Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Calculi”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources
PubMed1983

Determination of the chemical composition of urinary calculi by computerized tomography.

The clinical management of renal calculi would be aided if a direct in vivo determination of stone chemical composition could be made. We investigated the possibility of obtaining this information by a quantitative analysis of the computerized tomography scan images of 80 urinary calculi. Our results show that by using an appropriately calibrated computerized tomography scanner the differentiation of stone chemical composition can be made on the basis of 3 parameters, namely, absolute computerized tomography value at a single x-ray energy, the difference between computerized tomography values measured at 2 different x-ray energies, and computerized tomography value-frequency histograms (pixel patterns) of the stones. Uric acid stones were differentiated from all other stones at a significance level of p less than 0.001. Cystine was differentiated from calcium oxalate and brushite at the same significance level. Using pixel patterns cystine and struvite were separated from each other correctly with 70 per cent accuracy. Struvite stones of low or moderate calcium phosphate content were identified correctly with 80 per cent accuracy. Struvite stones of high calcium phosphate content could not be differentiated from calcium oxalate or brushite. Calcium oxalate and brushite could not be separated. The minimum stone size that allowed chemical identification was established for each stone type. In addition, we demonstrated that all the urinary calculi examined were visible on computerized tomography scan regardless of chemical composition or size.

Calcium Oxalate↗
PubMed1982

SEM and X-ray microanalysis of human prostatic calculi.

Calculi removed from human prostates affected with nodular hyperplasia were analyzed with scanning electron microscopy and EDAX system. The general spectrum was made up of Na, Al, Mg, S, P, Ca and Zn. Two types of stone were identified morphostructurally and microanalytically: calculi type I of nodular surface with high peaks of S, and calculi type II polyfaceted with high peaks of P and Ca. Their formation from corpora amylacea and/or exogenous constituents is discussed. The superficial deposit of Zn suggests its incorporation from the prostatic liquid and does not seem to play an important role in the genesis.

Calculi↗
PubMed1982

Ultrasonic scanning during operation for renal calculi.

Real-time B-mode ultrasound scanning was used during operations for nephrolithiasis. Scanning was done before pyelotomy or nephrotomy to confirm the presence of calculi. For stones in an intrarenal position, requiring an incision through renal parenchyma for extraction, ultrasound permitted guidance for an exploratory needle to localize the calculi precisely. Once the needle tip was in the proximity of the stone a nephrotomy incision was made along the needle track. This procedure enabled the use of relatively small nephrotomy incisions and reduced search time and tissue manipulation. After calculi were extracted ultrasonography was used to make certain that all stone fragments were removed. Ultrasound was considered helpful in 15 of 16 operations.

Adult↗
PubMed1981

Branched calculi: shapes and operative approaches.

Branched calculi (infection stones) typically arise in intrarenal pelves. They expand to touch the pelvic wall and then grow peripherally, keeping contact with the walls of the pelvis and greater than or equal to 1 infundibula. Filling the infundibulum obstructs the calix and allows terminal expansion of the stone. From study of a series of stones such a sequence might be reconstructed. The shape of the calculus and collecting structures was traced and classified from excretory urograms of 50 consecutive renal units. The funnel pelvis, usually intrarenal, contained a stone either extending into the ureteropelvic junction (24 cases) or stopping short of it (9 cases). Pelvic or infundibular and caliceal dilatation around the stone was found in the remaining 8 and 9 cases, respectively. These patterns of growth of branched calculi directly bear on the approaches and technique for the operative removal. Because typical branched calculi arise in the intrarenal pelvis a high transverse intrahilar incision is necessary. Less intrahilar dissection is needed for cases in which the pelvis is dilated above and around the stone. Counter-incisions through the parenchyma or anatrophic nephrolithotomy is reserved for those patients with infundibular obstruction and resulting expanded caliceal stones.

Humans↗
PubMed1981

A comparison of ultrasonography and radiography in the localization of renal calculi: experimental and operative experience.

The capabilities of radiography (mammography film) and ultrasonography (7 MHz. probe) were investigated in cadaver kidneys. Stones of varying size and composition were studied. Clinically, 11 patients then were studied with intraoperative radiography and ultrasonography. Both techniques appeared to localize calculi more than 3 mm. with high consistency in cadaver kidneys and in patients. Real-time B scan ultrasonography is a rapid and accurate technique that has the ability to identify lucent calculi. When used in association with intraoperative radiography, intraoperative ultrasonography can be a great aid in the surgical removal of renal calculi.

Adult↗
PubMed1979

Operative versus non-operative management of patients with staghorn calculi and neurogenic bladder.

During the last 5 years 22 patients have been treated at our hospital for staghorn calculi and neurogenic bladder. In 17 patients an operation was done soon after discovery of the calculi, while 5 patients were followed non-operatively. The latter 5 patients had a rapid downhill course marked by sepsis and renal function deterioration and an operation was necessary in 4 of the 5 cases. Injudicious non-operative therapy only prolongs the relentless effects of staghorn calculi in patients with spinal cord pathology.

Adult↗
PubMed1998

Endourologic therapy of bladder calculi in simultaneous kidney-pancreas transplant recipients.

OBJECTIVES: To identify the incidence and the success of endourologic therapy for symptomatic bladder-related calculi in simultaneous kidney-pancreas (SPK) transplant patients with bladder drainage. METHODS: A retrospective review of 300 SPK transplant patients with bladder drainage, treated at the University of Wisconsin, Madison from December 1985 to November 1995, is presented. A 3% incidence of bladder calculi was identified. All patients underwent cystolitholapaxy using electrohydraulic lithotripsy and endoscopic suture removal. Follow-up ranged from 15 to 86 months. RESULTS: A 100% stone-free rate was achieved after cystolitholapaxy and endoscopic suture removal. Two patients (22%) developed postprocedural urinary tract infections. No pancreaticoduodenocystotomy leaks or further complications were identified. CONCLUSIONS: SPK transplant patients with nonabsorbable sutures used for the duodenocystotomy anastomosis are at an increased risk for bladder calculi. Cystolitholapaxy with electrohydraulic lithotripsy is a safe and effective treatment for these suture-related stones.

Adult↗
PubMed1997

Management of calyceal calculi.

Management of calyceal calculi has changed dramatically during the past 20 years. Minimally invasive techniques virtually have replaced open surgical stone removal. Even large and complex calyceal calculi may be treated effectively with these minimally invasive techniques. Although open surgical stone removal is performed infrequently, a clear understanding of the subtle renal anatomy aids the urologist in more effectively treating patients with calyceal calculi and in limiting surgical complications.

Diverticulum↗
PubMed1983

Minor salivary gland calculi. A clinical and histopathological study of 49 cases.

The clinical and histopathological characteristics of 49 previously unpublished cases of sialolithiasis of minor salivary glands are presented. The lesions are usually solitary, small, submucosal nodules, which are hard or firm and freely movable in the surrounding tissue and on rare occasions may be multiple. They are most often seen in the buccal mucosa and the upper lip of patients in the 5th, 6th or 7th decade, but are rarely found in the lower lip and palate. The authors found that clinicians usually failed to include calculi in the differential diagnosis and further, they concluded that minor salivary gland calculi are more common than generally believed. In contrast to other studies of calculi in major and minor salivary glands, the periphery of the stones was found to be less frequently lamellated and mineralized. The authors also confirmed the finding of mucous cell metaplasia of ductal epithelium and commented on its possible role in the pathogenesis of sialolithiasis.

Adolescent↗
PubMed1986

Large calculi of the submandibular salivary glands.

Salivary calculi occur in the submandibular and parotid glands, and their ducts, and occasionally reach a large size. However, little information is available on the composition of these giant stones. 2 cases are reported of unusually large calculi of the submandibular salivary glands. The glands were excised, and the results of chemical and infrared analysis of the calculi are presented.

Aged↗
PubMed2003

Hematuria as an indicator for the presence or absence of urinary calculi.

The purpose of this study was to determine whether the presence of hematuria or its absence can predict the presence or absence of urinary calculi as determined by computed tomography (CT) scan in patients presenting to the ED with acute abdominal colic. We reviewed the urine analysis and CT scans of all patients presenting to the ED over a 12-month period with acute colic and a clinical suspicion of urinary calculi. Urine samples were drawn on arrival in the ED before CT scanning. Two hundred seventy-seven patients were included in the study. The prevalence of urinary stones as detected by CT was 57.4%. The positive predictive value, negative predictive value, and accuracy for hematuria as a marker for stone disease was 60.9%, 72.4%, and 62.1%, respectively. A total of 3.24% of patients had some degree of obstruction, all of whom had hematuria. The absence of hematuria is not a reliable exclusion criterion for urinary calculi. The detection of urinary stones without hematuria does not imply obstruction.

Biomarkers↗
PubMed1999

Unenhanced CT in the evaluation of urinary calculi: application of advanced computer methods.

Recent advances in computer hardware and software technology enable radiologists to examine tissues and structures using three-dimensional figures constructed from the multiple planar images acquired during a spiral CT examination. Three-dimensional CT techniques permit the linear dimensions of renal calculi to be determined along all three coordinate axes with a high degree of accuracy and enable direct volumetric analysis of calculi, yielding information that is not available from any other diagnostic modality. Additionally, three-dimensional techniques can help to identify and localize calculi in patients with suspected urinary colic.

Humans↗
PubMed2002

Cystinuria and other noncalcareous calculi.

Urinary stone disease is the only clinical presentation in patients with cystinuria. Two genes have been associated with type I (SLC3A1) and non-type I (SLC7A9) cystinuria and multiple mutations of these genes have been identified. The type I form is completely recessive while the non-type I form is incompletely recessive. Clinically, heterozygotes with type I mutations are silent while heterozygotes with non-type I (types II and III) present with a wide range of urinary cystine levels and some even have symptomatic urolithiasis. Although the exact molecular basis for these differences needs additional investigations, the future of medical management of cystinuria is based on molecular and gene therapy. Minimally invasive surgery using percutaneous and ureteroscopic techniques is the cornerstone of surgical management. Both cystine and struvite calculi can form staghorn configuration with propensity for rapid growth and frequent recurrences after surgical treatment. While urinary alkalinization for cystine calculi is an integral part of medical management, the effect of oral alkalinizing agents is limited because of the high pKa (8.3) of cystine. Chelating agents, therefore, are frequently used to decrease cystine solubility and stone recurrences. Similarly, urinary acidification for struvite calculi may dissolve existing stones and prevent recurrences. However, no effective oral agent is available today. A future challenge will be to introduce reliable oral agents for urinary acidification.

Amino Acid Transport Systems, Basic↗
PubMed2000

[Component analysis of urinary calculi in the etiologic diagnosis of urolithiasis in the child].

The potential risk of recurrence and degradation of renal function justifies the etiological investigation of all lithiasis-associated pathologies. Therefore calculus analysis of the crystalline phases and morphological characteristics is an important factor in the etiological diagnosis of the disease. Microscopic examination and infrared spectroscopy of calculi from 727 children showed that calcium oxalate was the main component in 36.7% of cases, followed by calcium phosphate (31%), struvite (9.9%) and purine groups (7.7%). The most frequently observed crystalline from was carbapatite (26%), then whewellite (21%) and weddellite (15.7%). As regards the etiopathogenic aspect in adults, the relations between hypercalciuria and weddellite, and between hyperoxaluria and whewellite are also found in the child: in subjects with hypercalciuria, 82% of the calculi contained over 20% weddellite; and in subjects with hyperoxaluria, whewellite was the major constituent in 79% of cases (or 95% in the absence of associated hypercalciuria). In 27 calculi mainly composed of whewellite, the morphological analysis indicated primary hyperoxaluria; this diagnosis was confirmed in 25 cases by specific biological investigation. Urinary tract infection is frequently associated with lithiasis, but its lithogenic role cannot be confirmed without calculus analysis. Several criteria can be used as markers to determine the lithogenic etiology of the infection, i.e., the presence of struvite, the carbonate rate of carbapatite, and the whitlockite and/or protein content of the calculus.

Adolescent↗
PubMed1980

Dissolution of vesical calculi with Renacidin in a paraplegic man.

Vesical calculi are common in spinal cord injury patients. The majority are composed of magnesium ammonium phosphate, a compound readily soluble in the solvent Renacidin. We describe a paraplegic man with recurrent bladder stones in whom cystolitholopaxy was unsuccessful. His calculi were completely dissolved by continuous Renacidin bladder irrigation. We recommend Renacidin for the initial treatment of vesical calculi in selected spinal cord injury patients. Many such stones will completely dissolve and others may be made softer or smaller, facilitating cystolitholopaxy. A significant number of patients will be spared the inconvenience, cost and morbidity of hospitalisation for a surgical procedure.

Adult↗
PubMed2003

Risk factors for urinary tract calculi in Trinidad.

OBJECTIVE: To identify risk factors for urinary tract stones in Trinidad and Tobago. METHODS: A consecutive series of patients presenting to institutions in Trinidad for the management of proven urinary tract calculi was interviewed by questionnaires designed to obtain data on age, gender, ethnicity, occupation, stone location, a family history of stone disease, a past history of certain medical diseases and a semiquantitative estimate of the magnesium intake in food, 'over the counter' drugs and drinking water. An equivalent number of patients attending the same institutions for follow-up and verified from hospital records as having a previous radiological diagnosis of urinary tract stones, as well as a group of asymptomatic members of the community working in the same area, underwent the same interview. Chi-square, anova and Kruskal-Wallis tests were used to examine differences between the groups. Multiple logistic regression analysis was used to determine persistence of the significance of these differences after controlling for confounding variables. RESULTS: Data sufficient for analysis were obtained for 122 previous and 102 prospective patients and 102 controls. The mean age of the patients was 32 years. The ratio of males to females was 0.9-1.8:1 for the affected groups, but significantly more males than females had calculi in the lower urinary tract (19%vs. 6%; P = 0.004). More patients (30%) than controls (7%) gave a positive family history of urinary tract stone disease (P < 0.001). Affected persons had a lower dietary magnesium intake (P = 0.003), which accounted for a significantly lower total magnesium intake (P = 0.02). Logistic regression analysis of the variables studied indicated that independent predictors of the disease were a positive family history (P = 0.001), total magnesium intake (P = 0.001) and age (P < 0.001). CONCLUSION: A low magnesium intake and a positive family history are highly predictive of urinary tract calculi in this population.

Adult↗
PubMed1999

Minimally invasive treatment of urinary tract calculi in children.

OBJECTIVE: To report experience of a broad multimodality approach to the treatment of calculi in children using extracorporeal shock wave lithotripsy (ESWL), ureteroscopy/laser lithotripsy, lithoclast and percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: The treatment and outcome were reviewed in 43 children managed by a range of minimally invasive modalities, either singly or in combination, between 1990 and 1997. These patients represent a selected group deemed suitable for minimally invasive management during a period of developing experience with these techniques. Of this cohort, six children had previously undergone open stone surgery and contributory metabolic abnormalities were identified in seven. ESWL was the sole treatment modality in 24 children (56%). In five children (12%) ureteroscopy/laser lithotripsy was combined with ESWL, eight (18%) underwent ureteroscopy/laser lithotripsy alone, whilst three with bladder stones were treated with the lithoclast. Combined therapy including PCNL was required in three patients. RESULTS: Of the 43 children treated, 38 (88%) were rendered stone-free. Metabolic disorders accounted for three of the five cases of residual calculi. Complications requiring intervention occurred in two children (7%) and three subsequently underwent open pyelolithotomy or ureterolithotomy after unsuccessful minimally invasive treatment. CONCLUSIONS: Used selectively, the range of minimally invasive procedures available for adults, including ureteroscopy and PCNL, can be safely and effectively extended to the treatment of urinary tract calculi in children. The role of open surgery will diminish further with the availability of specialized instruments for paediatric PCNL.

Adolescent↗
PubMed2000

Is the conservative management of ureteric calculi of > 4 mm safe?

OBJECTIVE: To determine the safety of the conservative management of ureteric calculi of > 4 mm in diameter, using mercapto-acetyltriglycine (MAG3) radioisotope renography to monitor renal parenchymal function. PATIENTS AND METHODS: Patients with symptomatic unilateral ureteric calculi were recruited prospectively. After confirming the position of the stone using contrast urography, a MAG3 radioisotope renogram was taken within 48 h of admission and again 1 month after the patients became stone-free. The indications for intervention were ipsilateral loss of function (>/= 5% loss), infection, pain or any combination of these factors. The recovery of function was determined by follow-up renography. RESULTS: In all, 54 patients were recruited; 18 were initially allocated to conservative treatment although four later required intervention for pain. The remainder required early intervention for pain (eight), diminished function only (15) or diminished function with infection (13). Of the 54 patients, 28% had 'silent' loss of renal function at presentation. No calculi of > 7 mm diameter passed without intervention. The mode of initial management was determined according to individual clinical need. The upper tracts of all patients were relieved of obstruction and all patients were rendered stone-free. Intervention for reduced function only (at </= 7 days) gave a significantly better (P = 0.03) recovery of function than those undergoing later intervention. The combination of reduced function and infection were unrelated to outcome after intervention. CONCLUSIONS: The conservative management of stones of 5-7 mm diameter is safe, providing that radioisotope renography is used to identify those renal units requiring intervention. This approach allows timely intervention to maximize the recovery of renal function.

Female↗