR (glomerular filtration rate) is a measure of glomerular function expressed as what unit?

Answer 19

mL of filtrate produced per minute

Question 20

GFR is the product of what 2 things?m Which one exerts the greatest influence on GFR?

Answer 20

1. the tendency of the glomerular membrane to allow filtration to occur (membrane permeability and surface area)
2. the pressure inside the glomerular capillary forcing fluid through the filter - changes in the pressure exerts the greatest influence on GFR

Question 21

What are the 2 main determinants of glomerular filtration pressure?

Answer 21

glomerular capillary pressure (most important) and glomerular oncotic pressure (which is directly dependent on plasma oncotic pressure)

glomerular oncotic pressure is a minor influence on filtration rate

Question 22

Auto-regulation of renal blood flow is effective for MAPs of what range?

Answer 22

50-150 mmHg

Question 23

What are the two mechanisms for regulating blood flow to the glomerulus? What do they both have in common?

Answer 23

They both involve modulation of afferent arteriolar tone.

1. Myogenic Reflex - decrease in arterial pressure cause arteriole dilation
2. Tuboglomerular Feedback - dec RBF-> dec GFR -> Inc Cl reabsorption and dec Cl to juxtaglomerular apparatus…causes 2 things- afferent arteriole dilation (inc RBF) and release of renin which -> efferent arteriole constriction (inc glom. pressure)…both lead to inc GFR

Question 24

Describe how water is reabsorbed at the various points in the nephron and what allows for the ability to produce concentrated urine - allowing for conservation of water and excretion of excess solutes

Answer 24

concentrated urine is accomplished by creating a hyperosmotic medullary interstitium (established within the countercurrrent flow if the limbs of the LoH) and regulating water permeability in the distal tubules and collecting ducts 65% is reabsorbed in the proximal tubule in isoosmotic fashion with Na and Cl 15 % in LoH- Descending limb of the Loop of Henle allows water to follow osmotic gradients - the thin and thick ascending limbs are relatively impermeable to water and play a key role in concentrating urine Last 20% of water reabsorption occurs in the distal conv. tubules and in the collecting duct - the amount reabsorbed is controlled completely by ADH which is secreted by the posterior pituitary gland

Question 25

During periods of decreased RBF, which area is especially vulnerable to ischemic injury and why?

Answer 25

the medullary Thick Ascending Limb (mTAL) - it only receives 2% of RBF but is very metabolically active

Question 26

What is prerenal azotemia and ATN (acute tubular necrosis)?

Answer 26

Prerenal azotemia is the inc BUN associated with renal hypo-perfusion or ischemia that has not caused renal parenchymal damage. Necrosis of tubular cells releases debris into the tubules, causing flow obstruction, inc tubular pressure and back flow of tubular fluid

Question 27

Acute Tubular Necrosis is often precipitated by what and is most common what types of patients?

Answer 27

Precipitated by nephrotoxin exposure or reduced cardiac output and in pts w/ preexisting renal vasoconstriction (volume depletion, CHF, sepsis)

Question 28

What is intrinsic acute renal failure?

Answer 28

"intrinsic" implies not only a primary renal etiology of ARF, but also includes ischemia, toxins, and renal parenchymal diseases ATN is the most common ischemic lesion

Question 29

List the 5 exogenous nephrotoxins commonly found in hospitals.

Answer 29

Antibiotics, anesthetic agents (methoxyflurane and enflurane), NSAIDs, Chemotherapeutic-immunosuppressive agents, contrast media

Question 30

List the 7 endogenous nephrotoxins that are commonly found in the hospital setting.

Answer 30

1. Calcium (hypercalcemia) 2. uric acid (hyperuricemia) 3. Myoglobin (rhabdomyolysis) 4. Hemoglobin (hemolysis) 5. Bilirubin (obstructive jaundiuce) 6. Oxalate crystals 7. Paraproteins

Question 31

What is postrenal azotemia?

Answer 31

an obstructive uropathy that occurs at any point in the collecting system (renal pelvis to distal urethra) ...accounts for < 5% of ARF cases

Question 32

Explain the difference in GFR for pts with ESRD, renal insufficiency, and decreased renal reserve.

Answer 32

ESRD = < 25% normal GFR Renal Insufficiency = 25-40% normal GFR, elevated BUN and Cr but no symptoms Decreased renal reserve = 60-75% normal GFR no elev of BUN pr Cr....or ~50% GFR with upper lim of norm BUN and Cr

Question 33

What is uremic syndrome?

Answer 33

The most extreme for of chronic renal failure. GFR < 10% of norm causes mult organ system dysfuntions, death without dialysis unable to reg vol and comp of ECF -> fluid expansion and electrolyte overload, metabol acidosis, anemia, plt dysfun., life threatening hyperkalemia

Question 34

What group of drugs is most likely to produce prolonged effects in ESRD pts due to their reliance on renal excretion?

Answer 34

Muscle relaxants. Only su, atracurium, cisatracurium, and mivacurium have minimal renal excretion of unchanged parent compound

Question 35

What is the best test available as the sole indicator of imminent ARF? Why?

Answer 35

The creatinine clearance test. It is a direct reflection of GFR. Collect urine volume for 24hr pd (2 hr correlates).. Ccr= (urine cr x urine volume)/ plasma cr

Question 36

What is TUR Syndrome and how do you treat it?

Answer 36

water intoxication from irrigation fluid absorption..causes mult neuro and cardiopulm sxs associated with hyponatremia ``` 120 = confusion, restlessness and poss QRS widening 115 = somnolence, nausea and wide QRS, elevated ST seg 110 = seizures, coma and v-tach or v-fib ``` Tx - 3% NaCl at rate of < 100mL/hr until Na > 120mEq/L