Nephrolithiasis Flashcards
Most often, stones form in … and move to…
Most often, stones form in the kidney (kidney stones) and move down to the ureter (ureteral stones).
When do stones cause pain?
When they block flow of urine (usually when they move down to the ureters).
What are kidney stones most often made of?
calcium oxalate
What is the difference between kidney stones and gallstones?
Gallstones are made of CHOLESTEROL, not calcium.?
Why do people have stones? (6)
- Poor fluid intake/hot weather
- Hereditary
- Recurrent UTIs
- Medications
- Immobility
- Genetic/metabolic diseases (rare)
What type of medications can cause stones?
Indinavir
Triameterene
Describe the pain caused by stones
Acute, colicky flank pain radiating to the groin.
CVA tenderness.
Summarize the clinical presentation of stones.
When you suspect a kidney stone, what investigations should be made?
- Urinalysis
- Low-dose (no contrast) CT scan (gold standard)
- KUB x-ray
- Ultrasound (in pregnant women)
What do we look for in a urine sample (microscopic examination) when investigating stones?
- blood
- crystals
- bacteria
When does a stone require urology consultation for emergent decompression (when is it an emergency)?
- Obstructing ureteral stone with infection (most important)
- Impending renal deterioration/failure
- Pain refractory to analgesics
- Intractable nausea/vomiting
- Patient preference (multiple ER visits)
Which hurts more and why?
Small stones…?
How do we manage stones when emergent decompression is not indicated?
Most small stones (<5mm) pass spontaneously.
Treatment:
- Lots of water and painkillers
- Lasts 3-6 weeks
- NSAIDs
How does stone size affect passage rates?
The larger the stone, the longer they will take to pass.
Stones of >5mm will usually require surgery (otherwise the patient may risk losing their kidney).
To remove kidney stones, we have 3 minimally-invasive surgery options…
- Shock-wave lithotripsy
- Ureteroscopy
- Percutaneous nephrolithotomy
Describe shock-wave lithotripsy.
Describe ureteroscopy.
Describe percutaneous nephrolithotomy.
Describe the preferred minimally-invasive surgical procedure for the following stones:
<2cm kidney stone
>2cm kidney stone
<2cm: shock-wave lithotripsy and ureteroscopy
>2cm: percutaneous nephrolithotomy
What measures can help prevent kidney stones (or recurrence)?
- Achieve better control of diabetes mellitus, gout, thyroid and parathyroid diseases, gut diseases
- Dietary modifications
?
Who should be referred to nephrology for a detailed metabolic stone work-up (important)?
- Patients with recurrent, multiple or bilateral stones
- Pregnant women with stones
- Children with stones
- Patients with non-calcium stones
- Patients with strong family history for stones
- Patients with a solitary kidney or anatomical abnormalities
- Patients with renal insufficiency
- Patients with systemic diseases
- Patients with critical occupations (pilots, sailors, firemen)
Dietary recommendations for all stone formers.
- Increase fluid intake
- Reduced salt intake
- Reduced animal protein intake
- Increased intake of citrate-rich fluids
- Moderate consumption of oxalate
- Limit vitamin C intake
- Moderate calcium intake
Note: Normal calcium intake.
Why is moderate calcium intake important to prevent kidney stone recurrence?
?
Should people living in northern climates completely avoid taking vitamin D if they are at risk of recurrent stone formation?
No. They should take vitamin D in moderation, due to prevalence of vitamin D deficiency in northern climates.
