A 9-year-old girl was admitted to hospital with status epilepticus. Earlier in the day, she had complained of a headache and started vomiting. She then lost consciousness and began having a fit; the status epilepticus lasted 30 min and was stopped by phenobarbital. She had a congenital heart defect—truncus arteriosus with interventricular communication—which was surgically corrected a few days after birth. The girl was on long-term treatment with low-dose aspirin as the antiaggregant. She had no features of Marfan's or Ehlers–Danlos syndromes. Laboratory investigations showed leucopenia, low platelet count, and anaemia. Her C-reactive protein (CRP) was 45 mg/L and her erythrocyte sedimentation rate (ESR) was 50 mm/h. Her liver enzymes were also slightly raised. A CT scan of her brain showed an intraparenchymal haematoma and intraventricular haemorrhage. Three-vessel arteriography showed a right Sylvian artery aneurysm ( figure). Successive blood cultures and broad-range 16S recombinant DNA PCR—as well as PCR for herpes simplex viruses 1–5—were all negative. At this stage, the working diagnosis was endocarditis leading to the mycotic cerebral aneurysm, despite no signs of a fever. The haematoma was drained and treatment was commenced with antibiotics; 2 days later, the aneurysm was embolised. The patient recovered and had a mild, left-sided hemiparesis when she left the hospital after 4 weeks. Source: https://www.thelancet.com/article/S0140-6736(19)31675-7/abstract?