Clinical significance of hypouricemia in children and adolescents.

BACKGROUND: Although hyperuricemia is a widely studied condition with well-known effects on the kidneys, hypouricemia is usually considered a biochemical abnormality of no clinical significance despite the fact that it can be a sign or major finding of serious metabolic or genetic diseases affecting kidney health. In this study, we aimed to investigate and emphasize the clinical significance of hypouricemia. METHODS: Patients were evaluated retrospectively for persistent hypouricemia defined as serum uric acid concentrations of < 2 mg/dL on at least 3 different occasions. According to the blood and urine uric acid (UA) levels, the patients were classified as having hypouricemia due to UA underproduction vs. overexcretion. Demographic, clinical, and genetic characteristics were noted for analysis. RESULTS: Fourteen patients (n = 14; M/F 8/6) with persistent hypouricemia were identified. Hypouricemia due to underproduction was the cause of 42.8% of these cases. All of the patients with a uric acid level of 0 mg/dL (n = 4) had hypouricemia due to underproduction. The median serum uric acid level was 0.85 (0-1.6) mg/dL. Isolated hypouricemia and hypouricemia with metabolic acidosis were equally distributed. Among the patients with hypouricemia due to underproduction, the final diagnoses were xanthine dehydrogenase deficiency (n = 5) and alkaptonuria (n = 1). In the overexcretion group, the final diagnoses were nephropathic cystinosis (n = 6), distal renal tubular acidosis (n = 1), and hereditary renal hypouricemia (n = 1). The diagnostic lag was longer for patients with isolated hypouricemia compared to other patients (p = 0.001). CONCLUSIONS: Hypouricemia may reflect underlying genetic or metabolic diseases, early diagnosis of which could help preserve kidney function. A higher resolution version of the Graphical abstract is available as Supplementary information.

Comparison of axial and coronal axis MRI kidney volume measurement in pediatric congenital solitary kidney.

BACKGROUND: Accurate estimation of kidney size and volume in the solitary functioning kidney is crucial because of a higher risk of developing kidney injury. MRI is an accurate method and is suitable for kidney volume measurement. Usually, axial axis images and measurement methods are preferred for kidney volume measurements. However, the anteroposterior diameter of the kidney is smaller than the longitudinal diameter, meaning that imaging in the coronal axis could provide needed information in a shorter time, enabling imaging of younger patients without sedation. Therefore, the purpose of this study was to compare coronal and axial axis kidney volume measurement methods and evaluate intra-observer and inter-observer reliability. METHODS: Axial axis T2W and coronal axis FIESTA images of kidneys were obtained with 10 mm slice thickness and no slice gap in pediatric patients with congenital solitary kidneys. Free-hand manual tracing was used to calculate volumes in both methods. Images were analyzed by two operators with different levels of experience. The expert operator computed solitary kidney volume twice in both methods for the intra-observer reliability, while the beginner operator's measurements were used for the inter-observer reliability. RESULTS: High intra-observer (0.965 for axial and 0.972 for coronal) and inter-observer reliability were revealed (0.964 for axial and 0.963 for the coronal) for both measurement methods. CONCLUSION: The coronal plane volume measurement method, which has a significantly shorter examination and post-processing time, is a highly reproducible and reliable method that can enable volume measurement with MRI in younger children, as the imaging time will be shortened. A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinical features of pediatric renal glucosuria cases due to SLC5A2 gene variants.

BACKGROUND: Familial renal glycosuria (FRG) is a rare renal tubular disorder characterized by a variable loss of glucose in the urine despite normal blood glucose levels, which is seen in a condition in which other tubular functions are preserved. In this study, the molecular and clinical characteristics of pediatric FRG cases due to SLC5A2 gene variants were defined. METHODS: Demographic features, diagnostic tests, and molecular analyses of patients with a diagnosis of FRG cases due to SLC5A2 gene variants were retrospectively analyzed between 2016 and 2019. RESULTS: The data of 16 patients who were clinically and genetically diagnosed with FRG in a 4-year period were analyzed. Seven (44%) of the cases were female and 9 (56%) were male. The median age at diagnosis was 6 years old (2 months old to 17 years old). Neuromotor development was found to be appropriate for the age in each case. Systemic blood pressure was evaluated as normal. A homozygous pathogenic variant in the SLC5A2 gene was detected in 14 patients in the genetic examination. A heterozygous variant was detected in one patient. In the other patient, two different heterozygous pathological variants were found in the SLC5A2 gene. CONCLUSIONS: It was revealed that growth and development were normal in children with glucosuria due to variations in the SCL5A2 gene. Renal function tests and urinary amino acid excretion were also within normal values. In our case series, the most common genetic variation in the SCL5A2 gene was the A219T (c.655G>A) variant.

Evaluation of GLUT1, IGF-2, VEGF, FGF 1, and angiopoietin 2 in infantile hemangioma.

INTRODUCTION: Infantile hemangioma (IH) is a common vascular tumor in children. It is reported that IHs are associated with immunochemical markers such as vascular endothelial growth factor (VEGF)-A, glucose transporter isoform 1 (GLUT1), and insulin-like growth factor-2 (IGF-2). MATERIAL AND METHODS: This cross-sectional study focused on pediatric patients with IH. A total of 46 patients (mean age 14.2±21.9 months) with IH and 45 healthy controls (mean age 21.8±15.08 months) were enrolled. Demographic data, clinical findings, and laboratory parameters were recorded. Blood samples were collected. Serum GLUT1, IGF-2, VEGF-A, fibroblast growth factor 1 (FGF1), and angiopoietin 2 levels were assessed by enzyme-linked immunosorbent assay. RESULTS: Serum GLUT1, IGF-2, and VEGF-A levels were significantly higher in patients with IH than in healthy controls (8.80±4.07pg/mL vs. 5.66±4.34pg/mL, 281.10±84.12pg/mL vs. 234.19±75.38pg/mL, 1196.99±389.34pg/mL vs. 996.99±349.16pg/mL, respectively, p=0.026, p=0.030, and p=0.036). Serum GLUT1, IGF-2, and VEGF-A levels in patients with complicated hemangioma were significantly higher than in healthy controls (9.69±3.94pg/mL vs. 5.66±4.34pg/mL, 289.94±83.18pg/mL vs. 234.19±75.38pg/mL, 1276.22±388.24pg/mL vs. 996.99±349.16pg/mL, respectively, p=0.017, p=0.022, and p=0.011). Serum GLUT1, IGF-2, and VEGF-A levels in patients with hemangioma receiving propranolol treatment were significantly higher than in healthy controls. Serum FGF1 levels were higher in patients with IH, complicated hemangioma, and hemangioma receiving propranolol treatment than in healthy controls but the difference was not statistically significantly. CONCLUSION: Serum GLUT1, IGF-2, and VEGF-A levels were positively correlated with disease severity in patients with hemangioma, for example, in complicated hemangioma and hemangioma requiring propranolol treatment. However, further research on larger and different age subgroups is warranted to assess these markers.

An Unusual Presentation of T-Cell Lymphoblastic Lymphoma with Isolated Renal Involvement.

The clinical presentation of Non-Hodgkin lymphoma (NHL) is frequently associated with the involvement of the abdomen and mediastinal lymphadenopathies, but rarely the kidney, ovaries, and testicles. Here, we report a rare case of T-cell lymphoblastic lymphoma (T-LBL) presenting with bilateral nephromegaly without acute renal failure (ARF) as the first manifestation. A 30-month-old boy was admitted to the department of pediatric nephrology exhibiting abdominal distension. Physical examination revealed bilateral renal palpation up to the inguinal region. Elevated lactate dehydrogenase (LDH) levels were detected in his blood. Bilateral diffuse enlarged kidneys with increased hypoechogenicity were found on abdominal ultrasonography. In the next step, contrast-enhanced computed tomography showed diffusely enlarged kidneys, which were compressing the intestinal bowels and midline structures. Renal biopsy demonstrated precursor T-LBL. We wish to report our patient with renal T-LBL presenting with diffuse renal enlargement, which has rarely been reported in the literature.

Tolvaptan Use to Treat SIADH in a Child.

Hyponatremia is one of the most common electrolyte abnormalities encountered in the clinical setting in hospitalized patients. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the leading cause of hyponatremia in most of these cases. While fluid restriction, hypertonic saline infusion, diuretics, and the treatment of underlying conditions constitute the first line of treatment of SIADH, in refractory cases, and especially for pediatric patients, there seems not to be any other choice for treatment. Tolvaptan, although its use in pediatric patients is still very limited, might be an attractive treatment option for correction of hyponatremia due to SIADH. Here we present a pediatric case of SIADH that was resistant to treatment with fluid restriction and hypertonic saline infusion and was treated successfully with tolvaptan. Tolvaptan could be a good, safe, and effective treatment option in pediatric SIADH cases that are resistant to treatment. However, the dosage should be titrated carefully.

The effects of type 1 diabetes mellitus on cardiac functions in children: evaluation by conventional and tissue Doppler echocardiography.

BACKGROUND: Several studies have pointed out the existence of cardiac dysfunction in patients with type 1 diabetes mellitus (DM) even in the absence of ischemic, valvular, or hypertensive heart disease. The present study evaluated cardiac dysfunction and the relationship between severity of disease and degree of cardiac dysfunction in children with type 1 DM. METHODS: In this prospective study, 31 patients with type 1 DM and 33 sex- and age-matched healthy children were evaluated with conventional echocardiography and tissue Doppler echocardiography (TDE). A correlation between cardiac functions and glycated hemoglobin (HbA1C) was examined. RESULTS: TDE results indicated that mitral valve early diastolic annular peak flow rate (E'), mitral valve systolic flow rate (S'), ratio of mitral valve early diastolic peak flow rate to mitral valve early diastolic annular peak flow rate (E/E'), and left ventricular (LV) myocardial performance index (MPI) were higher, and LV ejection time (ET) was shorter in patients with type 1 DM (p<0.05). In addition, tricuspid valve E' and right ventricular (RV) MPI were higher, while RV ET and tricuspid E/E' were lower in patients with type 1 DM compared to healthy children (p<0.05). CONCLUSIONS: Although conventional echocardiography revealed no difference between patients with type 1 DM and healthy children, TDE showed dysfunctions of both ventricles. This state is closely related to degree of blood glucose level control. These findings signify diagnostic value of TDE in the early detection of cardiac effects among patients with type 1 DM.

Causative pathogens and antibiotic resistance in children hospitalized for urinary tract infection.

BACKGROUND: Urinary tract infections (UTI) are one of the most common bacterial infections in children and a major cause of hospitalization. In this study we investigated the clinical characteristics, causative uropathogens; their antibiotic susceptibility and resistance patterns, treatment modalities and efficacy in children hospitalized for UTI in a tertiary care setting. METHODS: Patients hospitalized for an upper UTI between March 2009 and July 2014 were enrolled. The urine culture-antibiogram results and accompanying urinary tract abnormalities were recorded retrospectively. RESULTS: A total of 142 patients (104 girls, 73.2%; 38 boys, 26.8%) were enrolled. Mean patient age was 32.6 ± 4.1 months. History of recurrent UTI was present in 45.8% (n = 65), with prior hospitalization in 12.0% (n = 17). Frequency of vesicoureteral reflux was 18.3% (n = 26). Gram-negative enteric microorganisms yielded growth in all culture-positive UTI and the most common microorganism was Escherichia coli (n = 114, 80.3%). Extended spectrum beta-lactamase-producing (ESBL (+)) bacterial strains were detected in 49.3% (n = 70), with third-generation cephalosporin resistance in all and increased duration of hospitalization. CONCLUSIONS: The prevalence of UTI with ESBL (+) bacterial strains with multi-drug resistance is increasing in the hospitalized pediatric population, therefore rational use of antibiotics is essential.

Hemophagocytic lymphohistiocytosis secondary to Varicella zoster infection in a child with Henoch-Schönlein purpura.

Hemophagocytic lymphohistiocytosis (HLH) is a fatal, hyper-inflammatory syndrome that is characterized by untimely activation of macrophages, and manifests as cytopenia, organ dysfunction, and coagulopathy. Secondary HLH can be associated with infection, drugs, malignancy, and transplantation, and is mostly triggered by infection. Herein, we report the case of a patient with Henoch-Schönlein purpura (HSP) who developed severe HLH secondary to Varicella zoster infection.

Incidence of maternal vitamin D deficiency in a region of Ankara, Turkey: a preliminary study.

BACKGROUND/AIM: To evaluate vitamin D levels and risk factors for vitamin D deficiency in healthy newborns and their mothers. MATERIALS AND METHODS: Ninety-nine healthy pregnant women (≥ 37 weeks of gestation) were enrolled in the study. Previous history of pregnancies and births, nutritional status, multivitamin supplementation, educational status, type of clothing, and the economic level of the family were recorded. Blood samples were drawn from the mothers and the umbilical cord of the newborns to measure serum 25(OH)D3, calcium, phosphorus, and parathormone levels. RESULTS: While vitamin D insufficiency was identified as 62.6% in mothers, it was 58.6% in newborns; on the other hand, the incidence of vitamin D deficiency was 18.2% and 15.2% in mothers and newborns, respectively. Maternal serum 25(OH)D3 concentrations were not significantly related to the number of pregnancies or births, type of clothing, or the nutritional, economical, or educational status of the family (P > 0.05). CONCLUSION: These findings suggest that despite a sunny environment, maternal vitamin D deficiency and insufficiency are still important health problems in a developed region of Turkey. Therefore, more effective vitamin D prophylaxis programs are required to prevent vitamin D deficiency in pregnant women and their offspring.