Nephrolithiasis Flashcards
What are the signs and symptoms of a kidney stone?
Acute onset. Flank pain that radiates to testicles. Excruciating pain. Hematuria usually. Dysuria. N/V. Fever and chills.
T or F. Kidney stones are common with a lifetime risk of about 10%.
T
In which gender are kidney stones more common?
Men 2:1
What is the recurrence risk of kidney stones?
50% in 5-10 years
Which is more hazardous: small or large stone?
Small stone b/c they can pass into the ureters.
What are the 3 locations kidney stones are most susceptible to lodge?
- Ureteropelvic junction
- Pelvic brim aka iliac vessel crossing
- Bladder entry
What other disorders should be included in the differential Dx of this presentation?
Acute cholecystitis. Acute appendicitis. Diverticulitis. Cystitis. Pyelonephritis. Abdominal aortic aneurysm. Pancreatitis. Ureteral stricture. Musculoskeletal causes. Zoster. GYN causes. Clots. Papillary necrosis.
What do you look for in urinalysis when suspecting a kidney stone?
Hematuria (seen in 90%). Crystals suggest composition if present.
What do calcium oxalate crystals look like?
Envelopes
What is the best imaging study for Dx of a kidney stone?
Helical CT: detects stones as small as 1mm.
Why wouldn’t you do a plain x-ray to Dx a kidney stone?
It’s not sensitive or specific. Can’t see the stone sometimes. Will miss radiolucent stones.
What are the radiolucent stones?
Uric acid and indinavir stones.
What is the most common type of stone?
Calcium oxalate (65%). Then calcium phosphate alone (15%), struvite (10-15%), uric acid (3-5%), and lastly cystine (1-2%).
What size stones have a high likelihood of spontaneously passing?
<5mm
What size stones are unlikely to pass?
7+ mm
What 2 classes of medications increase the chance of passing a stone?
- Alpha-1-Adrenergic Antagonists (relaxes sphincter)
2. Calcium Channel Blockers
What is NNT?
Number Needed to Treat. If the NNT=4, this means that you will have to treat 4 patients in order to benefit one.
What percentage of kidney stones require invasive intervention?
15-20%
What are the 3 types of invasive intervention?
- Extracorporeal shock wave lithotripsy (ESWL)
- Ureteroscopy
- Percutaneous nephrolithotomy