Changing paradigms in the surgical management of hyperparathyroidism at a tertiary care hospital in a developing country.

We report the presentation, management and outcomes of patients operated for hyperparathyroidism at our hospital. Patient sunder going surgery for hyper parathyroidism from 20 05 to 2 015 were retrospectively reviewed. Preoperative biochemistry, diagnostic scans and surgical procedures were studied. Follow up for cure rates, complications and histology were recorded. Out of 72 patients reviewed 54 (75%) were females and the rest males. The mean age was 48.04±15.5 years. Musculoskeletal complains were the most common (76.4%) among the cases reviewed. Asymptomatic hypercalcemia was seen in 13 (18.1%). The mean preoperative PTH level was 658.95 pg/ml and the mean preoperative calcium was 11.9 mg/dl. Bilateral neck exploration was done in 42 (58.3%) while focused unilateral approach was done in 27 (37.5%) cases. Solitary adenoma was the most frequent pathology in 58 (80.5%) patients. Asymptomatic hyperparathyroidism was less frequently detected in our population owing to lack of screening programme. Our patients are younger with a greater severity of the disease both symptomatically and biochemically compared to the West. In almost two decades, preoperative symptoms, calcium and PTH levels have changed marginally. Bilateral explorations are now giving way to focused less invasive procedures.

Epidemiology of stone disease across the world.

Nephrolithiasis is a highly prevalent disease worldwide with rates ranging from 7 to 13% in North America, 5-9% in Europe, and 1-5% in Asia. Due to high rates of new and recurrent stones, management of stones is expensive and the disease has a high level of acute and chronic morbidity. The goal of this study is to review the epidemiology of stone disease in order to improve patient care. A review of the literature was conducted through a search on Pubmed®, Medline®, and Google Scholar®. This review was presented and peer-reviewed at the 3rd International Consultation on Stone Disease during the 2014 Société Internationale d'Urologie Congress in Glasgow. It represents an update of the 2008 consensus document based on expert opinion of the most relevant studies. There has been a rising incidence in stone disease throughout the world with a narrowing of the gender gap. Increased stone prevalence has been attributed to population growth and increases in obesity and diabetes. General dietary recommendations of increased fluid, decreased salt, and moderate intake of protein have not changed. However, specific recommended values have either changed or are more frequently reported. Geography and environment influenced the likelihood of stone disease and more information is needed regarding stone disease in a large portion of the world including Asia and Africa. Randomized controlled studies are lacking but are necessary to improve recommendations regarding diet and fluid intake. Understanding the impact of associated conditions that are rapidly increasing will improve the prevention of stone disease.

IDENTIFYING PARATHYROID HORMONE DISORDERS AND THEIR PHENOTYPES THROUGH A BONE HEALTH SCREENING PANEL: IT'S NOT SIMPLE VITAMIN D DEFICIENCY!

OBJECTIVES: To determine the utility of bone health screening panels in identifying disorders of parathyroid gland secretions. METHODS: A retrospective analysis of biochemical parameters in a bone health screening panel (BHSP) was conducted. Low and high cutoffs were applied to determine hypofunctioning and hyperfunctioning conditions related to parathyroid hormone. Clinical phenotypes of parathyroid gland abnormalities were determined using a combination of levels of calcium, 25-hydroxyvitamin D, and intact parathyroid hormone (iPTH). A PTH nomogram was applied to calculate the maximum expected PTH for existing levels of 25-hydroxyvitamin D. Medical records of patients were reviewed for clinical validation of biochemical findings. RESULTS: Sixty-eight percent of subjects showed abnormal PTH secretion. Primary hyper- and hypoparathyroidism were detected in 1% (n = 5) and 0.4% (n = 2) of subjects, respectively. Normocalcemic hyperparathyroidism and hypercalcemia with inappropriately high-normal PTH were identified in 8.5% (n = 37) and 2% (n = 10) of subjects, respectively. All subjects with primary and normocalcemic hyperparathyroidism had higher measured PTH than calculated maximum PTH using the PTH nomogram. Secondary hyperparathyroidism and functional hypoparathyroidism were present in 18% (n = 88) and 39% (n = 194) of subjects, respectively. High prevalence of bone pains, renal stones, and low bone mineral density were identified in patients with abnormal PTH secretion. CONCLUSION: Panel testing is useful in early diagnosis of metabolic bone disorders related to PTH. A BHSP helps identify normocalcemic hyperparathyroidism and hypercalcemia with inappropriately high PTH. ABBREVIATIONS: 25OHD = 25-hydroxyvitamin D AKUH = Aga Khan University Hospital BHSP = bone health screening panel iPTH = intact parathyroid hormone maxPTH = maximum parathyroid hormone MBD = metabolic bone disease NCHPT = normocalcemic hyperparathyroidism PHPT = primary hyperparathyroidism PTH = parathyroid hormone SHPT = secondary hyperparathyroidism VDD = vitamin D deficiency.

Analysis of 114 Pedigrees of Renal Stone Patients: A Retrospective Review.

BACKGROUND:  Renal and ureteric stones (RS) can form due to genetic, metabolic, environmental, and diet-hydration related factors. Studies have shown that patients with family history (FH) of RS have higher likelihood of recurrence. MATERIALS AND METHODS:  We conducted a retrospective cross-sectional study on 114 pedigrees to investigate the impact of FH on recurrence of RS and examine patterns of inheritance.  Results: Family history of renal stone disease was found in 42% of all patients. There was a significant increase of stone recurrence in RS patients with a positive FH (p=0.001). Seventy-one percent of patients with recurrent stones had at least one family member with RS. Interestingly, male penetrance was higher in RS recurrence, where a greater proportion of males had no FH of RS, indicating that there may be other factors involved as well.  Conclusion: Family history in RS patients should be continuously explored for the possible underlying genetic influence, whilst keeping in mind the dietary habits of the family.

Determination of reference interval (RI) of spot urinary oxalate to creatinine ratio in children of pakistani origin under six years of age: A cross-sectional study.

BACKGROUND: The gold standard screening method of hyperoxaluria in children is using 24-hour urine collection. Urine collection may be cumbersome and challenging for children. Reference intervals (RI) of oxalate for the Pakistani population are not readily available. Therefore we aimed to determine the oxalate to creatinine ratio (Ox: Cr) for Pakistani children <6 years of age. MATERIALS AND METHODS: A cross-sectional study was conducted at Aga Khan University from June 2018 to October 2019. Random urine samples from apparently healthy children < 6 years were collected and stored at -30°C until analysis after adding 6M HCl. Oxalate was measured on Micro lab 300 using a kit based on oxalate oxidase principle, while creatinine was measured by kinetic Jaffe reaction. Data was analyzed by EP evaluator and SPSS 23. Ox: Cr ratio was calculated and reported with 90% confidence interval (CI) and interquartile range (IQR). RESULTS: The mean age of study subjects (n=120) was 29 ±22.3 months with an M: F ratio of 1:1. Children of various ethnicities were included from all over Karachi. The majority of the subjects were Urdu speaking (37.5%). Median Ox: Cr was 0.13(0.10). No significant difference was noted in the median Ox: Cr ratio between various ethnicities (p>0.05). It was significantly different in group I to V which was 0.25 (IQR: 0.06), 0.19 (IQR: 0.11), 0.15 (IQR: 0.04), 0.11 (IQR: 0.06) and 0.08 (IQR: 0.04) respectively (pvalue <0.001). CONCLUSION: The established RIs of Ox: Cr ratio was 0.05-0.34 (90% CI). Ox: Cr ratio showed a declining trend with age. Large scale reference interval studies are encouraged, taking diet and age into consideration.

Relationship of spot urine oxalate to creatinine ratio and 24 hours urinary oxalate excretion in patients with urolithiasis.

BACKGROUND: The evaluation of 24 h urinary oxalate excretion is the gold standard for diagnosing hyperoxaluria in patients with recurrent urolithiasis. However, 24 h urine sample collection is cumbersome. Therefore we aim to see if oxalate to creatinine ratio in random urine sample can be used as an alternative. MATERIALS AND METHODS: A cross-sectional study was conducted at Section of Chemical Pathology, Department of Pathology and Laboratory Medicine Aga Khan University Karachi from 1st February to December 31, 2019. A total of 62 adult patients, 18-60 years of age with history of kidney stones presenting to the clinical laboratory for 24 h urine oxalate estimation were invited to participate in the study after informed consent. Clinical details were recorded on a structured questionnaire and patients were guided to submit 24 h urine and a random spot urine sample. Urinary oxalate was measured on Micro lab 300 using a kit based on oxalate oxidase principle by Trinity Biotech plc, Wicklow, Ireland following standard operating procedures. Urinary creatinine was measured on ADVIA 1800 by Siemens, US using kinetic Jaffe reaction according to the manufacturer's instructions. The data was analyzed on SPSS. RESULTS: In a period of ten months, a total of 62 subjects were recruited; mean age was 32.4 ± 2.6 years. Males were 49 (79.0%) and females were 13 (20.9%). Correlation was found to be (r = 0.289) by Spearman correlation (p value < 0.005). Taking 24 h urinary oxalate as gold standard the sensitivity, specificity, positive predictive value and negative predictive value of spot oxalate to creatinine ratio was 83.3%, 17.8%, 9.8% and 90.9% respectively. CONCLUSION: The random spot urine test cannot replace the 24 h urinary oxalate estimation in patients with urolithiasis.

Unique classification of parathyroid dysfunction in patients with transfusion dependent thalassemia major using Nomogram-A cross sectional study.

INTRODUCTION: Hypoparathyroidism is a rare complication of iron overload in patients with transfusion dependent ß thalassemia major (ß-TM). We aim to determine the prevalence of parathyroid dysfunction in patients with ß-TM. METHODS: Diagnosed cases of transfusion dependent ß-TM between 5 and 17 years of age were recruited from outpatient clinics of a non-profit organization in Karachi, Pakistan. Blood and urine samples were collected in fasting to determine Ca, P, Alb, Mg, Cr 25OHD and iPTH. Patients were grouped on the basis of upper and lower levels of Ca, 25OHD and iPTH for assessing parathyroid dysfunction into primary hypoparathyroidism [low calcium (Ca) & intact parathyroid hormone (iPTH)], sub-clinical hypoparathyroidism [low iPTH and 25 hydroxy vitamin D (25OHD), low/normal Ca], normal functioning parathyroid gland [Normal Ca, iPTH and 25OHD] and secondary hyperparathyroidism [high iPTH, low/normal Ca and/or 25OHD]. Using PTH nomogram subject specific expected PTH (maxPTH) was calculated. Difference between maxPTH and measured iPTH was determined to assess the utility of nomogram in identifying parathyroid gland dysfunction. The statistical analysis was performed using the Statistical Package of Social Sciences (SPSS) version 20. RESULTS: Median age of patients was 11 years (13-7) with males being 54.2% (n = 205).Based on Ca, 25OHD and iPTH, primary hypoparathyroidism was identified in 3.4% (n = 13) [median iPTH 11.3 pg/ml (12.6-7)], 52.3% (n = 192) had subclinical hypoparathyroidism [iPTH 40.4 pg/ml (52.7-28.7)], and 34% (n = 125) were identified as secondary hyperparathyroidism [iPTH 88.6 pg/ml (116-74.7)]. Normal response to Ca & 25OHD was seen in 10.6% (n = 39) [iPTH 44.2 pg/ml (53.8-33.4)] patients. High phosphorous was present in all groups. Difference between maxPTH & iPTH was highest in primary hypoparathyroidism, followed by subclinical and secondary hyperparathyroidism. CONCLUSION: Nomogram by Harvey et al. identify low secretion capacity of parathyroid gland that correlated with biochemical classification of patients. It requires clinical validation before using in clinical practice for assessing parathyroid dysfunction.

Assessing clinical reasoning skills using Script Concordance Test (SCT) and extended matching questions (EMQs): A pilot for urology trainees.

INTRODUCTION: Clinical reasoning skill is the core of medical competence. Commonly used assessment methods for medical competence have limited ability to evaluate critical thinking and reasoning skills. Script Concordance Test (SCT) and Extended Matching Questions (EMQs) are the evolving tests which are considered to be valid and reliable tools for assessing clinical reasoning and judgment. We performed this pilot study to determine whether SCT and EMQs can differentiate clinical reasoning ability among urology residents, interns and medical students. METHODS: This was a cross-sectional study in which an examination with 48 SCT-based items on eleven clinical scenarios and four themed EMQs with 21 items were administered to a total of 27 learners at three differing levels of experience i.e. 9 urology residents, 6 interns and 12 fifth year medical students. A non-probability convenience sampling was done. The SCTs and EMQs were developed from clinical situations representative of urological practice by 5 content experts (urologists) and assessed by a medical education expert. Learners' responses were scored using the standard and the graduated key. A one way analysis of variance (ANOVA) was conducted to compare the mean scores across the level of experience. A p-value of < 0.05 was considered statistically significant. Test reliability was estimated by Cronbach α. A focused group discussion with candidates was done to assess their perception of test. RESULTS: Both SCT and EMQs successfully differentiated residents from interns and students. Statistically significant difference in mean score was found for both SCT and EMQs among the 3 groups using both the standard and the graduated key. The mean scores were higher for all groups as measured by the graduated key compared to the standard key. The internal consistency (Cronbach's α) was 0.53 and 0.6 for EMQs and SCT, respectively. Majority of the participants were satisfied with regard to time, environment, instructions provided and the content covered and nearly all felt that the test helped them in thinking process particularly clinical reasoning. CONCLUSIONS: Our data suggest that both SCT and EMQs are capable of discriminating between learners according to their clinical experience in urology. As there is a wide acceptability by all candidates, these tests could be used to assess and enhance clinical reasoning skills. More research is needed to prove validity of these tests.

Fourier transform infrared spectroscopy for analysis of kidney stones.

PURPOSE: To compare the results of a chemical method of kidney stone analysis with the results of Fourier transform infrared (FT-IR) spectroscopy. MATERIALS AND METHODS: Kidney stones collected between June and October 2015 were simultaneously analyzed by chemical and FT-IR methods. RESULTS: Kidney stones (n=449) were collected from patients from 1 to 81 years old. Most stones were from adults, with only 11.5% from children (aged 3-16 years) and 1.5% from children aged <2 years. The male to female ratio was 4.6. In adults, the calcium oxalate stone type, calcium oxalate monohydrate (COM, n=224), was the most common crystal, followed by uric acid and calcium oxalate dihydrate (COD, n=83). In children, the most frequently occurring type was predominantly COD (n=21), followed by COM (n=11), ammonium urate (n=10), carbonate apatite (n=6), uric acid (n=4), and cystine (n=1). Core composition in 22 stones showed ammonium urate (n=2), COM (n=2), and carbonate apatite (n=1) in five stones, while uric acid crystals were detected (n=13) by FT-IR. While chemical analysis identified 3 stones as uric acid and the rest as calcium oxalate only. Agreement between the two methods was moderate, with a kappa statistic of 0.57 (95% confidence interval, 0.5-0.64). Disagreement was noted in the analysis of 77 stones. CONCLUSIONS: FT-IR analysis of kidney stones can overcome many limitations associated with chemical analysis.

Primary hyperoxaluria in populations of Pakistan origin: results from a literature review and two major registries.

Primary hyperoxalurias (PH) are devastating, autosomal recessive diseases causing renal stones. Undifferentiated hyperoxaluria is seen in up to 43% of Pakistani paediatric stone patients. High rates of consanguinity in Pakistan suggest significant local prevalence. There is no detailed information regarding number of cases, clinical features, and genetics in Pakistan-origin (P-o) patients. We reviewed available information on P-o PH patients recorded in the literature as well as from two major PH registries (the Rare Kidney Stone Consortium PH Registry (RKSCPHR) and the OxalEurope PH Registry (OxER); and the Aga Khan University Hospital in Pakistan. After excluding overlaps, we noted 217 P-o PH subjects (42 in OxER and 4 in RKSCPHR). Presentations were protean. Details of mutations were available for 94 patients of 201 who had genetic analyses. Unique mutations were noted. Mutation [c.508G>A (p. Gly170Arg)] (present in up to 25% in the West) was reported in only one case. In one series, only 30% had mutations on exons 1,4,7 of AGXT. Of 42 P-o patients in OxER, 52.4% were PH1, 45.2% PH2, and 2.4% PH3. Of concern is that diagnosis was made after renal transplant rejection (four cases) and on bone-marrow aspiration (in five). Lack of consideration of PH as a diagnosis, late diagnosis, and loss of transplanted kidneys mandates that PH be searched for diligently. Mutation analysis will need to extend to all exons and include PH 1,2,3. There is a need to spread awareness and identify patients through a scoring or screening system that alerts physicians to consider a diagnosis of PH.

Identification of myeloperoxidase, alpha-defensin and calgranulin in calcium oxalate renal stones.

BACKGROUND: In order to understand the mechanism of stone genesis, it is essential to determine the characteristics of macromolecules constituting the urinary stones. We characterized proteins from the inner core and outer matrix of calcium oxalate (CaOx) renal stones. METHODS: Inner core and outer matrix of CaOx renal stones were separated and proteins were extracted with a buffer containing SDS and beta-mercaptoethanol. Proteins were analyzed and purified by SDS-PAGE and RP-HPLC respectively. The protein bands from gel and protein fractions were sequenced by MALDI TOF mass spectrometry. ELISA, western and slot blot immunoassays were performed to confirm the identity of the proteins in stones and urine of the stone formers. The potential of the identified protein as an effective promoter or inhibitor was assessed by observing their effects on CaOx crystallization using aggregometer. RESULTS: The inner core extract predominantly exhibited protein species in the molecular weight range of 12-14 kDa. However, a 66 kDa band, identified as osteopontin was also detected in the inner core along with outer matrix and in the urine of stone formers and non stone formers. Purification of low molecular weight proteins was carried out by reversed phase HPLC. Tandem mass spectrometry analysis identified them as myeloperoxidase chain A (MPO-A), alpha-defensin, and calgranulin. ELISA, western blot and slot-blot immuno-assays further confirmed their presence restricted to the inner core and not in the outer matrix. Turbidity assays showed that low molecular weight renal stone proteins promoted the aggregation of CaOx crystals. CONCLUSIONS: Persistent hyperoxaluria leads to tubular epithelial injury, resulting in the release of these anti-inflammatory proteins. These proteins could have been first adsorbed on CaOx crystals thereby become a part of nucleation process leading to inner matrix formation.

Mediastinal parathyroid adenoma causing primary hyperparathyroidism.

An ectopically placed parathyroid adenoma in the anterior mediastinum is a rare cause of persistent or recurrent primary hyperparathyroidism (PHPT) and is recognized as an important cause of failed primary neck exploration. We encountered 3 such cases amongst 70 surgically treated patients with PHPT (4.3%) over a 20-year period. In 2 cases, the offending adenoma could be removed at first exploration whereas in the 3rd case, it was successfully removed with mediastinal exploration after 2 failed neck explorations. In established cases of PHPT with equivocal preoperative localization studies or negative neck explorations, an ectopically placed parathyroid adenoma should be considered and once localized, should be surgically removed for cure.

Migration, medical education, and health care: a view from Pakistan.

PURPOSE: To review physician flows in Pakistan in the contexts of capacity to educate and provide for anticipated health needs. METHOD: Literature review was used to refine estimates and assumptions about physician supply and demand. Net physician supply was calculated from data on physician inflows and estimates of migration and other causes of physician loss. Projections of anticipated needs up to 2020 were calculated, assuming different levels of physician need or demand. Reasons for emigration were extracted from interviews, questionnaires, and reports; health indicators and migration figures were obtained from literature and Web sites. RESULTS: Approximately 74,000 physicians were practicing in Pakistan in 2005. Annually, local medical schools and international medical graduate certification provide 5,400 physicians, soon to reach 6,800; 1,150 physicians emigrate; and an estimated 570 physicians stop practicing for various reasons. The current ratio (0.473) of physicians to 1,000 population is inadequate to maintain the nation's health. Future Physician Workforce Shortages (PWSs) for Pakistan range between 57,900 and 451,102 physicians in 2020, depending on assumptions about future need. CONCLUSIONS: Pakistan cannot meet its needs for health care given the current levels of production and dependency on physicians in the organization of the system. Although outmigration contributes to the problem, it is the growing demand for health care from increases in population; adverse conditions that generate ill-health; and increasing expectations that dramatically increase the PWSs. The anticipated shortfall in Pakistan reflects a global pattern. Definition of physician roles and improvement of standards through refined assessment require serious consideration.

The genesis and correction of unprofessional behavior in surgeons: The role of society, education and genetics.

BACKGROUND: Most surgeons are ethical. Increasingly, however, a variety of unprofessional behaviors are surfacing. Awareness of these behaviors and their causation is required to plan their eradication. OBJECTIVES: To (i) identify the prevalent causes of unprofessional behaviors amongst surgeons; and (ii) suggest corrective interventions. METHODS: Literature was searched and models constructed to interpret interrelationships between causes. FINDINGS: Unprofessional behaviors extend beyond those frequently discussed, necessitating the term 'dysprofessionalism'. Causal influences arise from (i) an overpowering society; (ii) limited education and (iii) the underdeveloped state of human nature at birth. Societies corrupt by role-modeling avarice and encouraging industry-despite consequent pollution. Society brooks no interference. Surgeons are loath to oppose, resulting in an unprofessional silence. Surgical education based on best evidence is an indoctrination, with little opportunity to deploy alternatives. Evidence based guidelines increasingly risk errors, as publication fraud increases. Effective interaction with government/legislation is not taught. Human nature and our brain remain arrested in a stage of strongly stabilized evolutionary selection. Humans are born with larval brains requiring intense educational interventions. Genetic modification holds promise as it can circumvent birth in undeveloped states, and facilitate trans-generational transfer of knowledge. CRISPR/Cas-9 techniques make this possible, necessitating ethical discussion-an urgent issue. Reforming society would otherwise be an impossible task as behaviors cannot be taught in classrooms. CONCLUSION: Instances of dysprofessionalism are unlikely to diminish using current approaches. Discussion of the ethics of genetically modifying embryos is urgently needed, as this could provide a possible shortcut to positive changes in human behavior, but risks unwanted changes and misuse.

Is measurement of stone surface area necessary for SWL treatment of nonstaghorn calculi?

BACKGROUND AND PURPOSE: The size of urinary tract stones is usually assessed by the longest diameter (LD) alone. Logically, however, two-dimensional measurement of the stone surface area (SSA) susceptible to shockwaves would give more useful information for the planning of treatment by extracorporeal shockwave lithotripsy (SWL). This has been shown for staghorn calculi. The aim of this study was to determine for nonstaghorn kidney and ureter stones whether the LD alone identifies as reliably a subgroup of patients with a stone of a certain size as does the SSA. Furthermore, we sought to determine whether the LD alone indicates as reliably the number of patients who would be rendered stone free after one SWL session within a certain subgroup as would the SSA. PATIENTS AND METHODS: Retrospectively, SWL treatment and radiographic data of 330 patients who had undergone SWL for a single stone were analyzed. RESULTS: Ureteral stones were significantly smaller on average, and ureteral stone patients needed fewer SWL treatment sessions and fewer shockwaves to become stone free. Stratification of both kidney and ureteral stones by either LD or SSA resulted in comparable groups of patients. There were no significant differences in patient, stone, or treatment data. More importantly, the stone-free rates after one treatment did not differ significantly. CONCLUSION: The LD does accurately reflect the size of a nonstaghorn kidney or ureteral stones. Therefore, the measurement of LD, as generally practiced, appears clinically sufficient and appropriate for the assessment of stone size prior to SWL in both kidney and ureteral stones.

[Composition of renal stones currently observed in non-industrialized countries]. / Composition des calculs observés aujourd'hui dans les pays non industrialisés.

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.

Lifelong learning: Established concepts and evolving values.

OBJECTIVE: To summarise the concepts critical for understanding the content and value of lifelong learning (LL). METHODS: Ideas generated by personal experience were combined with those of philosophers, social scientists, educational institutions, governments and UNESCO, to facilitate an understanding of the importance of the basic concepts of LL. RESULTS: Autopoietic, continuous, self-determined, informal, vicarious, biographical, lifelong reflexive learning, from and for society, when supported by self-chosen formal courses, can build capacities and portable skills that allow useful responses to challenges and society's new structures of governance. The need for LL is driven by challenges. LL flows continuously in pursuit of one agenda, which could either be citizenship, as is conventional, or as this article proposes, health. LL cannot be wholly centred on vocation. Continuous medical education and continuous professional development, important in their own right, cannot supply all that is needed. LL aids society with its learning, and it requires an awareness of the environment and structures of society. It is heavily vicarious, draws on formal learning and relies for effectiveness on reflection, self-assessment and personal shaping of views of the world from different perspectives. CONCLUSION: Health is critical to rational thought and peace, and determines society's capacity to govern itself, and improve its health. LL should be reshaped to focus on health not citizenship. Therefore, embedding learning in society and environment is critical. Each urologist must develop an understanding of the numerous concepts in LL, of which 'biographicisation' is the seed that will promote innovative strategies.