The Scientific Basis of Urinary Stone Formation
Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George in The Scientific Basis of Urology, 2010
Whatever the detailed mechanism of stone initiation, an individual’s propensity to produce crystals of one of the stone-forming constituents is an important prerequisite for stone formation, either because the crystals lead directly to the initiation of stones (as postulated in the free-particle model) or because their production is a signal that urine is so supersaturated with respect to that constituent that heterogeneous nucleation and crystal growth are likely to occur at one of the critical sites postulated in the fixed-particle model. Crystalluria occurs more frequently and more abundantly in the urine of stone formers than in that of controls, and, in patients with calcium stone disease, the crystals are larger and more agglomerated (18–19). The severity of the disorder, as defined by the stone episode rate in a given patient is proportional to the percentage of large crystals and aggregates in the patient’s urine (Fig. 7). It would appear that particle size is a vital factor in the stone-forming process.
Orotic aciduria
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop in Atlas of Inherited Metabolic Diseases, 2020
The crystalluria may lead to gross or microscopic hematuria. One patient [13] came to attention because of hematuria and was found to be anemic. Proteinuria is unusual, but has been found, along with urinary tract infection [13]. Oliguria may accompany infection, or decreased fluid intake or dehydration from some other source such as diarrhea [1]. Under such circumstances, there may be urinary tract obstruction because of orotic acid sludging in the ureters or urethra [1]. An intravenous pyelogram revealed a nephrogram effect with radiopaque material remaining in the kidney 1.5 hours after injection, presumably because of obstruction of the renal collecting tubules by crystalline orotic acid [12]. Urethral obstruction has been successfully relieved by catheterization [4]. Urea nitrogen and creatinine in blood are usually normal but will rise in the presence of obstruction.
Urinary System
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
Crystals occur frequently in the l]umina of tubules of both rodents and nonrodents in toxicologic studies, and perhaps even more frequently in the renal pelvis and lower urinary tract. Calculi are most often localized to the cortex and outer medulla. They usually appear clear to light brown in tissue sections and are birefringent under polarized light, which makes crystals easy to differentiate from mineralization or casts. However, many calculi formed in the urine dissolve or eventually are voided, leaving no sign of their presence except for their secondary degenerative effects (Cohen et al. 2002). Crystalluria will often be associated with a constellation of morphologic features known as obstructive nephropathy, which occurs from outflow obstruction. These changes include tubule dilation, degeneration, or necrosis in the affected or immediately preceding tubules (Figure 14.2d). Occasionally, obstructive nephropathy will also be accompanied by the presence of mononuclear or granulomatous inflammatory infiltrates as a result of secondary damage (Chevalier 2006). In the renal pelvis, crystalluria frequently is associated with urothelial hyperplasia and may result in hydronephrosis or pyelonephritis. Urolithiasis in the bladder or as far distally as the urethra may result in the same secondary degenerative tubular changes in the kidney from obstruction of filtration. Obstructive nephropathy can result in acute elevations in urea, sCR, and serum potassium, and can result in oligouric renal failure and be an important cause of mortality in some studies. Crystals may be identifiable by examination of urine sediments, but fresh samples are often necessary for best assessment.
Still More ICD-10-CM Updates!
Published in Oncology Issues, 2018
The subcategory of codes related to R82.99 (other abnormal findings in urine) had several inclusion terms deleted (cells and casts in urine, crystalluria, and melanuria) and was expanded to a new subcategory code allowing for more specification: R82.991 HypocitraturiaR82.992 Hyperoxaluria Excludes 1: Primary hyperoxaluria (E72.53)R82.993 HyperuricoscuriaR82.994 Hypercalciuria Idiopathic hypercalciuriaR82.998 Other abnormal findings in urine Cells and casts in urineCrystalluriaMelanuria.
Pharmacotherapeutic options for kidney disease in HIV positive patients
Published in Expert Opinion on Pharmacotherapy, 2021
Anam Tariq, Hannah Kim, Hashim Abbas, Gregory M. Lucas, Mohamed G. Atta
PIs, most notably indinavir and atazanavir, can crystalize in the kidney tubules, leading to nephropathy, AIN with subsequent AKI, acute on CKD, or progression of CKD [82,83]. Crystalluria occurred in 20% and nephrolithiasis in 3% in a large cohort of PLWH on indinavir [84]. Indinavir also has been associated with kidney papillary necrosis [85] and atrophy [86]. A Japanese case-control study suggested that certain genes, with single nucleotide polymorphism (SNP) in the UGT1A-3ʹ-UTR, were associated with atazanavir-induced nephrolithiasis [87]. Other risk factors include alkaline urine, reduced urine output in areas with warm climates, and the higher dosage of indinavir at 1000mg or more twice daily. Indinavir is no longer used in developed countries but individuals with prior exposure are now left with CKD and should be managed closely for kidney disease progression.
Urinary crystal formation and urothelial effects of pyroxasulfone administered to male rats
Published in Toxicology Mechanisms and Methods, 2020
Takahiro Kyoya, Lora L. Arnold, Karen L. Pennington, Satoko Kakiuchi-Kiyota, Megumi Terada, Koichi Abe, Samuel M. Cohen
In Experiment 1, light microscopic evaluation of urinary sediment collected on study day 7 prior to necropsy showed no differences between the 0 ppm pyroxasulfone group and the 2000 ppm pyroxasulfone group (data not shown). In Experiment 2, semi-quantitative evaluation by light microscopy of the amount of crystals in the urines from the control group and from the 20 000 ppm pyroxasulfone group showed that dietary administration of 20 000 ppm pyroxasulfone slightly increased crystalluria compared to the control group when urines were collected at the beginning of the light cycle on study day 6, but not when urines were collected 6 h prior to the light cycle (data not shown). However, this was not confirmed by SEM/EDS analysis of urinary filters (see Section 3.4.3 below). Overall, crystalluria in the control and 20 000 ppm pyroxasulfone groups was increased when urine was collected 6 h prior to the light period compared to when it was collected at the beginning of the light period. The majority of crystals in the control and the 20 000 ppm pyroxasulfone treated groups at both time points had the characteristic coffin shaped morphology of MgNH4PO4 crystals, although there were some irregular, round and rod-shaped crystals present in the urine in the control and treated groups at both time points.
Related Knowledge Centers
- Cystinuria
- Dysuria
- Hematuria
- Sulfonamide
- Transitional Epithelium
- Urine
- Urine Test
- Kidney Stone Disease