Extended-spectrum beta-lactamase Escherichia coli and Klebsiella pneumoniae urinary tract infections.

The prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae urinary tract infections (UTIs) is increasing worldwide. We investigated the prevalence, clinical findings, impact and risk factors of ESBL E. coli/K. pneumoniae UTI through a retrospective review of the medical records of children with UTI aged <15 years admitted to Prince of Songkla University Hospital, Thailand over 10 years (2004-2013). Thirty-seven boys and 46 girls had ESBL-positive isolates in 102 UTI episodes, compared with 85 boys and 103 girls with non-ESBL isolates in 222 UTI episodes. The age of presentation and gender were not significantly different between the two groups. The prevalence of ESBL rose between 2004 and 2008 before plateauing at around 30-40% per year, with a significant difference between first and recurrent UTI episodes of 27.3% and 46.5%, respectively (P = 0.003). Fever prior to UTI diagnosis was found in 78.4% of episodes in the non-ESBL group and 61.8% of episodes in the ESBL group (P = 0.003). Multivariate analysis indicated that children without fever (odds ratio (OR) 2.14, 95% confidence interval (CI) 1.23-3.74) and those with recurrent UTI (OR 2.67, 95% CI 1.37-5.19) were more likely to yield ESBL on culture. Congenital anomalies of the kidney and urinary tract were not linked to the presence of ESBL UTI. In conclusion, ESBL producers represented one-third of E. coli/K. pneumoniae UTI episodes but neither clinical condition nor imaging studies were predictive of ESBL infections. Recurrent UTI was the sole independent risk factor identified.

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.

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.

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.

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.

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.

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.

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.

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.