Mycotic aneurysms of the splenic artery and ruptured spleen as complications of infective endocarditis

A 52-year-old male patient was hospitalised for s. aureus infective endocarditis for 30 days. During his hospitalisation he underwent surgical replacement of the mitral valve, was on antibiotics and anticoagulants and had a high INR.The patient suddenly showed signs of severe abdominal pain, mostly located at the upper left quadrant.

CT scan following intravenous contrast administration shows i. two aneurysms of the splenic artery of ~2.35 cm and ~1.53 cm diameter respectively, the former being located near the visceral surface of the spleen; ii. ruptured spleen with active bleeding; iii. haemorrhagic ascites. (Fig. 1, 2).
There is a previous CTA scan, taken approximately 20 days before, which shows normal imaging of the splenic artery as well as splenic infarction (Fig. 3).

Infective endocarditis is a potentially life-threatening disease with various cardiac and non-cardiac complications [2]. People run a higher risk of being infected even after a short period of bacteraemia as in cases following dental or gastrointestinal procedures when they i. suffer from cardiac valve dysfunction; ii. have prosthetic valves; iii. are IV drug users; iv. are in need of haemodialysis; v. are on immunosuppressants. Among the most common complications are splenomegaly occurring in 60% of the patients and septic emboli causing infarcts or abscesses, mostly located in the brain and less often in the viscera [3].

Our reported case is a patient who while being hospitalised for infective endocarditis, showed signs of acute abdomen, mostly located in the left upper quadrant. The first CTA showed normal imaging of the splenic artery and splenic infarction. The signs of acute abdomen, however, necessitated a new contrast CT scan, which showed two aneurysms of the splenic artery, ruptured spleen with active bleeding and haemorrhagic ascites. The fact that the patient developed the aneurysms in between the two CT scans suggests that they were of mycotic origin.

Mycotic aneurysms of visceral arteries are extremely rare [2, 3]. To the best of our knowledge, there are less than ten reported cases of mycotic aneurysms of the splenic artery due to infective endocarditis following mitral valve replacements [2]. Researchers are yet to ascertain the length of time between the appearance of mycotic aneurysms and the onset of endocarditis. In our case the aneurysms were developed within a short period of time, i.e. 20 days, and were of large size. Large aneurysms of the splenic artery (> 2 cm) carry a high risk of rupture [1]. Indeed our patient suffered rupture, underwent splenectomy, and was in ICU for a short period of time before succumbing to the complications of endocarditis.