Usefulness of hounsfield unit and density in the assessment and treatment of urinary stones

Computed tomography (CT) is widely used to examine stones in the urinary system. In addition to the size and location of the stone and the overall health of the kidney, CT can also assess the density of the stone in Hounsfield units (HU). The HU, or Hounsfield density, measured by CT, is related to the density of the tissue or stone. A number of studies have assessed the use of HU in urology. HUs have been used to predict the type and opacity of stones during diagnosis, and the efficacy has been assessed using methods including extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), ureterorenoscopic ureterolithotripsy (URSL), and medical expulsive treatment (MET). Previous studies have focused on the success rate of HU for predicting the type of stone and of ESWL treatment. Understanding the composition of the stone plays a key role in determining the most appropriate treatment modality. The most recent reports have suggested that the HU value and its variants facilitate prediction of stone composition. However, the inclusion of data regarding urine, such as pH and presence of crystals, increases the predictive accuracy. HUs, which now form part of the clinical guidelines, allow us to predict the success of ESWL; therefore, they should be taken into account when ESWL is considered as a treatment option. However, there are currently insufficient data available regarding the value of HU for assessing the efficacy of PCNL, URSL, and MET. Studies performed to date suggest that these values would make a significant contribution to the diagnosis and treatment of urinary system stones. However, more data are required to assess this further.     

Strategies to optimize shock wave lithotripsy outcome:Patient selection and treatment parameters

Shock wave lithotripsy(SWL) was introduced in 1980, modernizing the treatment of upper urinary tract stones, and quickly became the most commonly utilized technique to treat kidney stones. Over the past 5-10 years, however, use of SWL has been declining because it is not as reliably effective as more modern technology. SWL success rates vary considerably and there is abundant literature predicting outcome based on patient- and stone-specific parameters. Herein we discuss the ways to optimize SWL outcomes by reviewing proper patient selection utilizing stone characteristics and patient features. Stone size, number, location, density, composition, and patient body habitus and renal anatomy are all discussed. We also review the technical parameters during SWL that can be controlled to improve results further, including type of anesthesia, coupling, shock wave rate, focal zones, pressures, and active monitoring. Following these basic principles and selection criteria will help maximize success rate.     

Effect of urinary stone disease and its treatment on renal function

Urolithiasis is a common disease that affects urinary tract in all age groups. Both in adults and in children, stone size, location, renal anatomy, and other factors, can influence the success of treatment modalities. Recently, there has been a great advancement in technology for minimally invasive management of urinary stones. The epoch of open treatment modalities has passed and currently there are much less invasive treatment approaches, such as percutaneous nephrolithotomy, ureteroscopy, shockwave lithotripsy, and retrograde internal Surgery. Furthermore, advancement in imaging technics ensures substantial knowledge that permit physician to decide the most convenient treatment method for the patient. Thus, effective and rapid treatment of urinary tract stones is substantial for the preservation of the renal function. In this review, the effects of the treatment options for urinary stones on renal function have been reviewed.     

Percutaneous nephrolithotomy in pediatric age group: Assessment of effectiveness and complications

Management of kidney stone disease in pediatric population is a challenging condition in urology practice. While the incidence of kidney stone is increasing in those group, technological innovations have conrtibuted to the development of minimally invasive treatment of urinary stone disease such as mini-percutenous nephrolitotomy (mini-PCNL), micro-PCNL, ultra mini-PCNL. In this review we tried to evaluate the effect of new teratment techniques on pediatric kidney stones.     

清热补肾排石方对上尿路结石患者PCNL术后残石排出及尿液成分的影响

目的探究清热补肾排石方对上尿路结石患者经皮肾镜碎石术(PCNL)术后残石排出及尿液成分的影响。方法选取2017年10月至2019年4月在衢州市人民医院诊治的上尿路结石患者83例作为研究对象,按照随机数字表法分为观察组(n=42)和对照组(n=41)。对照组患者采用PCNL进行治疗,观察组在对照组的基础上采用清热补肾排石方进行治疗,比较两组患者的临床总有效率、中医症候积分、结石排净时间、住院时间,24h尿枸橼酸,以及尿草酸、尿钙水平。结果观察组患者的临床总有效率明显高于对照组,差异具有统计学意义(P<0.05);治疗后两组患者的中医症候积分明显低于治疗前(P<0.05),且观察组患者的中医症候积分明显低于对照组(P<0.05),差异均具有统计学意义;观察组患者的结石排净时间、住院时间明显少于对照组,差异均具有统计学意义(P<0.05);治疗后两组患者的24h尿枸橼酸水平明显高于治疗前,尿草酸、尿钙水平明显低于治疗前(P<0.05),且观察组患者的24h尿枸橼酸水平明显高于对照组(P<0.05),差异具有统计学意义,但两组患者治疗后的尿草酸、尿钙水平比较差异无统计学意义(P>0.05)。结论清热补肾排石方对上尿路结石患者具有显著的临床疗效,能有效促进残石排出,改善尿液成分。     

Unilateral hypoplastic kidney in adults: An experience of a tertiary-level urology center

BACKGROUNDUnilateral small-sized kidney is a radiological term referring to both the congenital and acquired causes of reduced kidney volume. However, the hypoplastic kidney may have peculiar clinical and radiological characterizations.AIMTo evaluate the clinical presentations, complications, and management approaches of the radiologically diagnosed unilateral hypoplastic kidney. METHODSA retrospective review of the records of patients with a radiological diagnosis of unilateral hypoplastic kidney between July 2015 and June 2020 was done at Assiut Urology and Nephrology Hospital, Assiut University, Egypt.RESULTSA total of 33 cases were diagnosed to have unilateral hypoplastic kidney with a mean (range) age of 39.5 ± 11.2 (19-73) years. The main clinical presentation was loin pain (51.5%), stone passer (9.1%), anuria (12.1%), accidental discovery (15.2%), or manifestations of urinary tract infections (12.1%). Computed tomography was the most useful tool for radiological diagnosis. However, radioisotope scanning could be requested for verification of surgical interventions and nephrectomy decisions. Urolithiasis occurred in 23 (69.7%) cases and pyuria was detected in 22 (66.7%) cases where the infection was documented by culture and sensitivity test in 19 cases. While the non-complicated cases were managed by assurance only (12.1%), nephrectomy (15.2%) was performed for persistent complications. However, symptomatic (27.3%) and endoscopic (45.6%) approaches were used for the management of correctable complications. CONCLUSIONUnilateral hypoplastic kidney in adults has various complications that range from urinary tract infections to death from septicemia. Diagnosis is mainly radiological and management is usually conservative or minimally invasive.     

Percutaneous nephrolithotomy vs laparoscopic ureterolithotomy for large upper ureteral stone: A review article

To investigate the best treatment option for large upper ureteral stone,percutaneous nephrolithotomy or laparoscopic ureterolithotomy.We searched three key word of upper ureteral stone,laparoscopic ureterolithotomy,percutaneous nephrolithotomy in PubM ed,Scopus and Ebsco.We found approximately twenty suitable articles about this subject since January 1980 until January2014.All articles studies and reviewed meticulously and brief review of these articles was written and some Ideas of experts was added.In many studies,it is suggested that success rate and complications of laparoscopic ureterolithotomy and percutaneous nephrolithotomy are the same,but percutaneous nephrolithotomy has less hospital stay time,duration of surgery and it is more cost effective.Overall it seems that percutaneous nephrolithotomy for treatment of upper ureteral stones is preferable rather than laparoscopic ureterolitothomy     

Primary and secondary hyperoxaluria: Understanding the enigma

Hyperoxaluria is characterized by an increased urinary excretion of oxalate. Primary and secondary hyperoxaluria are two distinct clinical expressions of hyperoxaluria. Primary hyperoxaluria is an inherited error of metabolism due to defective enzyme activity. In contrast, secondary hyperoxaluria is caused by increased dietary ingestion of oxalate, precursors of oxalate or alteration in intestinal microflora. The disease spectrum extends from recurrent kidney stones, nephrocalcinosis and urinary tract infections to chronic kidney disease and end stage renal disease. When calcium oxalate burden exceeds the renal excretory ability, calcium oxalate starts to deposit in various organ systems in a process called systemic oxalosis. Increased urinary oxalate levels help to make the diagnosis while plasma oxalate levels are likely to be more accurate when patients develop chronic kidney disease. Definitive diagnosis of primary hyperoxaluria is achieved by genetic studies and if genetic studies prove inconclusive, liver biopsy is undertaken to establish diagnosis. Diagnostic clues pointing towards secondary hyperoxaluria are a supportive dietary history and tests to detect increased intestinal absorption of oxalate. Conservative treatment for both types of hyperoxaluria includes vigorous hydration and crystallization inhibitors to decrease calcium oxalate precipitation. Pyridoxine is also found to be helpful in approximately 30% patients with primary hyperoxaluria type 1. Liver-kidney and isolated kidney transplantation are the treatment of choice in primary hyperoxaluria type 1 and type 2 respectively. Data is scarce on role of transplantation in primary hyperoxaluria type 3 where there are no reports of end stage renal disease so far. There are ongoing investigations into newer modalities of diagnosis and treatment of hyperoxaluria. Clinical differentiation between primary and secondary hyperoxaluria and further between the types of primary hyperoxaluria is very important because of implications in treatment and diagnosis. Hyperoxaluria continues to be a challenging disease and a high index of clinical suspicion is often the first step on the path to accurate diagnosis and management.     

Kidney stone matrix proteins: Role in stone formation

Stone formation is induced by an increased level of urine crystallization promoters and reduced levels of its inhibitors. Crystallization inhibitors include citrate, magnesium, zinc, and organic compounds such as glycosaminoglycans. In the urine, there are various proteins, such as uromodulin (Tamm-Horsfall protein), calgranulin, osteopontin, bikunin, and nephrocalcin, that are present in the stone matrix. The presence of several carboxyl groups in these macromolecules reduces calcium oxalate monohydrate crystal adhesion to the urinary epithelium and could potentially protect against lithiasis. Proteins are the most abundant component of kidney stone matrix, and their presence may reflect the process of stone formation. Many recent studies have explored the proteomics of urinary stones. Among the stone matrix proteins, the most frequently identified were uromodulin, S100 proteins (calgranulins A and B), osteopontin, and several other proteins typically engaged in inflammation and immune response. The normal level and structure of these macromolecules may constitute protection against calcium salt formation. Paradoxically, most of them may act as both promoters and inhibitors depending on circumstances. Many of these proteins have other functions in modulating oxidative stress, immune function, and inflammation that could also influence stone formation. Yet, the role of these kidney stone matrix proteins needs to be established through more studies comparing urinary stone proteomics between stone formers and non-stone formers.     

Confounding risk factors and preventative measures driving nephrolithiasis global makeup

Nephrolithiasis is increasing in developed and developing countries at an alarming rate. With the global spike in kidney stone diseases, it is crucial to determine what risk factors are influencing the current global landscape for kidney stones. Our aims for this review are: to identity and analyze the four categories of risk factors in contributing to the global scale of stone formation: lifestyle, genetics, diet, and environment; and discuss preventative measures for kidney stone formation. We also performed data search through the published scientific literature, i.e., PubMed^® and found that there is a significant link between lifestyle and obesity with cases of calcium stones. Food and Agriculture Organization of the United Nations and World Health Organization factor indicators for dietary intake and obesity, along with climate data were used to create the projected total risk world map model for nephrolithiasis risk. Complete global analyses of nephrolithiasis deplete of generalizations is nearly insurmountable due to limited sources of medical and demographic information, but we hope this review can provide further elucidation into confounding risk factors and preventative measures for global nephrolithiasis analysis.     

From crystalluria to kidney stones,some physicochemical aspects of calcium nephrolithiasis

Nephrolithiasis seems to be the result of crystal formation, aggregation and retention in the kidney during crystalluria. These processes have to occur within the short urinary transit time through the kidney being in the order of few minutes. Recently much work was done on rather qualitative aspects of nephrolithiasis like genetics, metabolism and morphology. In this review we try to provide some quantitative information on urinary supersaturation with respect to stone minerals, especially Ca oxalate (CaOx), on the formation and aggregation of CaOx crystals and on crystal retention in the kidney. The paper is centered on idiopathic Ca nephrolithiasis being the most frequent stone disease with only partially known pathogenesis. New aspects of the role of urinary macromolecules in stone formation and of the mechanism of crystal aggregation are provided.     

Retrograde intrarenal surgery in pediatric patients

Urinary tract stone disease is seen at a level of 1%-2% in childhood (< 18 years). In recent years, however, there has been a marked increased in pediatric stone disease, particularly in adolescence. A carbohydrate- and salt-heavy diet and a more sedentary lifestyle are implicated in this increase. Although stone disease is rare in childhood, its presence is frequently associated with metabolic or anatomical disorders or infectious conditions, for which reason there is a high possibility of post-therapeutic recurrence. Factors such as a high possibility of recurrence and increasing incidence further enhance the importance of minimally invasive therapeutic options in children, with their expectations of a long life. In children in whom active stone removal is decided on, the way to achieve the highest level of success with the least morbidity is to select the most appropriate treatment modality. Thanks to today’s advanced technology, renal stones that were once treated only by surgery can now be treated with minimally invasive techniques, from invasion of the urinary system in an antegrade (percutaneous nephrolithotomy) or retrograde (retrograde intrarenal surgery) manner or shock wave lithotripsy to laparoscopic stone surgery. This compilation study examined studies involving the RIRS procedure, the latest minimally invasive technique, in children and compared the results of those studies with those from other techniques.     

How botulinum toxin in neurogenic detrusor overactivity can reduce upper urinary tract damage?

Intradetrusor injections of botulinum toxin are the cornerstone of medical treatment of neurogenic detrusor overactivity. The primary aim of this treatment is to ensure a low pressure regimen in the urinary bladder, but the mechanisms leading to long-term protection of the urinary tract remain poorly understood. In this paper, we highlight the potential benefits of intradetrusor injections of botulinum toxin regarding local effects on the bladder structures, urinary tract infections, stone disease, vesico ureteral reflux, hydronephrosis, renal function based on a comprehensive literature review.     

Acute management of symptomatic nephrolithiasis

Over half a million patients present to emergency departments and nearly 3 million patients visit healthcare providers annually due to problems associated with urolithiasis.Despite updated guidelines from the American Urological Association and European Association of Urology for the evaluation and management of nephrolithiasis,considerable variability still exists regarding treatment for acute symptomatic upper urinary tract stones.Therefore,this article will review the current evaluation and management of acute symptomatic nephrolithiasis.Initial management includes analgesia and antiemetics.Additionally,a urinalysis and creatinine are required laboratory evaluations.Acute imaging with a non-contrast computed tomography(CT)scan is the diagnostic imaging modality of choice.However,concerns over radiation exposure have led towards low-dose and even ultra-low-dose protocols for the detection of urinary calculi.Low-dose non-contrast CT scans are now standard of care for the initial diagnosis of renal colic in patients with a body mass index≤30.Medical expulsive therapy is recommended for patients with a ureteral calculus10 mm and no signs of infection.Emergency urinary decompression is mandatory for a specific subset of patients,especially those with infection.Although limited data exists,emergency ureteroscopy or even shock wave lithotripsy may also betherapeutic options.     

膀胱结石对经尿道前列腺电切术手术后患者疗效的影响

目的：探讨膀胱结石对经尿道前列腺电切手术（TURP）患者疗效的影响。方法：回顾性分析本院泌尿外科2011年6月至2012年6月行TURP治疗的35例前列腺增生（BPH）合并膀胱结石患者及同期行TURP治疗的40例单纯性前列腺增生患者的临床资料,对比分析单纯性前列腺患者与合并膀胱结石患者术后1个月、3个月、6个月及12个月国际前列腺症状评分（IPSS）,并对膀胱结石形态、大小、数量对TURP的影响进行分析。结果：单纯BPH组患者术后1个月、3个月、6个月及12个月IPSS评分显著低于BPH合并膀胱结石组,差异有统计学意义（P＜0.05）。单纯BPH组IPSS改善率为62.50％,BPH合并膀胱结石组IPSS改善率为80.00％,差异有统计学意义（P＜0.05）。BPH 合并结石组残余尿量及前膀胱出口梗阻（BOO）无统计学差异,但多发结石组残余尿量及BOO高于单发结石组,大结石组残余尿量及BOO高于小结石组,差异有统计学意义（P＜0.05）。结论：膀胱结石是影响TURP术后预后的重要因素,术前积极治疗膀胱结石对改善BPH合并膀胱结石TURP术后症状具有积极意义。     

SCAD syndrome: A vicious cycle of kidney stones,CKD, and AciDosis

Cumulative evidence has shown that kidney stone formers are at high risk for developing end-stage renal disease(ESRD) and cardiovascular disease. The aim of this mini-review is to summarize the present knowledge about the close relationships among kidney stone formation, chronic kidney disease(CKD), and plasma and urine acidosis(SCAD). Part of the cause of the positive relationships between higher risk of developing ESRD and cardiovascular diseases in stone formers may be explained by inflammation and cell death due to the components of kidney stones. In CKD patients, acidic urine and loss of anti-crystallization factors may cause stone formation. Acidosis can promote tissue inflammation and may affect vascular tone. Correction of plasma and urine acidosis may improve renal and cardiovascular outcome of stone formers and CKD patients. More intensive and long-term interventions, which include correction of plasma and urine p H in patients with reduced renal function and correction of urine p H in patients with normal renal function, may be considered in treating patients with SCAD syndrome.     

Kidney stones over 2 cm in diameter-between guidelines and individual approach

The prevalence of urolithiasis has been observed to increase during last decades. Kidney stones over 2 cm in diameter are the common urologic problem. European and American Associations of Urology has published guidelines on Urolithiasis and presented the most effective tools to treat large stones. On the other hand many experienced endourologic centres choose other modalities from their armamentarium. All treatment methods are characterized by their efficacy and safety which are usually inversely proportional. It is crucial for patients and physicians to find a golden mean. Percutaneous lithotripsy is still considered treatment of choice with more than 95% efficacy. Less invasive retrograde intrarenal surgery is also less effective, but burdened with lower complication rate. Extracorporeal shockwave lithotripsy is feasible in paediatric patients with acceptable stone free rates. Open surgery(pylolithotomy and anatrophic nephrolithotomy) are almost obsolete techniques. All methods have their pros and cons. Physicians should share decisions regarding treatment modalities with patients.     

Epidermoid carcinoma and perforating necrobiosis lipoidica: a rare association

We report the case of a 33-year-old patient who had had insulin-dependent diabetes mellitus (IDDM) since he was 11 months old, and who presented with major perforating necrobiosis lipoidica (PNL) complicated by a well-differentiated epidermoid carcinoma. PNL is a rare clinical form of NL, always associated with diabetes. Only seven cases have been reported to date in the literature, and to the best of our knowledge, an association of epidermoid carcinoma and PNL has never been described. The development of a tumoral transformation on a classical NL plaque has only been described 12 times. The presence of an epidermoid carcinoma on a weakened background with permanent ulceration suggests that early surgical excision of the tumour and of the NL followed by a skin graft might be the treatment of choice. Radiotherapy seems to be a poor therapeutic option.     

Perioperative risk factors associated with delayed graft function following deceased donor kidney transplantation:A retrospective,single center study

BACKGROUND There is an abundant need to increase the availability of deceased donor kidney transplantation(DDKT)to address the high incidence of kidney failure.Challenges exist in the utilization of higher risk donor organs into what appears to be increasingly complex recipients;thus the identification of modifiable risk factors associated with poor outcomes is paramount.AIM To identify risk factors associated with delayed graft function(DGF).METHODS Consecutive adults undergoing DDKT between January 2016 and July 2017 were identified with a study population of 294 patients.The primary outcome was the occurrence of DGF.RESULTS The incidence of DGF was 27%.Under logistic regression,eight independent risk factors for DGF were identified including recipient body mass index≥30 kg/m²,baseline mean arterial pressure<110 mmHg,intraoperative phenylephrine administration,cold storage time≥16 h,donation after cardiac death,donor history of coronary artery disease,donor terminal creatinine≥1.9 mg/dL,and a hypothermic machine perfusion(HMP)pump resistance≥0.23 mmHg/mL/min.CONCLUSION We delineate the association between DGF and recipient characteristics of preinduction mean arterial pressure below 110 mmHg,metabolic syndrome,donorspecific risk factors,HMP pump parameters,and intraoperative use of phenylephrine.     

Occurrence of supernumerary nipples in children with kidney and urinary tract malformations

The reported data on the association of kidney and urinary tract malformations with supernumerary nipples are contradictory. We examined 200 children, ages 1 month-16 years, who were being followed because of recurrent urinary tract infection for supernumerary nipples. The patients were divided into two groups: those who were found to have urinary tract malformations on radiographic studies (n=92) and those who were not (n=108). All children were examined for any abnormal pigmentation along the milk line, and the entire body was examined for ectopic supernumerary nipples. Two of the children with proved urinary tract pathology and two of the children with no urinary tract pathology had supernumerary nipples. The odds ratio for having supernumerary nipples among the first group was 1.18 (95% CI: 0.084-16.53, p=0.627). Our results indicate no association between kidney and urinary tract malformations and supernumerary nipples. We believe the message to the practicing physician is that there is no need for radiographic or ultrasonographic investigation of the urinary tract in asymptomatic children found to have supernumerary nipples on routine physical examination.