Crystalluria determined by polarization microscopy

Abstract

A retrospective study was done on the nature and degree of crystalluria in spontaneously voided fasting and postprandial urine of patients with recurrent idiopathic calcium urolithiasis (RCU) divided into normocalciuria (20 males, 20 females) and hypercalciuria patients (20 males, 20 females), and controls (20 males, 20 females). The crystals were obtained using a filter technique and identified by microscopy. In addition, individual data, clinical chemistry variables and indices reflecting the risk of calcium phosphate and calcium oxalate crystallization were evaluated. In contrast to findings of other investigators of crystalluria we observed only a few crystals on the filters. The most frequently occurring phases were (in this order) a urate-containing phase (tentatively termed uric), an amorphous calcium phosphate phase (tentatively termed isotropic) and a phase of spheroid-like particles, not yet definitely characterized (tentatively termed spheroid). Calcium oxalate crystals were found only exceptionally. There was no relationship between the degree of calciuria (normo- versus hypercalciuric RCU) and crystalluria. Among RCU, males generally had a predominance of the isotropic, females of the spheroid phase, as compared with controls. Also, RCU females were generally obese, and their spheroid score and lean body mass correlated negatively and significantly. The calcium phosphate and calcium oxalate risk indices were always low in normal individuals, higher in RCU. Patients of both sexes with urinary stones had normal parathyroid gland function, but higher total calcium in fasting serum and higher urinary pH as compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo efficacy of Trachyspermum ammi anticalcifying protein in urolithiatic rat model

“…A drop of urine obtained from bladder was spread on a glass slide and visualized under polarized light using Leica DM3000 light microscope (Herrmann et al, 1991).…”

Urinary phosphate excretion in the pathophysiology of idiopathic recurrent calcium urolithiasis: Hormonal interactions and lipid metabolism

“…Also, our work failed to detect differences in urinary pH (Table 2), allowing us to rule out the possibility that the renal tubules reabsorbed less monovalent versus divalent Pi, and that a renally mediated acid-base disturbance was followed by enhanced Pi-uria. On the other hand, enhanced calcium phosphate crystalluria in postprandial urine with an undefined state of Pi has repeatedly been observed [20,51]. Therefore further work in this area should not only include urinary pH, Pi-uria, and calcium phosphate supersaturation, but also pyrophosphate, which increases with increasing Pi-uria, but inhibits growth of crystals [5].…”

A critical appraisal of the hypothesis that urine is a saturated equilibrium with respect to stone‐forming calcium salts

“…Other results can be added, i.e. 4.2% of 122 random samples [22], 20% of 25 controls [23], < 4% of 82 normal samples [24] and 2.5% of 40 fasting controls [25] showed CaOx crystalluria. Most of these studies used centrifugation to concentrate any crystals present and viewed samples within 2 h of voiding.…”

“…CaP crystalluria in normal subjects is also a common finding, e.g. 13% of 54 subjects [30], 16% of samples from 18 subjects [31], ≈13% of 82 subjects [24], 32% of 25 controls [23], 40% of 40 fasting controls [25] and 20% of 202 samples from 16 controls [32]. While these frequencies are a little lower than the frequency of apparent CaP supersaturation amongst normal subjects (46% of cases cited in Table 1), the difference is perhaps not so great as to pose a serious challenge to the saturated equilibrium hypothesis with respect to CaP.…”