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Michel Daudon

Publications and source records attributed to Michel Daudon.

At least 37 records · Page 2Linked to original sources
PubMed2004

Clinical value of crystalluria and quantitative morphoconstitutional analysis of urinary calculi.

Morphoconstitutional analysis of urinary calculi, i.e. morphologic examination combined with Fourier transform infrared spectroscopy (FTIR), is of decisive interest for the diagnosis of rare but severe inherited or acquired stone diseases such as cystine, 2,8-dihydroxyadenine, xanthine, struvite, ammonium urate or drug-containing calculi as well as primary hyperoxalurias. In the absence of early diagnosis and proper management, these diseases may lead to progressive loss of renal function. Among common forms of calcium oxalate (CaOx) stones, predominant CaOx monohydrate (whewellite) is mainly associated with hyperoxaluric conditions whereas predominant CaOx dihydrate (weddellite) is mainly associated with hypercalciuria, and this distinction is of interest to orient metabolic evaluation and preventive measures. Crystalluria examination, also based on morphology and FTIR, is a valuable diagnostic method when no stone is available for analysis. Presence of specific crystals (cystine, 2,8-dihydroxyadenine, struvite, ammonium urate) is diagnostic by itself. In all types of nephrolithiasis, serial crystalluria determination appears as a simple, cheap and reliable method to evaluate the risk of stone formation and assess the effectiveness of preventive measures. Determination of urinary crystal volume was in our experience a useful tool in the management of patients with cystinuria or primary hyperoxaluria in the post-transplantation period. In conclusion, both accurate morphologic and FTIR analysis of stones and serial crystalluria determination should be more largely used, in view of their value in the diagnosis and management of renal stone formers.

Crystallization↗
PubMed2004

Automated Fourier transform infrared analysis of urinary stones: technical aspects and example of procedures applied to carbapatite/weddellite mixtures.

New software (ScanLith) was developed to provide an automated procedure for identifying and quantifying crystalline species in urinary calculi. The first step was to strictly define operative conditions of sample preparation because they have a significant influence on the stability of various crystalline phases. Second, we determined the quantification coefficients of a polynomial curve required to develop the automated procedure. This was illustrated by the study of carbapatite and weddellite, as both constituents represent one of the most frequent associations found in stones analyzed in our laboratory. The following quadratic equation was obtained with a correlation coefficient r2 = 0.9997: Y = -0.5144x2 + 1.5239x - 0.0141, where Y is the absorbance ratio carbapatite/weddellite and x is the percentage of carbapatite in the mixture. The absorbance of carbapatite and weddellite was measured at 1035 cm(-1) and 1325 cm(-1), respectively. The third step was to validate the ScanLith procedure in routine analysis by comparing computed results with those of an expert. Concordance (r2 = 0.9824) was better than that previously reported using various computerized systems with a mean deviation of 4%. Algorithms developed in ScanLith to identify main and minor components found in urinary stones, even in complex mixtures containing up to seven constituents, allowed us to lower the detection threshold down to 1 to 10% depending on the main component.

Algorithms↗
PubMed2004

Drug-induced renal calculi: epidemiology, prevention and management.

Drug-induced calculi represent 1-2% of all renal calculi. The drugs reported to produce calculi formation may be divided into two groups. The first one includes poorly soluble drugs with high urine excretion that favours crystallisation in the urine. Among poorly soluble molecules, triamterene was the leading cause of drug-containing urinary calculi in the 1970s, and it is still currently responsible for a significant number of calculi. In the last decade, drugs used for the treatment of HIV-infected patients, namely indinavir and sulfadiazine, have become the most frequent cause of drug-containing urinary calculi. Besides these drugs, about twenty other molecules may induce nephrolithiasis in patients receiving long-term treatment or high doses. Calculi analysis by physical methods, including infrared spectroscopy or x-ray diffraction, is needed to demonstrate the presence of the drug or its metabolites within the calculi. The second group includes drugs that provoke urinary calculi as a consequence of their metabolic effects. Here, diagnosis relies on careful clinical inquiry because physical methods are ineffective to differentiate between urinary calculi induced by the metabolic effects of a drug and common metabolic calculi. The incidence of such calculi, especially those resulting from calcium/vitamin D supplementation, is probably underestimated. Although drug-induced urinary calculi most often complicate high-dose, long-duration drug treatments, there also exist specific patient risk factors in relation to urine pH, urine output and other parameters, which provide a basis for preventive or curative treatment of calculi. Better awareness of the possible occurrence of lithogenic complications, preventive measures based on drug solubility characteristics and close surveillance of patients on long-term treatment with drugs with lithogenic potential, especially those with a history of urolithiasis, should reduce the incidence of drug-induced nephrolithiasis.

Drug-Related Side Effects and Adverse Reactions↗
PubMed2004

ESRD caused by nephrolithiasis: prevalence, mechanisms, and prevention.

BACKGROUND: The contribution of nephrolithiasis-related end-stage renal disease (ESRD) to patients requiring renal replacement therapy has never been specifically evaluated. METHODS: Of the entire cohort of 1,391 consecutive patients who started maintenance dialysis therapy at our nephrology department between January 1989 and December 2000, a total of 45 patients (21 men) had renal stone disease as the cause of ESRD and constitute the study material. Type and cause of renal stone disease was determined in the 45 patients, as well as the change in prevalence of nephrolithiasis-related ESRD with time during this 12-year period. RESULTS: The overall proportion of nephrolithiasis-related ESRD was 3.2%. Infection (struvite) stones accounted for 42.2%; calcium stones, 26.7%; uric acid nephrolithiasis, 17.8%; and hereditary diseases (including primary hyperoxaluria type 1 and cystinuria), 13.3% of cases. Women were predominant among patients with infection and calcium stones, whereas men were predominant among patients with uric acid or hereditary stone disease. The proportion of patients with nephrolithiasis-related ESRD decreased from 4.7% in the triennial period 1989 to 1991 to 2.2% in the most recent period, 1998 to 2000 ( P = 0.07). This tendency to a decreasing prevalence mainly was caused by a rarefaction of infection and calcium stones with time, whereas frequencies of uric acid and hereditary stone disease remained essentially unchanged. CONCLUSION: Severe forms of nephrolithiasis remain an underestimated cause of potentially avoidable ESRD and need for renal replacement therapy. These findings highlight the crucial importance of accurate stone analysis and metabolic evaluation to provide early diagnosis and proper therapy for conditions that may lead to ESRD through recurrent stone formation and/or parenchymal crystal infiltration.

Adult↗
PubMed2004

[Lithogenesis].

Explore the source record for details and available documents.

Crystallization↗
PubMed2004

[Medical treatment of urinary lithiasis].

Urinary stone disease is frequent, and characterized by a high recurrence rate. Prevention of recurrent urolithiasis is possible using an appropriate diet with or without medications. Patients should be encouraged to have a high fluid intake. For an adult, urine volume should exceed 2000 ml/day. Diet modification should be done according to the various metabolic factors contributing to the formation of the stone (ie, hypercalciuria, hyperoxaluria, hypocitraturia, hyperuricuria, and so forth). Calcium intake should be around 1000 mg/day, protein intake limited to 1.2 g/kg/day, and salt intake kept to less than 100-150 mEq/jour. For uric acid urolithiasis, patient should limit uric acid intake to less than 500 mg/day. If these dietary manoeuvers fail, one can use thiazide diuretics to treat hypercalciuria, potassium citrate to correct hypocitraturia or sodium bicarbonate to alkalanize urine and prevent uric acid stone formation.

Decision Trees↗
PubMed2004

[Infective lithiasis].

We report the case of a 69-year-old woman, with a BMI of 42.9, suffering from bilateral struvite calculi and who raised end stage renal failure. Urease-synthesizing bacteria, leading to the hydrolysis of urea into ammonium and to an alkaline urine (pH > 7.2), are required for struvite stone formation in humans. Struvite component constitutes the majority of staghom calculi. Patients with struvite stones could lose renal function because of obstructive or pyelonephritic episodes and surgical interventions on the kidney. Therapeutic success needs a follow up by a specialized uro-nephrologist team as soon as possible.

Aged↗
PubMed2004

[Massive hyperoxaluria].

Primary hyperoxaluria type I is a rare inborn error of metabolism caused by a deficiency of a liver-specific peroxisomal enzyme. It manifests by increased oxalate production that ultimately results in kidney failure, due to urolithiasis and nephrocalcinosis, and finally induces systemic oxalosis and risk of premature death. Primary hyperoxaluria type 2 is mainly responsible of urolithiasis. Enteric hyperoxaluria is a commonly seen adverse event of Crohn disease or after extensive intestinal resection. These affections represent the main etiologies of massive hyperoxaluria. If not recognized very soon and adequately treated, these conditions can progress rapidly to end stage renal failure.

Child↗
PubMed2004

[Radiologic and biochemical studies of urinary lithiasis].

Clinical investigations of a patient with urolithiasis include a careful history and radiological and biochemical evaluation. Stone analysis by infrared spectrophotometry remains the most important step. These investigations are essential in order to understand why a patient developed urolithiasis and, most importantly, how to avoid its recurrence in the future. Simple exams are often enough in a patient with a single urolithiasis episode. But biochemical evaluation should be extensive in a child, or an adult with several urolithiasis episodes or with renal insufficiency.

Decision Trees↗
PubMed2004

[Composition of renal stones currently observed in non-industrialized countries].

UNLABELLED: Up until relatively recently, renal stones in developing countries were considered to be very different from those observed in industrialized countries, essentially characterized by the predominance of phosphate and urate stones, while the predominant stones in industrialized countries are calcium oxalate stones. To verify whether this difference in the epidemiological profile is still observed today, we analysed renal stones collected in various regions of the globe and compared their composition to that of stones observed in France. MATERIAL AND METHOD: 1,042 stones were collected between 1991 and 2000 from 14 different countries or geographical zones: Sub-Saharan Africa (Cameroon, Mali, Senegal), North Africa (Algeria, Morocco, Tunisia), South America (Brazil, Paraguay), Asia Minor (Pakistan, Turkey), Far East (China, Laos, Vietnam) and French Polynesia (Tahiti). Stones were analysed by infrared spectrophotometry. The composition of these stones was compared to that of 24,706 stones collected in France over the same period and analysed according to the same protocol. RESULTS: Overall, the proportion of calcium oxalate stones was the same in adults in France and in developing countries (men: 75.7% contre 72%; women: 59.8% contre 56.3%), but was higher in children in non-industrialized countries (boys: 52.6% contre 31.8% in France; girls: 67.8% contre 48.8% in France, p<0.0001). The frequency of calcium phosphate stones was particularly low in boys in developing countries (8.3% contre 45.1% in France, p<0.0001) andfrequency of purine stones was higher in boys (21.3% contre 5.2% in France, p<0.0001) and in girls (13.6% contre 4.3% in France, p<0.05). Major differences were observed according to continent and region; struvite was present in 42.9% of stones in women in Sub-Saharan Africa contre 13% in South America and 2.7% in Asia Minor. Purines were 4 times more frequent in Tahitian men than in North African men. Calcium phosphate stones were 10 times less frequent in men in Asia Minor than in the Far East. CONCLUSION: The epidemiology of renal stones is continuing to change all over the world towards a predominance of calcium oxalate stones, which is now generalized. Major differences in the frequency of the other constituents, particularly purines and struvite, reflect particular eating habits and infectious risk factors specific to certain population.

Adult↗
PubMed2003

Cystine crystal volume determination: a useful tool in the management of cystinuric patients.

We prospectively determined cystine crystal volume (Vcys) in urine specimens from all consecutive patients with cystine urolithiasis followed at our institution over the past decade, in order to assess its predictive value as to the risk of recurrent cystine stone formation. A total of 57 patients (29 males, 28 females) with homozygous cystinuria entered in the study between January 1990 and December 2000, including 15 children aged less than 15 years and 42 patients aged 15 years or more. The clinical and radiological course was followed until December 2001, for a total of 243 patient-years of follow-up. From study entry until the end of follow-up, we serially examined first voided morning urine specimens in all patients, with determination of the number of cystine crystals per mm3, and the average size of crystals, thus allowing us to calculate Vcys using a simple formula based on crystal geometry. Recurrence was diagnosed on the basis of serial radiographic examinations using X-rays and echography. Overall, cystine crystals were present in 179 (39%) of the 460 examined urine specimens. Cystine crystalluria was significantly more frequent among the 27 patients who developed new cystine stones (SF) than in the other 30 who remained stone-free (63.3 vs 25.5% of samples, P<0.001). The presence of crystals in > or =50% of serially examined urine samples was more frequently found in patients with recurrent stone formation than in non-recurrent patients (24/27 vs 2/30, P<0.001). The average Vcys value was significantly higher in recurrent SF than in stone-free patients (8,173 +/- 1,544 vs 233 +/- 150 micro3/mm3, P<0.001) and there was no overlap in the individual values of recurrent vs stone-free patients. A Vcys value > or =3,000 micro3/mm3 was observed at least once prior to each of the 63 stone recurrences observed in 27 patients (2.3 per patient on the average). In addition, Vcys reflected the efficacy of treatment, with Vcys mean values of 12,097 +/- 3,214 micro3/mm3 at baseline, falling to 2,648 +/- 658 micro3/mm3 on basic therapy (hyperdiuresis plus alkalinization) alone, 1,141 +/- 522 micro3/mm3 on tiopronin therapy (median dose 1,000 mg/day) and 791 +/- 390 micro3/mm3 on D-penicillamine therapy (median dose 900 mg/day) whereas captopril had no effect (5,114 +/- 2,128 micro3/mm3). Based on the results of the present study, cystine crystalluria appears to accurately reflect active stone formation in cystinuric patients. Determination of total Vcys provides a simple, cheap and accurate means of predicting the risk of cystine stone recurrence with a Vcys value > or =3000 micro3/mm3 as the threshold risk value. We propose that serial Vcys determination be performed simultaneously with the measurement of urine pH and specific gravity to optimally monitor the medical treatment of cystine patients.

Adolescent↗
PubMed2003

[Urinary stones and urinary tract abnormalities. Is the stone composition independent of the anatomical abnormality?].

INTRODUCTION: More than ten per cent of stones are associated with a urinary tract abnormality. To verify whether the malformation influences stone composition, we studied the composition of stones observed in fifteen urological abnormalities. MATERIAL AND METHOD: This study is based on 1,461 stones associated with a clearly defined malformation analysed by infrared spectroscopy plus 402 bladder stones in men with benign prostatic hyperplasia. RESULTS: In this series of 1,863 abnormalities, 732 (39.3%) involved the kidney, 561 (30.1%) involved the ureter and 570 (30.6%) involved the lower tract. Whewellite stones were predominant in all renal abnormalities with the exception of cysts, which were mainly associated with uric acid. The main differences concerned the second constituent: weddellite in horseshoe kidneys, carbapatite in Cacchi-Ricci disease and caliceal abnormalities. Struvite was uncommon (<10%). Whewellite was the main component in ureteric abnormalities except for megaureter and reflux in which carbapatite was predominant. Struvite was present in 10% to 30% of stones. Vesicourethral abnormalities were accompanied by calcium and magnesium phosphate stones (90% of cases), and struvite was present in 58% to 90% of cases. The exception to this general rule was bladder stones associated with benign prostatic hyperplasia, in which the main component was uric acid. CONCLUSION: Significant differences in stone composition were observed as a function of anatomical abnormalities reflecting the fact that some abnormalities add infectious or metabolic risk factors to anatomical factors.

Female↗
PubMed2002

Indinavir-induced cholelithiasis in a patient infected with human immunodeficiency virus.

We report the first case of acute cholecystitis due to indinavir-induced cholelithiasis in a patient infected with human immunodeficiency virus who had been receiving indinavir for 56 months. Infrared spectroscopy demonstrated that the gallstone was composed of indinavir monohydrate (50%), calcium bilirubinate (28%), calcium palmitate (10%), cholesterol (7%), and proteins (5%). The role of high-level chronic unconjugated hyperbilirubinemia coupled with high blood concentrations of indinavir is discussed.

Acute Disease↗