2020 Feb;73(2):68-70.

Mycotic Aneurysm of the Middle Cerebral Artery Leading to Subarachnoid Hemorrhage, as the Initial Presentation of Bartonella henselae Endocarditis.


Bartonella species was first reported as a cause of endocarditis in 1993, currently it is thought to account for 3-4 percent of all diagnosed cases. Initial symptoms of Bartonella endocarditis are non-specific like weight loss, fever and fatigue. There are very few reported cases of Bartonella endocarditis causing mycotic aneurysm.

We present a case of a 60-year-old male who presented with subarachnoid hemorrhage secondary to mycotic aneurysm. Due to high suspicion of endocarditis leading to mycotic aneurysm he underwent transesophageal echocardiography which showed mitral valve vegetations. His blood cultures were negative, he was eventually diagnosed with Bartonella henselae by elevated IgG titers greater than 1:800. Due to repeated mycotic aneurysms on antibiotics, he underwent surgical mitral valve replacement along with the full course of antibiotics and has been asymptomatic since.



A mycotic aneurysm is an aneurysm caused by the growth of fungi or bacteria within the vascular wall, usually following impaction of a septic embolus.

In this case, Bartonella is the culprit and the patient presented with bleeding in the brain.

Please note the blood culture was negative.

Also note the “repeated mycotic aneurysms on antibiotics.”  I’m not pointing this out to avoid antibiotics but to show that there can be side-effects of treatment.

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