80% calcium oxalate from hypercalcuria which is usually idiopathic (less commonly from hyperparathyroidism)
Others are: struvite→ infxn w/proteus, klebsiella; uric acid (hyperuricemia); oxalate; cystine (rare)
Other contributors to stone formation include: low urine output (< 2 l/d), low urine citrate (stone inhibitor)

If stone obstructing kidney or ureter: acute colicky pain any where from flank → penis, urinary frequency/urgency, nausea, vomiting, patient cant sit still or find comfortable position
Non-obstructing stones can cause painless hematuria
Fever, chills, systemic illness if infection occurs behind obstructing stone

CT (non-contrast), Ultrasound to see stone (abdominal x-ray can be used to follow stone burden)
Stone analysis to determine content
24 H urine: volume, creatinine, calcium, oxalate, uric acid, citrate

Kidney Stones