Adolescence-onset atypical hemolytic uremic syndrome: is it different from infant-onset?

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare, mostly complement-mediated thrombotic microangiopathy. The majority of patients are infants. In contrast to infantile-onset aHUS, the clinical and genetic characteristics of adolescence-onset aHUS have not been sufficiently addressed to date. METHODS: A total of 28 patients (21 girls, 7 boys) who were diagnosed as aHUS between the ages of ≥10 years and <18 years were included in this study. All available data in the Turkish Pediatric aHUS registry were collected and analyzed. RESULTS: The mean age at diagnosis was 12.8±2.3 years. Extra-renal involvement was noted in 13 patients (46.4%); neurological involvement was the most common (32%). A total of 21 patients (75%) required kidney replacement therapy. Five patients (17.8%) received only plasma therapy and 23 (82%) of the patients received eculizumab. Hematologic remission and renal remission were achieved in 25 (89.3%) and 17 (60.7%) of the patients, respectively. Compared with the infantile-onset aHUS patients, adolescent patients had a lower complete remission rate during the first episode (p = 0.002). Genetic analyses were performed in all and a genetic variant was detected in 39.3% of the patients. The mean follow-up duration was 4.9±2.6 years. At the last visit, adolescent patients had lower eGFR levels (p = 0.03) and higher rates of chronic kidney disease stage 5 when compared to infantile-onset aHUS patients (p = 0.04). CONCLUSIONS: Adolescence-onset aHUS is a rare disease but tends to cause more permanent renal dysfunction than infantile-onset aHUS. These results may modify the management approaches in these patients.

Management of pediatric hemolytic uremic syndrome.

Classical clinical triad of hemolytic uremic syndrome (HUS) is microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury associated with endothelial cell injury. Several situations, including infections, medications, malignancies, and transplantation can trigger endothelial damage. On the HUS spectrum, atypical hemolytic uremic syndrome (aHUS) deserves special attention in pediatric patients, as it can cause endstage kidney disease and mortality. A dysfunction in the alternative complement pathway, either acquired or genetic, has been shown to be the main underlying cause. In the last decades, breathtaking advances have been made in understanding the pathophysiology of this rare disease, which has led to more efficient treatment. Recent studies have implicated genes in pathways beyond the alternative complement system, such as DGKE, TSEN2, and INF2 highlighting the importance of personalized management. Eculizumab has brought about dramatic improvements in the treatment of aHUS. Beyond eculizumab, there are many alternative therapeutics in the pipeline that target the complement system. Because of the rarity of aHUS, data from multiple patient registries are very important. The present report aimed to summarize the most important aspects of diagnosing and treating aHUS based on the Turkish national registry and the literature so as to improve clinical practice.

Allelic Variants of the Complement Genes in Acute Postinfectious Glomerulonephritis.

Acute postinfectious glomerulonephritis (APIGN) is one of the most common causes of acute glomerulonephritis in children. It may lead to inflammation and proliferation of glomerular tissue through immunologic mechanisms (Balasubramanian R, Paediatr Int Child Health 2017;37:240-247).

Spontaneous tendon or ligament ruptures in patients undergoing dialysis: First pediatric case report and literature review.

Spontaneous tendon or ligament ruptures are quite rare and mostly associated with chronic systemic diseases such as diabetes mellitus, systemic lupus erythematosus, rheumatoid arthritis, and chronic kidney disease (CKD). In this study, we present the first documented case of a spontaneous rupture of the medial patellofemoral ligament (MPFL) in a pediatric patient. The patient was undergoing long-term peritoneal dialysis (PD) and had a history of severe secondary hyperparathyroidism. Additionally, we discussed spontaneous tendon and ligament ruptures associated with CKD or dialysis through a comprehensive literature review. This case report highlights the importance of recognizing that spontaneous tendon or ligament injuries are not exclusive to adults; children with CKD can also be affected. Several factors including poor parathyroid hormone (PTH) and metabolic acidosis control, prolonged CKD duration and presence of malnutrition play role in the pathogenesis. Early diagnosis is crucial as it allows for timely surgical intervention and leads to a favorable functional recovery.

A rare cause and an even rarer treatment of hypertension in a 5-year-old boy: Mid-aortic syndrome.

Renal artery stenosis is one of the common vascular diseases that cause hypertension in children. However, renal artery aneurysms and abdominal aortic aneurysms, which may be components of mid-aortic syndrome, are rarely associated with renal artery stenosis. Despite its rarity, early diagnosis and treatment are critical to prevent fatal complications. Currently, non-surgical invasive techniques are considered the first choice for treatment, but in some cases, surgery is inevitable. Here, we present a 5-year-old boy with a mid-aortic syndrome. The patient presented with a history of severe headache and epistaxis 5-6 times a day and was diagnosed with hypertension. A 9 × 9 mm saccular aneurysm on the anterior surface of the abdominal aorta at the level of the left renal artery ostium, and a 12 mm aneurysm in the left renal artery after a stenotic segment at the hilum level was detected in the doppler USG and contrast-enhanced imaging techniques. The patient was operated on electively. We used a PTFE patch to repair the abdominal aorta and, saphenous vein which was taken from his father to repair the renal artery. The patient recovered well and was discharged on the 18th day.

LAMB2 gene: broad clinical spectrum in Pierson syndrome.

Pierson syndrome (PS) is a rare autosomal recessive disease, characterized by congenital nephrotic syndrome (CNS), and ocular and neurologic abnormalities. In affected cases, there is abnormal b-2 laminin which is compound of the several basement membranes caused by inherited mutations in the LAMB2 gene. Although patients have mutations in the same gene, the phenotype is highly variable. In this case series, the relationship between genotype and phenotype is emphasized, and information about the clinical follow-up of the patients is presented. Hereby, we report four pediatric cases with PS as a result of mutation in the LAMB2 gene. Clinical spectrum of LAMB2-associated disorders varies from mild-to-severe ocular, kidney, and neurologic involvement. Since genotype-phenotype correlation in PS has not been clearly demonstrated, we recommend that all patients with ophthalmic anomalies and glomerular proteinuria should be tested for LAMB2 mutations.

Electrocardiographic measurements in children with pre-dialysis chronic kidney disease and undergoing kidney replacement therapy.

Cardiovascular diseases are the main causes of morbidity in children with chronic kidney disease (CKD). Electrocardiography (ECG) can provide important information about cardiac functions and parameters associated with sudden cardiac death. This study aims to evaluate the potentially dangerous changes in CKD and kidney replacement therapies by ECG and to determine the value of ECG in predicting cardiovascular outcome compared with echocardiography. 101 patients with CKD were divided into subgroups according to treatment modalities as pre-dialysis CKD, hemodialysis (HD), peritoneal dialysis (PD) and kidney transplantation (KTx). Differences in anthropometric measurements, laboratory results, blood pressures, ECG monitoring were compared within groups as well as with 40 healthy controls. Available echocardiographic findings were noted. In the patients, HD group had highest frequency of hypertension. ECG revealed prolonged QTc as more frequent (16.8% vs 0%, p = 0.006) and higher QTcD (56.7 ± 6.5 vs 39.9 ± 5.1 ms, p = 0.001) in the patients compared to controls, especially in dialysis patients, whereas lowest values were in KTx subgroup. Left ventricular (LV) hypertrophy (LVH) was more frequent (47.1%) in HD compared to other CKD subgroups in ECG (p = 0.052). Echocardiography also showed LV mass index as highest in HD and lowest in KTx (121.4 ± 55.7 vs 63.7 ± 18.3 g/m2, p = 0.000), with numerically highest LVH in HD (58.3%, p = 0.063).  Conclusion: ECG can be used to detect cardiovascular problems in patients with CKD, especially in HD. As ECG results were in line with echocardiography, patients with ECG abnormalities suggestive of LVH should be referred for echocardiographic assessment. What is Known: • Cardiovascular diseases such as coronary artery disease, congestive heart failure, arrhythmias and sudden cardiac death are major causes of morbidity and mortality in chronic kidney disease. • Electrocardiography has significant advantages in demonstrating cardiac functions in children because it is readily available, non-invasive and often non-experts can interpret the results. What is New: • The heart rate is higher, QTc is longer and QTcD is higher in dialysis patients and the prolonged QTc is more frequent in patients with underlying glomerular diseases. • Left ventricular hypertrophy is more common in HD patients and those with hypertension, hypercalcemia, anemia or glomerular etiology. The cardiovascular risky conditions are less frequent in the patients with kidney transplantation.

A Rare Isolated Kidney Cyst: Hydatid Cyst.

Hydatid disease is a parasitic disease caused by Echinococcus granulosus or Echinococcus multilocularis. It is still a serious public health problem in endemic regions such as the Mediterranean basin. Since the complaints caused by the cysts are non-specific and routine laboratory tests do not always yield positive results, diagnosis may be difficult. While liver involvement is present in 70% of cases, larvae escaping from the filtration of the liver cause pulmonary disease in 25% of cases. Although the prevalence of kidney involvement in all hydatid cysts is approximately 2-4%, and isolated kidney involvement is extremely rare at 1.9%. In this case report, we present an extremely rare pediatric case of isolated renal hydatid cyst, the diagnosis of which was somewhat delayed.

A Well-Intentioned Enemy in Autoimmune and Autoinflammatory Diseases: NETosis.

Neutrophils are an essential member of the innate immune system derived from the myeloid stem cell series and develop in the bone marrow. The action of neutrophils defined in immune response includes phagocytosis, degranulation, cytokine production, and neutrophil extracellular traps. The success of the host immune defense depends on effective neutrophil activation. Recent studies have shown that neutrophils that have completed their task in the field of inflammation rejoin circulation. Uncontrolled inflammatory response and dysregulated immune responses to the host are important factors in the development of acute and chronic diseases. Neutrophils are the first cells to be drawn into the field at the time of inflammation. They have developed response strategies that produce proinflammatory cytokines and are known as neutrophil extracellular traps since they create mesh-like structures with their DNA contents into the external environment and release their granular proteins in this way. This article summarizes numerous recent studies and reviews the role of neutrophil extracellular traps in autoimmune and autoinflammatory diseases in the hope, that this will lead to the development of more effective treatments. In addition, in this review, the role of neutrophil extracellular trap formation in some pediatric autoimmune diseases is emphasized.

Encapsulated Peritoneal Sclerosis in an Adolescent With Kidney Transplant After Long-Term Peritoneal Dialysis.

Encapsulated peritoneal sclerosis is a rare complication of long-term peritoneal dialysis that has a high rate of morbidity and mortality. We present an 18-year-old female patient who was first diagnosed with renal failure at 8 years of age and who had 7 years of peritoneal dialysis and then hemodialysis before kidney transplant from a deceased donor. Before transplant, the patient developed encapsulated peritoneal sclerosis and was treated with tamoxifen and steroids. Three years after transplant, the patient presented with complaints of vomiting, abdominal pain, and abdominal distension and was again diagnosed with encapsulated peritoneal sclerosis. The patient required excretory paracentesis, pulse steroid treatment for 3 days, and treatment with methylprednisone and tamoxifen, which resulted in regression of signs and symptoms. Factors such as long-term peritoneal dialysis, a history of bacterial peritonitis, and use of high-concentration dialysate may cause encapsulated peritoneal sclerosis, but symptoms can recur after transplant, as shown in our patient. Thus, it is important to recognize that encapsulated peritoneal sclerosis may cause graft loss due to the various complications that it can cause.

Value of Neutrophil-Lymphocyte and Platelet-Lymphocyte Ratios in the Evaluation of Acute Rejection and Chronic Allograft Nephropathy in Children With Kidney Transplantation.

OBJECTIVES: Neutrophil-to-lymphocyte ratio and platelet (thrombocyte)-to-lymphocyte ratio have become accepted markers of inflammation in recent years and are used to assess disease activity in some diseases. In this study, we investigated the relationship between these values and acute rejection attacks, as well as their role in determining chronic allograft nephropathy, in follow-up of pediatric kidney transplant recipients. MATERIALS AND METHODS: Our study included 58 kidney transplant recipients (age 5-18 years) with at least 5-year follow-up at our center. Patients with history of secondary transplant, concomitant malignancy, and shorter follow-up were excluded. Medical history and laboratory parameters pretransplant and at 1, 3, and 6 months and 1, 2, 3, 4, and 5 years posttransplant, as well as kidney biopsy reports, were reviewed. RESULTS: Both neutrophil-to-lymphocyte (P = .003) and thrombocyte-to-lymphocyte (P = .002) ratios were significantly higher during acute rejection attacks. Although both values were higher in patients with chronic allograft nephropathy at 5 years posttransplant, differences were not statistically significant (P = .69 and P = .55). When patients with and without chronic allograft nephropathy within 5 years were compared, those who developed chronic allograft nephropathy had significantly higher neutrophil- tolymphocyte and thrombocyte-to-lymphocyte ratios at all periods in the first 2 and 4 years posttransplant, respectively. Among patients who had acute rejection attacks, those who subsequently developed chronic allograft nephropathy had higher neutrophil-tolymphocyte ratio in the first 3 years posttransplant, with higher thrombocyte-to-lymphocyte ratio at all posttransplant periods. CONCLUSIONS: This is the first study on neutrophil- tolymphocyte and thrombocyte-to-lymphocyte ratios in pediatric kidney transplant recipients. Our results indicated that both values can be useful and easily accessible markers in acute rejection diagnosis and determining chronic allograft nephropathy development risk, which are 2 major causes of kidney graft loss posttransplant. Pediatric studies with larger populations are needed to support our findings.

Eculizumab treatment and discontinuation in pediatric patients with atypical hemolytic uremic syndrome: a multicentric retrospective study.

INTRODUCTION: Eculizumab is effective treatment of pediatric atypical hemolytic uremic syndrome (aHUS). However, the optimal duration of treatment is not clearly defined. The aim of this study was to retrospectively analyze the outcome of pediatric patients with aHUS, who started eculizumab treatment but discontinued it during the follow-up period. METHODS: The clinical and laboratory findings of the pediatric patients with aHUS were recorded on a web-based, national registry system, known as the Turkish aHUS Registry. The study included 63 patients who had to have received more than four doses of eculizumab during the acute phase of the disease. RESULTS: The median age at diagnosis was 3.62 (IQR: 1.29-6.14) years. During the follow-up period, 39 patients continued to receive standard eculizumab treatment (standard treatment group, treatment every 2 weeks) while 24 received an extended dose of eculizumab at three-four-week intervals (non-standard treatment group). There was no significant difference between both groups in terms of clinical and laboratory parameters. Eculizumab treatment was discontinued in 18 patients (30.7%, F/M:11/7), and the median age of these patients at diagnosis and their median follow-up duration were 4.0 (IQR:2.7-10.2) and 4.2 (IQR:2.2-7) years respectively. The median eGFR at the last visit was 110 (84.7-146.1)ml/min/1.73 m2. Fourteen patients remained in remission without any sign of the disease. Recurrence occurred in four (22.2%) patients, in which eculizumab was immediately started again and complete remission was achieved. CONCLUSION: Eculizumab is a successful treatment option in pediatric patients with aHUS and it can be safely discontinued with close monitoring in a selected group of patients. In case of recurrence, eculizumab should be restarted immediately to achieve complete remission.