Renal Cysts

Question 1

What are age related reasons for developing renal cysts

Answer 1

Adults: genetic (PKD) or non-genetic

Kids and adults: chronic renal failure leading to acquired renal cysts

Question 2

What are simple renal cysts

Answer 2

round/oval cysts w/ ONE epithelial layer lining, filled with clear or straw colored fluid
in cortex or medulla

Question 3

Are simple renal cysts dangerous

Answer 3

Not really, no risk for HTN, cancer, CKD, or ESRD

Incidental findings

Question 4

Simple renal cysts rarely (but still might) cause

Answer 4

Obstruction of calyxes or renal pelvis
Rupture (Sx: flank pain, hemturia)
Infection (Sx: fever, lumbar/abd pain, hematuria, pyuria)
HTN (d/t compression of a&v in renal parenchyma)

Question 5

How do you treat hypertension caused by simple renal cysts

Answer 5

ACE/ARB

Question 6

On US, what do Simple renal cysts look like compared to complex renal cysts

Answer 6

Simple: sharply demarcated, smooth thin walls, no echoes/debris, enhanced back wall (good transmission)
Complex: thick walls, septations, calcifications, solid parts, mixed echogenicity, vascularity

Question 7

What if you get an US and it is shady?

Answer 7

Get a CT with and without to further eval the cyst

Question 8

What do we need to know about Bosniak categories

Answer 8

IIF: >3cm, thick walls, calcifications— likely benign, repeat imaging in 3-6 mo
III: masses, enhancement— high change malignancy, monitor or excise
IV: masses and soft tissue enhancement next to cyst wall– very high malignancy

Question 9

Describe acquired renal cysts

Answer 9

Bilateral, 4+ cysts, due to chronic renal failure
kidneys are small-normal size
rarely symptomatic

Question 10

When should you screen for acquired renal cysts

Answer 10

yearly after being on dialysis 3-5 yrs.

Use US vs CT with and without

Question 11

Acquired renal cysts have a small chance of

Answer 11

increase in Renal cell carcinoma risk

Question 12

How do you treat a simple/complex renal cyst

Answer 12

based on Bosniak!
Pain? APAP (or NSAID if they have normal renal fxn)
Persistent pain/ cyst >5cm? percutaneous aspiration w/ injection of sclerosing agent (tetracycline)// OR laparoscopic unroofing

Question 13

What is Autosomal Dominant PKD

Answer 13

hereditary PKD due to PKD1/2 mutation, often clinically silent

Question 14

How are PKD 1/2 different

Answer 14

PKD1: aggressive form
PKD2 slow growth
(most are due to family history, only 5% spontaneous)

Question 15

ADPKD leads to

Answer 15

irreversible decrease in renal function (in 40’s)
-GFR decreases 4.4-5.9 every year
1/2 pts have ESRD by 60 y/o

Question 16

What is the pathology of ADPKD

Answer 16

gene mutation= obstructed tubules= cysts= parenchyma compression= decrease in renal function

Question 17

What is the etiology of ADPKD

Answer 17

Bilateral cysts that cause gradual loss of renal parenchyma, significant renal enlargement (up to 4000g), and a decrease in GFR

Question 18

When does ADPKD present and how (Sx)

Answer 18

30-40 y/o
abd pain, flank pain, back pain, chest pain
frequent UTI’s
+/- hematuria, pyuria

Question 19

What is your RED FLAG symptom of ADPKD

Answer 19

Hypertension and palpable kidneys!!!

Question 20

How do you treat the recurrent UTI’s associated with ADPKD

Answer 20

Quinolones (Ciprofloxacin)

Question 21

What does ADPKD screening include

Answer 21

US (CT/MRI only if US is inconclusive)

CBC, CMP, UA, genetic screen for diagnosis

Question 22

What manifestations are associated with ADPKD

Answer 22

Hepatic cysts (estrogen sensitive) 
Pancreatic/splenic cysts 
aneurysm 
MVP
colonic diverticuli

Question 23

How do you treat ADPKD

Answer 23

Nothing definitive, only symptomatic Tx
HTN: ACE/ARB, decrease Na and caffeine
Pain manage, avoid nephrotoxic agents, avoid contact sports
ESRD: dialysis or transplant

Question 24

What is Medullary Sponge kidney

Answer 24

usually a sporadic congenital disorder (rarely FHx) that is asymptomatic
Leads to collecting tubule dilation and medullary cysts

Question 25

What are complications of medullary sponge kidney

Answer 25

Nephrolithiasis
UTI
Hematuria
Decreased urine concentration

Question 26

How do you diagnose medullary sponge kidney

Answer 26

CT (shows cystic dilation of distal collecting tubule)

usually in 40-50 y/o

Question 27

How do you treat medullary sponge kidney

Answer 27

good hydration
If hypercalcemic, thiazide diuretic
*Renal function is usually maintained

Question 28

What is medullary cystic disease

Answer 28

Autosomal Recessive disease due to multiple gene mutations
causes ESRD before 20 y/o
varies based on age of onset (infantile, juvenile, or adolescent)

Question 29

What are findings consistent with medullary cystic disease

Answer 29

Decreased urine concentrating ability (bland urine, polyuria, polydipsia)
tubulointerstitial nephritis with cysts developing after 9 years old

Question 30

How do you diagnose medullary cystic disease

Answer 30

Clinical characteristics (polyuria/dipsia)
retinitis pigmentosa (blindness)
confirm with genetic testing
US shows mild decrease in kidney size, increased echogenicity, and no corticomedullary differentiation

Question 31

How do you treat medullary cystic disease

Answer 31

Supportive care :(