Nephrolithiasis Flashcards
Kidney Stones
- what are they
- most commonly formed due to….
- types of stones
what is it
- solid mass of crystals (hence painful) which form in the kidney and pass through the GU tract (variation in size)
most common cause in inadequate hydration and love urine volume
types
- calcium oxalate stones MC
- calcium phosphate
- uric acid stone
- struvite (infection)
- cystine
reasons for calcium oxalate stones
calcium + oxalate in the stone = MOST COMMON type
- urine contains high amounts of oxalate AND calcium
- due to eating foods with high amoutns of oxalate (black tea, beets, chocolate, nuts, potatoes and spinach)
- conditions can increased calcium in the urine: hyerparathyroidiam, renal hyercalcemia, immobilization syndrome
reasons for calcium phosphate stones
(aka why might the urine be alkalyzed)
calcium phosphate stones: often occur with oxalate stones
- result due to : alkaline urine due to renal function
normal urine: between 6.0-7.5 (4.5-8.0) alkaline 8.0+
alkaline urine beacause of…
- lots of fruit and veggies
- antiacids and diuretics
- kideny disease or UTI
- dehydrated (concentrated urine = higher pH)
- pregnancy
reasons for struvite stones (magnesium, ammonium phosphate)
most commonly in women –> due to UTI!!! think infection when you see struvite
- these form as a result of bacteria causing UTIs –> proteus, pseudomonas, klebsiella, staph aureus
- fast growing: occupt entire kideny: staghorn caculi concern for urosepsis aka sepsis which arises from urinary causes
Uric Acid Stone formation
uric ACID: aka acidic conditions of the urine
- more common in men
- associated with chronic dehydration
- increased risk in those with gout
- cheomtherapy
- diets high in animal protein
- acidic urine pH <5
Cystine Stones
- due to a genetic condition called cystinuria
- failure of the renal tubes to reabsorb cystine which then accumulates in the urine
where can kidney stones obstrurt (within the GU tract)
- renal pelvis: where the kidney attaches to the ureter (think struvite here)
- UPJ: ureteropelvis junction: where the ureter first narrows coming out of the renal pelvis
- Pelvic Brim: where the ureter crosses the illiac vessel it narrows
- UVJ: ureterovesical junction: where the ureter meets the bladder most common site
Risk Factors for a kidney stone
Urinary Composition
what types of compositions
high urine calcium: elevted calcium in urine (50% more)
higher urine oxalate
low urine citrate: citrate helps PROTECT against stone formation (low levels = higher risk, higher levels = protective)
high urine uric acid: for uric acid stone formation risk
low urine volume: dehydration increased stone lieklihood
acidic urine: favors uric acid stones
alkaline urine: favors calcium phosphate stone formation
Risk factors for a kidney stone
Dietary considerations
(minerals)
Fluid Intake: low intake = low output = increased risk (increasing fluid intake can reduce secondary stone formation)
type of fluid matters: sugary drinks increase risk, caffeine reduces risk
Calcium: higher dietary intake = higher urine amount
oxalate: higher dietary intake = higher urine amount (think veggies, fruits, nuts, grains)
potassium: increased potassium decreases stone formation
sodium: excess sodium –> increases calcium excretion –> increased calcium in urine –> increase stone risk
Risk Factors
Dietary Factors
protein: increase animal protein increases calcium excretion & inc. risk (also increases high uric acic, low citrate)
phytate: increase phytate is protective against stones
sucrose: increased surcrose –> increase stone risk
Vit C: increase –> increase calcium oxalate formation and stones
hx. of calcium oxalate reduce vit C to daily RDA
DASH diet & mediterranean diet: helpful to reduce risk of stones
Risk Factors
medications
Calcium Stone
- acetazolamide
- ascorbic acid
- antiacids
Uric Acic Stone
- HCTZ
Xanthine Stone
- allopurinol
non-modifiable risk factors for stone formation
- family history for stones
- genetic predisposition: cystine stone disease
- medical conditions
- hyperparathyroidism (hypercalcemia)
- gout (hyperuricosuria)
- UTI
- IBD
- DM
- obesity
- cystinuria - environmental factors (inadequate fluid intake)
what mostly mimics kidney stones
AAA do not miss get good hx. to differentiate but they will present the same
etopic pregnancy
Signs & symptoms of a kidney stone
-
PAINNNN : acute, severe, intermittent spasm(colicky) pain
- primarily flank pain, abdominal pain which can radiate to the groin
- inability to find a comfortable position - systemtic symptoms
- nausea/vomiting
- sweating
- fever/chills if there is an infection too - Tachypnea, tachycardia
- CVA tenderness
Labs for kidney stones
urinalysis
- hematuria
- + nitrate, leukocytes = get cx. for infection
- crystals
- pH ( alkaline –> think struvite or calcium phosphate, acidic think uric acid)
CBC
- leukycytes for pain/infection
- scr: fr kideny function
pregnancy test!!!
