Mycotic aneurysm presenting as hip pain and severe anaemia

A 15-year-old boy with trisomy 21, moderate left atrioventricular (AV) valve regurgitation and a previously repaired AV septal defect developed Aerococcus urinae infective endocarditis. The infected left AV valve and surrounding tissue were surgically removed and replaced with a prosthetic mitral valve; this was followed by 6 weeks of intravenous antibiotics. Towards the end of his antibiotic course, his C reactive protein level began to rise, and he subsequently developed worsening hip pain and severe anaemia …