OnlineMedEd: Nephrology - "Kidney Stones"

Question 1

Describe the presentation of kidney stones.

Answer 1

• Colicky flank pain that radiates to the groin
• Hematuria
• No fever

Question 2

Review the workup for suspected kidney stone.

Answer 2

• Patient presents with colicky flank pain that radiates to the groin and doesn’t have fevers

• First, do a UA: if there is no microscopic hematuria, then they do not have a kidney stone (the contractions of the ureter will almost always lead to bleeding in the urine).
• Second, if they have microscopic hematuria then do a non-contrast CT of the abdomen (which is the best test).

Note: if the patient is pregnant, do an ultrasound instead of the NC CT.

Question 3

Go through the management of kidney stones by size of stone.

Answer 3

• Less than 5 mm: IVF and pain medication
• 5 mm - 7 mm: medical expulsive therapy (CCBs, terazosin)
• 7 mm - 1.5 cm: lithotripsy for proximal stones, ureteroscopy for distal stones
• Greater than 1.5 cm: surgery (distal = percutaneous anterograde nephroscopy; proximal = laparoscopy)

Question 4

For stones that are expelled, review the follow-up protocol.

Answer 4

• Modify risk factors: drink more water
• Strain urine to definitively identify the stone
• Have them come back in 6 weeks to screen urine for blood and stones.

Question 5

Go through the following for calcium oxalate stones:
•Radiolucency:
•Risk factors:
•Preventive management:

Answer 5

• Radiolucency: opaque
• Risk factors: increased protein intake
• Preventive management: decrease oxalate (less protein, less spinach); increase citrate (more fruits and veggies), and thiazide diuretics

Question 6

Go through the following for struvite (MAP) stones:
•Radiolucency:
•Risk factors:
•Preventive management:

Answer 6

• Radiolucency: opaque
• Risk factors: Proteus infection
• Preventive management: surgery and antibiotics

Question 7

Go through the following for uric acid stones:
•Radiolucency:
•Risk factors:
•Preventive management:

Answer 7

• Radiolucency: lucent
• Risk factors: gout, tumor lysis syndrome
• Preventive management: allopurinol for gout or TLS; rasburicase for treatment

Question 8

Go through the following for cystine stones:
•Radiolucency:
•Risk factors:
•Preventive management:

Answer 8

• Radiolucency: lucent
• Risk factors: cystinuria
• Preventive management: ???