Introduction: Atypical Hemolytic Uremic Syndrome (HUS) is defined as a heterogeneous group of disorders. Plasma infusion or plasma exchange is the rescue therapy for this life-threatening Syndrome. There is no evidence for the volume of plasma required to induce remission. Materials and Methods: Between 2007 and 2018, Forty – two patients (M=20, F=22) with a diagnosis of recurrent or familial Atypical Hemolytic Uremic Syndrome (aHUS) who were admitted to Ali-Asgar Children’ s Hospital were enrolled in this observational retrospective study. The total volume of plasma required for normalizing platelet (>150000) and LDH (<500 IU), eliminating hemolysis, and decreasing serum creatinine at first presentation of disease was calculated. Patients with TTP, vasculitis, and post infectious HUS were excluded. Results: The mean age of the patients was 53 months (3-144 m). The majority of patients achieved remission at first presentation by plasma infusion (5 under peritoneal dialysis and 4 under hemodialysis) but ten patients required plasmapheresis. A total of 980 units of FFP perfused with a total volume of 195. 975 L. The median (range) total plasma volume required for remission was 166 ml/kg (43-2850 ml/kg). Conclusions: This study showed that the required plasma volume for the acute phase of Atypical HUS for controlling the first attack of disease.

Introduction. Atypical Hemolytic Uremic Syndrome (aHUS) is associated with mutations or antibodies that affect the regulation of the alternative complement pathway. Several studies were published recently, describing these mutations. We present the initial clinical findings, treatments, and long-term follow-up results of 19 patients hospitalized with the diagnosis of aHUS. Methods. Nineteen patients who were diagnosed as aHUS were enrolled from January 2010 to March 2017. Initial clinical signs and clinical follow-up of patients with aHUS were evaluated. The reasons for complement factor H (CFH) mutations were investigated. Results. CFH mutations were detected in 5 of the 19 aHUS cases. Of these, one was novel, while four were previously reported. We reported here the clinical course of aHUS patients with CFH previously defined mutations (p. Glu936Asp, Val 1197Ala) and a novel mutation (Glu927Lys), which caused previously defined aHUS. Two of the CFH mutation cases developed end-stage kidney disease that required hemodialysis, and one patient developed chronic kidney disease. Two cases were in remission; one of them under supportive therapy and the other one in remission with eculizumab treatment. Conclusions. Morbidity rates are higher in children with aHUS. However, renal prognosis and morbidity rates are higher in children with CFH mutations than other children with aHUS. Poor prognosis in aHUS-children with CFH mutation depends on the genetic background.

Microthrombi formation and Hemolytic anemia are signs of Hemolytic-Uremic Syndrome (HUS) that result from platelet consumption and red blood cell (RBC) destruction due to vascular damage. HUS manifests as a triad of signs: micro-angiopathic Hemolytic anemia, thrombocytopenia, and uremia. Prenatal asphyxia (PA) also leads to renal insufficiency and vascular damage. There is an overlap between the clinical presentation of PA and neonatal Atypical HUS. We have reported the case of a neonate with a primary diagnosis of PA and clinical presentation of acute renal failure (ARF), anemia (Hb=10 g/dl) and thrombocytopenia (Plt = 80000). His APGAR scores were 1 (1 minute), 3 (5 minutes), and 7 (10 minutes). A peripheral blood smear (PBS) was performed, which contained schistocytes (32%) with helmet and burr cells. The neonate's cord blood gas values were: pH of 7.07, HCO3=11mmol/L, and CO2 = 57mmHg. The first two days of life, he was anuric with elevated BUN and Cr (2.1mg/dL) levels. Complement (C3) was within normal limits at 0.65 g/L (0.89-1.87 g/L), however C4 was below the lower limit of normal at 0.14 g/L (0.16-0.38 g/L). We ruled out other causes of PA such as maternal illness, placenta abnormalities and infections (TORCH). We hypothesized that Atypical neonatal HUS can progress to PA because of the presence of severe anemia and microthrombi formation.

Hemolytic-Uremic Syndrome (HUS) is a rare life-threatening disorder characterized by microangiopathic Hemolytic anemia, thrombocytopenia, and impaired renal function. A thrombotic microangiopathy underlies the clinical features of HUS. In the majority of cases, HUS follows an infection with toxin-producing bacteria such as verotoxin-producing Escherichia coli. In some cases, HUS is not preceded by a clinically apparent infection, and therefore, is named Atypical HUS. The prognosis of Atypical HUS is poor. While mortality approaches 25% during the acute phase, endstage renal disease develops in nearly half of patients within a year. Evidence is accumulating that complement activation through the alternative pathway is at the heart of the pathophysiology leading to Atypical HUS. Genetic abnormalities involving complement regulatory proteins and complement components form the molecular basis for complement activation. Since microvascular thrombosis is a quintessential feature of Atypical HUS, complements and the coagulation system must work in tandem to give rise to the pathologic alterations observed in this condition. Here, a brief discussion of clinical and morphologic features of Atypical HUS is followed by a concise presentation of the complement and coagulation systems. The interplay between complements and the coagulation system is graphically highlighted. Last but not least, conventional and emerging therapies for Atypical HUS are outlined.

Introduction: Atypical Hemolytic Uremic Syndrome (HUS) is accompanied by a poor prognosis and high mortality rate. We investigated the predictive value of severity of renal involvement, as evaluated by pathologic examination, for long-term outcome of Atypical HUS.Materials and Methods: Kidney biopsies of 29 children diagnosed with Atypical HUS between 1992 and 2005 were reviewed. The severity of glomerular, vascular (arteriolar and arterial), interstitial, and tubular involvement were determined. Scores of renal involvement were determined by re-evaluating kidney specimens. The outcome measures were death, chronic kidney disease (CKD), hypertension, and proteinuria.Results: After a mean of 3.7 years of follow-up, 24.1% of the patients had normal kidney function and blood pressure, 24.1% showed proteinuria, and 41.4% had CKD, and 10.3% had unknown prognosis. Overall, 24.1% of the patients died due to emergent hypertension with or without CKD. The existence of arteriolar and arterial thrombosis attributed to severe CKD (risk ratio, 3.67, 95% confidence interval, 1.63 to 8.2). Presence of thrombosis in the vessels, and thickening of the arterial medial and intimal layers had brought about a significantly higher mortality rate. Chronic kidney disease was more frequent in the children with vascular scores higher than 0.14 and a final score of more than 0.2.Conclusions: The severity of renal pathological involvement, especially the degree of vascular damage, is a good predictor of long-term outcome of patient with Atypical HUS.