What type of kidney stones are most commonly associated with a urinary pH below 5.0?

Uric acid stones are indeed most commonly associated with a urinary pH below 5.0. These stones form in acidic urine; hence, when the urinary pH is lowered, uric acid becomes less soluble and precipitates out, leading to stone formation. This is important to understand in the context of patient management since therapy to prevent uric acid stone formation often includes measures to alkalinize the urine, thereby increasing uric acid solubility.

In contrast, the other types of stones listed have different relationships with urinary pH. Struvite stones, for example, typically form in alkaline urine, often associated with urinary infections caused by urea-splitting bacteria. Calcium phosphate stones are likewise more prevalent in alkaline conditions. Calcium oxalate stones can form in a wide range of urinary pH values but are more commonly associated with neutral to slightly acidic urine. Thus, the association of uric acid stones with low urinary pH is a key distinguishing feature in understanding the various types of kidney stones and their formation conditions.