Fatal haemophagocytic lymphohistiocytosis and atypical haemolytic uraemic syndrome following coronavirus disease 2019 infection.

A previously healthy woman in her early 30s developed rash, fever and arthralgia 3 weeks after SARS-CoV-2 infection, rapidly progressing to multiorgan failure. Laboratory studies revealed severe thrombocytopenia (23×109/L), microangiopathic haemolytic anaemia, acute kidney injury and ferritin >100 000 ng/mL. Kidney biopsy demonstrated thrombotic microangiopathy with negative antinuclear antibody, supporting atypical haemolytic uraemic syndrome (aHUS). Concurrently, low haptoglobin, elevated lactate dehydrogenase (2500 U/L), interleukin-2 receptor (18 644), triglycerides (425 mg/dL) and splenomegaly supported haemophagocytic lymphohistiocytosis (HLH). Despite plasmapheresis, corticosteroids, etoposide, eculizumab and continuous renal replacement therapy, she died 7 weeks after SARS-CoV-2 infection. Autopsy confirmed aHUS with extensive thrombotic microangiopathy and HLH with bone marrow haemophagocytosis. This case underscores the importance of recognising concurrent aHUS and HLH after COVID-19, as complement-mediated injury and hyperinflammation may produce catastrophic outcomes.