Pregnancy-induced haemophagocytic lymphohistiocytosis.

Haemophagocytic lymphohistiocytosis is an aggressive and life-threatening syndrome of excessive immune activation. It is associated with various aetiologies, including infections, collagen vascular diseases and malignancies. Pregnancy-induced immune dysregulation in genetically susceptible women may also play a critical role in haemophagocytic lymphohistiocytosis. Our case involves that of a 23-year-old pregnant woman who presented at 22 weeks gestation with tachycardia, swinging pyrexia, rigors and generalised myalgia. Refractory hypotension to intravenous fluids and rise in lactate level required admission to the intensive care unit for vasopressor support. Despite treatment with broad-spectrum antibiotics for presumed sepsis, she made little clinical improvement. Investigations for infection and rheumatological disease were unremarkable. A pronounced hyperferritinaemia, hypertriglyceridaemia and cytopenia raised the suspicion of haemophagocytic lymphohistiocytosis. Subsequent elevated CD25 levels helped establish the diagnosis. Treatment with corticosteroids and intravenous immunoglobulin provided a transient response in regard to temperature control and cardiovascular stability. The decision was made to treat her with anakinra, an interleukin-1 receptor antagonist. She responded well to this with a complete resolution of her symptoms and normalisation of her ferritin levels over the course of some weeks. Because of progressive slowing of foetal growth and abnormal umbilical artery Dopplers and cardiotocography, she eventually had an emergency caesarean section at 31 + 5 weeks. There were no foetal abnormalities.