Calcium Containing Kidney StonesAs stated above, approximately 75% of kidney stones contain calcium. The most common calcium containing stones include: calcium oxalate (60%), followed by hydroxyapatite (20%) and the rare, brushite (2%) stones. The most common metabolic abnormalities associated with calcium-containing kidney stones include:
containing stone is
- hypercalciuria (most common abnormality)
|Electron microscopy of calcium |
Calcium Oxalate Stones
|The needle-like crystals of calcium|
phosphate in the urine.
Calcium Phosphate StonesLike calcium oxalate stones, calcium phosphate stones are made of normally occurring components of the urine when the urine pH is alkaline (>7.0). Calcium phosphate stones are also known as apatite or brushite stones. Calcium phosphate stones form needle-like crystals in the urine (below).
Non-Calcium Containing Stones
|Uric acid crystals.|
Uric Acid StonesUric Acid (7%) stones form only in acid urine. People more likely to form uric acid stones have conditions that predispose to acidic urine including: low urine output, a diet high in animal protein (such as red meat), high alcohol intake, and may have obesity, gout or inflammatory bowel disease.
|The coffin-lid appearance of struvite|
stones in the urine.
|Cystine kidney stones.|