• from: nephrolithiasis 󰒖

Types of stones and risk factors

(Nat Rev Dis Prim 2016;2:16008)

• Calcium oxalate stones are most common (75%); next, in order, are calcium phosphate (15%), uric acid (8%), struvite (1%), and cystine (<1%) stones.
• 草酸鈣結石最常見 (75%) ;接下來，依次是磷酸鈣 (15%) 、尿酸 (8%) 、鳥糞石/感染性結石 (1%) 和胱氨酸 (<1%) 結石。

Calcium

• (Ca oxalate >Ca phosphate):
  • 70-90% of kidney stones (NEJM 2010;363:954)
• Urine findings:
  • ↑ Ca,
  • ↑ oxalate (Ca-ox only),
  • ↑ pH (Ca-phos only),
  • ↓ citrate,
  • ↓ volume
• 2° hypercalciuria: 1° hyperparathyroidism, distal RTA (type 1), sarcoid, Li use
• 2° hyperoxaluria: Crohn’s → CD, ileal disease w/ intact colon, gastric bypass, pancreatic insuffic.
• Diet: ↑ animal protein, ↑ sucrose, ↑ Na, ↓ K, ↓ fluid, ↓ fruits/vegetables, ↑ vit. C, ↓ Ca

Uric acid

• 5-10% of kidney stones, radiolucent on plain film
• Urine findings: ↑ uric acid, ↓ pH (eg, from chronic diarrhea)

Magnesium ammonium phosphate

• (“struvite” or “triple phosphate”)
• Chronic upper UTI w/ urea-splitting organisms (eg, Proteus, Klebs) →
• ↑ urine NH3, pH >7

Cystine

• inherited defects of tubular amino acid reabsorption