1.17 + 18 urolithiasis Flashcards
Epidemiology of urolithiasis?
gender
recurrent rate
age
- 5% will have a stone related event in the developed world
- Incidence increases
- Male-female ratio: 3:1
- Most frequent between 20-50 years
- The recurrence rate is 50% in 10 years
Etiology of urolithiasis?
Lifestyle
Endogenic factors
what are the risk factors in life style perdisposing urolithiasis?
- Lack of physical activity
- Western unhealthy diet which is high in:
(salt
protein
fat
carbohydrates) - Insufficient fluid intake!
- Insufficient fiber intake
- Iatrogenic:
(Vitamin C& D, other drugs)
give examples about Endogenic factors perdisposing urolithiasis?
Hypercalciuria
Hyperoxaluria
- Idiopathic hypercalciuria
- Cystinuria
- Primary hyperoxaluria
- increased urine pH
- decreased urine volume
- male gender
- Hyperparathyroidism
- Familial renal tubular acidosis
name the Theories of stone formation?
Nucleation theory
organic matrix theory
crystallization inhibition theory
briefly explain Nucleation theory..
Urine is supersaturated, and
the presence of crystal or foreign body
initiates stone formation
briefly explain Organic matrix theory…
An organic matrix of serum and urinary proteins (albumins, globulins, mucoproteins)
provides a framework for deposition of crystals.
briefly explain Inhibitor of crystallization theory…
Absence of inhibitors (Mg, citrate, mucoproteins) permits crystallization.
do you know about any additional factors that might be found influencing the pathological development of urolithiasis?
It is more likely that more than one factor operates in causing stone disease.
Additional risk factors include:
- anatomical abnormalities
- infectios
Process of stone formation?
- Supersaturation of the content of stone in the urine
- Crystallization – homogenous or heterogenous (blood clot, damaged renal papilla, foreign body)
- Stone retention
- Phase of growing
what’s the Stone composition of?
Calcium oxalate - monohydrate
Calcium oxalate - dihydrate
Calcium phosphate
Uric acid
Cystine
Infected stones (struvite)- ammonium, Mg, phosphate
what’s the pH of Calcium oxalate - monohydrate?
5,5-6,4
what’s the pH of Calcium oxalate - dihydrate?
5,5-6,5
same as monohydrate
what’s the pH of Calcium phosphate?
6,5-7,5
what’s the pH of Uric acid?
4,5-5,5
what’s the pH of Cystine?
5,5-7,0
what’s the pH of Infected stones (struvite)
6,5-8,5
describe briefly the features of Calcium oxalate - monohydrate stone…
Dark brown
smooth
hard (thats what she said)
less than 1cm
radiopaque
describe briefly the features of Calcium oxalate - dihydrate stone…
light brown
speculated
fragile
radiopaque
>2cm
describe briefly the features of Calcium phosphate stone..
White light brown
speculated
hard (thats what she said)
very radiopaque
which is more common calcium oxalate stones or Ca-P in general?
- Ca-oxalate More common than calcium phosphate
calcium phosphate stones?
Therapy
th:
-low-sodium diet
-thiazides
describe briefly the features of Uric acid stone..
Yellow-brown
Rhomboid or rosettes
smooth
hard (as she said)
radiolucent (the only one that’s radiolucent)
Uric acid stones
-Risk factors
-therapy
risk factors:
–>decrease urine volume
–>decrease urine pH
- Strong association with hyperuricemia (eg. gout)
-often coexist with diseases in which there is high cell
turnover (eg. leukemia) - th:
–> alkalization of urine
–>allopurinol
describe briefly the features of Cystine stone..
Yellow to brown
Hexagonal
smooth
hard (ts’she said)
Faintly radiopaque
Cystine stone
Etiology
Therapy
- Hereditary (AR)
- cystine reabsorbing-PCT-transporter loses function resulting in:
1. cystinuria (is poorly soluble) –> stones form in urine
2. poor reabsorption of:
->irnithine
->lysine
->arginien (COLA) - Usually begins in childhood
- Can form staghorn calculi
- Positive sodium cyanide nitroprusside test
-th:
->low Na diet
->alkalinization of urine
->chelating agents (eg. penicillamine) if refractory
describe briefly the features of Ammonium
magnesium phosphate (sturvite) Infected stone
Smooth
Coffin lid
soft
lightly colored
rapidly growing into staghorn calculi
slightly radiopaque
Ammonium magnesium phosphate (sturvite) infected stones
caused by
therapy
- Caused by infection with urease +’s:
–> P.mirabilis
–> S. saprophyticus
–> Klebsiella that hydrolyze urea->amonia-> urine alkalinization - Commonly form staghorn calculi
- th:
–>eradication of underlying infection
–>surgical removal of stone
what are the symptoms of urolithiasis?
Asymptomatic (when stone in renal collecting system)
ureteric stones –>obstruction which leads to:
->colic pain (localized to the tip of the penis)
->hydronephrosis pain
-> Hematuria
->AKI (obstructive)
->nfection -> obstructive pyelonephritis
how do you diagnose urolithiasis?
- US:
->mainly for renal stones
->stones appear echogenic with shadows behind - plain Xray
- IV pyelography, retrograde pyrography
->stones creates filling defect
-Low-dose CT (gold-std) info about:
-> size
->location
->HU value >1000 is considered hard stone
->HU <800 is considered soft stone which is more susceptible to ESWL treatment (Extracorporeal shock wave lithotripsy)
-Consider renal function tests (BUN/Cr)
how do you treat urolithiasis?
Conservative approach
Extracorporeal shock wave lithotripsy (ESWL)
Percutaneous nephrolithotomy:
Retrograde uretero-renoscopy
Open surgery
Management of obstructive pyelonephritis
what is the Conservative approach in the treatment of urolithiasis
consider if patient is mildly symptomatic and stone is small:
- Pain control (NSAIDs, opioids)
- Spasmolytics (drotaverine)
- Phytotherapy (induces ureter peristalsis)
- beta-blockers (if small stone in the lower part of the ureter)
what is the (ESWL) in the treatment of urolithiasis?
- xtracorporeal shock wave lithotripsy
- US shock wave creates pressure differences between surface and core of the stone –> stone is crashed into smaller fragments
- Effective for treating kidney stones <2 cm in diameter, as long as no obstruction to the passage of stone fragments is present.
what is Percutaneous nephrolithotomy in the treatment of urolithiasis?
- for Stones >2 cm in diameter
- Under fluoroscopic control, a track with a diameter of ~1cm is introduced into the collecting system
- Disintegrating devices (US-based), which can be introduced through a nephroscope, are used
to break the stone into fragments that can be evacuated
what is Retrograde uretero-renoscopy procedure in the treatment of urolithiasis?
- Laser fiber is introduced through a flexible guide wire, which is introduced through the urethra and bladder, up the ureter to the renal collecting system
- Stones < 1 cm in diameter can be disintegrated
- Use a Dormia basket or forceps to collect stone fragments
describe the Open surgery in the treatment of urolithiasis..
- Not frequently indicated
- Staghorn stones, in which the bulk of the stone lies within calices rather than within the renal pelvis, are treated best by open surgery.
- Kidneys that contribute < 10% of overall renal
function should usually be removed
describe the Management of obstructive pyelonephritis in the treatment of urolithiasis…
->Antibiotics
->antipyretics
->fluids
-> Urine deviation (nephrostomy or Double-J stent)
-> Stone removal
how do you prevent urolithiasis?
-Up to 50% of patients who produce their first stone will have a recurrence within 10 years.
- we Consider analysis of stone composition
- determine further metabolic changes that can have beneficial effect on reducing the risk of stone reoccurrence:
->increase fluid intake (aim for >2L/day urine output)
->Thiazide diuretics (for idiopathic hypercalciuria)
-> decrease uric acid lvls (lifestyle changes, allopurinol)
-> AB to eradicate any urinary tract infection
-> Low-sodium diet, low-protein diet, low-purine diet
Ca-oxalate stones Can result from
–> ethylene glycol (antifreeze) ingestion
–> VitC abuse
–> hypocitraturia associated with decreased urine ph (eg. Crohn disease)
