Yu Hyeon Choi

Fluid-fluid levels in ovarian teratomas.

AbstractBackground: We evaluated the imaging features of ovarian teratomas containing fluid–fluid levels on ultrasonography (US). Methods: We retrospectively reviewed US examinations of two groups with 805 masses (370 benign ovarian teratomas and 435 nonteratomatous adnexal masses). Results: In 27 teratomas and eight nonteratomatous adnexal masses, fluid–fluid levels were detected on US. According to the echogenicity of each layer, 27 teratomas were classified as three types: 1, supernatant hypoechoic and dependent hyperechoic layers (n= 16); 2, supernatant hyperechoic and dependent hypoechoic layers (n= 8); and 3, supernatant hypoechoic and dependent hypoechoic layers with bright fluid interface (n= 3). In eight (30%) of 27 teratomas, US showed floating nodules at the interface, five of which had posterior acoustic shadowing. All eight nonteratomatous adnexal masses showed type 1 fluid–fluid levels. Conclusion: The fluid–fluid level seen on US is strongly suggestive but not pathognomonic of dermoids. Fluid–fluid levels with supernatant hyperechoic and dependent hypoechoic layers, supernatant hypoechoic and dependent hypoechoic layers with bright interface, and a floating nodule might pathognomonic findings of benign ovarian teratomas.

Mutational analysis of COL4A5 gene in Korean Alport syndrome.

Abstract Mutational analysis of the COL4A5 gene in X-linked Alport syndrome (AS) requires an expensive and time-consuming procedure with a detection rate of 50%, at best. There have been three multicenter collaborative studies of mutation analysis in the COL4A5 gene using systematic screening of entire coding regions of the gene. This is a similar study executed in a single center in Korea. Twenty-five unrelated Korean patients with AS in whom the diagnosis was confirmed pathologically were included in the study. By systematic screening of all 51 exons of the gene using polymerase chain reaction/single-strand conformation polymorphism analysis, ten mutations were detected in 10 unrelated patients. These included one medium-sized deletion involving exon 49–51, one single base pair deletion, one nonsense point mutation, one splice site mutation, and six missense point mutations. Of the six missense mutations, four involved a glycine residue and disrupted the Gly-X-Y repeats in the collagenous domain. The overall detection rate of mutations was 40%. Although DNA analysis in AS is currently not applicable to routine clinical diagnosis due to several practical and technical problems, it is likely to replace morphological diagnosis in the near future.

Home Mechanical Ventilation in Childhood-Onset Hereditary Neuromuscular Diseases: 13 Years’ Experience at a Single Center in Korea

Introduction Children with hereditary neuromuscular diseases (NMDs) are at a high risk of morbidity and mortality related to respiratory failure. The use of home mechanical ventilation (HMV) has saved the lives of many children with NMD but, due to a lack of studies, dependable guidelines are not available. We drew upon our experience to compare the various underlying NMDs and to evaluate HMV with regard to respiratory morbidity, the proper indications and timing for its use, and to develop a policy to improve the quality of home noninvasive ventilation (NIV). Methods We retrospectively analyzed the medical records of 57 children with childhood-onset hereditary NMDs in whom HMV was initiated between January 2000 and May 2013 at Seoul National University Childrens Hospital. The degree of respiratory morbidity was estimated by the frequency and duration of hospitalizations caused by respiratory distress. Results The most common NMD was spinal muscular atrophy (SMA, n = 33). Emergent mechanical ventilation was initiated in 44% of the patients before the confirmed diagnosis, and the indicators of pre-HMV respiratory morbidity (e.g., extubation trials, hypoxia, hospitalizations, and intensive care unit stay) were greater in these patients than in others. The proportion of post-HMV hospitalizations (range, 0.00−0.52; median, 0.01) was lower than that of pre-HMV hospitalizations (0.02−1.00; 0.99) (P < 0.001). Eight patients were able to maintain home NIV. The main causes of NIV failure were air leakage and a large amount of airway secretions. Conclusions The application of HMV helped reduce respiratory morbidity in children with childhood-onset hereditary NMD. Patients with SMA type I can benefit from an early diagnosis and the timely application of HMV. The choice between invasive and noninvasive HMV should be based on the patient’s age and NIV trial tolerance. Systematic follow-up guidelines provided by a multidisciplinary team are needed.

Factors affecting serum concentration of vancomycin in critically ill oliguric pediatric patients receiving continuous venovenous hemodiafiltration

Vancomycin is known to be unintentionally eliminated by continuous renal replacement therapy, and the protein bound fraction of vancomycin is also known to be different in adults and children. However, there are only a few studies investigating the relationship between the dose of continuous venovenous hemodiafiltration (CVVHDF) parameters and serum concentration of vancomycin in pediatric patients. The aim of this study was to determine clinical and demographic parameters that significantly affect serum vancomycin concentrations. This retrospective cohort study was conducted at a pediatric intensive care unit in a tertiary university children’s hospital. Data from oliguric patients who underwent CVVHDF and vancomycin therapeutic drug monitoring were collected. The correlation between factors affecting serum concentration of vancomycin was analyzed using mixed effect model. A total of 177 serum samples undergoing vancomycin therapeutic drug monitoring were analyzed. The median age of study participants was 2.23 (interquartile range, 0.3–11.84) years, and 126 (71.19%) were male patients. Serum concentration of vancomycin decreased significantly as the effluent flow rate (EFR; P < 0.001), dialysate flow rate (DFR; P = 0.009), replacement fluid flow rate (RFFR; P = 0.008), the proportion of RFFR in the sum of DFR and RFFR (P = 0.025), and residual urine output increased. The adjusted R2 of the multivariate regression model was 0.874 (P < 0.001) and the equation was as follows: Vancomycin trough level (mg/L) = (0.283 × daily dose of vancomycin [mg/kg/d]) + (365.139 / EFR [mL/h/kg])–(15.842 × residual urine output [mL/h/kg]). This study demonstrated that the serum concentration of vancomycin was associated with EFR, DFR, RFFR, the proportion of RFFR, and residual urine output in oliguric pediatric patients receiving CVVHDF.

Extensive and Progressive Cerebral Infarction after Mycoplasma pneumoniae Infection

Acute cerebral infarctions are rare in children, however they can occur as a complication of a Mycoplasma pneumoniae (MP) infection due to direct invasion, vasculitis, or a hypercoagulable state. We report on the case of a 5-year-old boy who had an extensive stroke in multiple cerebrovascular territories 10 days after the diagnosis of MP infection. Based on the suspicion that the cerebral infarction was associated with a macrolide-resistant MP infection, the patient was treated with levofloxacin, methyl-prednisolone, intravenous immunoglobulin, and enoxaparin. Despite this medical management, cerebral vascular narrowing progressed and a decompressive craniectomy became necessary for the patient’s survival. According to laboratory tests, brain magnetic resonance imaging, and clinical manifestations, the cerebral infarction in this case appeared to be due to the combined effects of hypercoagulability and cytokine-induced vascular inflammation.

Early predictors of mortality in children with pulmonary complications after haematopoietic stem cell transplantation

PC are a main cause of death following HSCT in children. We aimed to evaluate early predictors of mortality in paediatric recipients with PCs. A retrospective observational study of 35 patients with 49 episodes of PI on chest radiography (of 124 patients) who had undergone HSCT at a tertiary university hospital between January 2011 and December 2012 was performed. During follow‐up (median 26.1 months), 15 episodes led to death (30.6%). An aetiologic diagnosis was made by non‐invasive tests in 24 episodes (49.0%) and by adding bronchoalveolar lavage and/or lung biopsy in 7 episodes with diagnostic yield (77.8%, P = .001). Thus, a specific diagnosis was obtained in 63.3% of the episodes. Aetiology identification and treatment modification after diagnosis did not decrease mortality (P = .057, P = .481). However, the number of organ dysfunctions at the beginning of PI was higher in the mortality group, compared to the survivor group (1.7 ± 1.2 vs 0.32 ± 0.59; P = .001). Hepatic dysfunction (OR, 11.145; 95% CI, 1.23 to 101.29; P = .032) and neutropaenia (OR, 10.558; 95% CI, 1.07 to 104.65; P = .044) were independently associated with risk of mortality. Therefore, hepatic dysfunction and neutropaenia are independent early predictors of mortality in HSCT recipients with PCs.

Association of systolic blood pressure drop with intravenous administration of itraconazole in children with hemato-oncologic disease

Purpose Although few adverse effects have been reported for itraconazole, a widely used antifungal therapy for febrile neutropenia, we found intravenous (IV) itraconazole to be associated with serious cases of blood pressure (BP) drop. We therefore evaluated the incidence and risk factors for BP drop during IV administration of the drug. Materials and methods We reviewed the medical records of children with hemato-oncologic disease who were treated with IV itraconazole from January 2012 to December 2013. By analyzing systolic BP (SBP) measurements made from 4 hours before through to 4 hours after itraconazole administration, we evaluated the changes in SBP and the risk factors for an SBP drop, especially clinically meaningful (≥20%) drops. Results Itraconazole was administered 2,627 times to 180 patients. The SBP during the 4 hours following itraconazole administration was lower than during the 4 hours before administration (104 [53.0–160.33 mmHg] versus 105 [59.8–148.3 mmHg]; P<0.001). The decrease in SBP was associated with the application of continuous renal replacement therapy (CRRT) (P=0.012) and the use of inotropic (P=0.005) and hypotensive drugs (P=0.021). A clinically meaningful SBP drop was seen in 5.37% (141 out of 2,627) of the administrations, and the use of inotropics (odds ratio [OR] 6.70, 95% confidence interval [CI] 3.22–13.92; P<0.001), reducing the dose of inotropics (OR 8.08; 95% CI 1.39–46.94; P=0.02), CRRT (OR 3.10, 95% CI 1.41–6.81; P=0.005), and bacteremia (OR 2.70, 95% CI 1.32–5.51; P=0.007) were risk factors, while age was a protective factor (OR 0.93, 95% CI 0.89–0.97; P<0.001). Conclusion A decrease in SBP was associated with IV administration of itraconazole. It was particularly significant in younger patients with bacteremia using inotropic agents and during application of CRRT. Careful attention to hypotension is warranted during IV administration of itraconazole in this group of patients.