Baby Jordan was born at full term with a birth weight of 3.2 kg. The antenatal history was uneventful, and antenatal ultrasound scans were normal. He was well after birth and was discharged home on day 3 with his mother uneventfully. He was well until 25 days old when he was noticed to kick up a temperature of 38.9 °C. He was brought to see a private doctor, and a bag of urine was saved. The urine microscopy showed numerous white blood cells. He was then referred to the emergency department and was admitted. Upon examination, Joran had a fever of up to 40 °C, his heart rate increased to 200 beats per minute with sinus rhythm, respiratory rate increased to 50 breaths per minute, and oxygen saturation was 94% in room air. He was tired-looking with skill mottling, and the blood pressure was 65/45 mmHg. He was resuscitated with nasal oxygen and intravenous normal saline bolus at 20 ml/kg infusion. His heart rate improved to 180 beats per minute. Initial blood test showed haemoglobin 10 g/dL, white blood cell of 2.3 × 109/L, platelet 65 × 109/L, aPTT 74.7 s, PT of 18 s, INR 1.7, D-dimer 4686 ng/ml and serum lactate 3.6 mmol/L. His chest X-ray was normal. Why did baby Jordan present with such critical symptoms?