Nephrolithiasis Flashcards

1
Q

Kidney Stones
- what are they
- most commonly formed due to….
- types of stones

A

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

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2
Q

reasons for calcium oxalate stones

A

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
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3
Q

reasons for calcium phosphate stones
(aka why might the urine be alkalyzed)

A

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

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4
Q

reasons for struvite stones (magnesium, ammonium phosphate)

A

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
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5
Q

Uric Acid Stone formation

A

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

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6
Q

Cystine Stones

A
  • due to a genetic condition called cystinuria
  • failure of the renal tubes to reabsorb cystine which then accumulates in the urine
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7
Q

where can kidney stones obstrurt (within the GU tract)

A
  1. renal pelvis: where the kidney attaches to the ureter (think struvite here)
  2. UPJ: ureteropelvis junction: where the ureter first narrows coming out of the renal pelvis
  3. Pelvic Brim: where the ureter crosses the illiac vessel it narrows
  4. UVJ: ureterovesical junction: where the ureter meets the bladder most common site
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8
Q

Risk Factors for a kidney stone
Urinary Composition
what types of compositions

A

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

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9
Q

Risk factors for a kidney stone
Dietary considerations
(minerals)

A

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

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10
Q

Risk Factors
Dietary Factors

A

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

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11
Q

Risk Factors
medications

A

Calcium Stone
- acetazolamide
- ascorbic acid
- antiacids

Uric Acic Stone
- HCTZ

Xanthine Stone
- allopurinol

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12
Q

non-modifiable risk factors for stone formation

A
  1. family history for stones
  2. genetic predisposition: cystine stone disease
  3. medical conditions
    - hyperparathyroidism (hypercalcemia)
    - gout (hyperuricosuria)
    - UTI
    - IBD
    - DM
    - obesity
    - cystinuria
  4. environmental factors (inadequate fluid intake)
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13
Q

what mostly mimics kidney stones

A

AAA do not miss get good hx. to differentiate but they will present the same

etopic pregnancy

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14
Q

Signs & symptoms of a kidney stone

A
  1. PAINNNN : acute, severe, intermittent spasm(colicky) pain
    - primarily flank pain, abdominal pain which can radiate to the groin
    - inability to find a comfortable position
  2. systemtic symptoms
    - nausea/vomiting
    - sweating
    - fever/chills if there is an infection too
  3. Tachypnea, tachycardia
  4. CVA tenderness
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15
Q

Labs for kidney stones

A

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!!!

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16
Q

Imaging for kidney stones

A
  • done normally to rule out other causes

spiral/non contrast CT : first-line for suspected stone
- can be used to dx. hydronephritis or other issues
- can be used to rule in/out AAA

other possible imaging

abdominal US: readily avalible but less sensitive for < 5mm
- sensitive for hydronephrosis
- use in pregnancy, contrast dye allergy
- good for gyn. pain

KUB (x-ray)
- 90% of stones wont show up on x-ray
- but those with known stone disease – good to tract them
- good for calcium or struvite

intravenous pyelography
- good for hydronephritis
- must assess kidney function, hydration
- good idea of kideny function and degree of obstruction
- need to use contrast media

16
Q

Hydronephrosis & kideny stones
what is it
patho

A

hydronephorisis = backup of fluid into the kidney caused by the stone blockage

17
Q

management of urolithiasis ACUTE

A

analgesia
- #1: NSAIDS for pain -ketorolac IV
- narcotics

Antibiotics
- IV antibiotics imipenem + vancomycin

Hydration
- isotonic saline (helps to compensate for the diuresis after lost obstruction)

Antiemetics for N/V

18
Q

who need to be admitted?

A
  1. stone obstruction + UTI, fever urosepsis
  2. uncontrolled pain/nauseas
  3. obsturcting stone in the only functioning kdiney they have
  4. bilateral kidney stones
  5. obstruction + rising creatitine (shows kideny problem)
  6. size and location made need surgery
19
Q

Outpatienet managemnet of stone

meds
stone passing

A

1: NSAIDS (ketoralac, ibuprofen)

must be able to tolerate oral meds and fluids

(opioids if needed)

antiemetics for vomiting (ondansetron, promethazine)

Infection treatment (no risk of urosepsis)
- ciprofloxicin
- levofloxicin
- cefpodoxime

Stone passing
- stones < 5 mm and distal can pass on their own
- stones > 5mm and < 10mm need MET treatment with alpha 1 blocker: tamsulosin to help stone pass
- confirmation of stone passing: after 4 weeks of met and no evidence –> urology

20
Q

how does stone size change treatment guidance
- < 4 mm
- < 5
- > 5

A

< 4 mm: the stone will pass withint 2 weeks
< 5 mm: the stone could pass within 2 weeks (less likely than if smaller)
5 or > 5 mm: refer to urology

refer when…
stone > 5 mm
stone hasnt passed in two/four weeks

21
Q

how does stone location change guidelines for treatment

renal
ureteral

A

renal stones
- asymptomatic normally
- if staghorn –> < 2 cm : get lithotripsy to break it up
- > 2 cm : get percutanesous nephrolithotmy

ureteral stones
- < 1 cm : lithotripsy
- > 1 cm: percutaneous nephrolithotomy

22
Q

follow-up treatment for stones

A

analyze diet and fluids
analyze medications and risk
- thiazides can help
- potassium citrate can help

annual 24hr. urine
blood tests
F/U imaging