Persistent Elevation of Troponin I in a Pediatric Patient Resulting From Macrotroponin Complex.

ABSTRACT: Although chest pain is a common chief complaint among pediatric patients, cardiac pathology historically has accounted for a small percentage of cases. However, the emergence of COVID-19 and particularly its potential for leading to multisystem inflammatory syndrome has changed the threshold for the evaluation of cardiac etiologies of chest pain. This evaluation often includes measurement of the serum cardiac troponin I level. We present a case of a 16-year-old male athlete who presented to an outside emergency department with chest pain and was found to have elevated serum troponin I levels. Despite sports restriction, his troponin level remained elevated for months in the absence of other clinical findings and he was subsequently referred to our outpatient pediatric cardiology clinic. Further laboratory evaluation revealed that, in addition to troponin I, the assay measured an immune complex of uncertain significance formed by anti-troponin I antibodies bound to troponin I, known as macrotroponin. Delayed clearance of this complex from the bloodstream can result in overestimation of troponin I levels that can affect clinical management and create anxiety for our patients and their families. Macrotroponin complex deserves increased recognition among the research and clinical communities, especially in the pediatric realm.

Low-density lipoprotein apheresis for recurrent focal segmental glomerulosclerosis post renal transplant in pediatric patients.

Low-density lipoprotein (LDL) apheresis has been shown to improve remission in patients with steroid-resistant nephrotic syndrome (SRNS). Here, we report a case study of two patients who failed apheresis treatment for SRNS and required transplant with subsequent recurrence of nephrotic syndrome and response to apheresis treatment. Two patients were treated with 12 sessions of LDL apheresis for SRNS without improvement and subsequently required renal transplantation. The first patient received an ABO-incompatible kidney transplant requiring plasma exchange (PE) with subsequent recurrence of focal segmental glomerulosclerosis. The second patient also received a renal transplant after treatment failure and subsequently developed recurrence of nephrotic syndrome in the transplanted kidney. Both patients underwent repeat therapy with lipoprotein apheresis. The first patient underwent lipoprotein apheresis after completing PE with significant improvement in serum creatinine and urine protein creatinine ratio. Three years later, he continued to do well and remains in remission. The second patient also responded well to repeat therapy with lipoprotein apheresis and had significant improvement with a urine protein creatinine ratio of 0.8 and a serum creatinine of 0.9 mg/dL 6 months after transplant. Lipoprotein apheresis was able to result in remission of nephrotic syndrome in these patients with posttransplant recurrence of disease. This is the first report of patients not responding to treatment pretransplant but responding posttransplant. Lipoprotein apheresis should be considered in patients with recurrence of nephrotic syndrome after renal transplantation even with a history of treatment failure prior to transplantation.

Liposorber® LA-15 system for LDL apheresis in resistant nephrotic syndrome patients.

BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS) is a major cause of stage 5 chronic kidney disease (CKD 5) in children. LDL apheresis (LDL-A) is now FDA approved for the treatment of pediatric focal segmental glomerulosclerosis (FSGS). Effective management of hyperlipidemia with LDL-A in SRNS patients may prevent progression of kidney disease and lead to remission. We report a case series of patients who received LDL-A for treatment of SRNS METHODS: We describe five children with SRNS who were treated with 12 sessions of LDL-A. Partial remission (PR) is defined as urine protein to creatinine ratio (UPC) of 0.2-2 (g/g) or decrease in UPC ≥ 50%, and complete remission (CR) is defined as UPC < 0.2 (g/g). RESULTS: One patient achieved CR and three achieved PR. One patient did not respond to therapy. The earliest that a patient achieved PR was at treatment #10 and some did not respond until after LDL-A was completed. Those who responded stayed in either CR or PR for extended periods of time. LDL-A was successful at significantly reducing LDL (p < 0.001), total cholesterol (p < 0.001), and triglyceride (p < 0.001). CONCLUSIONS: LDL-A was able to significantly decrease the lipid levels in these patients and induce CR and PR in the majority. The current study confirms previous studies showing those with a higher glomerular sclerosis burden were less likely to respond. LDL-A should be considered in patients with treatment-resistant SRNS and should be considered before there is a high burden of glomerular sclerosis to provide the best chance of success.

Aortic size in children: Systolic measurements are different from diastolic measurements.

BACKGROUND: Current guidelines recommended aortic measurements during diastole in adults and during systole in children. Recent studies in adults have demonstrated noteworthy differences in aortic measurements during systole and diastole in the same subjects. In the present study, we aimed to characterize systolic and diastolic differences in aortic measurements in healthy children. MATERIALS AND METHODS: This retrospective study included 272 children who had a complete echocardiogram and no heart disease. Aortic measurements at the annulus (ANN), aortic root (AOR), sinotubular junction (STJ), and ascending aorta (AAO) were performed. Systolic and diastolic values were compared by calculating the mean systolic to diastolic (SD) percent difference for each segment; if the SD difference was >5%, it was considered clinically important. Similar measurements were conducted by another observer in 18% of the subjects. RESULTS: Systolic measurements were larger than diastolic measurements with mean SD percent differences >5% (P < 0.001) for the AOR (7.3% ± 5.5%), STJ (10.24% ± 7.1%), and AAO (9.8% ± 7.4%). There was no clinically significant SD difference for the ANN. There was an excellent intraclass correlation coefficient between observers (0.982-0.995). CONCLUSIONS: Systolic measurements for the AOR, STJ, and AAO were larger than diastolic measurements. Normal reference values are utilized to design treatment for patients with abnormal aortic sizes, and the timing in the cardiovascular cycle used to decide the reference values should be equivalent to the timing used to make measurements in clinical practice. This is particularly imperative as patients transition their care from a pediatric to an adult cardiologist.

The incidence of chromosome abnormalities in neonates with structural heart disease.

OBJECTIVES: This study was conducted to determine the prevalence of chromosomal anomalies in newborns with structural heart disease admitted to the cardiac intensive care unit (CICU) at Nicklaus Children's Hospital (NCH). METHODS: A retrospective review identified newborns age 30 days or less admitted to NCH CICU between 2004 and 2010. Patients with structural heart disease who required admission to our CICU and received karyotype or karyotype and fluorescent in situ hybridization (FISH) testing were included in the study. All patients were examined for the presence of dysmorphic features. RESULTS: Four hundred and eighty-two patients met the criteria for the study; 405 (84%) received both karyotype and FISH. Chromosome abnormalities were present in 86 (17.8%) patients. Syndromes accounted for 20 (5.1%) of those with normal chromosomes. Dysmorphic features were seen in 79.1% of patients with abnormal chromosomes and 25.5% of those with normal chromosomes. All patients with syndromes were dysmorphic. Race and gender did not significantly affect the incidence of genetic abnormalities. CONCLUSIONS: Chromosome abnormalities, including syndromes, are prevalent in newborns with congenital heart disease. Further research is needed to evaluate the utility of cytogenetic screening in all children with congenital heart disease.