Renal Cysts Flashcards
How can cysts develop?
genetic and non genetic processes
variety of childhood and adulthood diseases
How are cysts categorized?
Size Location Septations Calcifications Contents Enhancement
How common are simple renal cysts?
65-70% of all renal masses
freq. seen in normal kidneys
MC incidental findings
M >W
little clinical significance
Is there a risk of HTN with simple renal cysts?
rarely but not really
no risk of: CA, CKD, or ESRD
Describe simple renal cysts
develop in the cortex and medulla
Solitary or multiple / unilateral or bilateral < 1 cm to > 10 cm Round or oval Lining is single epithelial layer Fluid filled Clear to straw-colored fluid
Clinical manifestations of simple renal cysts?
usually NONE
obstruction of calyxes or renal pelvis is rare, rupture is rare, inf. rare, HTN rare
What happens when a simple renal cyst does become infected?
presents as renal abscess
- insidious fever
- vague lumbo-abd pain
- +/- hematuria or pyuria
What do simple renal cysts look like on US?
Sharply demarcated w/ smooth thin walls
No echoes (anechoic) within the mass
Enhanced back wall indicating good transmission through the cyst
What do complex cysts look like on US?
Thick walls and/or septations
Calcifications
Solid components
Mixed echogenicity
Vascularity
~Associated with malignancy!
What should you do if US is concerning or consistent with complex cyst?
order CT w/ and w/out contrast
FU for simple cyst?
repeat imagining in 6-12 months
FU for complex renal cysts?
follow up more closely, repeat imaging
What is the MC reason for acquired renal cysts?
chronic renal failure
-dialysis pts
Dx criteria for acquired renal cysts?
Bilateral involvement
> 4 cysts
Diameter range <0.5 cm up to 2 – 3 cm
Describe acquired renal cysts?
can be simple or complex
kidneys are small/norm size
rarely sxs
clinical sig: may increase risk of RCC
When should you screen for acquired renal cysts?
yearly screening after being on dialysis for 3-5 yrs
US > CT w and w/out contrast
Tx for renal cysts?
excision based on Bosniak classification
Acute/intermittent pain > Acetaminophen or NSAIDS if normal kidney func.
Persistent pain, usually with large cyst: percutaneous aspiration w/ injection of sclerosing agent or laparoscopic unroofing
Epidemiology of Autosomal Dominant Polycystic kidney Disease (ADPKD)
Autosomal Dominant
but variable penetrance > disease is often clinical silent
ADPKD results in a…
irreversible decline in renal func.
usually starts in 4th decade of life
50% will have ESRD by 60
Etiology of ADPKD?
PKD1/2 gene mutation → obstructed tubules →
cyst formation →
fluid accumulation → enlargement →
separate from nephron → compress neighboring renal parenchyma →
progressive compromise renal function
Describe ADPKD
multiple cysts with bi involvement
gradual cyst growth
gradual loss of renal parenchyma
sig. kidney enlargement > progressive decline in renal func.
In ADPKD GFR will be maintained until around age? Why is this?
30 y/o
hyperfiltration
What are some sxs associated with ADPKD
urinary concentrating defects
HTN
dull pain and discomfort
proteinuria
clinical presentation of ADPKD?
30-40s
pain: abd, flank, back, chest
50% w/ HTN (100% by ESRD)
large palpable kidneys on PE
freq. UTIS or recurrent nephrolithiasis can be early indicator
hematuria-typically microscopic
proteinuria initially mild
What are the abx of choice for UTI in pts with ADPKD?
quinolones
Dx studies for ADPKD?
US for screening and monitoring
CBC, CMP, UA, genetic screening
What are some associated manifestations in pts with ADPKD?
hepatic cysts (Estrogen sensitive)
Pancreatic and/or splenic cysts
cerebral aneurysm
MVP
colonic diverticula are more common
~All assoc. with gene mutation
Tx for ADPKD?
No definitive tx
Manage HTN: ACE or ARB, low salt diet, limit caffeine
Pain management
Avoid nephrotoxic agents i.e. IV contrast
Manage comps
ESRD- dialysis of kidney transplant
What is medullary sponge kidney ?
congenital disorder
most sporadic
usually asxs
often found incidentally
Path of medullary sponge kidney?
Dilation of collecting tubules:
- 1 or more renal papillae
- 1 or both kidneys
Medullary cysts of variable size
Comps of medullary sponge kidney?
Nephrolithiasis
UTI
Hematuria
Decreased urinary concentrating ability but renal insufficiency is rare
When is medullary sponge kidney usually dx? How?
usually not until 4th or 5th decade
CT >Cystic dilated of the distal collecting tubules
Tx for medullary sponge kidney?
No known therapy
Good hydration
Thiazide diuretic if hypercalciuria is present
Renal function is typically well maintained
What can cause decline in renal func in pt with medullary sponge kidney?
recurrent UTIs or nephrolithiasis
Transmission of medullary cystic disease?
Autosomal recessive- mutations in a number of genes
What are the clinical variants of medullary cystic disease?
infantile, juvenile and adolescent forms
progression to ESRD usually by 20 y/o
Characterisitics findings of medullary cystic disease?
Reduced urinary concentrating ability
-Bland urinary sediment, polyuria, polydipsia
Chronic tubulointerstitial nephritis w/ renal cysts appearing after 9 years of age
Dx of medullary cystic disease?
suggested by clinical characteristics
Confirmed by genetic testing
Ultrasound: Normal or slightly decrease in kidney size for age, increased echogenicity w/ loss of corticomedullary differentiation
What are some extrarenal manifestations of medullary cystic disease?
Retinitis pigmentosa
Tx for medullary cystic disease?
supportive care
no specific tx
