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Maryem Ferjani,1 Yosra Zaimi,2 Nouha Trad,2 Yousra Hammi,1 Myriam Ayari,2 Shema Ayadi,2 Taha Sayari,1 Tahar Gargah1 1Department of Pediatrics, Charles Nicolle Hospital, Tunis, Tunisia; 2Department of Gastroenterology, Charles Nicolle Hospital, Tunis, TunisiaCorrespondence: Nouha Trad, Department of Gastroenterology, Charles Nicolle Hospital, Boulevard of April 9, 1938, Bab Saadoun, Tunis, 1007, Tunisia, Tel +216 50858104, Email nouha1med7@gmail.comBackground: Nephrotic syndrome (NS) is associated with a hypercoagulable state and may be complicated by thrombotic events. Venous thrombosis is well-acknowledged, while arterial thrombosis is rather unusual.Case Presentation: We present the case of a 20-year-old woman with a 12-year history of idiopathic NS revealed by extensive cerebral venous thrombosis with pulmonary embolism treated with anticoagulation therapy and oral corticosteroid therapy followed by mycophenolate mofetil (MMF). The thrombophilia assessment did not show any abnormalities. The evolution was marked by the occurrence of several NS relapses controlled by oral corticosteroid therapy until 2017. Subsequently, the patient had not presented a relapse of her disease. The anticoagulant treatment and the MMF were therefore stopped. One year later, the patient presented with severe diffuse acute abdominal pain associated with postprandial vomiting and bilateral lower limb edema. Laboratory results confirmed a NS relapse. An abdominal CT scan revealed acute thrombosis of the superior mesenteric artery with acute mesenteric ischemia. Intraoperative exploration showed mesenteric ischemia with extensive necrosis of the small intestine making their resections incompatible with life. The patient died after 48 hours.Conclusion: Mesenteric arterial thrombosis, which is a rare but life-threatening NS complication, should always be considered, especially in the case of acute non-specific digestive symptoms.Keywords: nephrotic syndrome, mesenteric ischemia, recurrence

Introduction: Children undergoing long-term hemodialysis (HD) face a reduction in life expectancy mostly due to cardiovascular mortality. Effects of HD on cardiac function have not been fully elucidated in pediatric population., Aim: This study aimed to assess HD session impact on cardiac function in pediatric patients using conventional and strain echocardiography., Methods: We performed a prospective, comparative study of echocardiographic parameters before and after single HD session in a chronic HD pediatric population. We enrolled between the 1st and 30th September 2023, all consecutive patients with end-stage renal disease (ESRD) aged up to 18 years old on maintenance HD three times weekly for at least three months. All patients underwent conventional and left ventricular (LV) longitudinal strain echocardiography in a window of 30-60 minutes before and after HD., Results: 23 patients, 14.8 ± 2.1 years old and 47.8% male, were enrolled. Reductions in body weight and blood pressure were observed after HD, whereas heart rate increased. Significant decrease in LV and left atrial diameters and volumes after HD session were observed. Mitral peak E velocity, as well as average E/e' were significantly lower after HD. Although LV ejection fraction was unchanged, global longitudinal strain for LV was significantly reduced after dialysis (-17.3 ± 3.0% vs. -14.9 ± 2.4%, p=4.10-8)., Conclusion: Patent deterioration in LV systolic function following HD was identified by speckle tracking echocardiography (STE). STE has the potential to unmask early myocardial dysfunction even when there is no evident alteration in conventional systolic function parameters in children with ESRD.

Background: Alport syndrome is a genetic disorder affecting the kidneys, ears, and eyes, causing chronic kidney disease, sensorineural hearing loss, and ocular abnormalities. It results from pathogenic variants in the COL4A3, COL4A4, or COL4A5 genes, with different inheritance patterns: X-linked from COL4A5 variants, autosomal recessive from homozygous variants in COL4A3 or COL4A4, digenic from variants in both COL4A3 and COL4A4, and autosomal dominant from heterozygous variants in COL4A3 or COL4A4., Methods: We analyzed 45 patients with Alport syndrome from 11 Tunisian families to determine their clinical and genetic characteristics. Clinical data were collected retrospectively, and whole-exome sequencing was conducted on one patient from each family. Sanger sequencing validated pathogenic variants, and cascade screening extended the analysis to 53 individuals., Results: We identified nine likely pathogenic variants among 11 index cases: six novel and three known variations. Of these, five were in COL4A3, and four were in COL4A5, with variants including frameshift, nonsense, missense, and alternative splicing. Most variations affected the Gly-XY codon. Among the 45 clinically identified siblings, 30 tested positive for Alport syndrome. The cascade screening identified 3 additional affected individuals, 10 unaffected siblings, and 10 unaffected parents. The mode of inheritance was autosomal recessive in six families and X-linked in four families., Conclusions: This study is the first to screen the mutational spectrum of Alport syndrome in Tunisia. It reveals novel pathogenic variants and suggests that autosomal recessive inheritance may be more common in the Tunisian population than X-linked inheritance, contrary to existing literature., Competing Interests: Declarations. Ethics approval: The study was performed according to the ethical standards of the Ethics Committee of Charles Nicolle Hospital. Conflict of interest: The authors declare no competing interests. Preprint disclosure: This manuscript has been posted on a preprint server https://doi.org/10.21203/rs.3.rs-3645854/v1 ., (© 2024. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Polyuria-polydipsia syndrome is a frequent symptom in pediatrics, primarily attributed to diabetes mellitus. In the context of diabetes insipidus, this syndrome can stem from central or nephrogenic factors. Sjögren's syndrome, an uncommon autoimmune disease in children, can affect multiple organs. Kidney involvement as described in adults is usually related to glomerular or tubular impairment, often linked to distal tubular acidosis. As a kidney involvement during childhood, Sjögren's syndrome has rarely been reported. Hereby, we present the case of Sjögren's syndrome revealed by polyuria-polydipsia syndrome in a 10-year-old boy., (© 2023. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Introduction: Pediatric end-stage renal disease is a rare but severe condition that causes numerous complications and impairs the quality of life of children. Kidney transplantation is the therapy of choice in pediatric end-stage renal disease., Aim: Our study aimed to identify the predictive factors of renal graft failure after kidney transplantation in Tunisian children and young adults., Methods: We conducted a retrospective bicentric study of children and young adults (age≤20 years) who had undergone renal transplantation between 1989 and 2019 in Tunisia. We analyzed long-term survival rates and complications after pediatric kidney transplantation and searched for predictive parameters for graft dysfunction. We used a univariate and a multivariate analysis to identify predictive factors of graft survival., Results: A total of 112 patients underwent 115 kidney transplantations. Graft failure occurred in 30% of the cases. The overall 1-, 3-, 5- and 10-year graft survival rates were 92%, 89.1%, 85.9% and 74.5% respectively. The following parameters strongly influenced graft survival: immunosuppressive regimen including an association other than Mycophenolate mofetil- tacrolimus and corticosteroids (p=0.002), year of transplant (p<0.0001 for 1987-2000), deceased donor (p = 0.039), underlying etiology of end-stage renal disease (p=0.045), occurrence of acute or chronic rejection (p<0.001), a urine protein greater than 0.3 g/l per day (p=0.002), post-transplant urologic complications (p=0.002), five-year creatinine level>1.28 mg/dl (p<0.001). The overall 1-, 3-, 5- and 10-year patients survival rates were 97%, 95%, 90.2% and 84.4% respectively., Conclusions: Our study identified several predictive factors of graft failure in Tunisian children and young adults undergoing renal transplantation.

Objectives: We aimed to identify risk factors and outcomes of delayed graft function in pediatric kidney transplant., Materials and Methods: This retrospective study included all kidney transplant recipients ≤19 years old followed up in our department for a period of 34 years, from January 1989 to December 2022., Results: We included 113 kidney transplant recipients. Delayed graft function occurred in 17 cases (15%). Posttransplant red blood cell transfusion was strongly associated with delayed graft function (adjusted odds ratio = 23.91; 95% CI, 2.889-197.915). Use of allografts with multiple arteries and cold ischemia time >20 hours were risk factors for delayed graft function (adjusted odds ratio = 52.51 and 49.4; 95% CI, 2.576-1070.407 and 1.833-1334.204, respectively). Sex-matched transplants and living donors were protective factors for delayed graft function (adjusted odds ratio = 0.043 and 0.027; 95% CI, 0.005-0.344 and 0.003-0.247, respectively). Total HLA mismatches <3 played a protective role for delayed graft function (adjusted odds ratio = 0.114; 95% CI, 0.020-0.662), whereas transplant within compatible but different blood types increased the risk of delayed graft function (adjusted odds ratio = 20.54; 95% CI, 1.960- 215.263). No significant correlation was shown between delayed graft function and allograft survival (P = .190). Our study suggested delayed graft function as a key factor in allograft rejection-free survival (adjusted odds ratio = 3.832; 95% CI, 1.186-12.377). Delayed graft function was a negative factor for early graft function; patients with delayed graft function had a lower estimated glomerular filtration rate at discharge (P = .024) and at 3 (P = .034), 6 (P = .019), and 12 months (P = .011) posttransplant., Conclusions: Delayed graft function is a major determinant of early graft function and allograft rejection-free survival. Further research is required to establish proper preventive measures.

Objectives: Attitudes and knowledge toward organ donation can influence a person's willingness to donate. The aim of this study was to assess attitudes and knowledge regarding organ donation among Tunisian adults., Materials and Methods: We conducted a crosssectional survey at the national level from January 23 to February 15, 2017, among 1026 Tunisian adults. We used a standardized questionnaire to collect data by phone call. We performed statistical analyses with Stata software (version 11)., Results: The study included 495 male and 531 female participants. Forty-one percent of participants were 18 to 30 years old. In total, 81.7% had heard about organ donation. Fewer than half of respondents (47.8%) were aware that organ donation is regulated. In total, 80.7% accepted to donate their organs after death, and 32.2% had mentioned their opinion to relatives or friends. Only 1% had added their donor status on their national identity cards., Conclusions: Tunisian adults seem to have positive attitudes regarding organ donation. However, the proportion of respondents who included their donor status on their national identity cards was low. It is important to enhance information and education on organ donation in an effort to mitigate the shortage of organs.

Background: Childhood vesico-sphincteric disorders are the cause of functional and psychological disability. They are also responsible for serious uronephrologic complications akin to neuro-bladder complications. In this study, we looked for the clinical manifestations linked to these disorders as well as the paraclinical and urodynamic anomalies and their therapeutic management., Methods: We carried out a retrospective and descriptive study of patients with vesico-sphincteric disorders, followed in the pediatrics department of Charles Nicolle hospital in Tunis., Results: In total 26 patients were included in our study. The median age at the first consultation in a pediatric nephrology department was 9 years (IQR 25 = 6 years; IQR 75 = 11 years). There was a predominance of girls: 19 boys and 43 girls. The filling phase and the voiding phase were dominated by the combination of three or more symptoms. Bladder tenderness was reduced in 12% of cases. Nineteen percent of patients reported post micturition dribble in the post-voiding phase. The flow rate curve was polyphasic in 36% of cases and flat in 11% of cases. The median of the post void residual was 62, 2 mL (IQR 25 = 25 mL; IQR 75 = 102 mL). Cystometry showed reduced bladder sensation in 14% of cases, detrusor overactivity in 65% of cases, bladder hypocontractility in 8% of cases, hypocompliant bladder in 42% of cases and small capacity in 88% of cases. Sphincter dysynergia was noted in 34% of patients. Anticholinergics were the most used in the treatment of disorders (53%). Renal failure was noted in 45% of the patients of which 11% had end-renal stage failure. During follow-up 16% of our patients required kidney replacement therapy., Conclusion: Given the seriousness of vesico-sphincteric disorders in children and the late discovery in the majority of cases at the complication stage, targeted primary prevention must be carried out based on continuous training of primary care physicians to minimize the appearance of complications involving the functional and vital prognosis of these children.

Introduction: Nephronophthisis (NPHP) is a tubulointerstitial kidney disorder with an autosomal recessive inheritance pattern. Its genetic heterogeneity contributes to phenotype variability. The most frequent etiology of juvenile nephronophthisis is a mutation in the nephronophthisis type 1 ( NPHP1 ) gene. This study aimed to evaluate the genotype-phenotype correlation in NPHP1 gene mutation., Methods: A multicenter retrospective study was performed over 20 years from 1998 to 2018 to describe the clinical, biological, and radiological features associated with the large deletion NPHP1 gene in 32 patients., Results: The incidence of NPHP1 was 1.6/204041. Eighty-one percent of our patients were born out of consanguineous marriages. The mean age at diagnosis was 14 ± 7 years. The patients were divided into three groups: isolated nephronophthisis (72%), syndromic nephronophthisis (19%), and patients without recognizable syndrome (9%). Intrafamilial and geographical variability was observed in syndrome diagnoses and in age at the onset of CKD stage 5. Genotype frequency varied between 50% and 100% in genealogical data. Juvenile (47%), adolescent (37%), and adult (13%) clinical forms have been distinguished by the onset of CKD stage 5. The five-year survival rate of renal transplantation was 80%., Conclusion: Given the broad clinical spectrum of NPHP1 associated with the large deletion of the NPHP1 gene, no genotype-phenotype correlation could be established., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Indian Journal of Nephrology.)

Introduction: Peritoneal dialysis (PD) is the method of choice for extra-renal replacement therapy (ERT) for children with end-stage renal disease (ESRD), because of its various advantages. However, it presents different infectious and non-infectious complications, causes of important morbidity and mortality., Aim: To determine the mechanical complications of PD in our center and to identify risk factors of their occurrence., Methods: We retrospectively collected the records of 99 patients who were treated with PD within the past eleven years in the department of pediatrics of the University Hospital Charles Nicolle of Tunis. Analysis examining possible risque factors were performed using parametric and non-parametric tests., Results: A total of 63 patients had mechanical complications with an incidence of peritoneal dialysis catheter revision of 1 procedure every 38 months. The causes were dominated by catheter migration (27.5%) and obstruction by fibrin or blood clotting (19.8%). A history of peritonitis (p=0.046) and the presence of comorbidity (p=0.008) were the two independent risk factors for catheter revision. Inguinal hernia was noted in six patients. No patient presented with a hydrothorax. Seven patients presented an episode of hemoperitoneum., Conclusion: Our results lead us to focus our efforts on preventing peritonitis and controlling morbidity. Prospective studies will enable us to confirm our results.

Introduction: Distal renal tubular acidosis (dRTA) is a rare genetic disorder due to the incapacity of the α intercalated cells to excrete protons in the collecting duct. This impaired distal acidification of urine leads to a chronic hyperchloremic metabolic acidosis with a normal plasma anion gap, hypokalemia, and hypercalciuria with hypocitraturia causing nephrocalcinosis. Primary dRTA is inherited either as an autosomal dominant (SLC1A4 gene) or autosomal recessive trait (ATP6V0A1/ATP6V1B1 genes)., Aim: To analyze the genotype-phenotype correlation of dTA in Tunisia., Methods: In this study we present all available data of patients followed in our center for dRTA over the last 28 years and who had a genetic study. This was a retrospective descriptive study from January 1991 to December 2018, conducted in the Pediatrics Department of the Charles Nicolle Hospital in Tunis., Results: Twenty-five cases of dRTA were collected and were offered genetic analysis to confirm the diagnosis. The molecular mutation was confirmed in 13 patients of whom 11 had homozygous mutations in ATP6V1B1(G1) and 2 had homozygous mutations in ATP6V0A4(G2). Median age of diagnosis was 8.9 months. Severe growth retardation was documented in nine children with mutations in ATP6V1B1, in eight children with no genetic mutation and in the two patients with a mutation in ATP6V0A4. All children were found to have metabolic acidosis at initial presentation. Hypokalemia was found in 19 children. All patients were polyuric. Twenty-two patients had nephrocalcinosis (88%). The treatment was based on alkali prescription and substitution of potassium chloride. Sensorineural hearing loss (SNHL) was documented in 12 children. At the last consultation, 14 patients had chronic kidney disease (CKD) stage 2 or higher, 8 of whom were in the group with negative genetic analysis., Conclusion: According to the early onset in patients, the recessive mode seems to be the mode of transmission in Tunisia. dRTA was long considered to not affect renal function, but we note a decline in eDFG.

Background: Takayasu arteritis is a rare and chronic granulomatous vasculitis that affects the large vessels. Takayasu arteritis targets the aorta and its branches and is still of unknown etiology. It often affects female patients under 50 years of age. A relationship between Takayasu arteritis and tuberculosis has been suggested for a long time., Case Presentation: We report a severe case of Takayasu arteritis in a 10-year-old Tunisian child revealed by renovascular hypertension with concomitant pulmonary tuberculosis., Conclusions: Our patient is among only a few cases of Takayasu arteritis published worldwide affecting young infants and adolescents, which underlines the strong relationship between Takayasu arteritis and tuberculosis., (© 2023. The Author(s).)

Introduction: There are three types of primary hyperoxaluria, with type 1 considered the most severe., Aim: To analyze the clinical, genetic, and evolutionary characteristics of type 1 primary hyperoxaluria with pediatric onset., Methods: This was a retrospective, descriptive study that included Tunisian children under the age of 18 at the time of diagnosis over a period of 25 years (January 1, 1996, to December 31, 2022)., Results: Thirty-five patients were included, with a mean age of 4.1 years. The most common presenting circumstances of the disease were nephrolithiasis and end-stage renal failure. The average serum creatinine level was 225.42 µmol/l. Five mutations were identified, with the p.Ile244Thr mutation being the most prevalent. Nephrocalcinosis, surgical intervention, and a creatinine level ≥57 µmol/l were predictive of progression to end-stage renal failure. The infantile form was predictive of mortality., Conclusions: Screening for the disease would improve the prognosis of this condition.