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 721 records · Page 40Linked to original sources
PubMed1982

Urine cytology in patients with calculi.

The cytological changes in voided urines were analysed in 154 patients with calculi. No abnormality was seen in 52.6%; 40.9% contained smooth-bordered clusters of transitional cells with essentially normal, centrally placed nuclei. These, when found in routine urines, were reliable in predicting calculi in 62.5% of cases. Of the calculus urines, 6.5% showed features suspicious of differentiated transitional carcinoma. Although their morphological features overlapped with those observed in urines from 40 cases of proved differentiated transitional carcinoma, they contained significantly fewer single and clusters of transitional cells with abnormal nuclear morphology. Histological examination of urothelium adjacent to calculi in eight patients showed no evidence of malignancy although one case showed hyperplasia and severe epithelial atypia.

Carcinoma, Transitional Cell↗
PubMed1991

Ureteral jets in healthy subjects and in patients with unilateral ureteral calculi: comparison with color Doppler US.

Color Doppler ultrasound was used to image the ureteral jets in 17 healthy subjects and 26 patients with ureteral calculi proved with intravenous urography. In patients with ureteral calculi, three patterns of ureteral jets were seen: no detectable urine flow from the symptomatic side (12 patients), low-level continuous flow from the symptomatic side (four patients), and periodic ureteral jets on the symptomatic side that were not significantly different from ureteral jets of healthy subjects (10 patients). Of the 12 patients with high-grade obstruction on urograms, 11 had ureteral jets significantly different from those of healthy subjects (either no detectable ureteral jets or continuous low-level jets on the symptomatic side). Only three of the 11 patients with low-grade obstruction or nonobstructing stones had ureteral jets that were different from those of healthy subjects. It is concluded that analysis of ureteral jets with color Doppler can enable detection and qualitative determination of the degree of ureteral obstruction in many patients with unilateral ureteral calculi.

Adult↗
PubMed1994

Distal ureteral calculi: detection with vaginal US.

PURPOSE: To describe the use of vaginal ultrasonography to identify distal ureteral calculi and hydroureter. MATERIALS AND METHODS: Abdominal and vaginal sonography were performed in 13 women with distal ureteral calculi. Indications for sonography included flank pain, hematuria, and suspected appendicitis. Six patients were pregnant. RESULTS: In each patient, vaginal sonograms demonstrated a distal ureteral calculus; in only two cases was the calculus detected with transabdominal sonography. Distal hydroureter was identified with vaginal scanning in each patient but with abdominal scanning in only two. Hydronephrosis was absent in three patients, mild in six, and moderate in four. Symmetric ureteral jets were noted at transabdominal sonography in two of nine patients. Follow-up transvaginal scans obtained shortly after passage of stones in two patients revealed swelling of the trigone but normal ureteral jets. CONCLUSION: In symptomatic female patients, use of vaginal sonography should be considered to evaluate the distal ureter for calculi, particularly if the results of transabdominal examination are normal or inconclusive.

Adult↗
PubMed1999

Ureterolithiasis: value of the tail sign in differentiating phleboliths from ureteral calculi at nonenhanced helical CT.

PURPOSE: To determine the value of the tail sign in differentiating phleboliths from ureteral calculi at nonenhanced helical computed tomography (CT). MATERIALS AND METHODS: The nonenhanced helical CT scans in 82 patients with a confirmed diagnosis of pelvic ureterolithiasis were retrospectively reviewed. Each calcification along the ureter was classified as a phlebolith or a ureteral calculus on the basis of clinical and imaging findings and was analyzed for the presence of a tail sign. RESULTS: Eighty-two patients each had a single ureteral calculus. None of these calculi were associated with a positive tail sign. Sixty-nine phleboliths were present in 35 patients. Forty-five phleboliths (65%) were associated with a positive tail sign. Of the remaining 24 phleboliths, 17 (25%) were associated with a negative tail sign and seven (10%) were indeterminate. The tail sign has a sensitivity of 65% (45 of 69; 95% CI: 53%, 75%) and a specificity of 100% (82 of 82; 95% CI: 96%, 100%) in differentiating phleboliths from ureteral calculi. CONCLUSION: The tail sign is an important indicator that a suspicious calcification represents a phlebolith. Absence of the tail sign indicates that the calcification remains indeterminate.

Adolescent↗
PubMed1999

Primary endoscopic treatment of ureteric calculi. A review of 378 cases.

AIM OF THE STUDY: In the post-ESWL period, ureteroscopy represented the solution giving a second choice in the treatment of ureteral calculi in case of failure of extracorporeal lithotripsy. The aim of this study is to review a wide series of ureteral stones in which ureteroscopy combined with endoscopic lithotripsy can be chosen as the first approach for the treatment of ureteral calculi. METHODS: Between January 1994 and September 1997, 378 patients underwent ureteroscopy and endoscopic lithotripsy for ureteral stones with a miniscope associated with either a pneumatic or electropneumatic lithotriptor. Three different miniscopes were used: Olympus (8 Fr), Wolf (7 Fr) and Circon Acmi (7.7 Fr). 238 patients were male and 140 were female. The stones were localized in the upper tract of the ureter in 62 cases (16.4%), 96 (25.3%) in the mid ureter and 220 (58. 3%) in the lower ureter. RESULTS: A complete stone fragmentation with spontaneous expulsion of the fragments occurred in 354 patients (93.6%). In 22 patients (5.8%) the stones were accidentally pushed up and successfully underwent ESWL. In 38 patients (10%) the fragments were completely removed by basket. A single J polyethylene catheter was placed in 21 (5.5%) and a JJ stent in 147 patients (38. 8%). The operative time ranged from 10 to 60 min, with an average time span of 32. In 22 cases (5.8%) an iterative ureteroscopy for stenosis or incomplete fragmentation was needed. Five cases (1.3%) of ureteral perforation were successfully treated by JJ stent, and only 1 case of ureteral avulsion (upper ureter) was treated by open surgery. In the attempt of overcoming an ureteral stenosis, we had 1 case (0.2%) of ureteral reimplantation. One patient (0.2%) underwent ureterolithotomy for an extremely narrow stenosis just before the ureteropelvic junction. No relevant complication was recorded in the postoperative period. Patients were dismissed after 1- 4 days (average 1.9). Up until now, no case of postoperative ureteral stricture has been observed, although we were not able to carry out a specific follow-up in all our patients. CONCLUSIONS: Ureteroscopy with miniscopes has a high success rate (93.6%) with low morbidity and can be given as a primary approach in the management of ureteral calculi. In the lumbar ureter (especially in women) this technique can represent a good alternative to ESWL in the treatment of obstructing stones (which need stenting) or when the patient asks for a 'one-shot' treatment.

Adult↗
PubMed2001

Study on concretions developed around urinary catheters and mechanisms of renal calculi development.

AIMS: To study the structure and composition of encrustation and concretions developed on urinary catheters to better understand their formation mechanism to be able to prevent them. METHODS: The surface of catheters was studied by direct and scanning electron microscopy observation. In vitro formation of encrustations was performed in synthetic urine. RESULTS: The surface of catheters was covered by a continuous layer of organic matter, on which a thin scale consisting of crystals of calcium oxalate monohydrate (COM), uric acid anhydrous or calcium phosphate developed. Encrustations observed on catheters generally exhibited the same composition as the previously developed renal calculi. In catheters collected from patients without previous episodes of renal calculi or with previous episodes of infected renal calculi in which infection was afterwards eradicated, on the first organic layer, in that case plate-like COM crystals forming a columnar layer were observed. In vitro experiments demonstrated that COM columnar structures were only formed when normocalciuric urine containing organic matter was used, and the presence of crystallization inhibitors, as phytate, notably delayed their formation. CONCLUSION: Calcium oxalate was the main crystalline phase developed on catheters inserted in patients, specially in the absence of urinary infection or urinary pH values <5.5 and high urinary uric acid levels. Thus, prophylaxis of encrustations may consist of preventive measures usually applied in cases of recurrent idiopathic calcium oxalate urolithiasis.

Adult↗
PubMed2002

Incidence and management of dialysis patients with renal calculi.

OBJECTIVE: The incidence of renal stones in patients on dialysis, while lower in number compared to the general population because of decreased renal function, is nonetheless a clinical dilemma. We wanted to evaluate the incidence and management of stone disease in patients on hemodialysis. METHODS: We reviewed the literature from 1966 to the present using Medline. Study inclusion criteria were detection and treatment of stone disease in both hemodialysis and peritoneal dialysis patients. RESULTS: It is estimated that between 5 and 13% of all dialysis patients will develop symptomatic renal calculi and many more asymptomatic calculi. Many of the stone-forming dialysis patients will have recurring stone disease with one study finding an 83.3% recurrence rate. CONCLUSION: Since dialysis patients have a wide range of urine output, the clinician should be alert to the possibility of stone formation. We recommend yearly ultrasound examinations on all dialysis patients as well as citrate and magnesium supplements with careful follow-up of laboratory results and urine electrolytes. We also recommend careful follow-up of all patients on aluminum-hydroxide phosphate binders as they are predisposed to form Al-Mg-urate stones. For those dialysis patients that form renal calculi, watchful waiting and symptomatic treatment is recommended since almost all patients will spontaneously pass their stones. However, ESWL and other current modalities may be used with no greater morbidity compared to nondialysis cohorts. We also suggest that patients with severe recurring intractable stone disease who are candidates for renal transplantation should be offered bilateral nephrectomies.

Humans↗
PubMed2004

Percutaneous pneumatic and laser lithotripsy as a possible therapeutic strategy for bilateral large calculi in a horseshoe kidney.

This report concerns a case of bilateral large calculi in a horseshoe kidney. Three sessions of percutaneous nephrolithotripsy for the calculi successfully disintegrated and removed the fragments without any complications. For complete stone removal we used pneumatic and laser lithotriptors which were passed, respectively, through a rigid nephroscope and a flexible pyeloscope. It is emphasized that the selection of the most suitable lithotriptor by taking their various features into account is important in endoscopic surgery for calculi which are likely to recur such as stones accompanied by infection or for anatomically anomalous kidneys such as horseshoe kidneys.

Female↗
PubMed1989

Formation of bobierrite (magnesium phosphate) crystal aggregates by bacteria from human urine and renal calculi.

The formation of extracellular crystal aggregates of bobierrite [Mg3(PO4)2.8H2O] by bacteria isolated from renal calculi and urine of urolithiasic patients is found with the use of B-17 and B-43 media. The crystal aggregates were observed in the colonies as deposits of brown-yellow coloration, and were identified by X-ray powder diffraction, chemical analysis and scanning electron microscopy. The production of bobierrite by bacteria from human urine and renal calculi implies further versatility of crystal formation by microorganisms, and it may be interesting to investigate the possible relationships between calculi precipitation and urinary infection.

Bacteria↗
PubMed1991

Extracorporeal shock-wave lithotripsy for small symptomatic renal calculi: is it effective?

Renal calculi with a diameter of less than 5 mm can pass spontaneously. However, some patients have small symptomatic renal calculi for more than 3 months. We evaluated the results of extracorporeal shock-wave lithotripsy in 38 patients with such stones. Patients presented with loin pain, hematuria, infection, or a combination of complaints. Average stone size was 18 mm2. After a wait of 3 months for spontaneous evacuation without success, all patients were treated with a Siemens Lithostar. Three months after treatment, 19 patients (50%) were completely free of stones, but 7 still had complaints; of the 19 patients with residual fragments, 8 (42%) were free of complaints. Both evacuation and resolution of complaints were achieved in only 12 of the 38 patients (32%). We conclude that one should be reluctant to treat small renal calculi, because spontaneous evacuation occurs in about 80% and the results of treatment are restricted.

Adult↗
PubMed1993

Sonography of urethral calculi.

We performed sonography in 7 males with membranous and posterior urethral calculi. Sonography demonstrated the urethral calculi in all 7 patients. These findings suggest that sonography is useful as a noninvasive screening technique for urethral calculi.

Adult↗
PubMed1992

Effect of testosterone on the development of bladder tumors and calculi in female rats.

In order to study the effect of testosterone on bladder calculi and tumor formation in female rats, Wistar rats were administered testosterone for 12, 18 or 24 weeks. Testosterone was found to increase the incidence of both bladder calculi and tumors in intact, but not in oophorectomized rats. It is suggested that testosterone in combination with estrogen may contribute to hyperplasia formation, in turn leading to an increased incidence of bladder calculi and tumors.

Animals↗
PubMed1986

Efficacy of in situ extracorporeal shock wave lithotripsy for upper ureteral calculi.

In contrast to the majority of renal calculi, in situ extracorporeal shock wave lithotripsy (ESWL) for upper ureteral stones is still controversial. Some centers recommend retrograde mobilization of the calculus into the renal pelvis prior to ESWL as a routine procedure (UC + ESWL). To evaluate the efficiency of in situ ESWL for upper ureteric stones, we initiated a prospective clinical trial. From July 1985 to January 1986, 122 patients presented with upper ureteral calculi, necessitating a total of 146 different procedures: 88 in situ ESWL; 31 UC + ESWL; 15 antegrade ureteroscopies (URS); 6 retrograde URS; 2 open surgery (ureterolithotomy, nephrectomy), and 4 patients were managed conservatively. Of all 99 patients treated at the lithotripter, 80 patients received in situ ESWL (no emergency case, no location problems): in 60 patients (75%) the stone could be disintegrated in one session; 8 patients (10%) required a second ESWL session due to partial fragmentation. Retrograde mobilization using a ureteral catheter or URS was necessary in 9 patients due to failure of in situ ESWL (11%) and, in only 3 patients, we had to remove the stone by antegrade URS (4%). In conclusion, 96% of all upper ureteric stones suitable for primary ESWL could be treated by a noninvasive (in situ ESWL) or minimally invasive (UC + ESWL) procedure. Therefore we recommend in situ ESWL for these calculi. Primary retrograde mobilization is only indicated in case of location problems (stone close to the spine, obesity, skeleton deformation) or emergency cases (colic, hydronephrosis). Antegrade URS should be performed if retrograde mobilization fails or in emergency cases (acute pyelonephritis, following percutaneous nephrostomy, after clinical stabilization). The rate of open surgery is below 2%.

Clinical Trials as Topic↗
PubMed1988

Local shock-wave lithotripsy of distal ureteral calculi.

Since the initiation of the clinical trial utilizing a second-generation lithotripor (Lithostar, Siemens, Erlangen, FRG), 96 patients with distal ureteral calculi (i.e. calculi below the pelvic brim) underwent local shock-wave lithotripsy. Routine treatment was conducted under intravenous sedation and light analgesia only. Complete stone disintegration was achieved in 84 patients (87.5%), 11 requiring two sessions and 1 patient, three. In 7 patients ureteroscopy became necessary after unsuccessful local shock-wave treatment. In 2 of these patients a 9-french flexible ureteroscope and the Storz Q-switched neodymium-YAG laser was used for stone disintegration. In 3 cases loop extraction and in 2 cases open surgery had to be performed for definitive stone removal. All pre- and postoperative manipulations (except open surgery) were done on the Lithostar. Local shock-wave lithotripsy is a highly successful, noninvasive, time-saving and easily applicable technique. It has become our primary approach in the treatment of distal ureteral calculi.

Clinical Trials as Topic↗
PubMed1980

Analysis of urinary calculi in adults. Attempt of correlations between morphology and composition.

The analysis of 322 urinary calculi in adults by microdissection, infrared spectromorphometry and microchemistry has shown that stones could be classified in several groups according to their morphology and composition: 8 morphological types have been defined (2 for the oxalic, 2 for the uric, 2 for the phosphatic and 2 for the cystinic stones). Correlations between morphology and composition have been established dividing the calculi into 10 categories, 4 for the pure forms and 6 for the mixed forms; the total includes approximately 94% of the calculi analyzed. An 11th category gathering various lithiases (rare or with multiple components) represents 6% of the cases. Moreover, the study of the localization of the component in stones emphasizes the high frequency of Ca phosphates in the nucleus of oxalic lithiases: 80% in mixed forms, in which the oxalate is the main constituent.

Adult↗
PubMed1982

10,000 analyses of urinary calculi using X-ray diffraction and polarizing microscopy.

To make qualitative as well as semiquantitative analyses of 10,000 urinary calculi of large city population, a combined crystal-optical X-ray diffractometric method proved to be very useful. This combination goes to complement the advantages of polarization microscopy (with its minimal substance requirements, its proof limits of less than 1%, and its insight into stone texture) with those of X-ray diffraction (with its fast semiquantitative analysis and simple differentiation of all the stone components). About 30% of the calculi were found to have a monomineral composition. The most frequent types of calculi in our examination were: 33.2% whewellite/weddellite, 24.9% whewellite, 13.5% whewellite/weddellite/apatite, 7.0% struvite/apatite, and 3.9% uric acid/uric acid dihydrate.

Humans↗
PubMed1978

Analysis of urinary calculi formed by Nigerians.

50 stones formed by Nigerians were analysed using a combination of qualitative chemical analysis, and petrographic analysis with the Reichert Model NR 333 254, polarization microscope. The Bausch and Lomb binocular dissecting microscope was used for macroscopic examination of the specimens and for taking samples from the 'nucleus', inner and outer surfaces of the stones, for analysis. The results showed that calcium phosphate and magnesium ammonium phosphate accounted for 64% of the stones, calcium oxalate for 28% while uric acid accounted for 8%. This is in contrast to modern times Caucasian stones which are predominantly calcium oxalate. There appears to be a greater tendency for Nigerians to form large staghorn calculi than small stones that can passed spontaneously. The phosphate stones are known to be related to infection in the urinary tract. The findings on the composition of these calculi correlate with the previous findings of a high incidence of obstruction and infection in Nigerian patients with urinary calculi.

Black People↗
PubMed1978

Monosodium urate in urinary calculi.

In 3,000 calculi, monosodium urate was detected in 50 cases (1.66%). Infrared frequencies of monosodium urate are reported. In thin sections it appeared as long and thin fan-shaped or feather-like arranged crystals. Six calculi had monosodium urate as the sole component but all other cases were of mixed composition, with whewellite as the main secondary substance. The relative scarcity of monosodium urate cannot be explained by its high aqueous solubility because in urine the solubility decreases with increasing sodium concentration. Monosodium urate should be suspected in radiolucent calculi with neutral or light alkaline reaction and high uric acid and sodium concentrations in the patient's urine.

Crystallography↗