Adverse outcomes in obstetric-atypical haemolytic uraemic syndrome: a case series analysis

Objective: The aim of this case series is to raise awareness of obstetric-related atypical haemolytic uraemic syndrome (aHUS) amongst obstetricians and gynaecologists. Study design: Data from 20 consecutive patients, aged 19-38, with obstetric-aHUS manifestation during or immediately after pregnancy are reported. Patients were diagnosed and treatment was initiated between 2012 and 2016. Results: Presentation of aHUS was mainly preceded by preeclampsia and/or haemolysis, elevated liver enzymes and low platelet count syndrome, other obstetric complications, or by diarrhoea. Thrombotic microangiopathy (TMA) was evident in all patients with signs of microangiopathic haemolysis (sharp decline in haemoglobin; mean 67 g/L), elevated lactate dehydrogenase (LDH; mean 2953.1 U/L), schistocytosis, thrombocytopenia (mean platelet count 52.5 × 10⁹/µL), and acute kidney injury (AKI) (hypercreatininaemia, mean 456.4 µmol/L; oliguria or anuria). The majority of patients (80%) initially presented with arterial hypertension. Diagnosis of obstetric-aHUS was complicated, as multiple organs were affected. Time taken to make the diagnosis of aHUS delayed the initiation of fresh-frozen plasma infusions and plasma exchange (80% of patients) and subsequent eculizumab treatment (40% of patients). Maternal mortality was high (35%) as was foetal mortality (25%). Conclusions: Obstetric-aHUS is a serious condition characterized by multiple organ failure (MOF) and a high mortality rate. Presentation of obstetric-aHUS is preceded by various precipitating factors, suggesting pregnancy complications, and not the pregnancy per se, often induce aHUS in women with a genetic predisposition to its development. A delay in the correct diagnosis and initiation of the most effective treatment can have serious consequences, reinforcing the need to raise awareness of obstetric-aHUS.