Gastrointestinal involvement in STEC-associated hemolytic uremic syndrome: 10 years in a pediatric center.

BACKGROUND: The gastrointestinal (GI) tract represents one of the main targets of typical hemolytic uremic syndrome (HUS) in children. In this observational study, we tried to establish (1) the main features of GI complications during STEC-HUS and (2) the relationship between Escherichia coli serotypes and Shiga toxin (Stx) variants with hepatopancreatic involvement. METHODS: A total of 79 STEC-HUS patients were admitted to our pediatric nephrology department between January 2012 and June 2021. Evidence of intestinal, hepatobiliary, and pancreatic involvements was reported for each patient, alongside demographic, clinical, and laboratory features. Frequency of gastrointestinal complications across groups of patients infected by specific E. coli serotypes and Stx gene variants was evaluated. RESULTS: Six patients developed a bowel complication: two developed rectal prolapse, and four developed bowel perforation which resulted in death for three of them and in bowel stenosis in one patient. Acute pancreatitis was diagnosed in 13 patients. An isolated increase in pancreatic enzymes and/or liver transaminases was observed in 41 and 15 patients, respectively. Biliary sludge was detected in three, cholelithiasis in one. Forty-seven patients developed direct hyperbilirubinemia. Neither E. coli serotypes nor Shiga toxin variants correlated with hepatic or pancreatic involvement. CONCLUSIONS: During STEC-HUS, GI complications are common, ranging from self-limited elevation of laboratory markers to bowel perforation, a severe complication with a relevant impact on morbidity and mortality. Hepatopancreatic involvement is frequent, but usually short-lasting and self-limiting.

Therapeutic Approach for Recurrent Focal Segmental Glomerulosclerosis in Pediatric Renal Transplant Recipients: A Single-Center Experience.

INTRODUCTION: Recurrence of focal segmental glomerulosclerosis (FSGS) after kidney transplantation (KTx) develops in 40% of patients, leading to graft loss in half of cases. Extracorporeal apheretic treatments, combined with immunosuppressive drugs, seem to be the most promising therapies, but at now limited reports are available, mainly in pediatric patients. OBJECTIVE: We aimed to assess the efficacy of immunoadsorption (IA) to treat recurrent FSGS in pediatric patients. METHODS: We report a case series of 4 pediatric patients (aged 4-12 years) followed at our institution for early recurrent FSGS after KTx. FSGS recurrence was treated with early and intensive apheretic treatments IA. RESULTS: After IA initiation, a partial remission (PR) of proteinuria at 24-month follow-up was achieved only in 1 patient. The others showed a mild reduction of nephrotic proteinuria, without PR, but gained a significant improvement in clinical signs of nephrotic syndrome (reduction of edema, increased serum albumin, and total protein levels). After a median follow-up of 38 (22-48) months, renal function was almost stable over time in all patients, except one who returned to hemodialysis after 22 months. No severe IA-related complications occurred. CONCLUSIONS: According to our clinical experience, IA revealed as a safe and effective therapy to treat patients with recurrent FSGS after KTx and it could maintain stable renal function in 75% of patients.

Peripheral nervous system manifestations of Shiga toxin-producing E. coli-induced haemolytic uremic syndrome in children.

BACKGROUND: The Neurological involvement is the most common extra-renal complication of Shiga toxin-producing E. coli-hemolytic uremic syndrome (HUS) or typical HUS. On brain magnetic resonance examination, main neurological signs encompass acute lesions of the basal ganglia and the white matter, which could usually regress after Eculizumab infusion. In contrast, peripheral nervous system (PNS) manifestations in typical HUS are very rare and, when occurring, they require a careful management of neurological sequelae and an intensive multidisciplinary neuro-rehabilitation program. CASE PRESENTATION: Here, we present two pediatric cases of severe and complicated typical HUS with PNS manifestations who required therapeutic treatment and an intensive multidisciplinary neuro-rehabilitation program. In both cases, PNS manifestations were followed by the recovery from typical HUS-related severe central neurological damage and manifested mainly with marked bilateral motor deficit and hyporeflexia/areflexia in the lower limbs. The peripheral polyneuropathy was treated with immunosuppressive therapy (methylprednisolone boluses, i.v. immunoglobulins, plasma exchange), followed by a prolonged intensive neuro-rehabilitation program. After 8 months of rehabilitation, both patients gained complete functional recovery. CONCLUSIONS: PNS manifestations during typical HUS are a rare event and potentially leading to severe disability. A timely clinical assessment is mandatory to set up a prompt therapeutic and rehabilitation program and to obtain a complete clinical and functional recovery.

Low C3 Serum Levels Predict Severe Forms of STEC-HUS With Neurologic Involvement.

Background: The correlation between the severity of hemolytic uremic syndrome related to Shiga toxin-producing Escherichia coli (STEC-HUS) and involvement of the complement system has been examined in a small number of studies, with conflicting results. In the present study, we investigated whether serum C3 levels on admission are associated with neurologic involvement. Methods: To this purpose, 68 consecutive STEC-HUS patients were recruited and main clinical and laboratory variables ad hospital admission were compared between those with or without neurologic involvement. Results: STEC-HUS patients who developed neurologic involvement (NI) showed significant higher leukocyte count, C-reactive protein and hemoglobin, and lower sodium levels as compared with those without. Interestingly, baseline serum levels of C3 were significantly lower in patients with NI as compared with those without (p < 0.001). Moreover, when stratified according to need of Eculizumab rescue therapy due to severe NI, patients treated with this drug showed baseline C3 serum levels significantly lower than those who were not (p < 0.001). Low C3 was independent risk factor for NI in our patients' population when entered as covariate in a multivariate logistic regression analysis including other major variables previously proposed as possible predictors of poor prognosis in STEC-HUS (for instance, leukocyte count, c-reactive protein, sodium levels) (HR 6.401, 95%CI 1.617-25.334, p = 0.008 for C3). To underline the role of complement in the worsening of STEC-HUS patients' clinical conditions and outcomes, all patients were divided into two groups according to the baseline lower vs. normal serum levels of C3 and the main data on care needs were assessed. Interestingly more patients with lower C3 serum levels required renal replacement therapy (p = 0.024), anti-hypertensive therapy (p = 0.011), Intensive Care Unit admission (p = 0.009), and longer hospitalization (p = 0.003), thus displaying significantly more severe disease features as compared with those with normal C3 serum levels. Conclusions: Our data suggests that children with STEC-HUS with decreased C3 concentrations at admission are more likely to develop neurologic involvement and are at increased risk of having severe clinical complications.

Mid-Aortic Syndrome: A Rare Cause of Renovascular Hypertension in Childhood Treated Percutaneously with an Unusual Vascular Access.

INTRODUCTION: Mid-Aortic Syndrome (MAS) is a rare vascular malformation characterized by segmental narrowing of the abdominal aorta and stenosis of its principal branches. Patients affected by MAS typically present malignant renovascular hypertension, with variable clinical symptoms like claudication, abdominal angina, and headache. Moreover, they can develop other complications, such as hypertensive encephalopathy, congestive heart failure and vascular brain accidents. Hypertension with MAS is often resistant to multidrug therapy, requiring a surgical approach to treat the clinical symptoms, prevent or block organ damage and normalize the blood pressure. CASE REPORT: Here, the case of a 4-year-old boy showing elevated blood pressure with left ventricular hypertrophy leading to idiopathic MAS, who was successfully treated with percutaneous transcatheter renal angioplasty (PTRA) using an unusual, anterograde access, is reported. DISCUSSION AND CONCLUSION: In children and adolescents, vascular malformations like MAS must be considered as a possible cause of hypertension. PTRA is a successful therapeutic strategy in children with severe renovascular hypertension. Anterograde access, using an axillary artery, can be a valid approach for PTRA when femoral access is difficult to achieve.

Correction to: Case-management protocol for bloody diarrhea as a model to reduce the clinical impact of Shiga toxin-producing Escherichia coli infections. Experience from Southern Italy.

In the originally published article, the name of the 8th author Michele Quarto was inadvertently omitted during typesetting. Author's name is now correctly captured above. Also, the collaborators of the institutional group "Bloody Diarrhea Apulia Working Group" are also given here.

Case-management protocol for bloody diarrhea as a model to reduce the clinical impact of Shiga toxin-producing Escherichia coli infections. Experience from Southern Italy.

To describe an operating protocol for bloody diarrhea (BD) in a pediatric population as a rapid response to a public health threat represented by an excess of pediatric HUS cases in the Apulia region (Southern Italy) starting from 2013. The protocol was set up with the goal of correct clinical management of Shiga toxin-producing Escherichia coli (STEC) infections, reductions in subsequent cases of hemolytic uremic syndrome (HUS), and improved short- and long-term disease outcomes. The protocol consisted of rapid hospitalization of children with bloody diarrhea (BD), hematochemical laboratory tests every 12-24 hours, and prompt laboratory diagnosis of STEC. No antibiotics were recommended until diagnosis. Children positive for STEC infections underwent early vigorous volume expansion. In June-December 2018, 438 children with BD were hospitalized, of which 53 (12.1%) had a STEC infection. The most common serogroups were O26 (36.1%), O111 (23.0%), and O157 (14.8%). Thirty-one samples carried the stx2 gene. Four cases evolved into HUS (7.5%), all with favorable outcome despite neurological involvement in two cases. Prompt and accurate laboratory diagnosis of STEC infections is of the utmost importance in patients with BD for correct clinical management. The strict adherence to the protocol could reduce the progression rate of STEC infections to HUS and prevents complications. Enhanced BD surveillance may help reduce cases of pediatric HUS in Southern Italy.

Management of STEC Gastroenteritis: Is There a Role for Probiotics?

Shiga toxin-producing Escherichia Coli (STEC) infections routinely run as a common gastroenteritis, but in many cases they may evolve towards hemolytic uremic syndrome (HUS). HUS is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Gut microorganisms have a fundamental impact on human physiology, because they modulate normal intestinal functions and play a pivotal role in influencing the local and systemic immune responses. Despite surveillance established in many countries and major progresses in the understanding of STEC-HUS mechanisms, no specific treatment is currently available. Targeting the gut microbiota could represent a new potential therapeutic strategy in STEC infection. In this paper, we reviewed the current knowledge about microbiota characteristics of patients with STEC infections, as well as in vitro and in vivo evidence of probiotic supplementation in managing STEC gastroenteritis and in HUS onset prevention.

From Uganda to Italy: a case of nephrotic syndrome secondary to Plasmodium infection, Quartan malarial nephropathy and kidney failure.

Gentile F, Martino M, Santangelo L, Giordano P, Torres DD, Carbone V, Di Palma AM, Rossini M, Gesualdo L, Giordano P, Giordano M. From Uganda to Italy: a case of nephrotic syndrome secondary to Plasmodium infection, Quartan malarial nephropathy and kidney failure. Turk J Pediatr 2019; 61: 776-779. Malaria (M), the first parasitic infection, is sometimes associated with nephrotic syndrome (NS) in tropical areas. Kidney involvement during quartan malaria is represented by immune-complex mediated glomerulonephritis (GN). Generally, NS develops several weeks after onset of quartan fever and its clinical course proceeds slowly to end-stage kidney disease (ESKD) even after eradication of the infection. We describe a case of Plasmodium malariaeassociated nephrotic syndrome and chronic proliferative glomerulopathy in a boy from Uganda. Renal biopsy revealed chronic proliferative GN with capillary wall thickening producing a double contour, segmental sclerosis and tubular atrophy. Blood Giemsa smear contained rare ring-form trophozoites and gametocytes of Plasmodium spp. This case highlights the importance of obtaining remote travel histories from immigrants presenting with nephrotic syndrome especially due to the current immigration crisis in Europe. Malaria has low prevalence or less known in our continent and requires more medical attention by European doctors.

A pediatric neurologic assessment score may drive the eculizumab-based treatment of Escherichia coli-related hemolytic uremic syndrome with neurological involvement.

BACKGROUND: Thrombotic microangiopathy (TMA) is a clinical syndrome encompassing a large group of rare but severe disorders including thrombotic thrombocytopenic purpura (TTP) and both typical and atypical forms of hemolytic uremic syndrome (HUS). The key role of the complement system is well known in TTP and atypical HUS, but recent reports describe its involvement in the pathogenesis of HUS secondary to gastrointestinal infections due to Shiga toxin-producing Escherichia coli (STEC). METHODS: TMA mainly affects the kidney, but extra-renal complications are frequently described. The involvement of the central nervous system (CNS) represents often a life-threatening condition and it can result in serious long-term disability in HUS patients who overcome the acute phase of illness. In the present study, we retrospectively analyzed a pediatric cohort of a single tertiary pediatric hospital in Southern Italy, in which this complication occurred in 12/54 children (22% of cases), of whom five with severe neurological involvement had been successfully treated with eculizumab. RESULTS: The great clinical variability of brain injury in our cohort has led us to retrospectively build a "neurological score" useful to assess the clinical severity of neurologic involvement. Subjects with higher neurologic score due to the most severe CNS involvement resulted in the group of patients early treated with eculizumab, obtaining a good clinical response (four out five patients). In conclusion, the early treatment with eculizumab in children with severe neurological involvement during STEC-HUS was associated with complete regression of both acute kidney injury (AKI) and neurological lesions observed at magnetic resonance imaging (MRI). CONCLUSIONS: A "neurological score" may be a useful tool to drive the early treatment of CNS complications in STEC-HUS with eculizumab, although future perspective controlled studies are urgently needed to validate this therapeutic approach.

Indications and results of renal biopsy in children: a 36-year experience.

BACKGROUND: This study was conducted to investigate retrospectively the indications for renal biopsy (RB) in native kidneys and to analyze pathological findings in a single tertiary pediatric hospital in Southern Italy for the last 36 years. METHODS: All patients who underwent RB at our hospital from 1979 to 2014 were included. All renal tissue specimens were studied under light and immunofluorescent microscopy, while electron microscopy was performed only for specific clinical indications. RESULTS: The study group included 213 patients (female 43.2%) who underwent 225 percutaneous native kidney biopsies. Median age was 10.4 years (range 0.6-24 years). The most frequent indication for RB was nephrotic syndrome (44.4%), followed by proteinuria (27.6%), asymptomatic hematuria (17.3%) and acute kidney injury (9.8%). Gross hematuria appeared after biopsy in less than 5% of the patients, but none of them needed blood transfusion. Adequate renal tissue sample was obtained in 95.5% of the renal biopsies. Primary glomerulonephritis (GN) was the most common finding (61.4%), followed by secondary GN (21.4%), tubulointerstitial diseases (3.7%) and hereditary nephropathy (2.8%), while in 10.7% of the cases, normal renal tissues were found. According to histopathological diagnosis, the most common causes of primary GN were IgA nephropathy (20.9%), followed by minimal change disease (18.1%) and focal segmental glomerulosclerosis (11.6%). CONCLUSIONS: The epidemiology of glomerular disease in our single-center cohort is similar to that shown in other national and international reports. Moreover, our study shows that percutaneous ultrasound-guided RB is a safe, reliable and effective technique in children.

Community-wide outbreak of haemolytic uraemic syndrome associated with Shiga toxin 2-producing Escherichia coli O26:H11 in southern Italy, summer 2013.

In summer 2013, an excess of paediatric cases of haemolytic uraemic syndrome (HUS) in a southern region of Italy prompted the investigation of a community-wide outbreak of Shiga toxin 2-producing Escherichia coli (STEC) O26:H11 infections. Case finding was based on testing patients with HUS or bloody diarrhoea for STEC infection by microbiological and serological methods. A case-control study was conducted to identify the source of the outbreak. STEC O26 infection was identified in 20 children (median age 17 months) with HUS, two of whom reported severe neurological sequelae. No cases in adults were detected. Molecular typing showed that two distinct STEC O26:H11 strains were involved. The case-control study showed an association between STEC O26 infection and consumption of dairy products from two local plants, but not with specific ready-to-eat products. E.coli O26:H11 strains lacking the stx genes were isolated from bulk milk and curd samples, but their PFGE profiles did not match those of the outbreak isolates. This outbreak supports the view that infections with Stx2-producing E. coli O26 in children have a high probability of progressing to HUS and represent an emerging public health problem in Europe.

Mutational Spectrum of CYP24A1 Gene in a Cohort of Italian Patients with Idiopathic Infantile Hypercalcemia.

BACKGROUND/AIMS: Loss-of-function mutations in the CYP24A1 gene, which encodes the vitamin D-24 hydroxylase, have been recognized as a cause of elevated 1,25-dihydroxyvitamin D concentrations, hypercalcemia, hypercalciuria, nephrocalcinosis and nephrolithiasis in infants and adults. As only a case report describing 2 adult patients has been reported in Italian population, we report here the mutation analysis of CYP24A1 gene in an Italian cohort of 12 pediatric and adult patients with idiopathic infantile hypercalcemia (IIH). METHODS: We performed mutational screening of CYP24A1 gene in a cohort of 12 Italian patients: 8 children with nephrocalcinosis, hypercalcemia and PTH levels <10 pg/ml and 4 adult patients with nephrolithiasis, mild hypercalcemia and PTH levels <10 pg/ml from 11 unrelated Italian families. Clinical and biochemical data were collected. Genomic DNA was extracted from peripheral blood leucocytes using standard methods, and whole coding sequence of CYP24A1 gene was analysed in all patients and family members by polymerase chain reaction and direct sequencing. The potential pathogenicity of the newly identified missense mutations was evaluated by 3 different in silico approaches (Sorting Intolerant from Tolerant, Polyphen and Mutation Taster) and by comparative analysis in 14 different species using ClustalW software. RESULTS: CYP24A1 bi-allelic mutations were found in 8 individuals from 7 Italian families (7/11; 64%). Overall, 6 different CYP24A1 mutations, including one small deletion (p.Glu143del), 4 missense mutations (p.Leu148Pro; p.Arg396Trp; p.Pro503Leu; p.Glu383Gln) and one nonsense mutation (p.Tyr220*) were identified. Two out of 6 mutations (p.Tyr220* and p.Pro503Leu) were not previously described. Moreover, a new CYP24A1 variant was identified by genetic screening of asymptomatic controls. CONCLUSION: To the best of our knowledge, this is the first report of a CYP24A1 molecular analysis performed in an Italian cohort of adult and pediatric Italian patients. This study (1) confirms that CYP24A1 plays a causal role in some but not all cases of IIH (64%); (2) expands the spectrum of known CYP24A1 pathogenic mutations; (3) describes 2 hotspots detected in 50% of all Italian cases; and (4) emphasizes the importance of recognition and genetic diagnosis of CYP24A1 defects in infantile as well as adult hypercalcemia.

Aneurysmal bone cyst does not hinder the success of kidney transplantation. A case report.

Uremic osteodystrophy is an expected complication in subjects with chronic renal insufficiency. It develops gradually and progressively already during the conservative treatment and then during the dialysis treatment. It can present a wide histopathological spectrum including typical alterations (from osteitis fibrosa to osteomalacia and/or mixed lesions) or, more rarely, isolated bone lesions indicative of a brown tumor of the bone. These conditions must be clearly identified in the pretransplant phase, especially if a bone lesion indicative of a pathological condition possibly evolving into a neoplasm is detected fortuitously. We report the case of a 19-yr-old boy with renal insufficiency and candidate for a pre-emptive renal transplantation from a living donor, in whom the diagnosis of ABC of the pubic symphysis - asymptomatic and fortuitously detected while performing instrumental investigations - was suspected through the imaging studies (CT scan, MRI) and was confirmed by the histological examination. This made it possible to perform the renal transplant. The immunosuppressive treatment, which was subsequently administered, was based on steroids, calcineurin inhibitors (tacrolimus), and mycophenolate and did not determine any modification in the radiological aspect of the bone lesion, even after more than one yr from the transplant.

A novel SMARCAL1 mutation associated with a mild phenotype of Schimke immuno-osseous dysplasia (SIOD).

BACKGROUND: Schimke immuno-osseous dysplasia (SIOD, OMIM #242900) is an autosomal-recessive pleiotropic disorder characterized by spondyloepiphyseal dysplasia, renal dysfunction and T-cell immunodeficiency. SIOD is caused by mutations in the gene SMARCAL1. CASE PRESENTATION: We report the clinical and genetic diagnosis of a 5-years old girl with SIOD, referred to our Center because of nephrotic-range proteinuria occasionally detected during the follow-up for congenital hypothyroidism. Mutational analysis of SMARCAL1 gene was performed by polymerase chain reaction (PCR) and bidirectional sequencing. Sequence analysis revealed that patient was compound heterozygous for two SMARCAL1 mutations: a novel missense change (p.Arg247Pro) and a well-known nonsense mutation (p.Glu848*). CONCLUSION: This report provided the clinical and genetic description of a mild phenotype of Schimke immuno-osseous dysplasia associated with nephrotic proteinuria, decreasing after combined therapy with ACE inhibitors and sartans. Our experience highlighted the importance of detailed clinical evaluation, appropriate genetic counseling and molecular testing, to provide timely treatment and more accurate prognosis.