Chung-Kwong Yeung

Fatal Interaction between Clarithromycin and Colchicine in Patients with Renal Insufficiency: A Retrospective Study

BACKGROUND Clarithromycin is frequently used to treat community-acquired pneumonia in elderly persons. Like erythromycin, it may interact with other drugs by interfering with metabolism by cytochrome P450 enzymes and with the P-glycoprotein transporter system. Colchicine, used for treatment of acute gout and for prophylaxis, may cause bone marrow toxicity. It is metabolized by CYP3A4 and is transported by P-glycoprotein. Initial case reports suggested potentially fatal interactions between clarithromycin and colchicine. METHODS A retrospective study was conducted with 116 patients who were prescribed clarithromycin and colchicine during the same clinical admission. Case-control comparisons were made between patients who received concomitant therapy with the 2 drugs and patients who received sequential therapy. We assessed the clinical presentations and outcomes of the 2 patient groups and analyzed the risk factors associated with fatal outcomes. RESULTS Nine (10.2%) of the 88 patients who received the 2 drugs concomitantly died. Only 1 (3.6%) of the 28 patients who received the drugs sequentially died. Multivariate analysis of the 88 patients who received concomitant therapy showed that longer overlapped therapy (relative risk [RR], 2.16; 95% confidence interval [CI], 1.41-3.31; P< or =.01), the presence of baseline renal impairment (RR, 9.1; 95% CI, 1.75-47.06; P<.001), and the development of pancytopenia (RR, 23.4; 95% CI, 4.48-122.7; P<.001) were independently associated with death. CONCLUSIONS Clarithromycin increases the risk of fatal colchicine toxicity, especially for patients with renal insufficiency. Since there are other drugs for treatment of pneumonia and gout, these 2 drugs should not be coprescribed, because of the risk of fatality.

Laparoscopic Kasai portoenterostomy for biliary atresia

Abstract.Conventional surgery for extrahepatic bile-duct atresia (EHBDA) usually requires a large, painful, muscle-cutting laparotomy, dislodgment of the liver, and wide manipulations, followed by adhesions and possible complications that may disturb the postoperative course and hamper liver transplantation (LT). The main role of laparoscopy in EHBDA has been for diagnostic purposes. Besides all the advantages of minimally-invasive access, it allows excellent visibility and dissection of tiny hilar structures. The authors present the first two cases of successful Roux-en-Y laparoscopic portoenterostomy (LARP) for EHBDA, showing the importance of advanced technical skills and a new approach for extracorporeal enteroanastomosis. Laparoscopic hilar dissection and portoenterostomy was accomplished using four trocars. The umbilical site was used for extracorporeal Roux-en-Y enteroenterostomy, in the first case using a laparoscopic stapler and in the second a hand-sewn suture. Mean operative time was 190 min, and no operative complications were observed. Both girls became anicteric. The first is doing well 15 months after the operation with good hepatic function. The other was anicteric for 6 months, had one episode of cholangitis, developed an umbilical hernia, has shown slow and progressive hepatic failure, and is now being evaluated for possible LT. It is concluded that LARP for EHBDA can be done safely in infants using an extracorporeal transumbilical enteric anastomosis, with several advantages compared with open surgery. The role of LARP in facilitating LT is yet to be defined.

Correlation between ultrasonographic bladder measurements and urodynamic findings in children with recurrent urinary tract infection

Authors from Hong Kong evaluated the role of ultrasonographically measured bladder variables in assessing bladder dysfunction in children with UTI. In a relatively large study, they confirmed the finding that the bladder volume and wall thickness index is a sensitive method for diagnosing bladder dysfunction in children.

Testicular catch-up growth after varicocele correction in adolescents.

Abstract We evaluated retrospectively the outcome of artery-sparing (AS) versus non-artery-sparing (NAS) laparoscopic varicocelectomy and measured any reversal of testicular growth. Twenty patients (13 left and 7 bilateral varicoceles) were evaluated after surgery. A total of 27 varicocelectomies (20 AS and 7 NAS) were performed. The indication for surgery was smaller testicular size on the affected side in all patients and discomfort/pain in 3. The mean age was 12.9 years (range 8–15 years) at surgery. The testicular volumes were determined clinically and by color Doppler sonography (US). The follow-up time was 6–48 months after surgery. There were 4 recurrences out of 27 varicocelectomies (15%), of which 1 has been reoperated. Testicular volumes were equal in both groups after surgery, indicating catch-up growth except in the cases with minor recurrences (2 AS and 2 NAS varicocelectomies). In 12 testes, dilated veins in the pampiniform plexus were revealed by US. No severe intraoperative complications occurred. Three patients had a hydrocele after surgery (11%). These data show that there is testicular catch-up growth after varicocelectomy, but some questions remain unanswered: (1) should the remaining dilated veins detected by Doppler US be tackled; and (2) is an AS operation worthwhile?

Potential utility of MRI in the evaluation of children at risk of renal scarring.

Background. Gadolinium-enhanced MRI has recently been employed in the diagnosis of acute pyelonephritis. Its potential utility in the diagnosis of renal scars in children is unknown. Objective. To evaluate the potential utility of MRI using fat-saturated T1-weighted (T1-W) and post-gadolinium, short-tau inversion-recovery (STIR) sequences in detecting renal scarring by comparison with technetium dimercaptosuccinic acid (99 mTc-DMSA) renal scintigraphy in children at risk of renal scarring. Materials and methods. A group of 24 children with spina bifida and neurogenic bladder or anorectal anomaly was studied. No patient had a history of acute pyelonephritis. Documented urinary tract infection (UTI) was present in 10 children (42 %). The remaining 14 (58 %) children had a history of asymptomatic bacteriuria. None had clinical signs or symptoms of acute UTI at the time of the study. 99 mTc-DMSA and MRI were performed to detect renal scarring. 99 mTc-DMSA scans were supplemented with pinhole imaging. MRI of the kidneys employed a fat-saturated T1-W sequence and a post-gadolinium STIR sequence employing a short echo time. Results. Of the kidneys studied, 33 % (n = 16) had evidence of a renal parenchymal defect suggestive of scarring on 99 mTc-DMSA. The concordance in the detection of a scarred kidney by post-gadolinium STIR sequence and 99 mTc-DMSA is 94 %; that by fat-saturated T1-W sequence and 99 mTc-DMSA is 82 %; that by both sequences (positive result on either sequence) and 99 mTc-DMSA is 100 %. Using 99 mTc-DMSA as the gold standard, MRI had a sensitivity of 100 % and a specificity of 78 % in the diagnosis of a scarred kidney. The concordance in the detection of a scarred zone by post-gadolinium STIR sequence and 99 mTc-DMSA is 68 %; that by fat-saturated T1-W sequence and DMSA is 44 %; that by both sequences (positive result on either sequence) and 99 mTc-DMSA is 84 %. MRI had a sensitivity of 84 % and a specificity of 86 % in the diagnosis of a scarred zone, using 99 mTc-DMSA as the gold standard. Conclusion. The detection rate for renal scarring on MRI using the fat-saturated T1-W and post-gadolinium STIR sequences is comparable to planar 99 mTc-DMSA. MRI is of potential utility in the evaluation of children at risk of renal scarring.

Nomograms of total renal volume, urinary bladder volume and bladder wall thickness index in 3,376 children with a normal urinary tract

BackgroundWe have previously shown that urinary bladder volume index (BVI = length × width × depth of bladder) and bladder volume wall thickness index (BVWI = BVI at full bladder/average bladder wall thickness) are useful indicators of bladder dysfunction in children with enuresis and urinary tract infection. These indices show a good correlation with urodynamic studies. We have expanded the study to include normal paediatric subjects with a wide age range. We illustrate a simple sonography protocol with nomograms of different parameters, which provide useful references for functional assessment in children with urological abnormalities.ObjectiveTo construct nomograms of total renal volume, maximum BVI and BVWI based on a Chinese paediatric population with age range from newborn to adolescence.Materials and methodsSonography was performed in consecutive children with normal urinary tracts on imaging, using a standardized protocol. Data were collected for construction of nomograms for different parameters.ResultsNomograms of total renal volume, BVI and BVWI were constructed based on 3,376 consecutive paediatric subjects. All parameters consistently increased with age.ConclusionNomograms of total renal volume, BVI and BVWI could provide useful references for studying bladder dysfunction in children using noninvasive dynamic sonography.

Sonic Hedgehog Mediator Gli2 Regulates Bladder Mesenchymal Patterning

PURPOSE Congenital bladder anomalies are a major challenge to pediatric urologists. Understanding the mechanism of bladder development is crucial for advancing patient treatment. Current evidence suggests that Shh (R&D Systems) is an epithelial signal regulating bladder development, although the mechanism of the regulation is still unclear. We examined the regulation of bladder mesenchymal development. MATERIALS AND METHODS Mutation analysis, immunohistochemistry, immunoblot, in situ hybridization, and primary cell culture and transfection were performed. The mesenchyma proximal to the epithelium was defined as the inner zone and that distal to the epithelium was defined as the outer zone. RESULTS We found that the Shh transcriptional factor Gli2 and the Shh target gene Bmp4 (R&D Systems) were expressed in the inner mesenchymal zone of the bladder, where active cell proliferation was observed. In Gli2(-/-) bladder primary mesenchymal cell cultures transfection with adenoviruses expressing DeltaNGli2, a constitutionally active form of Gli2, up-regulated Bmp4 expression and promoted cell proliferation. In the outer mesenchymal zone, where Gli2 and Bmp4 expression was not detectable, smooth muscle alpha-actin was expressed. In Gli2(-/-) embryo bladders Bmp4 expression in the inner zone was lost and ectopic smooth muscle was detected in the inner mesenchymal zone. Exogenous Bmp4 (10 ng/ml) in primary smooth muscle cell culture repressed smooth muscle differentiation and repression was partially rescued by the Bmp4 antagonist Noggin (R&D Systems) (300 ng/ml). CONCLUSIONS Our data suggests that the Shh transcriptional factor Gli2 regulates radial patterning of the bladder mesenchyma.

Laparoscopically assisted ureterocystoplasty

The concept of ureterocystoplasty, in this case laparoscopically assisted, is addressed by several authors from the USA. The details of their technique are described, and avoiding a large midline incision was found to be particularly beneficial to the patient.

Ureteric Jet Doppler Waveform and Bladder Wall Thickness in Children With Nocturnal Enuresis

To test the hypothesis that the presence of nocturnal enuresis is related to increased frequency of immature vesicoureteric function, which is further associated with detrusor overactivity, we compared the incidence of immature monophasic ureteric jet in children with and without nocturnal enuresis. The relationship between monophasic ureteric jet Doppler wave form and bladder wall thickness was further explored in the enuresis group. Ultrasound examinations were performed in 511 children suffering from nocturnal enuresis and 266 normal controls. Doppler wave forms of the ureteric jet on each side and the bladder wall thickness after voiding were recorded. Standard urodynamic studies were obtained in 203 enuretic children for correlations with ultrasound findings. There was a significant increase in the incidence of monophasic ureteric jet waveforms in enuretic children when compared with the controls (19.2% versus 6.4% on the right side, 19.2% versus 8.3% on the left side, all p < 0.01). Furthermore, immature monophasic waveforms were more commonly seen in the enuretic group with markedly thickened bladder wall. Enuretic children with bilateral immature ureteric jet waveforms and markedly thickened bladder wall showed multiple significant urodynamic abnormalities (p < 0.05). The above observations could be accounted for by immaturity of both vesicoureteric junction and detrusor muscle.

Pediatric pyeloplasty: 50 Patients with 59 hydronephrotic kidneys

A report of 59 hydronephrotic kidneys due to pelviureteric junction (PUJ) obstruction in 50 children less than 12 years of age is presented. Thirty-two percent of the patients were less than 1 year of age, with their main presenting feature being an abdominal mass (88%). For older children, loin or abdominal pain was the chief presenting symptom (68%). During infancy, the left and right sides were equally affected, followed closely by bilateral involvement. On the other hand, in older children, the left side was predominantly affected, being twice as common as the right, and the latter again was twice as common as bilateral involvement. Dismembered pyeloplasty was the procedure used in most cases (88%); the nephrectomy rate was 8% for grossly dilated or dysplastic kidneys. During follow-up (of 6 months to 10 years) of 54 pyeloplasties, improvement was seen in 36 (67%), 12 were unchanged (22%), and one reverted to normal (2%) after the initial operation. Two (4%) worsened initially but achieved stabilization after reoperation; the remaining 3 patients (6%) showed unsatisfactory results. Stents were used in 65% of the cases and nephrostomies in 53%.