Perinatal asphyxia may present with features of neonatal atypical hemolytic uremic syndrome

Neonatal Atypical Hemolytic Uremic Syndrome in the Eculizumab Era

The atypical hemolytic uremic syndrome (aHUS) in the newborn is a rare disease, with high morbidity. Eculizumab, considered a first-line drug in older children, is not approved in neonates and in children weighing less than 5 kg. We present a 5-day-old female newborn, born at 36 weeks' twin gestation, by emergency cesarean section due to cord prolapse, with birth weight of 2,035 g and Apgar score of 7/7/7, who develops microangiopathic hemolytic anemia, thrombocytopenia, and progressive acute renal failure. In day 5, after diagnosis of aHUS, a daily infusion of fresh frozen plasma begins, with improvement of thrombocytopenia and very slight improvement in renal function. The etiologic study (congenital infection, Shiga toxin, ADAMTS13 activity, directed metabolic study) was normal. C3c was slightly decreased. On day 16 for maintenance of anemia and severe renal failure, she started 300 mg/dose eculizumab. Anemia resolves in 10 weeks and creatinine has normal values after 13 weeks of treatment. The genetic study was normal. In this case, eculizumab is effective in controlling microangiopathy and in the recovery of renal function. Diagnosis of neonatal aHUS can be challenging because of phenotypic heterogeneity and potential overlap with other manifestations that may confound it, such as perinatal asphyxia or sepsis/disseminated intravascular coagulation.

Case Report: Neonatal Unexplained HUS Treated With Complement Inhibitor Eculizumab

Background: Hemolytic uremic syndrome (HUS) is rare in neonates. It is probably an under-recognized condition in the early postnatal period as it presents similarly to the most common perinatal asphyxia and to differentiate the two conditions is challenging. We describe the clinical presentation of a potential new subtype of neonatal HUS triggered by hypoxic-ischemic event. Our patient was successfully treated by a single dose of Eculizumab as early as at 9 days of life. Case Report: A 35-weeks infant was born with low hemoglobin and subsequently developed respiratory distress, hypotension, and acidosis. Blood transfusion was administered, acidosis corrected, neurological examination remained reassuring. Few hours later he developed renal failure, macroscopic hematuria, hemobilia, thrombocytopenia and coagulopathy refractory to platelet and fresh frozen plasma transfusions. No infection was found. Haptoglobin was non-measurable, and schistocytes present, complement factors C3, C4 and B were low, FBb increased. HUS was suspected. A single dose of Eculizumab™ was administered on day 9 of life. No genetic mutation of atypical HUS was found. He was discharged with improving renal function and developing cholestasis. Conclusion: In neonates with hemolytic anemia, thrombocytopenia, hematuria and renal failure, HUS should be suspected. In neonatal HUS Eculizumab should be considered as first-line therapy and discontinuation can be considered if no genetic mutation is found and clinical condition improves. In very young patients, cholestasis could appear as potential side effect of Eculizumab™.

Exchange transfusion for neonate with haemolytic uremic syndrome

Introduction

Haemolytic uremic syndrome (HUS) is one of the most common causes of acute renal failure in children but it is uncommon in newborns. To our knowledge only five cases have been reported so far (probably underreported). The known modalities of treatment include transfusion of plasma and plasmapheresis. We report a case of neonatal HUS for whom we performed an exchange transfusion to good effect.

Case description

A term vaginally born baby, meconium stained and floppy at birth presented with severe anaemia in the first few hours of life. The baby later on developed renal failure and blood picture was suggestive of severe thrombocytopenia and microangiopathic haemolytic anaemia. No extra renal manifestations of birth asphyxia were noted. A double volume exchange transfusion was performed relatively early and subsequently platelet and haemoglobin stabilised and renal failure improved.

Discussion and evaluation

The clinical impression in this case was convincing of neonatal HUS, likely attributable to birth asphyxia but needs to be differentiated from disseminated intravascular coagulation (DIC) and thrombotic thrombocytopenic purpura (TTP). The coagulation profile is usually normal in HUS but it is abnormal in DIC, whereas in TTP one would find hyperbilirubinemia, increased creatinine, haemolysis etc. TTP is rare but not very uncommon in infancy. Congenital TTP is attributed to an inherent deficiency of ADAMTS-13, which is a vWF-cleaving metalloprotease. Irrespective of the etiology of HUS in our case, a dramatic response was observed with exchange transfusion. Transfusion of fresh frozen plasma (FFP) and plasmapheresis are known treatment modalities. FFP replaces the missing or altered complement factors and plasmapheresis removes antibodies, immune complexes and toxins. An exchange transfusion combines both these functions.

Conclusions

In the absence of facilities for plasmapheresis, exchange transfusion is a good alternative.