Relapsing and refractory peritoneal dialysis peritonitis caused by Corynebacterium amycolatum.

BACKGROUND: Peritonitis is an important complication and cause of morbidity in patients undergoing peritoneal dialysis (PD). Corynebacterium species, often considered skin and mucosal contaminants, are a rare cause of PD-associated peritonitis and have been acknowledged in published guidelines for the diagnosis and treatment of PD peritonitis only over the last decade. CASE-DIAGNOSIS/TREATMENT: We present two children with difficult-to-treat episodes of PD peritonitis due to Corynebacterium amycolatum. Episodes were associated with fever, abdominal pain and cloudy dialysate, high dialysate polymorphonuclear leukocyte counts, and elevated serum C-reactive protein and procalcitonin concentrations. Symptoms persisted beyond 5 days in 4 of 5 peritonitis episodes, and peritonitis relapsed despite in vitro sensitivity of the bacterial isolates to guideline-recommended antibiotics. C. amycolatum was cultured from the PD catheter tip despite 4 weeks of intraperitoneal glycopeptide therapy and clinical peritonitis resolution suggestive of efficient biofilm formation. Our systematic literature search identified three previous (adult) case descriptions of C. amycolatum peritonitis, all with repeat episodes by the same organism. The incidence of C. amycolatum as a cause of PD peritonitis has not yet been established but is likely underreported due to challenges in species differentiation. CONCLUSIONS: C. amycolatum is a rarely identified cause of refractory and/or relapsing PD peritonitis. Species differentiation of non-diphtheriae Corynebacterium isolates is critical, and prolonged antibiotic treatment, preferably with a glycopeptide antibiotic, is recommended, with a low threshold for PD catheter change or removal in case of repeat peritonitis.

A Multicenter Study Evaluating the Discontinuation of Eculizumab Therapy in Children with Atypical Hemolytic Uremic Syndrome.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening thrombotic microangiopathy (TMA), which has been treated successfully with eculizumab. The optimal duration of eculizumab in treating patients with aHUS remains poorly defined. METHODS: We conducted a multicenter retrospective study in the Arabian Gulf region for children of less than 18 years of age who were diagnosed with aHUS and who discontinued eculizumab between June 2013 and June 2021 to assess the rate and risk factors of aHUS recurrence. RESULTS: We analyzed 28 patients with a clinical diagnosis of aHUS who had discontinued eculizumab. The most common reason for the discontinuation of eculizumab was renal and hematological remission (71.4%), followed by negative genetic testing (28.6%). During a median follow-up period of 24 months after discontinuation, 8 patients (28.5%) experienced HUS relapse. The risk factors of recurrence were positive genetic mutations (p = 0.020). On the other hand, there was no significant relationship between the relapse and age of presentation, the need for acute dialysis, the duration of eculizumab therapy before discontinuation, or the timing of eculizumab after the presentation. Regarding the renal outcomes after discontinuation, 23 patients were in remission with normal renal function, while 4 patients had chronic kidney disease (CKD) (three of them had pre-existing chronic kidney disease (CKD) before discontinuation, and one case developed a new CKD after discontinuation) and one patient underwent transplantation. CONCLUSIONS: The discontinuation of eculizumab in patients with aHUS is not without risk; it can result in HUS recurrence. Eculizumab discontinuation can be performed with close monitoring of the patients. It is essential to assess risk the factors for relapse before eculizumab discontinuation, in particular in children with a positive complement variant and any degree of residual CKD, as HUS relapse may lead to additional loss of kidney function. Resuming eculizumab promptly after relapse is effective in most patients.

Practice of Childhood Nephrotic Syndrome Management amongPediatric Nephrologists in the GCC Countries.

Childhood nephrotic syndrome (NS) management is greatly variable among pediatric nephrologists worldwide. We aimed to evaluate if this variability exists among pediatric nephrologists in the gulf countries and whether certain training programs influence this variability. A web-based multiple-choice survey of 35 NS management questions distributed to certified pediatric nephrologists working in the Gulf countries. Amongst 92 invitees, the response rate was 67%. The majority (73%) were older than 50 years and male (58%). Sixty percent trained in North America and 41% had >10 years of experience. Sixty-three percent use a 12- week corticosteroids regimen for the initial treatment of childhood NS and only 10% never consider long-term small alternate dose corticosteroids therapy to sustain remission before commencing a corticosteroids-sparing agent for frequently relapsing or corticosteroids-dependent NS. Mycophenolate mofetil was the drug of choice for frequently relapsing and corticosteroids dependent NS in 51% and 58% of the participants, respectively, whereas calcineurin inhibitors were preferred by the vast majority (95%) of the participants for corticosteroids-resistant childhood NS. Regarding rituximab treatment, almost half of the participants (48%) give two doses of rituximab one to two weeks apart and 61% do not give another course of rituximab until the child relapse. Fellowship training site and the duration of the clinical experience did not seem to influence certain management of childhood NS. As shown in North American studies, great variability in the management of childhood NS does exist in the Gulf countries. The country of fellowship training and the experience did not seem to contribute to this variability.