Urolithiasis in patients with end stage renal failure.

Renal stones from 30 chronic hemodialysis patients were subjected to morphological study by means of microscopic examination and to constitutional analysis with infrared spectrophotometry. In 29 patients calculi could be classified into 3 main types: 1) protein stones made of pure proteins or with a protein core and less than 30% calcium oxalate (9 cases, or 30%)--they were observed predominantly in patients with primary glomerular disease, 2) oxalo-protein stones with a core of calcium oxalate and a total stone content of more than 30% calcium oxalate (15 cases, or 50%)--they appeared to be related to metabolic factors, such as high urinary oxalate and low urinary citrate concentration, and to iatrogenic factors, namely vitamin D3 and calcium salt supplementation, and 3) aluminum-magnesium urate stones, probably induced by aluminum overload (6 cases, or 20%). Thus, our study indicates that a significant proportion (70%) of stones formed by hemodialysis patients may be due to metabolic and iatrogenic factors. Our data suggest that accurate analysis of such stones provides useful information on pathogenetic factors and consequently may give clues to their prophylaxis.

[Anti-hypertensive drugs prescribed to the elderly. Multicenter study at the hospital admission of 631 patients aged 70 plus years]. / Les anti-hypertenseurs prescrits aux personnes âgées. Etude multicentrique lors de l'entrée à l'hôpital de 631 patients de 70 ans et plus.

The anti-hypertensive treatment of 631 patients 70 years old and over was evaluated at the time of their hospitalization in 12 Internal Medicine departments in the western Paris suburbs, in May and June 1990. 49.6 +/- 3.9% received no such therapy; 30.3 +/- 3.6% were being treated for hypertension (group 1); 8.7 +/- 2.2% were taking anti-hypertensive drugs for poorly specified reasons (group 2); 11.4 +/- 2.5% were under such treatment for another reason. In groups 1 or 1 + 2, the most frequently prescribed medications were, in decreasing order: diuretics, calcium channel blockers, converting enzyme inhibitors, beta-blockers or central inhibitors. In the oldest patients, the beta-blockers were prescribed less and converting enzyme inhibitors more. More than half of the patients in groups 1 + 2 were taking a single drug. The most frequently prescribed combined therapy was diuretic + converting enzyme inhibitor. Our results seem to indicate that the prescription modalities depended, for the most part, upon an associated or suspected pathology, notably cardiac insufficiency.

[Should fragments of stone expelled after extracorporeal lithotripsy always be analyzed?]. / Faut-il toujours analyser les fragments de calculs expulsés après lithotritie extracorporelle?

The morphological and constitutional analysis of renal stone fragments expelled after extracorporeal shock wave lithotripsy enables the structure and morphological type of stones to be reconstructed in 92.8 per cent of the cases as regards surface and section and in 74.5 per cent of the cases down to the core. A study of the molecular and crystalline composition of such fragments demonstrated the preponderance of whewellite in both sexes (men 85.4 per cent; women 72.4 per cent). The frequency of weddellite was 1.6 times higher in men (73.8 per cent) than in women (44.8 per cent), and the frequencies of struvite and ammonium urate were 2.8 and 2.6 times respectively higher in women than in men, despite a significant fall in frequency as compared to a previous series. Correlations between morphological type of stone and biochemical data (when available) could be established in 84 per cent of the cases. This made it possible to initiate treatments aimed at preventing recurrences, the cost of these treatments in the long term being lower than that of the curative urological treatments, including extracorporeal shock wave lithotripsy.

Doxazosin in the treatment of patients with mild or moderate hypertension and mild or moderate renal insufficiency.

The antihypertensive efficacy and safety of doxazosin, a selective alpha 1-inhibitor, were assessed in 23 hypertensive patients with renal insufficiency. The study involved three phases: (1) a 2-week baseline period, (2) a 10-week period during which patients received doxazosin, 1 to 16 mg, once daily, and (3) a 4-week maintenance period. After 14 weeks of active treatment, systolic/diastolic blood pressures of efficacy evaluable patients were reduced by 8.9/9.2 and 4.6/9.1 mm Hg to final values of 153/90 and 149/91 mm Hg in the supine and standing positions, respectively. The mean dose of the efficacy evaluable patients was 9.8 mg/day. Eleven patients experienced one or more side effects, most of which were mild or moderate and disappeared or were tolerated with continued therapy. No clinically significant laboratory changes were apparent, and no trends were observed with regard to organ systems or correlations with dose or duration of treatment. There were no significant differences in serum creatinine levels between baseline and final visits. The overall lipid profile indicated a decrease in total cholesterol with increases in high-density lipoprotein cholesterol and the high-density lipoprotein/total cholesterol ratio. From baseline to final visit there was a highly significant reduction of 19% (p less than 0.05) in calculated risk scores for coronary heart disease on the basis of the Framingham equation.

[13 cases of drug-induced calculi]. / A propos de treize cas de calculs médicamenteux.

All urinary stones should undergo detailed studies to identify those related to drug therapy. Among 520 stones analyzed by infrared spectrophotometry, we found 13 drug-induced stones (13/520: 2.5%). Drug-induced stones were caused by glafenine in 7 cases, piridoxylate in 4 cases, triamterene in one case and an unknown organic compound in one case. Glafenine stones appear to develop more readily in infected urine. Triamterene stones are often associated with uric acid disorders. Piridoxylate induces the formation of glyoxylate which is responsible for hyperoxaluria and formation of oxalocalcium stones.

Piridoxilate-induced calcium oxalate calculi: a new drug-induced metabolic nephrolithiasis.

During the last 4 years we collected 27 specimens of calcium oxalate nephrolithiasis in patients receiving long-term treatment with piridoxilate, a drug composed of an equimolar combination of glyoxylate and pyridoxine. The mean duration of treatment was 3.6 years (range 4 months to 10 years) and the mean daily dose was 580 mg. piridoxilate, which contained 160 mg. glyoxylate. Calculi often recurred, with an average number of 9.9 per patient, and an open operation, shock wave lithotripsy or percutaneous nephrolithotomy was required in 22 patients (81 per cent). Oxalate excretion was 727 +/- 246 mumol. per day while on the drug and 382 +/- 201 mumol. per day after the drug was withdrawn. Whewellite was the major component of calculi in all cases but the stones exhibited a peculiar morphological arrangement, with multiple small indentations and a fine mamillary structure. Freshly voided urine specimens contained unusual crystals, which on infrared spectroscopy were composed of calcium oxalate trihydrate, a variety of crystal never observed previously in human urine. Piridoxilate-induced calcium oxalate nephrolithiasis is a new variety of metabolic drug-induced nephrolithiasis. Our observations suggest that even large doses of pyridoxine may be unable to prevent the excessive production of oxalate from glyoxylate.

[Principal methods for studying the composition and structure of urinary calculi]. / Principales méthodes d'étude de la composition et de la structure des calculs urinaires.

Since stones are the only objective elements of lithiasis, the cause of this disease can only be determined by an accurate analysis of the morphology and composition of the stones. To identify the crystal phases and the distribution of constituents between superficial and central structures such efficient techniques as scanning electron microscopy, X-ray diffraction or infrared spectroscopy are required. At least two complementary techniques must be combined to obtain enough information on the morphology as well as on the molecular and crystalline composition of the stones. The importance of morphological typing for the aetiological evaluation of the disease is demonstrated by examples which clearly show that each stone must first be examined optically. The different techniques used for the study of stones are reviewed and their relative efficiency and adaptability to routine analysis is discussed.

[Severe ocular toxicity of desferrioxamine in the hemodialyzed patient]. / Toxicité oculaire sévère de la desferrioxamine chez l'hémodialysé.

Severe and persistent visual loss with retinitis pigmentosa occurred in a hemodialyzed patient, treated with desferrioxamine (DFO) for aluminium intoxication, with a total DFO dose of 18 g given over 9 weeks. Cases reported since 1983 are reviewed, and hypothesis and risk factors for DFO toxicity are discussed. Caution should be exercised in using DFO in hemodialyzed patients.

[Study of spontaneous crystalluria in patients with calcium oxalate calculi]. / Etude de la cristallurie spontanée chez les lithiasiques oxalo-calciques.

We studied crystalluria in healthy subjects and in calcium oxalate stone formers using polarization microscopy and infrared spectroscopy, in freshly voided urine and after 48 h urine storage at +4 degrees C. 412 urine specimens from 39 normal subjects and from 172 stone formers were examined. In the latter, 90 voidings were obtained while on free diet, 61 on moderately calcium restricted diet, 34 in the fasting state and 136 while on thiazide therapy. In the normal subjects, all 91 voidings were obtained while on free diet. Crystalluria was more frequent in urine specimens collected on free diet in stone formers (48.9%) than in normal subjects (13.9%, p less than 0.001) and slightly decreased in patients on thiazide therapy (41.2%). Crystalluria increased following +4 degrees C urine storage in all groups. The most frequent crystalline phase was weddellite. Comparison of crystalline phases of calcium oxalate observed before and after +4 degrees C storage showed that crystallization spontaneously progressed to weddellite whatever the calcium oxalate phase initially present. On thiazide therapy we observed, in addition to lower calcium content, a decreased frequency of urate crystallization especially in +4 degrees C stored urine, in parallel with a decrease in urate concentration.

[Drug-induced crystalluria: myths and realities]. / Cristalluries médicamenteuses: mythes et réalités.

Medicinal crystalluria is often difficult to recognize and identify. Whether due to therapeutic overdoses or individual susceptibility, the diagnosis is always important. 70% of the drugs involved in crystalluria can induce kidney stones or promote their growth. In addition, approximately one medicinal crystalluria out of ten is clinically or biologically accompanied by kidney failure. On the basis of 59 cases of medicinal crystalluria, the means of identification, the molecules involved and the frequency of these iatrogenic crystalluria is discusses.

[Morphological typing of calcium oxalate calculi and etiopathogenic findings]. / Typage morphologique des calculs oxalocalciques et données étiopathogéniques.

The occurrence of different hydrate forms derived from a single chemical compound results from the selective conditions of crystallization. Identification of the crystalline phases and the structural types of stones may provide the physician with important data concerning the etiopathogenesis of the complaint. The authors have studied the crystallization of calcium oxalate in an aqueous solution and the process of spontaneous crystalluria. They noted that whewellite resulted, in many cases, from a concentration of oxalate, and weddellite from a concentration of calcium. This article discusses the correlations between morphological types of oxalate stones, the localization of the stones in the urinary tract, the biological disorders noted, and the sex of the patients.

[Whewellite and weddellite: toward a different etiopathogenesis. The significance of morphological typing of calculi]. / Whewellite et weddellite: vers des étiopathogénies différentes. Intérêt du typage morphologique des calculs.

From 3000 urinary calculi analysis, a morphological classification allowed us to appoint 7 structural types of oxalate stones, dependent on whewellite or/and weddellite. We observed evidence for correlations between biological data and these structural types, mainly between types I and hyperoxaluria, types II and hypercalciuria, types II + IV or IV and hyperparathyroïdism, as well as between whewellite and hyperuricuria. We determined in vitro calcium and oxalate concentrations ranges to crystallize various hydrate forms of calcium oxalate and we observed that whewellite form is almost the only one fitted for crystallizing in renal papilla. From this various data, it results that, in vivo, whewellite is dependent on oxalate concentration whereas weddellite is rather dependent on calcium concentration. Otherwise, differences in occurrence of morphological types of oxalate calculi were observed as a function of the patient' sex, the urinary tract localisation of calculi, or the crystalluria.

[Drug-induced urinary lithiasis]. / Les lithiases urinaires médicamenteuses.

All urinary calculi should be thoroughly examined. Among 2 000 calculi analyzed by infra-red spectrophotometry, some were found to contain rare constituants and drugs which might be held responsible for urinary stone formation. These included glafenine, triamterene, co-trimoxazole, sulphaguanidine, allopurinol, phenazopyridine, flumequine and anti-acid powders containing aluminium, calcium and magnesium trisilicates and/or carbonates or bicarbonates. Considering that these drugs are widely used, the incidence of drug-induced urinary calculi appears to be very low.