Posterior urethral valve in thai boys

BACKGROUND

Posterior urethral valve (PUV) is the most common congenital bladder outlet obstruction in boys, causing renal damage beginning in utero. There are scarce data from Thailand regarding the long-term outcomes of PUV in boys, thus the aim of this study was to examine the presentation, clinical course, complications, outcomes and renal survival in PUV boys.

METHODS

We reviewed the medical records of PUV boys treated at the Pediatric Nephrology Clinic, Prince of Songkla University, Thailand, over a 30-year-period.

RESULTS

Seventy-seven PUV boys were identified, with a median age at diagnosis of 4.8 months. The most common presentations were urinary tract infection (UTI), poor urine stream and urinary dribbling in 26 (33.8%), 19 (24.7%) and 11 (14.3%) boys, respectively. Renal ultrasound results in 70 boys showed 8 (11.4%) unilateral and 56 (80%) bilateral hydronephroses. Of 72 voiding cystourethrograms, 18 (25.0%) showed unilateral and 22 (30.6%) bilateral vesicoureteral refluxes. 99mTc dimercaptosuccinic acid renal scans in 30 boys showed 12 (40%) unilateral and 8 (26.7%) bilateral renal damage. Fifty-nine (76.6%) boys had 149 UTIs; 42 (54.4%) had recurrent UTI. Forty-eight boys had valve ablation at the median age of 30.3 months. 22 boys (28.6%) developed chronic kidney disease (CKD) at a median age of 15.0 years.

CONCLUSION

Of 77 PUV Thai boys, UTI was the most common presentation. Recurrence of UTI and CKD was the most common consequence. Lifelong follow-up for renal and bladder functions is essential for all PUV patients.

Multi-population genome-wide association study implicates immune and non-immune factors in pediatric steroid-sensitive nephrotic syndrome

Pediatric steroid-sensitive nephrotic syndrome (pSSNS) is the most common childhood glomerular disease. Previous genome-wide association studies (GWAS) identified a risk locus in the HLA Class II region and three additional independent risk loci. But the genetic architecture of pSSNS, and its genetically driven pathobiology, is largely unknown. Here, we conduct a multi-population GWAS meta-analysis in 38,463 participants (2440 cases). We then conduct conditional analyses and population specific GWAS. We discover twelve significant associations-eight from the multi-population meta-analysis (four novel), two from the multi-population conditional analysis (one novel), and two additional novel loci from the European meta-analysis. Fine-mapping implicates specific amino acid haplotypes in HLA-DQA1 and HLA-DQB1 driving the HLA Class II risk locus. Non-HLA loci colocalize with eQTLs of monocytes and numerous T-cell subsets in independent datasets. Colocalization with kidney eQTLs is lacking but overlap with kidney cell open chromatin suggests an uncharacterized disease mechanism in kidney cells. A polygenic risk score (PRS) associates with earlier disease onset. Altogether, these discoveries expand our knowledge of pSSNS genetic architecture across populations and provide cell-specific insights into its molecular drivers. Evaluating these associations in additional cohorts will refine our understanding of population specificity, heterogeneity, and clinical and molecular associations.

Acute kidney injury and childhood acute myeloid leukemia

BACKGROUND

Acute kidney injury (AKI) appears to be particularly common in children with acute myeloid leukemia (AML), although the epidemiology data on this patient population is sparse. The objective of this study was to assess the prevalence and factors associated with AKI in childhood AML during chemotherapy treatment.

METHODS

The medical records of 112 children aged under 15 years diagnosed with AML who received chemotherapy in a major tertiary-care referral center in southern Thailand were reviewed. Logistic regression was used to identify factors associated with AKI.

RESULTS

Fifty-six (50%) children had AKI events. The median time from AML diagnosis to the first AKI was 29.5 days (interquartile range: 11.0-92.8) and the median follow-up time was 10.9 months (interquartile range: 3.6-31.1). Age at diagnosis ≥ 10 years (OR 2.75, 95% CI 1.09-6.93), glomerular filtration rate < 90 mL/min/1.73 m² at AML diagnosis (OR 7.58, 95% CI 1.89-30.5), and septic shock (OR 22.0, 95% CI 4.63-104.3) were independently associated with AKI.

CONCLUSIONS

Childhood AML has a high rate of kidney injury with 50% having AKI. Age ≥ 10 years at diagnosis, impaired kidney function before treatment, and septic shock were strongly associated with AKI. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hemolytic Uremic Syndrome Caused by Mycoplasma Pneumoniae Infection in Children: A Case Report and Literature Review

We describe the case of a 6-year-old boy with a Mycoplasma pneumoniae (M. pneumoniae) respiratory tract infection associated with thrombotic microangiopathic hemolytic anemia and thrombocytopenia with renal failure which was diagnosed as atypical hemolytic uremic syndrome. Renal biopsy showed features of thrombotic microangiopathy. The patient was treated with azithromycin for the M. pneumoniae infection, and supportive care with red cell transfusion and renal dialysis in the acute period. The microangiopathic hemolytic anemia and thrombocytopenia resolved within 2 months after diagnosis but the renal function damage was irreversible. The patient developed end-stage renal disease and required long term renal replacement therapy.

Childhood-onset systemic lupus erythematosus and immune thrombocytopenia: Prevalence and risk factors

BACKGROUND

There are few studies examining the prevalence and clinical risk factors for subsequent systemic lupus erythematosus (SLE) development after long-term follow-up in childhood immune thrombocytopenia (ITP). The aims of this study were to evaluate the prevalence and risk factors for subsequent SLE development in childhood ITP.

METHODS

The medical records of childhood ITP patients aged under 15 years in a major tertiary care center in Southern Thailand were retrospectively reviewed. The Kaplan-Meier method was used to estimate the cumulative probability of subsequent SLE development after ITP. Logistic regression analysis was used to identify independent risk factors for SLE development.

RESULTS

A total of 473 childhood ITP cases were included in the study. During a mean follow-up time of 6.1 ± 6.7 years, the prevalence of subsequent SLE development was 2.96%. Older age at ITP diagnosis (odds ratio [OR]: 1.24, 95% CI: 1.07-1.45) and chronic ITP (OR: 24.67, 95% CI: 3.14-100.0) were independent risk factors. The cumulative probabilities of subsequently developing SLE at 5 and 10 years after diagnosis of ITP were 3.8% (95% CI: 1.4-6.2) and 6.5% (95% CI: 2.9-9.8), respectively.

CONCLUSION

Older age at ITP diagnosis and chronic ITP were risk factors for subsequent SLE developed in childhood ITP.

A 30-year retrospective study on causes of death in childhood-onset systemic lupus erythematosus in a tertiary care centre in Southern Thailand

OBJECTIVES

We set out to determine the causes of death in childhood-onset systemic lupus erythematosus (cSLE).

METHODS

The medical records of children aged <18 years who were diagnosed with SLE from 1985 to 2016 in the Division of Nephrology, Department of Paediatrics, Faculty of Medicine, Prince of Songkla University, Thailand, were reviewed.

RESULTS

There was a total of 331 patients, 272 girls and 59 boys, of whom 77 (23.3%) died, 28.6% within the first year after diagnosis. Only 29 medical records of the 77 confirmed-death patients were available for evaluation of cause of death; 7 boys and 22 girls, with a mean age at presentation of 10.9±3.1 years. The mean follow-up duration was 4.6±3.7 (range 0.2-12.6) years. The major cause of death was sepsis (n=13 patients with 15 identified organisms, which were Acinetobacter baumannii (9), Escherichia coli (3), Candida albicans (2) and Aspergillosis (1)), followed by acute respiratory distress syndrome (ARDS) (6), severe heart condition (3), acute kidney injury (AKI) (2), chronic kidney disease (CKD) (2) and intracranial haemorrhage (1). Conditions at the time of death were sepsis (25), pneumonia (16), AKI (15), bleeding disorders (11), neurological complications (10), ARDS (10), CKD (4), AKI in addition to CKD (3).

CONCLUSIONS

The cause of death in cSLE is usually multi-factorial and it is difficult to assign a single dominant cause. Sepsis was the most common cause of death and, together with sepsis-related organ failure, was the most common condition at the time of death. The most common organism was Acinetobacter baumannii.

Characteristics and Findings of Childhood Urinary Tract Infection in the Last Decade

BACKGROUND

The strong association between kidney and urinary tract anomalies and childhood urinary tract infection (UTI) often leads to imaging tests being performed. -Objective: To describe the epidemiology, characteristics, and imaging findings in Thai children with UTI and compare results between boys and girls.

METHODS

We retrospectively reviewed the medical records of children with UTI aged < 15 years. Demographic characteristics and findings of investigations are presented.

RESULTS

One hundred seventy-eight boys and 170 girls with 432 UTI episodes were identified. The median (interquartile range) age at presentation was 1.4 (0.6-3.4) years, 1.0 for boys and 2.1 for girls (p < 0.001). Renal ultrasound, voiding cystourethrogram and 99mTc dimercaptosuccinic acid (DMSA) renal scans were performed in 273, 223 and 113 children, respectively. Overall, 283 children (81.3%) had at least one imaging study done and anomalies of the kidney and urinary tract were detected in 158 (45.4%). Primary vesicoureteral reflux was detected in 73 (32.7%) children. The remaining abnormalities were hydronephrosis (n = 54). DMSA scans detected 54 children with dysplastic or scarred kidneys.

CONCLUSIONS

First UTI in a group of Thai children occurred in approximately equal proportion in boys and girls but boys were younger at diagnosis. Kidney and urinary tract anomalies were detected in half of the children.

Improvement of survival rates in the last decade in Thai childhood-onset systemic lupus erythematosus

BACKGROUND

Morbidity and mortality in childhood onset systemic lupus erythematosus (SLE) is more severe than adult onset SLE. Long-term follow up is needed to determine the prognosis. The objectives of this study are to describe the mortality of childhood SLE in a single tertiary care centre over three decades, compare trends in survival over time, and determine predictors for survival.

METHODS

We retrospectively reviewed the medical records of children aged < 18 years who were diagnosed with SLE at the Department of Pediatrics, Songklanagarind Hospital, Thailand, from 1985 to 2016.

RESULTS

There were 331 children (272 girls, 59 boys) with a mean age at presentation of 11.5 ± 2.6 years. The mean follow-up duration was 7.0 ± 5.0 (range 1-28) years, 77 children (23.3%) died, 28.6% within the first year after diagnosis. The overall mortality rate was 3.3 per 100 person-years. Survival rates at 1, 5 and 10 years were 93.4%, 83.1% and 72.6%, respectively. Ten-year survival rates for the children diagnosed in the decades 1985-1996, 1997-2006 and 2007-2016 were 67.4%, 63.4% and 82.8%, respectively (p < 0.001). Boys had worse survival than girls (hazard ratio = 2.3, 95% CI: 1.4-3.7) even after adjusting for decade of diagnosis. Lupus nephritis (LN) class IV had similar survival compared to LN classes II/III/V combined (hazard ratio = 1.0, 95% CI: 0.6-1.7).

CONCLUSION

In our setting, the survival rate of childhood onset SLE has improved during the past 10 years, but mortality is still high compared to developed countries, particularly in boys.

What Did We Find From Imaging Studies in Childhood Urinary Tract Infection and Which Studies Are Mandatory?

OBJECTIVE

To evaluate the imaging results of childhood urinary tract infection (UTI) in our setting, and examine if it would be appropriate to apply the recent guideline changes regarding imaging studies as routine practice in Thailand.

METHODS

Medical records of children with UTI aged 0-15 years were reviewed, with focus on renal ultrasound (RUS), cystogram, and ^99mTc dimercaptosuccinic acid (DMSA) renal scan results to determine congenital anomalies of the kidney and urinary tract (CAKUT) and renal damage. Mild CAKUT was defined as primary vesicoureteral reflux grades I-III or isolated hydronephrosis, and all other abnormalities were defined as severe CAKUT.

RESULTS

A total of 142 boys and 129 girls had at least 1 imaging study after UTI. Their median (interquartile range) age was 1.0 (0.5-2.7) year: 0.7 and 1.4 years for boys and girls, respectively (P = .006). A total of 262 children had an RUS performed, of which 99 (37.8%) were abnormal. Cystograms were performed in 221 children, from which 83 (37.6%) CAKUTs were detected, and 108 children had a DMSA performed, of which 53 (49.1%) were abnormal. Overall, CAKUTs were detected in 148 (54.6%) children, of which 43 were severe. RUS together with cystogram provided higher sensitivity (100% vs 88.9%) and specificity (53.8% vs 42.4%) to detect severe CAKUT than RUS together with DMSA.

CONCLUSION

A CAKUT was detected in more than half of the children with first UTI, with one-third having severe CAKUT. In our setting, RUS combined with cystogram is still the most reliable way to detect potentially harmful post-UTI problems, and the new western guidelines are not appropriate.

Dengue hemorrhagic fever and the kidney

Dengue virus infection (DVI)/dengue hemorrhagic fever (DHF) is a common febrile illness with a variety of severities. The mortality rate is high in dengue shock syndrome (DSS), caused by circulatory failure due to plasma leakage resulting in multi-organ failure. However, acute kidney injury (AKI) is rarely reported. In areas of endemic DVI, the prevalence of AKI due to DVI has been reported to be as high as 6.0 % in children with AKI, and 0.9 % in children with DVI who were admitted to a hospital. The mechanism of AKI in DVI is not clear. It may result from (a) direct injury as in other infectious diseases, (b) an indirect mechanism such as via the immune system, since DHF is an immunological disease, or (c) hypotensive DSS, leading in turn to reduced renal blood supply and renal failure. The mortality rates of DF/DHF, DSS and DHF/DSS-related AKI are <1 %, 12-44 %, and >60 %, respectively. Kidney involvement is not actually that rare, but is under-recognized and often only reported when microscopic hematuria, proteinuria, electrolyte imbalance, or even AKI is found. The prevalence of proteinuria and hematuria has been reported as high as 70-80 % in DVI. A correct diagnosis depends on basic investigations of kidney function such as urinalysis, serum creatinine and electrolytes. Although DVI-related renal involvement is treated supportively, it is still important to make an early diagnosis to prevent AKI and its complications, and if AKI does occur, dialysis may be required. Fortunately, in patients who recover, kidney function usually completely recovers as well.

Primary vesicoureteral reflux: A 26-year experience in a single centre

AIM

To determine the nature of primary vesicoureteral reflux (VUR) and the association of VUR with hydronephrosis and renal damage.

METHODS

The medical records of children ≤ 15 years diagnosed with VUR, attending the Department of Pediatrics, Prince of Songkla University, Thailand between 1987 and 2013 were reviewed. Renal ultrasound and technetium-99m dimercaptosuccinic acid renal scan (DMSA) results were examined to determine the severity of hydronephrosis and renal damage, respectively.

RESULTS

There were 177 boys and 211 girls. 350 (90.2%) were diagnosed following urinary tract infection (UTI). The median (IQR) age at diagnosis of first VUR was 7.6 (4.3-12.2) months in boys and 18.6 (9.0-46.6) months in girls (P < 0.001). Renal ultrasound was performed in 340 patients. Hydronephrosis was found in 105 patients and 135 kidneys and 22.5% VUR kidneys and 11.0% non-VUR kidneys (P = 0.01). The severity of hydronephrosis was associated with VUR grade (44.2% of grades IV and V VUR had hydronephrosis vs 11.9% of grades I-III VUR, P < 0.001). DMSA was performed in 332 patients. Abnormalities were found in 30.1% VUR kidneys and 4.1% non-VUR kidneys (P < 0.001). Abnormal DMSA results were strongly associated with VUR grade (17.8% for VUR grades I-III vs 60.5% for VUR grades IV and V, P < 0.001).

CONCLUSION

Primary VUR in this group was most commonly diagnosed following investigation of UTI and detected during infancy, earlier in boys. Hydronephrosis and renal damage were associated with severity of VUR.

ELECTROLYTE DISTURBANCE AND KIDNEY DYSFUNCTION IN DENGUE VIRAL INFECTION

Dengue virus infection (DVI) is endemic in tropical countries in both children and adults. The classical presentation includes fever, hepatomegaly, thrombocytopenia-related bleeding disorders, and plasma leakage. Multi-organ involvement, including kidneys is found in complex cases. Asymptomatic electrolyte disturbances, abnormal urinalysis, and more severe manifestation such as acute kidney injury (AKI) usually indicate kidney involvement. Such manifestations are not rare in DVI, but are often not recognized and can cause the physician to misread the real situation of the patient. The prevalence of electrolyte disturbances or kidney involvement reported in studies varies widely by country and mainly depends on the severity of DVI and age of the patients. The prevalence of DVI-induced AKI ranges from 0.2%-10.0% in children and 2.2%-35.7% in adults. The prevalence among all age groups appears to be increasing in the last decade. Dengue shock syndrome (DSS) has been reported to be an independent risk factor for AKI development. The mechanism of DVI-induced AKI is complex and the details are to date undetermined. Urinalysis, serum electrolytes and creatinine measurements should be performed to document renal involvement in DVI patients for early detection and initiation of appropriate fluid therapy with close monitoring. Renal replacement therapy may be required in some cases. The presence of AKI dramatically increases the mortality rate among both childhood and adulthood DVI from 12%-44% to more than 60%.

Tuberculosis in SLE patients: rare diagnosis, risky treatment

We document three cases of tuberculosis (TB) in 237 systemic lupus erythematosus (SLE) patients. Their ages at SLE and TB diagnoses were 13/15, 10/25, and 13/24 years. All were female and in all the TB was diagnosed during a period of lupus flare-up when they were receiving prednisolone and other immunosuppressive drugs. All three patients had extrapulmonary TB: Two had miliary TB and one had disseminated TB through the muscles, left knee joint, and lungs. All three patients experienced anti-TB drug-induced hepatotoxicity manifesting as jaundice along with elevated transaminase enzymes from the first-line anti-TB drugs they received, leading to a change to second-line drugs in two of them. In conclusion, although TB in SLE patients is not common, it should be considered when a patient is nonresponsive to the SLE treatment. Higher rates of extrapulmonary TB and anti-TB drug-induced hepatotoxicity in SLE patients with TB were noted.

Pediatric lupus nephritis: more options, more chances?

Lupus nephritis (LN) is more common and severe in childhood-onset systemic lupus erythematosus (SLE) than in adults. It is one of the major causes of acute kidney injury (AKI) and chronic kidney disease (CKD) in children. Steroid therapy has been used as the first-line treatment for SLE since 1970, and has improved the survival of SLE patients from ∼ 50% to >80%. Over the years many immunosuppressive drugs, including pulse methylprednisolone, oral cyclophosphamide, pulse intravenous cyclophosphamide, mycophenolate mofitil, rituximab, and tacrolimus, have been combined with prednisolone, further improving survival rates to 90%-95%. However, the effectiveness of these drugs is still uncertain, as most seem very good in the beginning, but in studies examining longer-term follow-up the remission of disease does not remain. Fatal infection is still a major complication of aggressive chemotherapy, and the potential benefits as well as adverse events from each drug need to be considered. Induction of remission is the major aim of therapy, with safe and effective maintenance therapy for long-term remission. The survival rates of many published studies vary widely because of differences in patients and treatment modalities, severity of disease, renal histopathology, racial factors, and duration of follow-up. Finding the optimal treatment for SLE and related co-morbidities is highly challenging, and will likely involve a complex combination of different drugs for different patients in the search for giving them an opportunity to be free from this debilitating disease.

Childhood recurrent urinary tract infection in southern Thailand

INTRODUCTION

Recurrent urinary tract infection (UTI) is one of the major health problems in children because of its high rate of occurrence.

OBJECTIVE

Our aim of the study was to evaluate the prevalence and determine risk factors of recurrent UTI in Thai children.

PATIENTS AND METHODS

The medical records of children aged less than 15 years diagnosed with UTI at the Department of Pediatrics, Songklanagarind Hospital were reviewed.

RESULTS

A total of 307 children (144 boys, 163 girls) were followed up for at least 1 year. Fifty-six children, 31 (19.0%) boys and 25 (17.4%) girls, developed at least one recurrence totaling 153 recurrent UTI episodes. The recurrence rate was not statistically different between the sexes (p = 0.8). On multivariate analysis, genitourinary system (GU) anomalies, particularly vesicoureteral reflux (VUR), were the most significant risk factors. Children aged greater than 5 years had a slightly higher risk of recurrence, irrespective of gender. Comparison of organisms associated with recurrent UTI with those associated with first UTI showed that the prevalence of Escherichia coli decreased from 76.9% to 56.2% but was still the major causative agent. In contrast, the prevalence of Klebsiella pneumoniae and unusual or mixed organisms significantly increased from 7.8% to 15.0% and 6.2% to 16.3%, respectively.

CONCLUSION

One-fifth of children who had UTI developed recurrence and the rates were similar for males and females. Independent risk factors for recurrent UTI were found to be at age of >5 years and underlying disease of either GU anomaly or VUR.

Neonatal acute kidney injury in a tertiary center in a developing country

BACKGROUND

Acute kidney injury (AKI) is a common contributor to morbidity and mortality in newborns, with prevalences varying by population and hospital. A study of AKI in newborns in tertiary care centers in Thailand, a developing country with limited resources, has not been conducted yet.

METHODS

The aim of this study was to determine the prevalence of AKI in newborns in a tertiary care hospital in southern Thailand and to investigate the etiology, mortality and risk factors of mortality. The records of patients aged <30 days with high serum creatinine, admitted from 1984 to 2007, were retrospectively reviewed.

RESULTS

Eighty-eight boys and 51 girls were enrolled; 61.4% were premature and 56.5% had a birth weight <2500 g. The prevalence of newborn AKI increased from 0.9 to 6.3% during the 24-year study period. Thirty-nine and 65% had renal failure within 2 and 7 days post-birth, respectively. Sepsis was the most common cause of AKI (30.9%) followed by hypovolemia (18.7%), kidney, ureter and bladder (KUB) anomalies (12.2%), congestive heart failure (12.2%) and birth asphyxia (11.5%). Indomethacin caused AKI in 24.4% with gestational age <32 weeks. Sepsis-induced AKI had the highest mortality rate (65.1%) with an overall mortality rate of 38.8% and nearly 14 times the risk of death compared to hypovolemia-induced AKI.

CONCLUSIONS

The prevalence of newborn AKI in our Thai tertiary center over 24 years was 6.3% of admitted newborns. Sepsis was the most common cause of AKI and sepsis-induced AKI is the most common cause of death. Disease etiology was the only risk factor for mortality.

Twenty-two years' experience with childhood-onset SLE in a developing country: are outcomes similar to developed countries?

INTRODUCTION

The outcome of systemic lupus erythematosus (SLE) has dramatically improved since the introduction of corticosteroids; however, although many regimens of treatment have been supplemented, the mortality has not improved further.

OBJECTIVE

To describe the severity and outcome in patients diagnosed with SLE aged ≤18 years in a group of Thai children, compare gender and age differences, and our outcomes with those from developed countries.

METHODS

The authors retrospectively reviewed the files of patients aged ≤18 years diagnosed with SLE admitted to Songklanagarind University Hospital in southern Thailand, for the period 1985-2007. Patient survival rates were calculated.

RESULTS

There were 213 SLE patients, 41 males and 172 females, average age 11.6±2.6 years, with a median follow-up of 3.6 years. Outcomes were alive (109), lost to follow-up (22), referred (31) or deceased (51). Of the patients who were alive, 23 were not on any treatment, 59 were on prednisolone alone while 27 were on prednisolone plus some other immunosuppressive drug. Total survival rates were 88%, 76% and 64% at 2, 5 and 10 years, respectively. Males had significantly worse survival than females at 2 and 5 years (78% vs 91% and 58% vs 80%, respectively, p=0.018). There were no differences in mortality between age groups. The 5-year survival rates in the periods 1985-1993, 1994-2000 and 2001-2007 were not significantly different.

CONCLUSION

This retrospective study of patients with SLE in southern Thailand showed different outcomes compared to some studies and similar survival rates and treatment status to other studies, with one-fourth of surviving patients being free of medication.

Outcome of dengue hemorrhagic fever-caused acute kidney injury in Thai children

OBJECTIVES

To examine the outcome of acute kidney injury (AKI) in children with dengue hemorrhagic fever (DHF), the cause(s) of AKI, and the risk of AKI and fatality.

STUDY DESIGN

The medical records of patients age <15 years during 1989 to 2007 were reviewed. DHF-caused AKI and patients with DHF with no AKI were matched 1:2 by age.

RESULTS

DHF-caused AKI was clinically estimated to be 0.9% (25/2893) of admissions, with a high mortality rate of 64.0%. Risk factors of AKI were DHF grade IV and obesity (odds ratio, 16.9; 95% CI, 4.2 to 68.5, and odds ratio, 6.3; 95% CI, 1.4 to 28.8, respectively). Respiratory failure, hepatic failure, and massive bleeding were complications found in 80.0%, 96.0%, and 84.0% of cases with AKI, respectively. Fatality was more likely in cases with DHF grade IV, oliguric AKI, respiratory failure, or prolongation of prothrombin or activated partial thromboplastin time more than twice that of reference specimens. Among the survivors, none had chronic kidney disease, and serum creatinine levels returned to normal in 32 (1 to 48) days.

CONCLUSIONS

Patients with DHF and AKI had a high mortality rate, although those who survived had a full return to normal function within 1 month. DHF grade IV and obesity were the major risk factors of AKI.

Intravenous cyclophosphamide for lupus nephritis in Thai children

OBJECTIVE

To evaluate the efficacy of a 36-month course of intravenous cyclophosphamide therapy for severe lupus nephritis in Thai children between October 1993 and December 2000.

METHODS

Intravenous cyclophosphamide combined with oral prednisolone was given for 36 months to patients with systemic lupus erythematosus (SLE) who had severe renal involvement. Serum creatinine (Cr), creatinine clearance (CCr), urinary protein, C3, and complete blood count (CBC) were measured each visit for intravenous cyclophosphamide. Repeated measures ANOVA and Kaplan-Meier survival analysis were used.

RESULTS

Of 21 patients enrolled in the study, three died and two were lost to follow-up, leaving 16 patients who completed therapy (13 females and three males) with age at diagnosis 12.1+/-2.3 years (range 7.2-20.6 years). The follow-up period was 6.3+/-2.3 years (range 3.3-13.8 years). Fourteen patients had lupus nephritis WHO classification class IV and two had lupus nephritis WHO classification class II. Hypertension was detected in ten patients. Lowess smoothing curves and repeated measures ANOVA indicated no significant change in Cr and CCr [probability (p) > 0.05)], but significantly increased C3 and haemoglobin and significantly decreased urinary protein and white blood cell count (p < 0.001). Five patients had six episodes of acute renal failure; one died, renal function returned to normal in two patients, two continued to chronic renal failure, and one died of chronic renal failure. The 5-year survival and renal survival were 86.5% and 87.5% (95% CI 55.8-96.5% and 58.6-96.7%), respectively.

CONCLUSION

Intravenous cyclophosphamide in severe lupus nephritis in Thai children showed a satisfactory outcome with minimal complications. Further follow-up is needed.

Childhood chronic kidney disease in a developing country

We have retrospectively reviewed the records of children aged >1 month to 16 years who had been referred to the Department of Pediatrics of Prince of Songkla University's Faculty of Medicine, a tertiary referral center in Thailand, between 1982 and 2005 and subsequently diagnosed with chronic kidney disease (CKD). Our aim was to evaluate the prevalence and etiology of CKD in southern Thailand. There were 101 cases of CKD, with one case each diagnosed in 1988, 1989 and 1993, respectively, and 98 cases diagnosed between 1994 and 2005. These latter cases were divided into two 6-year periods: an early period (1994-1999), with 32 cases, and a later period (2000-2005), with 66 cases. The majority of this pediatric population with CKD were male (62/101, 61.4%). The etiologies of CKD were 35 cases of chronic glomerulonephritis (CGN) (34.7%), 29 of genitourinary tract (GU) anomalies (28.7%), nine of systemic lupus erythematosus (SLE) (8.9%), four malignancies (4.0%), four miscellaneous (4.0%) and 19 of unknown causes (18.8%). The patients were divided into age groups of <2 years (20 CKD patients), 2-6 years (15), >6-10 years (22), >10-13 years (20) and >13 years (24). The etiologies of CKD were significantly different in each age group, with GU anomalies and glomerulonephritis being the major causes of CKD in children aged <or=6 years (20/36, 55.6%) and >6 years (40/65, 61.5%), respectively. In conclusion, the incidence of CKD in our university hospital situation was not rare, with the prevalence doubling during the past 6 years, and the etiologies varying by age group.

Characteristics of primary vesico-ureteral reflux in Thai children

BACKGROUND

The purpose of the present paper was to evaluate the clinical features of primary vesico-ureteral reflux (VUR) in Thai children.

METHODS

Children with primary VUR attending in the Nephrology Division, Department of Pediatrics, Prince of Songkla University between 1987-2002 were studied.

RESULTS

Sixty-five girls and 60 boys with primary VUR were evaluated. Age of diagnosis was significantly younger in boys than girls (median 0.6 and 2.2 years respectively, P < 0.001). In 73% of boys and 34% of girls VUR diagnosis was made in the first year of life. Hydronephrosis was found in 22% of boys and 8% of girls (P = 0.004). Five per cent of children who had VUR grades I-III had hydronephrosis (6/121). Only children who had VUR grades IV and V had significant hydronephrosis: 33% (14/42) and 53% (10/19), respectively. Bilateral VUR was 60% overall and was significantly more common in boys (70% vs 40% P < 0.028), found in grades I-V at 33%, 61%, 60%, 65%, and 77%, respectively. Of 200 refluxing ureters, the total numbers of VUR grades I-V were 32, 37, 67, 45 and 19 respectively. VUR grade was significantly different by age (P = 0.014) but not by left-right side or sex.

CONCLUSION

Primary VUR occurs equally in boys and girls, but in boys at a younger age. Bilateral VUR and hydronephrosis were significantly more common in boys, and VUR in boys was more severe. But hydronephrosis is a poor indicator for VUR screening even in high-grade VUR.

Primary vesicoureteral reflux mediated renal scarring after urinary tract infection in Thai children

AIM

To evaluate the association between primary vesicoureteral reflux (VUR) and renal scarring in children using 99 m Technetium-labelled dimercaptosuccinic acid (DMSA).

METHODS

Children attending at Songklanagarind Hospital from 1987 to 2002 were evaluated.

RESULTS

Ages at diagnosis of VUR in 46 boys and 52 girls were 1.1+/-1.6 and 2.9+/-2.5 years, median 0.6 and 2.3 years, respectively (P<0.001). DMSA scans were performed at 4.1+/-3.6 years. Renal parenchymal damage was detected in 34 kidneys (22%) of 154 demonstrated refluxing ureters, and one kidney (2%) of 42 non-refluxing ureters (P=0.002). Of 79 refluxing ureters in boys and 75 refluxing ureters in girls, there were 25 and nine renal scars, respectively (32% and 12%, P=0.003). Renal scars in VUR grades I-V were 11%, 7%, 12%, 44% and 64%, respectively (P<0.001). Multivariate analysis revealed that high grade VUR (P<0.001), age of diagnosis of VUR greater than 5 years (P=0.001), and male gender (P=0.002) were the most significant risk factors for renal scarring.

CONCLUSION

High-grade VUR, age of diagnosis of VUR greater than 5 years and male gender were the most significant risk factors for renal scarring.

Peritoneal dialysis-related peritonitis in southern Thailand

OBJECTIVE

To evaluate peritonitis in children receiving peritoneal dialysis (PD) in southern Thailand.

PATIENTS AND METHODS

We reviewed the records of patients who received PD at the Department of Pediatrics, Prince of Songkla University from January 1994 to December 2003.

RESULTS

Forty-six patients had PD performed for 228.6 patient-months. Their mean age was 9.5+/-4.8 years (range 3.0 months-16.7 years). Twenty-eight patients had complications with 61 episodes of peritonitis. The age, sex and causes of renal failure did not display any differences between patients who had or did not have peritonitis (p=0.2, 0.6 and 0.6, respectively). The first peritonitis occurrence was on average at 2.7+/-4.0 patient-months (median 0.4, range 0-12.5) following catheter insertion, with an average incidence rate of one infection per 3.5+/-4.8 patientmonths (median 1.0, range 0-23.2). The causative agents were both gram-positive and gram negative bacteria, and fungi at 24%, 44%, and 8% respectively (24% of the cultures did not grow). There was no significant difference in causative agents between home- and hospital-acquired peritonitis (p=1.0).

CONCLUSION

PD-related peritonitis in this study occurred earlier and more often than in other studies, probably because all of our PDs were performed immediately after catheter insertion.

Timing of voiding cystourethrogram after urinary tract infection

Of the 363 Thai children upon whom a voiding cystouretrogram was performed, a vesicoureteral reflux was detected in 22.8% (17.1%-28.5%) of those for whom it was performed within 7 days (n = 215) of a urinary tract infection diagnosis and in 24.3% (17.4%-31.2%) of those for whom it was performed 7 days (n = 148) after diagnosis. There was no statistically significant difference in reflux prevalence between these two groups.

Urinary tract infection: one lingering effect of childhood kidney diseases--review of the literature

Urinary tract infection (UTI) is a possible warning sign of the presence of anomalies of the urinary tract. Following a UTI there is concern with recurrences which can contribute to scarring which may lead to hypertension, pregnancy-induced hypertension and even renal failure in later years. Prospective studies using 99mTc-labeled dimercaptosuccinic acid (DMSA) have shown that 30%-40% of children will have renal scarring after febrile UTI, regardless of the presence or absence of vesicoureteral reflux (VUR). Many studies have demonstrated that VUR is an important risk factor for renal scarring after UTI. Hypertension affects at least 10% of children with renal scarring, and in adults with reflux nephropathy (RN), the prevalence of hypertension is also much higher (38%-50%). UTI, pregnancy-induced hypertension (PIH) or renal function deterioration alone or in some combination has been reported to be as high as 39% in women with renal scarring. RN is one of the important causes of end-stage renal disease (ESRD) worldwide. Prevention of renal scar development should reduce the incidence of hypertension in patients as they age. The appropriate management of childhood UTI includes education of parents, patients and general physicians to be sure that everyone is aware of not only the current condition, but also the possibility of future UTI-related situations.

IN CONCLUSION

UTI itself is a warning sign of possible anomalies of the urinary tract, renal problems and/or chronic renal complications. Although VUR is primarily a disease of childhood, scarring from the disease can cause problems in later years, with the complicating factor that because only the renal scar remains, the VUR may be forgotten and not considered when diagnosing the current problem.

Outcome of conservative treatment of primary vesicoureteral reflux in 87 Thai children in a single center

AIM

To evaluate the outcome of primary vesicoureteral reflux (VUR) using conservative treatment.

METHODS

Eighty-seven children with primary VUR who had been treated with a conservative medical regimen and monitored through a yearly cystogram were recruited for the study. The study was conducted at the Pediatric Nephrology Clinic in Songklanagarind Hospital, the major tertiary care center in southern Thailand. Statistical analyses using Kaplan-Meier survival curves, chi-squared test, Fisher's exact test and multivariate analysis with Cox regression were performed.

RESULTS

The study group consisted of 41 boys and 46 girls, with a total of 133 VUR. The age of the boys was significantly lower than that of the girls (P < 0.001). Resolution of the low grades (grades I-III) of VUR was significantly more frequent than that of the high grades (grades IV-V) (68/95, 72%vs 14/38, 37%; P < 0.001). Using the Kaplan-Meier survival analysis and log-rank test, the resolutions of VUR in boys versus girls, and age <1 years versus >or=1 years were not significantly different (P = 0.2252 and 0.4756, respectively). Low-grade VUR and unilateral VUR had significantly higher probabilities of resolution than high-grade VUR and bilateral VUR, respectively (P = 0.0041 and 0.0467, respectively). Multivariate Cox regression analysis indicated that among low-grade VUR, boys and unilateral VUR had significantly higher probabilities of resolution. Among the high-grade VUR, neither sex nor laterality had a significant effect on the probabilities of VUR resolution.

CONCLUSION

This study offers more evidence that children with low-grade VUR have a higher chance of reflux resolution if they are boys and have only unilateral VUR. There is still no good guide for resolution of reflux in children with high-grade VUR.

Childhood acute renal failure: 22-year experience in a university hospital in southern Thailand

OBJECTIVES

The objectives of this study were to review the prevalence, cause, and morbidity and mortality rates of acute renal failure in a large tertiary care institution in southern Thailand, to examine any differences in acute renal failure cases diagnosed during a 22-year period, and to determine the risk factors indicating death.

METHODS

The case records for children 1 month to 17 years of age who were diagnosed as having acute renal failure between February 1982 and December 2004, in the Department of Pediatrics, Songklanagarind Hospital, in southern Thailand, were reviewed.

RESULTS

A total of 311 children with 318 episodes of acute renal failure were included, that is, 177 boys (55.7%) and 141 girls (44.3%), 1 month to 16.7 years of age (mean age: 7.6 +/- 5.1 years; median age: 7.8 years). The causes of acute renal failure in each age group were significantly different. Overall, sepsis was the major cause of acute renal failure, accounting for 68 episodes (21.4%), followed by hypovolemia, poststreptococcal glomerulonephritis, systemic lupus erythematosus, and infectious diseases. Renal replacement therapy was performed in 55 cases (17.3%). The overall mortality rate was 41.5%. Logistic regression analysis showed that disease groups and creatinine levels were significant independent predictors of outcomes.

CONCLUSIONS

The incidence of acute renal failure in Songklanagarind Hospital was 0.5 to 9.9 cases per 1000 pediatric patients, with a mortality rate of 41.5%. Sepsis was a major cause of acute renal failure and death. Causes of acute renal failure and serum creatinine levels were significant independent predictors of death.

Impaired differential renal function in a child with pheochromocytoma

We report a girl with extra-adrenal pheochromocytoma complicated with impaired renal function of the ipsilateral kidney, discussing aetiologies. A 14-year-old girl presented with uncontrolled hypertension, high urinary vanillylmandelic acid level and a 5 x 6 cm mass at the right renal hilum. Her blood pressure was under control with propranolol, prazosin, and nifedipine before surgery, and with sodium nitroprusside during surgical intervention. The total tumour removal required reconstruction of the right renal vein. Histopathology confirmed pheochromocytoma. Dimercaptosuccinic acid (DMSA) after surgery showed low uptake of isotope by the right kidney; it was unclear if this was due to the surgery or the tumour causing renal artery stenosis, but fortunately her blood pressure returned to normal thereafter. We recommend obtaining a DMSA in the preoperative evaluation of pheochromocytoma.

Congenital and infantile nephrotic syndrome in Thai infants

Congenital and infantile nephrotic syndrome reported from the Eastern world is rare and might be a different entity from that in the West. In a retrospective review of 10 nephrotic syndrome in Thai infants (5 girls and 5 boys), 7 were diagnosed with congenital nephrotic syndrome and 3 with infantile nephrotic syndrome. Two had congenital nephrotic syndrome secondary to congenital syphilis. All had edema, ascites, and failure to thrive. Of the 3 patients tested for thyroid function, all showed hypothyroidism. Two patients developed renal failure. Renal tissue was examined from 4 patients from 3 biopsies and 2 autopsies; only 1 patient showed tubular microcysts. Symptomatic therapy was performed concurrently with penicillin therapy in 2 patients having congenital syphilis. Prednisolone, cyclophosphamide, captopril, and enalapril were tried in some patients, with little effect. Five patients died from respiratory failure complicated by later infection, 1 patient died from renal failure, and 4 patients were lost to follow-up. Nephrotic syndrome in the first year of life in the Eastern world is rare. Prognosis of nephrotic syndrome in Thai infants at this time is still poor.

Simple estimation of the glomerular filtration rate in sick Thai children

The objective of this study was to establish an appropriate formula for the estimation of creatinine clearance (CCr) in sick Thai children, and to evaluate the accuracy of using the Schwartz formula. Children aged between 0 and 19 years with various diseases and varying levels of renal function (but remained stable) were studied. Height in centimetres (L) and weight in kilograms (W), time of urine collection and urine volume were measured to provide urine flow (mL/min (V)) measurements. Body surface area (m2; SA) was also assessed. Quantitative urinary and plasma creatinine concentration (UCr and PCr, respectively) were determined. Creatinine clearance was calculated by using the following formula: UCr x V x 1.73/(PCr x SA). The linear association between CCr and L/PCr derived from these data was compared with the Schwartz formula by using bootstrap statistics. One-hundred and sixty children were studied. A least squares straight-line regression through the origin of CCr against L/PCr provided a good fit to the data. Our dataset revealed no evidence of an age or sex affect on the relationship. Creatinine clearance was estimated by using the following formula: 0.465 x (L/PCr), in which the calculated 95% confidence interval of the coefficient was 0.44-0.49. A comparison of this coefficient with that for the Schwartz formula for children aged > or =1 year (0.55), using 1000 bootstrapped resamples, showed an incompatibility between the two coefficients (P < 0.00005). In conclusion, we suggest estimating CCr in sick Thai children of either sex by using a modification of the Schwartz formula in which the coefficient equals 0.465.

Recurrent abdominal and flank pain in children with idiopathic hypercalciuria

OBJECTIVE

To evaluate the role of idiopathic hypercalciuria (IH) as a cause of recurrent abdominal pain (RAP) in children.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of 124 children referred for various complaints who had 24-h urine calcium excretion greater than 2 mg/kg/d or random urine calcium-creatinine ratio greater than 0.18 mg/mg.

RESULTS

Fifty-two children with various clinical complaints had RAP or flank pain. These comprised of 22 males and 30 females, 9 mo to 15.9 y of age, mean 6.7 +/- 3.5 y. A family history of urolithiasis was present in 50% of all the children. Only 6 of the 52 children with abdominal pain had renal stones. In addition to abdominal pain, 27 children had hematuria and 10 had urinary incontinence. Mild metabolic acidosis was present in three children, parathyroid hormone activity elevated in two and serum vitamin D activity was increased in nine. All children were treated with increased fluid intake and a reduction in dietary sodium and oxalate and some required treatment with thiazide and antispasmodics. Forty-five cases responded to treatment, 5 failed to improve from therapy, and 2, which were not followed up as patients, were not available.

CONCLUSION

We describe 52 children with RAP or back pain due to IH and recommend that IH be considered in the differential diagnosis of RAP in childhood.

Urinary tract infection in children associated with idiopathic hypercalciuria

OBJECTIVE

The aim of this study was to evaluate the association of symptomatic non-calculous idiopathic hypercalciuria (IH) with urinary tract infection (UTI) in children.

MATERIAL AND METHODS

This was a retrospective case review of children who had urinary calcium excretion greater than 2 mg/kg/day or random urine calcium-creatinine ratio (UCa/UCr) greater than 0.18 mg/mg.

RESULTS

One hundred and twenty-four consecutive children with clinical complaints and elevated urine calcium excretion were reviewed. Fifty children (40%) had UTI of which 39 (78%) had recurrent UTI. There was no difference in age between children with UTI and those without UTI. Twenty-four-hour urine calcium and random UCa/UCr were also not different. Only 4 children (8%) had renal stones whereas hematuria, abdominal pain and urine incontinence were frequent associated findings. Six of the children with recurrent UTI (15%) had an anatomical urinary tract abnormality. Therapy in all children consisted of increased fluid intake and reduction in diet sodium and oxalate; however, 14 of the 39 children with recurrent UTI (36%) required therapy with a thiazide diuretic. Recurrent UTI was abolished in 24 children, one child had a single recurrence and 4 children had no response to treatment.

CONCLUSIONS

We propose that non-calculous IH may be an important contributing factor to recurrent UTI in children.

Urinary calcium excretion in healthy Thai children

The objective of this study was to determine age-specific reference values for urinary calcium/creatinine ratios (UCa/Cr) of children in southern Thailand. Non-fasting urine samples were collected from a random population of 488 healthy children (282 males, 206 females) ranging in age from 17 days to 15 years. Samples were divided into six groups by age. Subjects whose calcium levels exceeded the 95th percentile within each age group were classified as having hypercalciuria. Pyuria, hematuria, proteinuria, urinary sodium, and potassium levels in children with normal UCa/Cr were compared with levels in children with high UCa/Cr. The 95th percentiles for UCa/Cr (mg/mg) by age were: <6 months, 0.75; 6 months to <12 months, 0.64; 12 months to <2 years, 0.40; 2 years to <5 years, 0.38; 5 years to <10 years, 0.29; and 10 years to <15 years, 0.26. Pyuria, hematuria, and proteinuria were no more prevalent in the 22 children with hypercalciuria than in children with normal urinary calcium levels. Urinary sodium/creatinine ratios (UNa/Cr) and urinary sodium/potassium ratios (UNa/K) were correlated with UCa/Cr (r=0.41, P<0.0001 and r=0.24, P<0.0001, respectively). Urinary potassium/creatinine ratios (UK/Cr) were not (r=0.05, P>0.1)). Children with high UCa/Cr ratios also had higher UNa/Cr and UNa/K (5.6+/-7.1 vs. 2.6+/-1.5, P<0.001 and 5.4+/-2.3 vs. 2.5+/-0.23, P<0.05, respectively). The study established reference values for random, non-fasting UCa/Cr for healthy Thai children and indicated that urinalysis is not a good indicator of hypercalciuria.

Tubulointerstitial renal failure in childhood leptospirosis

We report three children with tubulointerstitial renal failure following leptospirosis. All had acute nonoliguric renal failure with mild hypocalemia and mild metabolic acidosis. Maximum blood urea nitrogen (BUN) and creatinine were 217 and 7.1 mg/dl, respectively, on the 6th day of disease, and no patient required dialysis. They presented with acute febrile illness and dehydration, and required intravenous fluid supplements. Myalgia, vomiting, and bleeding were found in two children. Abdominal pain, arthralgia, diarrhea, and conjunctival suffusion were found in one child. Only one child, who had an underlying disease of beta-thalassemia/Hb E, had jaundice, hepatosplenomegaly, anemia, and thrombocytopenia. Penicillin treatment was given in one case. All recovered, with normal renal function. The leptospirosis complement fixation test was used to confirm diagnosis. L. batavia was considered the etiologic agent in two of the children.

Non-fatal acute renal failure due to wasp stings in children

We report two children who developed acute renal failure after multiple wasp stings. Each case involved intravascular hemolysis which caused acute renal failure, volume overload, hypertension, anemia, hyponatremia, hyperkalemia, and metabolic acidosis. Peritoneal dialysis was required for short periods. The children recovered completely with blood urea nitrogen and creatinine returning to normal within 3 months. One child had a renal biopsy which showed mild tubulointerstitial nephritis. Although there is no specific treatment or antivenom, dialysis and supportive care have proved to be successful.

Djenkol beans as a cause of hematuria in children

BACKGROUND

Djenkolism is djenkol bean poisoning, characterized by acute renal failure, urinary obstruction and spasmodic pain. The effects of djenkol bean consumption on the urinary tract without overt symptoms and long-term outcome are not established. This paper examines the association between djenkol bean ingestion and urine abnormalities in school children.

METHOD

609 school children aged 7-11 years in five urban Hat-Yai schools were interviewed, and had their urine analyzed. All children included in the study had normal blood pressure for age, no illness (including respiratory tract symptoms) and were not taking medication.

RESULTS

78% of the children had a history of eating djenkol bean and of these 31% had done so in the past 24 h. Children with hematuria were almost four times (crude odds ratio = 3.7) as likely to have a history of eating djenkol beans as those with normal urine. Crystaluria and pyuria were not significantly more common among those eating the beans. The risk of having hematuria did not change with increasing consumption, or time since last eaten, or type of preparation even after adjustment for sex and age.

CONCLUSION

Djenkol bean consumption may be defined as one of the probable causes of hematuria in the area where the djenkol tree grows.

Absence of DA1/DA2 dopamine receptor interactions in proximal tubules of spontaneously hypertensive rats

The impact of defective DA1 dopamine receptors in proximal tubules (PT) of the spontaneously hypertensive rat (SHR) on DA1/DA2 receptor interactions was assessed with the DA1-selective photoaffinity ligand, (+/-)-7-[125I]iodo-8-hydroxy-3-methyl-1-(4-azidophenyl)- 2,3,4,5-tetrahydro-1H-3-benzazepine ([125I]MAB). In PT membranes from both normotensive (Wistar-Kyoto, WKY) and spontaneously hypertensive rats (SHR), [125I]MAB was specifically incorporated into a polypeptide with an M(r) of 74,000 Da, corresponding to the DA1 receptor. The labeling of this band by [125I]MAB in both SHR and WKY was not prevented by SKF-82526, a potent DA1-selective agonist. However, in the presence of the DA2 antagonist, (-)-sulpiride, but not DA2 agonist, LY-171555, SKF-82526 abolished photoincorporation of [125I]MAB into the 74,000-Da band in WKY. In SHR, (-)-sulpiride failed to enhance the ability of SKF-82526 to compete with [125I]MAB for binding to the 74,000-Da subunit. In competition binding studies with SKF-82526, (-)-sulpiride induced the formation of agonist high-affinity binding sites in WKY but not in SHR. These data suggest that in membranes of SHR, but not WKY, DA1/DA2 dopamine receptor interactions are lacking.

Alpha 1B-adrenergic receptors in rat renal microvessels

Although several alpha-adrenergic receptor genes are expressed in the rat kidney, their expression in the renal vasculature has not been studied. Since pharmacological studies have suggested that an alpha 1B-adrenergic receptor may mediate renal vasoconstriction, we studied the expression of alpha 1B-adrenergic receptors in renal microvessels, from 10- to 14-week-old male spontaneously hypertensive rats (SHR) and their normotensive control, the Wistar-Kyoto rat (WKY). In these microvessels, isolated by perfusion with iron, alpha 1B-adrenergic receptor mRNA levels (by ribonuclease protection assay) were similar in SHR and WKY rats. Photo-affinity labeling with [125I]-arylazidoprazosin demonstrated the presence of alpha 1B-adrenergic receptor protein. Maximum receptor density (determined by 3H-prazosin binding: Bmax 59.8 +/- 4.1 and 58.7 +/- 4.3; Kd 0.48 +/- 0.05 nM and 0.31 +/- 0.06 nM in SHR and WKY, respectively) and chloroethylclonidine (CEC)-sensitive binding sites (determined by [125I]-(2-beta(4-hydroxyphenyl)-ethylaminomethyl)-tetralone binding) (125I-HEAT) were similar in SHR and WKY rats. There are two novel findings in these studies: (1) the alpha 1B-adrenergic receptor gene is expressed in renal microvessels of WKY and SHR; (2) alpha 1B-adrenergic receptor gene expression in renal microvessels is not altered in adult SHR. The failure to down-regulate expression of the alpha 1B-adrenergic receptor at the mRNA and protein level in the SHR could result in persistence of alpha 1B-adrenergic receptor effects and contribute to the increased vascular resistance in hypertension.

Differences in photoaffinity labeling of DA1 receptors in renal proximal tubules from normotensive rat and SHR

Renal DA1 dopamine receptors in proximal tubule membranes of normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) were characterized with the novel D1 dopamine receptor-selective photoaffinity probe, (+/-)-7-[125I]iodo-8-hydroxy-3-methyl-1-(4-azidophenyl)-2,3,4,5- tetrahydro-1H-3-benzazepine ([125I]MAB). Under nonphotolyzing conditions, saturation studies showed that [125I]MAB bound with similar affinity to DA1 dopamine receptors in both WKY [dissociation constant (Kd) = 16.3 nM] and SHR (Kd = 19.5 nM). At photolysis, [125I]MAB was irreversibly incorporated into a single major protein of 74,000 Da in both WKY and SHR. DA1-selective antagonists blocked photolabeling of DA1 sites with similar efficiency and specificity in SHR and WKY. However, under identical assay conditions, dopaminergic agonists were unable to block photoincorporation of [125I]MAB in SHR but not in WKY. This pattern of labeling of DA1 sites by [125I]MAB may suggest the presence of defective agonist, but not antagonist, binding domains on the receptor in SHR but not in WKY rats.

Acute renal failure in a child associated with acyclovir

A 9-year-old boy developed acute renal failure following intravenous acyclovir (30 mg/kg per day) administered for 6 days to treat herpetic encephalitis. Physical findings and urine output were normal, except for increasing blood urea nitrogen (BUN), serum creatinine and mild proteinuria. Acyclovir was discontinued. However BUN and serum creatinine continued to increase and peaked on the following day at 8.6 mmol/l of urea (24 mg/dl) and 194 mumol/l (2.2 mg/ml), respectively. Conservative treatment and hydration were carried out. The kidney function returned to normal within 1 week. The use of acyclovir when necessary in renal failure patients is discussed.

Severe hyperphosphatemia following acute tumor lysis syndrome

We report on a 14-year-old boy with acute lymphoblastic leukemia (lymphoma-leukemia) who had two episodes of acute tumor lysis syndrome during induction of remission with oral prednisolone alone and oral prednisolone, intravenous vincristine, and doxorubicin, respectively. Subsequently he had severe hyperphosphatemia (29.3 and 14.1 mg/dl; 9.46 and 4.55 mmol/L), hypocalcemia, hyperuricemia, hyperkalemia, and azotemia. Multiple stones and tumor cells infiltration were demonstrated in both kidney. He responded favorably to hemodialysis.

Urinary incontinence due to idiopathic hypercalciuria in children

Idiopathic hypercalciuria is known to cause many nonstone urinary tract disorders in childhood. In addition to being the most common cause of microhematuria in children, our study demonstrates that idiopathic hypercalciuria is also frequently associated with urinary incontinence of all types. Of 124 children evaluated for idiopathic hypercalciuria 28 (23%) had urinary incontinence. Of the 28 children 15 (54%) had nocturnal, 6 (21%) diurnal, and 7 (25%) nocturnal and diurnal incontinence. The random urinary calcium-creatinine ratio, which was used to screen for hypercalciuria, should be part of the initial evaluation for urinary incontinence in children. Diagnosis may be confirmed by quantitative urinary calcium excretion. Most urinary incontinence in children that is due to idiopathic hypercalciuria responds to a combination of general treatment for hypercalciuria or thiazide diuretics.

Induction of G protein-independent agonist high-affinity binding sites of D-1 dopamine receptors by beta-mercaptoethanol

We have purified the D-1 dopamine receptor 8200-fold to 78% purity from rat striatal membranes. Critical to this purification was the N-ethylmaleimide (NEM)-mediated alkylation of all endogenous sulfhydryl groups, except those associated with the D-1 dopamine receptors, which were protected by the D-1 agonist SKF R-38393. Such NEM treatment of D-1 receptors abolished all agonist high-affinity binding sites of the receptors, but did not alter the antagonist binding properties. When NEM-treated D-1 receptors were affinity-purified by mercury-agarose columns, the pharmacological properties of these purified receptors were examined, after removal of beta-mercaptoethanol (beta ME), which was used for elution of receptors from the affinity column. Purified D-1 receptors displayed typical dopaminergic antagonist binding values; however, agonists bound to the purified receptors with only high-affinity binding values, despite the prior absence of high-affinity sites in crude soluble extracts of NEM-treated receptors. The agonist high-affinity binding of purified D-1 receptors was insensitive to modulation by the GTP analog Gpp(NH)p and occurred in the absence of any G proteins. These Gpp(NH)p-insensitive high-affinity sites appeared to be induced by beta ME, since similar high-affinity binding was also restored by beta ME to crude soluble and membrane-bound receptors, which had been pretreated with NEM. The ability of D-1 dopamine receptors to bind with high-affinity to agonists in the absence of functionally active G proteins may be an intrinsic property of the reduced state of D-1 dopamine receptors.