NEPHROLITHIASIS

Question 1

……………… (1–5% of the population) is a common cause of emergency room visits and is
often severely painful

Answer 1

Nephrolithiasis

Question 2

All stones form more readily in concentrated urine, so volume depletion may

Answer 2

precipitate them.

Question 3

Types of stones include:

Answer 3

• Calcium oxalate (70%) and calcium phosphate (10%)
• Struvite/infection (Mg/aluminum/phosphate) (5–10%)
• Uric acid (5%)
• Cystine (1%)
• Indinavir

Question 4

Calcium Stones (80% of all stones) have several risk factors:

Answer 4

1-Hypercalciuria
2-Hyperoxaluria
3-Hypocitraturia

Question 5

Hypercalciuria may be due to

Answer 5

1– Idiopathic renal hypercalciuria (normal serum calcium)
2– Resorptive from bone: hyperparathyroidism (10- 30% of patients present with stones); multiple myeloma, metastatic disease to bone, hypercalcemia of malignancy (serum calcium high)
3– Increased GI calcium absorption: vitamin D intoxication; increased vitamin D with sarcoid and other granulomatous disease; familial (serum calcium high)

Question 6

Hyperoxaluria may be due to

Answer 6

1– Primary familial oxaluria
2– Enteric: with fat malabsorption as in Crohn’s disease, the fat binds to calcium, leaving unbound oxalate to be reabsorbed in increased amounts, then excreted into the urine.

Question 7

Hypocitraturia may be due to

Answer 7

– Urine citrate is a stone inhibitor, binding with calcium. Patients with low urinary citrate have a higher risk for calcium stones. Patients with type 1 (distal) renal tubular acidosis often have hypocitraturia.

Question 8

Struvite/Infection Stones
Chronic urinary infections with urease-producing organisms such as ………………………
give a highly alkaline urine that leads to struvite ……………………………………… stones. These often produce large “staghorn” calculi filling the renal pelvis. The urinalysis may show characteristic “…………….” crystals.

Answer 8

1-Proteus, 
2-Pseudomonas,
3-and Klebsiella 
-(Mg/aluminum/phosphate) 
-coffin lid

Question 9

Uric acid stones form in an ………… environment and are associated with diseases that increase serum uric acid levels, such as …………………………….
Unlike other stones, they are radiolucent on x-ray but can be seen on …………………

Answer 9

• acid
• gout, hematologic malignancies, and Crohn’s disease
• renal ultrasound.