1: Renal Stones Flashcards
What age is the peak incidence of renal stones
20-40 year-olds
What are the 5 types of renal stones
- Calcium oxalate
- Calcium phosphate
- Struvite
- Uric acid
- Cystine
What are risk factors for calcium oxalate stones
High-calcium
Low urine pH
High oxalate
Low citric acid
What pH of urine increases risk of calcium oxalate stones
Low urine pH (acidic)
What type of renal stones is hypercalcaemia most associated with
Calcium oxalate
What causes calcium phosphate stones
High calcium
Renal tubular acidosis (Type I)
What are risk factors for uric acid stones
High uric acid - such as in gout
What cause struvite stones
Urease producing bacteria
What are two urease producing bacteria
- Klebsiella pseudomonas
- Proteus mirabilis
What is a RF for cystine stones
Cystinuria
What is protective against renal stones
Thiazide diuretics - as they increase calcium re-absorption
What are symptoms of renal stones
- Colicky loin to groin pain
- Patient is unable to lie still
- Nausea and Vomiting
- Tenderness over costa-vertebral angle
What 3 medications increase risk of calcium oxalate or calcium phosphate stones
- Acetazolamide
- Loop diuretics
- Topiramate
What are the 3 most common sites for stones to become lodged
- Pelvic-ureteric junction
- Narrowing ureter
- Vesico-ureteric junction
What is the most common site for stones to be lodged
Vesico-ureteric junction
What is the most common type of renal stone
Calcium oxalate (85%)
What % of renal stones are calcium oxalate
85%
How do calcium oxalate stones present on x-ray
Radio-opaque = can be seen on x-ray
What % of stones are uric acid stones
10%
How do uric acid stones present on x-ray
Radiolucent
What % of stones are cystine stones
1%
What causes cystine stones
Inherited disorder of metabolism presenting reabsorption of cystine from gut or GI tract
What are struvate stones made of
Ammonium, magnesium, phosphate
What % of stones are struvite
20%
How do struvite stones present on x-ray
staghoon calculi - radio-opaque
What causes struvite stones
urease producing bacteria
What % of stones are calcium phosphate
10%
How do calcium phosphate stones appear on x-ray
radio-opaque
What are the only stones to be radio-lucent
uric acid stones
What is gold-standard investigation for renal stones
CT KUB
When should CT KUB be offered
Within 24-hours
If poor renal function or pregnant, what is the alternative to CT KUB
- USS
what other investigations are ordered in renal stones
- Urinalysis: determine pH (for struvite stones)
- FBC (Infection)
- U+E (Renal Function)
- Bone Profile (Calcium)
what is first line management for renal stones
KT KUB
what analgesia is offered
IV Diclofenac
what does diclofenac increase risk of
Cardiac events
aside from analgesia, what else is important when managing renal stones
IV Fluids
when are antibiotics offered in renal stones
Tazosin
what antibiotics are offered for renal stones
Tazosin (piperaceillin and tazobactum)
what % of stones less than 5mm pass spontaneously
90
what does surgical management of renal stones depend on
Size of the stone
how is a renal stone under 10mm managed first-line
medical exclusion
a-blocker
what is used to medically expel small renal stones
a-blocker (tamsulosin)
if medical expulsion fails what is used
shockwave lithotripsy
what is used to expel stones 10-20mm
ureteroscopy
how are renal stones >20mm removed
percutaneous nephrolithotomy (PCNL)
if there is evidence of infection what is required
Percutaneous nephrostomy or ureteric stent to relieve obstruction
what may be used to aid management of calcium oxalate stones
thiazide diuretics
what is specific to management of struvite stones
treat infection
how are uric acid stones managed
colchicine, alkalise urine
what is used to alkalise the urine
potassium citrate
sodium bicarbonate
what can be used to manage cystine stones
penicillamine
what can renal stones cause
- UTI, may cause pyelonephritis
- Obstruction can lead to hydronephrosis
- Bilateral = AKI
