The Clinical Usefulness of Cystatin C in Evaluating Renal Function in Children with Various Renal Diseases

PURPOSE: GFR(glomerular filtration rate) is a fundamental parameter in detecting renal impairment and predicts the progression of renal disease. Because serum creatinine has several disadvantages, serum cystatin C has been recently proposed as a new endogenous marker for GFR. We compared serum cystatin C with creatinine and creatinine clearance to investigate the clinical usefulness of cystatin C. METHODS: We retrospectively analyzed 46 patients(60 case numbers) who had various renal diseases and classified them into 3 groups according to creatinine clearance(Group 1 : CrCl 60 mL/min/1.73 m2). We measured serum creatinine, cystatin C and creatinine clearance and also analyzed the correlations among them. RESULTS: Serum cystatin C and creatinine showed a similar correlation to creatinine clearance (r=0.685, r=0.640, respectively) and showed similar diagnostic accuracy in detecting decreased GFR(AUC, cystatin C 0.829 vs. creatinine 0.826, P=0.848). Serum cystatin C showed a greater sensitivity for detecting a decreased GFR than creatinine in Group 2 and 3(Group 1 : 100% vs. 100%, Group 2 : 70% vs. 35%, Group 3 : 46% vs. 15%). CONCLUSIONS: Serum cystatin C could be a useful endogenous marker for GFR and would be superior to serum creatinine in early detection of renal impairment in pediatric patients with renal diseases.

Outcome and Prognosis in Critically Ill Children Receiving Continuous Renal Replacement Therapy

PURPOSE: Continuous renal replacement therapy(CRRT) has been the first choice for the treatment of acute renal failure in critically ill children not only in western countries but also in Korea. However, there are very few studies that have analyzed the outcome and prognosis of this modality in Korean children. We performed this study to evaluate the factors associated with the outcome and prognosis of patients treated with CRRT. METHODS: We retrospectively reviewed the medical records of 32 children who had received CRRT at Severance hospital from 2003 to 2006. The mean age was 7.5 years(range 4 days- 16 years) and the mean body weight was 25.8 kg (range 3.2-63 kg). RESULTS: Eleven(34.4%) of the 32 patients survived. Bone marrow transplantation and malignancy were the most common causes of death and underlying disease leading to the need for CRRT. Mean patient weight, age, duration of CRRT, number of organ failures, urine output, estimated glomerular filtration rate(eGFR), C-reactive protein, and blood urea level did not differ significantly between survivors and nonsurvivors. (1) Pediatric risk of mortality(PRISM) III score at CRRT initiation(9.8+/-5.3 vs. 26.7+/-7.6, P<0.0001), (2) maximum pressor number (2.1+/-1.2 vs. 3.0+/-1.0, P=0.038), and (3) the degree of fluid overload(5.2+/-6.0 vs. 15.0+/-8.9, P=0.002) were significantly lower in survivors than in nonsurvivors. Multivariate analysis revealed that fluid overload was the only independent factor reducing survival rate. CONCLUSION: CRRT was successfully applied to the treatment of acute renal failure in a wide range of critically ill children. To improve survival, we suggest the early initiation of CRRT to prevent the systemic worsening and progression of fluid overload in critically ill children with acute renal failure.

Renal manifestations in tuberous sclerosis complex / 소아과

PURPOSE: The renal manifestations of tuberous sclerosis complex (TSC) are remarkably diverse, including polycystic kidney disease, simple renal cysts, renal cell carcinomas, and angiomyolipomas. All of these occur in children as well as adults in TSC. Angiomyolipomas, which can cause spontaneous life-threatening hemorrhages, are by far the most prevalent and the greatest source of morbidity. Here, we will address our experience, adding to the literature on pediatric patients with TSC requiring evaluation and treatment for renal manifestations. METHODS: A retrospective analysis was made on 19 patients in whom TSC was diagnosed between May 2001 and Oct. 2005 at Severance Hospital. All patients had clinical diagnoses of TSC as defined by the 1998 tuberous sclerosis complex consensus conference. RESULTS: The patients consisted of 13 boys and 6 girls with a mean age of 7.3 years (range 1 to 22). The renal disease associated with TSC included angiomyolipoma in nine patients (47.4 percent), renal simple cyst in one (5.3 percent), hydronephrosis in one (5.3 percent) patient. Eight patients (42.1 percent) presented with normal kidney contours at abdominal ultrasonography. One patient underwent renal replacement therapy due to chronic renal insufficiency after nephrectomy. Hemorrhage from angiomyolipoma was not detected. CONCLUSION: In our review of 19 cases of TSC, renal manifestations are reported in 57.9 percent of patients. Asymptomatic angiomyolipoma associated with TSC grow gradually, although severe hemorrhages are rare. So patients with TSC should be followed up with serial computerized tomography or abdominal ultrasonography. And also, renal function should be monitored conservatively.

A Case Report of Acute Pancreatitis Caused by Mycoplasma Pneumoniae Infection / 대한소아소화기영양학회지

Acute pancreatitis is associated with a wide variety of infectious agents including mumps, hepatitis B virus, Coxsackie virus, Mycoplasma, Legionella, Aspergillus and Toxoplasma. There are a few reports of acute pancreatitis caused by Mycoplasma pneumoniae infection abroad, but rare in Korea. We treated a case of acute pancreatitis in a 13-year-old girl who presented with nausea, vomiting, diarrhea and severe abdominal pain. The clinical and laboratory findings led to the diagnosis of acute pancreatitis; the cause was confirmed by serological evidence of mycoplasma pneumoniae infection. We report acute pancreatitis caused by mycoplasma pneumoniae infection and review the literature.

Clinical Outcome of Multicystic Dysplastic Kidney in 46 Children

PURPOSE: Conservative management of multicystic dysplastic kidney(MCDK) without nephrectomy has recently been advocated. The purpose of this study was to determine the clinical course of conservatively managed MCDK and to find out possible predictive factors for involution of MCDK by ultrasonography(US). METHODS: A retrospective analysis was made on 46 patients(26 boys and 20 girls) in whom MCDK was detected and had been traced by US between Dec. 1993 and Aug. 2005 at Severance Hospital. RESULTS: Median follow-up time was 30 months(range 2-102 months). All patients underwent radionuclide scans and voiding cystourethrograms. The serial follow-up US showed complete involution in 11(24%), partial involution in 19(41%), and no interval change or increased in cyst size in 13(28%) patients. Nephrectomy was done in 3 patients(7%) due to relapsing urinary tract infection(UTI) and severe abdominal distension. The mean age of complete involution of MCDK was 37 months(range 12-84 months). Episodes of UTI were present in 17 patients(37%) and additional genitourinary(GU) abnormalities were found in 22 patients(44%). Hypertension and renal insufficiency was complicated in one patient. No child developed malignant tumor. Univariate analysis showed that five variables were associated with complete involution of the MCDK; gender, site, UTI episode, additional GU abnormalities, and renal length on initial US. After adjusting using the Pearson model, the presence of additional GU abnormalities was exclusively associated with complete involution among the 5 variables(P=0.034). CONCLUSION: In our review of 46 cases of MCDK, non-surgical approach for patients with MCDK was advisable and we could predict poor prognosis when MCDK is associated with other GU anomalies.

A Case of ANCA-associated Pauci-immune Crescentic Glomerulonephritis in Juvenile Rheumatoid Arthritis

Juvenile rheumatoid arthritis(JRA) is the most common major connective tissue disease in children. Renal involvement in JRA is rare. Among the renal lesions that have been reported in JRA, amyloidosis and drug-induced nephropathy are the most common. Crescentic glomerulonephritis in JRA has rarely been reported. We report a case of ANCA-associated pauci-immune crescentic glomerulonephritis in JRA. The patient was a 15-year old boy with a 3-year history of JRA. He presented with gross hematuria, proteinuria, positive p-ANCA and elevation of BUN and creatinine. Pathologic findings revealed focal necrotizing and crescentic glomerulonephritis. There were no significant immunoglobulin or complement deposits. His renal function recovered after intravenous methylprednisolone pulse therapy and oral steroid use. In Korea, this is the first reported case of pauci-immune crescentic glomerulonephritis in JRA.

Flow Velocity of Left Renal Vein in Children with Asymptomatic Hematuria or Proteinuria

PURPOSE: Nutcracker syndrome must be considered when hematuria or proteinuria occurs in a healthy child. The purpose of this study is to investigate the prevalence of nutcracker syndrome among children with asymptomatic hematuria or proteinuria, and to obtain the ratios of the peak velocity of the left renal vein between the aortomesenteric portion and the hilar portion in children with asymptomatic hematuria or proteinuria in which nutcracker syndrome was excluded and to observe whether the ratios are affected by sex, age or urinalysis findings. METHODS: Using Doppler ultrasonography, we measured the flow velocity and obtained the peak velocity ratios of the left renal vein at the aortomesenteric portion and at the hilar portion of the left kidney in children with asymptomatic hematuria or proteinuria who visited the Division of Pediatric Nephrology, Severance Hospital from May 2001 to March 2004. RESULTS: Of 304 children with asymptomatic hematuria or proteinuria, 107 children(35.2%) were diagnosed with nutcracker syndrome. For 197 children with asymptomatic hematuria or proteinuria excluding nutcracker syndrome, the mean ratio of the peak velocity was 2.54+/-0.73, which was not affected by sex, age or urinalysis findings. CONCLUSION: Nutcracker syndrome was the major cause of asymptomatic hematuria or proteinuria in children, comprising 35% of all cases. Doppler ultrasonography was helpful in the screening of nutcracker syndrome and prevention of its complications. For children with asymptomatic hematuria or proteinuria excluding nutcracker syndrome, the peak velocity ratio of the left renal vein did not differ from that of normal children and was not affected by sex, age or urinalysis findings.

A Clinical Study of Renal Abscesses in Children

PURPOSE: Renal abscess is very rare in children and its diagnosis is difficult because symptoms are often nonspecific. In previous studies, only 15% to 25% of patients were reported to be diagnosed at the time of admission. Early diagnosis and treatment are important because mortality rate correlates positively with the time of diagnosis. The purpose of this study is to clarify the clinical features of children with renal abscess and to investigate the possible indicators of this disease for early diagnosis and proper treatment. METHODS: Twelve children diagnosed with renal abscess from Jan. 1996 to Jul. 2004 were included. The age of patients ranged from 5 months to 15 years. We retrospectively analyzed the demographics of patients, their symptoms, predisposing factors, diagnostic methods and causative organisms and the treatment modalities. RESULTS: Fever was the most common manifestation. Five children(42%) had vesicoureteral reflux. Renal ultrasonography and computerized tomography were the most frequently used imaging tools to detect renal abscess. Gram negative bacteria were isolated in 7 patients and Staphylococcus aureus grew in 2 patients. All patients received intravenous antibiotics and 4 patients underwent aspiration or drainage of renal abscess. The average admission duration was 30 days. CONCLUSION: Renal abscess should be included in the differential diagnosis of prolonged fever in children, especially when flank pain is combined. For early diagnosis and a better prognosis, patients should be promptly investigated with ultrasonography or computerized tomography.