LAUSR

A 53-year-old woman with a past medical history of Streptococcus viridans prosthetic valve endocarditis presented with a 12-h history of haematochezia. On arrival she was haemodynamically stable but clinically jaundiced. Abdominal examination revealed right upper quadrant tenderness and guarding. Laboratory examination demonstrated a bilirubin level of 85 μmol/L (normal: 2–24) and elevated liver enzyme levels: aspartate aminotransferase, 905 U/L (normal: <45); alanine aminotransferase, 472 U/L (normal: <55); gamma glutamyl transferase, 1140 U/L (normal: <60); and alkaline phosphatase, 432 U/L (normal: 30–110). Viral hepatitis serology was negative. Computed tomography (CT) scanning showed an abnormal contrast pattern in the porta hepatis region (Fig. 1), with no evidence of diverticular disease. The following day the patient suffered several large episodes of melaena, resulting in hypovolaemic shock. She was transferred to the high-dependency unit, with multiple units of red blood cells and platelets transfused. Urgent endoscopy found a blood clot adherent to the papilla (Fig. 2). No active bleeding, ulceration or varices were seen. CT angiography revealed an 18-mm saccular aneurysm involving a branch of the right hepatic artery. Appearances were consistent with a mycotic aneurysm. Erosion into intrahepatic bile ducts was hypothesized to be causing biliary obstruction and acute gastrointestinal bleeding. The aneurysm was successfully embolized under radiological guidance using platinum coils (Fig. 3). The patient’s melaena and jaundice subsequently resolved. She remained stable and was discharged home 4 days later. Mycotic aneurysm is a rare but important complication of infective endocarditis. The phenomenon was first described by Sir William Osler in 1885 as aneurysmal degeneration of the arterial wall resulting from embolization of septic vegetations. The term mycotic is a misnomer; lesions are usually due to bacterial rather than fungal infection. Emboli lodge in the vasa vasorum or vessel lumen causing spread of infection throughout the vessel wall. Mycotic aneurysm may be caused by high or low virulence organisms, with Staphylococcus aureus, S. viridans and Enterococcus most commonly isolated. The intracranial arteries are most frequently involved, followed by intra-abdominal arteries. Mycotic aneurysms are prone to early rupture from bleeding into a weakened media. Spontaneous resolution of extracranial mycotic aneurysms with antibiotic therapy alone has been described. However, the lesions are typically refractory to antibiotic penetration with a high risk of recurrence.