Case Report: Renal artery stenosis in children: ultrasound as a decisive diagnostic and therapy-accompanying technique!

Introduction: Renal artery stenosis in children is rare, and the recommended diagnostic algorithm, including techniques such as catheter-based angiography, CT angiography, magnetic resonance angiography, and ultrasound, is controversial in pediatric cohorts. Case presentation: We report a case of an 11-year-old girl with renal artery stenosis in whom ultrasonography played a decisive role in confirming the diagnosis and accompanying therapeutic percutaneous transluminal renal artery angioplasty. Conclusion: Improved ultrasound techniques and the examiner's experience contribute to improving renal artery stenosis diagnosis in children. In particular, localized sensitive blood flow velocity analysis indicates the advantages of ultrasound compared to other imaging modalities in renal artery stenosis. Therefore, ultrasound should be a focus of future study designs addressing the search for the best diagnostic algorithm. Summary: The advantages of ultrasound techniques in pediatric patients with renal artery stenosis compared to other imaging modalities are highlighted.

Validation of attenuation imaging coefficient, shear wave elastography, and dispersion as emerging tools for non-invasive evaluation of liver tissue in children.

Introduction: The number of children with acute and chronic liver disease is rising. Moreover, liver involvement may be limited to subtle changes in organ texture especially in early childhood and some syndromic conditions, such as ciliopathies. Attenuation imaging coefficient (ATI), shear wave elastography (SWE), and dispersion (SWD) are emerging ultrasound technologies providing data about attenuation, elasticity, and viscosity of liver tissue. This additional and qualitative information has been correlated with certain liver pathologies. However, limited data are available for healthy controls and have mainly been raised in adults. Methods: This prospective monocentric study was conducted at a university hospital with a specialization in pediatric liver disease and transplantation. Between February and July 2021, 129 children aged 0-17.92 years were recruited. Study participants attended outpatient clinics due to minor illnesses excluding liver or cardiac diseases, acute (febrile) infections or other conditions affecting liver tissue and function. ATI, SWE, and SWD measurements were performed on an Aplio i800 (Canon Medical Systems) with an i8CX1 curved transducer by two different investigators with long-standing experience in pediatric ultrasound according to a standardized protocol. Results: Considering multiple potential covariates, we derived percentile charts for all 3 devices relying on the Lambda-Mu-Sigma (LMS) approach. 112 children were considered for further analysis, excluding those with abnormal liver function and under-/overweight (BMI SDS<-1.96/> 1.96, respectively). Age range was 0-17.92 years (mean 6.89±0.50SD), 58% were male. The mean duration of the ultrasound examination (basic ultrasound plus SWE, SWD, and ATI) was 6.67±0.22 minutes and it was well tolerated in 83% (n=92) of cases. While ATI was related to age, SWD was found to depend on BMI SDS, and SWE on abdominal wall thickness and sex. ATI correlated with neither SWE nor SWD, but SWE was correlated with SWD. Conclusions: Our study provides norm values and reference charts for ATI, SWE, and SWD considering important covariates including age, sex and, BMI. This may help to implement these promising tools into imaging diagnostics of liver disease and to improve the diagnostic relevance of liver ultrasound. In addition, these noninvasive techniques proved to be time-effective and highly reliable, which make them ideal for application in children.

Unusual Presentation of Polyautoimmunity and Renal Tubular Acidosis in an Adolescent With Hashimoto's Thyroiditis and Central Pontine Myelinolysis.

Background: Hashimoto's thyroiditis is frequently associated with other autoimmune diseases and may include renal involvement. Case description: A 17-year-old female with previously diagnosed Hashimoto's thyroiditis and vitiligo was admitted to a pediatric intensive care unit with hypokalemic paralysis and acidosis, after having suffered from recurrent muscular weakness for approximately one year. A few days later she developed central pontine myelinolysis. After initial stabilization she was also diagnosed with distal renal tubular acidosis (dRTA) and tubular proteinuria which can occur in Sjögren's syndrome. Extended screening for autoimmune diseases additionally revealed celiac disease. Treatment with Prednisone and substitution of potassium quickly lead to the resolution of proteinuria and dRTA, but unilateral paralysis of the sixth nerve as a result of central pontine myelinolysis was irreversible. Conclusions: This is the rare case of polyautoimmunity including autoimmune thyroiditis, Sjögren's syndrome, vitiligo and celiac disease in an adolescent with few disease-specific symptoms. The diagnoses were made via a complicating nephritis causing dRTA and proteinuria. Delay in diagnosis lead to permanent neurological damage. This case highlights the need for pediatricians to be aware of rare accompanying diseases and their complications in "common" pediatric autoimmune diseases like Hashimoto's thyroiditis and celiac disease.

Donor and recipient ACE I/D genotype are associated with loss of renal function in children following renal transplantation.

Genetic polymorphisms of the RAS correlate with allograft function. We therefore analyzed common RAS polymorphisms in kidney donors and in children following RTx to determine the relationship between genotype and decline in GFR, blood pressure, and LVM. A total of 107 children who underwent RTx were included: 70 male, 37 female, mean age 8.8±4.9 yr, mean follow up 5.4 yr. The following RAS polymorphisms were studied in all 107 recipients, 48 donors, and 120 healthy controls: Renin (Renin Mbol 18G/A), ACE I/D; angiotensinogen (AGT M235T), and angiotensin II receptor type-1 (AT1R A1166C). Only patients homozygous for the ACE D allele had a significantly steeper decline in GFR compared with homozygous carriers of the ACE I allele (slope DD: -4.3±0.8 vs. II: -1.3±1.1 mL/min/1.73 m2 per yr; p=0.035). In four cases, a DD recipient received a kidney from a DD donor, and these patients showed a more pronounced decline in GFR (-5.2±0.5 mL/min/1.73 m2 per yr; p=0.002). MABP was not different before vs. after RTx and was independent of ACE I/D genotype. LVMI increased significantly in the majority of patients (36.6±13.9 g/m2.7 six months before RTx vs. 46.4±15.3 g/m2.7 12 months after RTx, p=0.015). However, this difference disappeared after stratification by ACE I/D genotype. The ACE DD genotype is a potential marker for identifying patients at high risk of poor allograft outcome.