Renal

Question 1

Wilms’ Tumor

Answer 1

most common renal malignancy of young children; proliferation of *metanephric blastema; associated w WT1 mut;

Question 2

Renal agenesis

Answer 2

Uteric bud fails to develop due to lack of signals to mesenchyme; if unilateral then the remaining kidney compensates (hypertrophy and hyperfiltration), pts are at increased risk for *focal segmental glomerular sclerosis (FSGS)

Question 3

Multicystic Dysplastic Kidney

Answer 3

abnormal uremic bud-mesenchyme interaction (no interaction = agenesis); this is a form of renal dysplasia where kidney is replaced by cysts; there is no/little functioning renal tissue

Question 4

Duplex Collecting System

Answer 4

two uteric buds or a bifurcation of a ureteric bud; may lead to poor urine flow, hydronephrosis and UTIs; associated w *vesicoureteral reflux

Question 5

Vesicoureteral reflux

Answer 5

backward urine flow from bladder to kidneys; leads to recurrent UTIs; primary cause is an abnormal closure of ureterovesical junction (UVJ) and associated w duplex ureters; secondary cause: high bladder pressure - seen in posterior urethral valves

Question 6

Oligohydramnios

Answer 6

decreased formation in fetal *urine; typically occurs in the 2nd trimester of pregnancy (13-27 weeks)

Question 7

Posterior urethral valves

Answer 7

only occurs in males; there is tissue (valve) that obstructs the bladder outflow (persistent urogenital membrane); on US you will see dilated bladder and kidneys (both); a cause of Potter syndrome in boys

Question 8

Horseshoe Kidney

Answer 8

inferior poles fuse; kidneys cannot ascend to pelvis to the retroperotineum; they are trapped by the *IMA; associated w *Turner and Down syndrome

Question 9

Urachus (allantois)

Answer 9

embryonic structure that connects the dome of the bladder to the umbilicus; should be obliterated at birth to form the *median umbilical ligament; if does not obliterate then can serve as a connection between the bladder and umbilical and can leak urine; can lead to infections and *adenocarcinoma of the dome of the bladder

Question 10

Special Kidney features

Answer 10

the right kidney is slightly smaller (due to the liver); the left kidney has a longer renal vein and is often taken for transplant

Question 11

IgA vasculitis

Answer 11

Henoch-Schonlein purpura is a IgA-mediated, leukocytoclastic vasculitis that presents w palpable, arthralgia/arthritis, abdominal pain and/or hematuria; renal involvement is due to mesangial deposition of IgA immune complexes w subsequent mesangial cell proliferation, neutrophilic inflation and glomerular damage

Question 12

Vitamin D deficiency (rickets)

Answer 12

lack of the vitamin D effect causes hypocalcemia due to inadequate Ca2+ absorption; compensatory rise in PTH leads to increased bone resorption, renal Ca2+ reabsorption and renal phosphorus wasting; PTH also induces 1-alpha-hydroxylase activity leading to elevated 1,25OH

Question 13

Ototoxicity secondary to loop diuretics

Answer 13

occurs when higher dosages, pre-existing chronic renal disease, rapid IV admin or when used in combination w other ototoxic agents; hearing impairment is usually reversible but may be permanent in some cases

Question 14

cardiorenal syndrome

Answer 14

decompensated HF involves a vicious cycle of hemodynamic alteration and maladaptive neurohomormal changes resulting from decreased renal perfusion; cardiorenal syndrome is a complication of this cycle, in which back pressure from the failing heart increases renal venous pressure to the point that the glomerular filtration rate drops substantially

Question 15

primary nocturnal enuresis

Answer 15

bed-wetting at the age >5 w/o prior nighttime urinary continence is caused primarily by a brain maturational delay in the development of bladder control

Question 16

Carbamazepine induced SIADH

Answer 16

syndrome of inappropriate antidiuretic hormone presents w hypotonic hyponatremia, concentrated urine and envolemia; carbamazepine can cause SIADH by increasing ADH secretion and renal sensitivity to ADH

Question 17

NSAID-induced acute kidney injury

Answer 17

pts w intravascular volume depletion and CKD depend on renal prostaglandin production to dilate the afferent arteriole and maintain GFR; NSAIDs inhibit PGE synthesis which can cause pre-renal azotemia in at-risk pts

Question 18

blunt lower abdominal trauma

Answer 18

the dome of the bladder rises into the peritoneal cavity when distended w urine; blunt lower abdominal trauma can abruptly increase intravesical pressure and rupture the bladder dome, spilling urine into the intraperitoneal cavity

Question 19

Autosomal dominant polycystic kidney disease

Answer 19

AD PKD typically manifests in pts age 40-50 e enlarged kidneys, flank pain and HTN; in newborns the kidneys are normal size and the cysts are too small to be detected; as the cysts enlarge, they compress renal parenchyma and cause symptoms

Question 20

Minimal change disease (MCD)

Answer 20

MCD is caused by immune dysregulation and overproduction of a glomerular permeability factor, which damages podocytes and decreases the anionic properties of the glomerular basement membrane; resulting in selective loss of albumin in the urine, in contrast to the nonselective proteinuria seen in other forms of nephrotic syndrome

Question 21

ACEi

Answer 21

ACEi reduce angiotensin II levels and cause efferent arteriole dilation thereby decreasing the GFP and filtration rate; this can precipitate acute renal failure in pts w reduced infrarenal perfusion pressure at baseline (ex: renal artery stenosis, CHF and hypovolemia)

acts on the thick ascending limb of Henle loop

Question 22

Patiromer MOA

Answer 22

a nonabsorbable cation exchange resin used to tx hyperkalemia; binds colonic K+ in exchange for Ca2+, trapping K+ within the resin where it is then excreted in feces; adverse effects include diarrhea, hypokalemia, hypercalcemia and hypo magnesium

Question 23

Poststeptococcal glomerulonephritis (PSGN)

Answer 23

presents w edema, HTN and hematuria after a strep infection most children recover completely, but adult pt have a relatively poor prognosis and higher risk for chronic HTN and renal insufficiency

Question 24

ureter injury

Answer 24

the proximal ureter receives its blood supply from the renal artery whereas the distal ureter is supplied by the superior vesicle artery; circulation to the middle portions of the ureter is variable and anastomotic

Question 25

Risk of recombinant EPO therapy

Answer 25

pts w CKD often develop normocytic anemia due to EPO deficiency; tx w rEPO can dramatically improve tissue oxygenation and reduced mortality; prolonged use can have serious side effects of HTN and thromboembolism

Question 26

Urinary catheters associated UTIs

Answer 26

UTIs are common in hospitalized pt w indwelling urinary catheters; the risk for UTI can be reduced by avoiding unnecessary catheterization, using sterile techniques when inserting the catheter and removing catheter as soon as possible

Question 27

low citrate associated w kidney stones

Answer 27

normally citrate excreted from the kidneys bind ionized Ca2+ in the urine preventing the formation of insoluble calcium-oxalate complexes; when urinary citrate is low there is increased Ca2+ available to form calcium-oxalate complexes that precipitate to form calcium oxalate stones

Question 28

BPH associated bladder outlet obstruction

Answer 28

BPH leads to progressive bladder outlet obstruction; over time increased urinary pressure can cause hydronephrosis and renal parenchymal atrophy w scarring; this can progress to CKD

Question 29

Risk of injury during pelvic surgery in females

Answer 29

ureters run in close proximity to the pelvic lymph nodes and the uterine artery in the female pelvis, which predisposes them to injury during pelvic surgery

Question 30

clear cell carcinoma

Answer 30

the most common subtype of renal cell carcinoma and is composed of large, rounded or polygonal cells w clear cytoplasm; these tumors are often detected incidentally at an advanced stage; the lung is the most common site for metastasis, followed by osteolytic bone and liver

Question 31

high altitude

Answer 31

respiratory alkalosis; decreased PAO2 leading to decrease PaO2; so hyperventilation breathing off CO2; kidneys will try to compensate by reabsorbing less bicarb and secreting less H+ into the renal tubules (keeping in serum)

Question 32

renal cell carcinoma and IVC obstruction

Answer 32

RCC tends to invade the renal vein; IVC obstruction can occur by intraluminal extension of the tumor; obstruction of the IVC produces symmetric b/l LE edema often associated w prominent development of venous collaterals in the abdominal wall

Question 33

contrast-induced nephropathy

Answer 33

characterized by an acute rise in creatine and BUN after radiologic contrast admin followed by a gradual return to baseline; characterized histo by diffuse necrosis of the proximal tubular cells (acute tubular necrosis); urinalysis usually demonstrates *muddy brown casts

Question 34

angle-closure glaucoma drugs on renal function

Answer 34

aqueous humor production is promoted by carbonic anhydrase; inhibitors such as acetazolamide rapidly reduce IOP; carbonic anhydrase is also found in the renal proximal tubule, necessary for bicarb reabsorption; acetazolamide induces a mild diuresis w increased urine pH and resulting in mild metabolic acidosis

Question 35

mannitol

Answer 35

mannitol increases plasma osmolarity leading to the flow of water down its [ ] gradient from the intracellular space to the plasma, helping reduce intracranial pressure; the resulting plasma expansion also reduced Na+ levels and increases glomerular filtration/tubular flow; mannitol is freely filtered and not reabsorbed by the renal tubules, resulting in a hyperosmolar glomerular filtrate

Question 36

Fibromuscular dysplasia

Answer 36

characterized by abnormal tissue growth within arterial walls, resulting in stenotic and tortuous arteries that can cause tissue ischemia and are prone to aneurysm formation; typically there is alternating fibromuscular webs and aneurysmal dilation w absent internal elastic lamina (string-of-beads appearance); occurs due to renal artery stenosis and activation of RAAS

Question 37

stress incontinence

Answer 37

stress incontinence, involuntary leakage of urine w increased intra-abdominal pressure, *can occur due to urethral sphincter dysfunction; risk factors include multiple prior vaginal deliveries, which can injure the external urethral sphincter or pudendal nerve

Question 38

lithium diffusion in dialysis

Answer 38

diffusion speed across a semipermeable membrane increases w higher molecular concentration gradients, larger membrane surface areas and increased solubility of the diffusing substance; diffusion speed decreases w increased membrane thickness, smaller pore size, higher molecular weights and lower temperatures

Question 39

RTA type 4

Answer 39

RTA type 4 results from a reduced aldosterone effect on the kidneys and is characterized by hyperkalemia (reduced K+ excretion) and nonunion gap metabolic acidosis; Na+ reabsorption is decreased leading to decreased total body Na+ but the serum Na+ is often unchanged due to the appropriate function of ADH