Renal

Question 1

Calcium Stones:

• Precipitates at
• X-ray findings
• Urine crystal shape
• Conditions that increase stone formation
• Tx

Answer 1

Calcium Stones:

Precipitates at: ACIDIC: Ca oxalate, ALKA: Ca phosphate

X-ray findings: Radioopaque

Urine crystal shape: Envelope or Dumbbell

Conditions that increase stone formation:
-Hyperuricemia (Cancer or Inc. PTH can cause hypercalcemia, though often pts are normocalcemic)

-Oxalate Crystal - ethylene glycol poisoning

Tx:
Citrate - bind up the free Ca++ in urine
Thiazide - decrease Ca++ excretion (inc. serum Ca)

Question 2

Ammonium Mg PO4 (Struvite)

• Precipitates at
• X-ray findings
• Urine crystal shape
• Conditions that increase stone formation
• Tx

Answer 2

Precipitates at: ALKA

X-ray findings: Radioopaque

Urine crystal shape: Coffin Lid

Conditions that increase stone formation:
- Urease (+) bugs: Proteus, E coli, Klebsiella - hydrolyze urea to ammonia -> alkaline urine

Can form Staghorn calculi that predispose to UTI.

Tx:
Treat underlying infection
Remove stone surgically

Question 3

Uric Acid Stones
Precipitates at
X-ray findings
Urine crystal shape
Conditions that increase stone formation
Tx

Answer 3

Precipitates at ACID - esp distal tubule, collecting duct

X-ray findings: RadioLUCENT

Urine crystal shape: Rhomboid, Rosettes

Conditions that increase stone formation:
Hyperuricemia (gout, leukemia)

Tx:
Alkalinization of urine

Question 4

Cystine Stones
Precipitates at
X-ray findings
Urine crystal shape
Conditions that increase stone formation
Tx

Answer 4

Precipitates at ACID

X-ray findings: Radioopaque

Urine crystal shape: Hexagonal

Conditions that increase stone formation:
Mostly in children, 2/2 cystinuria
Dx: Na Nitroprusside

Tx:
Alkalinization of urine