Sometimes a very large calculus nearly fills the calyceal system, with extensions into calyces that give the appearance of a stag's (deer) horns. Hence, the name "staghorn calculus". Seen here is a horn-like stone extending into a dilated calyx, with nearly unrecognizable overlying renal cortex from severe hydronephrosis and pyelonephritis. Nephrectomy may be performed because the kidney is non-functional and serves only as a source for infection. Shown below are typical urinalysis findings for this condition, with evidence for "infection stones" of magnesium ammonium phosphate. |
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Characteristic | Result |
---|---|
Color | Yellow |
Appearance | Cloudy |
Leukocyte Esterase | 3+ |
Nitrite | Pos |
pH | 7.5 |
Protein | Trace |
Blood | 1+ |
Specific Gravity | 1.030 |
Ketones | Neg |
Glucose | Neg |
Bilirubin | Neg |
Characteristic | Result |
---|---|
WBC/hpf | >100/hpf |
RBC/hpf | 5-10/hpf |
Casts | None |
Other | Many triple phosphate crystals |